Biology

• sum of all chemical reactions that occur in the body
• can be divided into catabolic and anabolic reactions

Break down large chemicals and release energy

Build up large chemicals and release energy

acquisition of food and other raw materials

process of converting food into a usable soluble form so that it can pass through membranes in the digestive tract and enter the body

• passage of nutrient molecules through the linign of the digestive tract into the body proper
• absorbed molecules pass through cells lining the digestive tract by diffusion or active transport

circulation of essential compounds required to nourish the tissues and the removal of waste products from the tissues

building up of new tissues from digested food materials

• consumption of oxygen by the body
• cells use oxygen to convert glucose into ATP, a ready source of energy for cellular activities

removal of waste products (such as carbon dioxide, water, and urea) produced during metabolic processes like respiration and assimilation

creation of complex molecules from simple ones(anabolism)

• Control of physiological activities
• body's metabolism functions to maintainits internal environment in a changing environment: Homeostasis and includes regulation by hormones and the nervous system

ability to respond to a stimulus and is part of regulation

An increase in size caused by a synthesis of new materials

• process by which plants convert CO₂ and H₂O into carbohydrates.
• Sunlight is harnessed by chlorophyll to drive this reaction

generation of additional individuals of a species

Substance of life

• Unit of an ELEMENT is the ATOM
• Unit of an COMPOUND is the MOLECULE
• ATOMS are JOINED by chemical bonds to form COMPOUNDS

Compounds that do not contain the element carbon including salts and HCl

• Made by living systems and contain carbon
• Include:
• CARBOHYDRATES
• LIPIDS
• PROTEINS
• NUCLEIC ACIDS

• composed of elements carbon, hydrogen, and oxygenin a 1:2:1 ratio
• used as storage forms of energy or as structural molecules
• Glucose and Fructose are single sugar subunits

Maltose and Sucrose of two monosaccharide subunits joined by dehydration synthesis which involved loss of a water molecule

• polymers or chains of repeating monosaccharide subunits
• insoluble in water
• Glycogen, Starch, and Cellulose
• formed by removing water (Dehydration)
• By adding water large polymers can be broken down into smaller subunits in a process called hydrolysis]

• composed of C, H, and O; have more H than O
• consists of 3 Fatty Acid molecules bonded to a single glycerol backbone

• long carbon chains that give them their hydrophobic (fatty) character and carboxylic acid groups that make them acidic
• three dehydration reactions are needed to form one fat molecule
• do not form polymers

• Lipids are chief means of food storage in ANIMALS
• release more energy per gran werigh than any other class of compounds
• provide insulation and protection agains injury because they are a major component of fatty (adipose) tissue
• PHOSPHOLIPIDS
• WAXES
• STEROIDS
• CAROTENOIDS
• PROPHYRINS

• contain glycerol, two fatty acids, a phosphate group and nitrogen containing alcohol
• ex. lecithin (cell membranes)
• ex. cephalin (brain, nerve tissue, and nerves)

esters of fatty acids and monohydroxylic alcohols

• have three fused cyclohexane rings and one fused cyclopentane ring
• include, cholesterol and sex hormones and corticosteroids

• fatty acid like carbon chains containing conjugated double bonds and carrying six membered carbon rings at each end
• compounds are the pigments that produce red, yellow, orange and brown colors in plants and animals
• two subgroups are carotenes and xanthophylls

• tetrapyrroles, contain four joined pyrrole rings
• complexed with a metal

• composed of primarily C, H, O and N but may contain P and S
• polymers of amino acids
• amino acids are joined by peptide bond through dehydration
• primary protein: peptide bonds
• secondary protein: helices and B-pleated sheets

• Simple Proteins
• Albumins and Globulins
• Scleroproteins
• Conjugated Proteins
• Lipoproteins
• Mucoproteins
• Chromoproteins
• Metalloproteins
• Nucleoproteins

composed of amino acids

• primarily globular in nature
• fuctional proteins that act as carriers or enzymes

• fibrous in nature and act as structural proteins
• ex. collage

contain a simple protein portion plus at least one nonprotein fraction

Protein Bound to lipid

protein bound to carbohydrates

protein bound to pigmented molecules

Protein bound around a metal ion

containing a histon or protamine (nuclear protein) bound to nucleic acids

Hormones: proteins that funcation as chemical messengers secreted into the circulation; Insulin

Enzymes: catalysts that act by increasing the rate of chemical reactions important for biological functions; amylase or lipase

Structural Proteins: contribute to the physical support of a cell or tissue; may be extracellular (collagen in cartilage) or intracellular (in cell membranes)

Transport Proteins: carriers of important materials; hemoglobin carries oxygen; cytochromes carry electrons during respiration

Antibodies: bind to foreign particles (antigens)

• organic catalysts
• crucial since all living systems must have continuous controlled chemical activity
• regulate metabolism by speeding up or slowing down reactions
• decrease activation energy
• are proteins
• many have coenzymes
• action and reaction rate depends on environmental features such as temperature, pH and the concentration of enzyme and substrate
• ex. temperature increases, rate of enzyme action increases, until an optimum temperature is reached (40 celsius); beyond this optimum, heat alters the shape of the active site of the enzyme molecule and deactivates it, leading to a rapid drop in rate
• selective
• ex. increasing substrate concentration affects rate as well
• when substrate concentration is low and the enzymes, the raction rate is slow and many of the active sites are unoccupied
• increasing substrate concentration will increase the reaction rate until all of the acitve sites are occupied
• after this point, further increasing of the substrate will not affect the reaction rate

• nonprotein
• needed along with conjugated proteins to function the enzyme
• cannot be synthesized by the body and are obtained from the diet

molecule upon which an enzyme acts

area on each enzyme to which the substrate binds

• receptors are large proteins that contain a recognition site (lock) that is directly linked to transduction systems
• when a drug or substance (key) binds to the receptor, sequence of events is started

• active site as having flexibility of the shape
• when the appropriate substrate comes in contact witht he active site, the conformation of the active site changes to fit the substrate
• most enzyme reactions are reversible

• which works best in highly acidic conditions of the stomach pH = 2
• pancreatic enzymes which work in ALKALINE conditions at pH = 8.5

function to digest large molecules into smaller components

hydrolyzes lactose to the monosaccharides glucose and galactose

degreade proteins to amino acids

break down lipids to fatty acids and glycerol

• can be catalyzed by the same enzymes as hydrolysis reactions, but the directions of the reactions are reversed
• occur in different parts of the cells
• required for growth, repair, regulation, protection, and production of food reserves such as fat and glycogen by the cell
• survival depends on ability to ingest substances that it needs but not synthesize
• then converted into useful products

• enzymes require nonprotein molecule to become active
• can be metal cations or small organic groups called coenzymes
• bind to the enzyme by strong covalent bonds: PROSTHETIC GROUPS

• contain the element C, H, O, N, and P.
• polymers of subunits called nucleotides
• DNA and RNA code all of the information required by an organism to produce proteins and replicate
• sugar, base and phosphate group

• -All living things are composed of cells
• -The cell is the basic functional unit of life
• -The chemical reactions of life take place inside the cell
• -Cells arise only from pre-existing cells
• -Cells carry genetic information in the form of DNA. This genetic material is passed from parent cell to daughter cell.

Increase in apparent size of an object

differentiation of two closely situated objects

two lenses or lens sytems to magnify an object

product of the magnification of the eyepiece and the magnification of the objective

Controls the amount of light passing through the specimen

knob roughly focuses the image

knob sharply focuses the image

• observe nonlinving specimens
• requires contrast between cells and cell structures
• staining techniques that result in death

• special type of light microscope that permits the study of living cells
• differences in refractive index are used to produce contrast between cellular structures
• technique does not kill the specimen

• uses a beam of electrons to allow a 1000 fold higher magnification than is possible with light microscopy
• not examine living things
• tissues must be fixed
• sectioned and stained with heavy metal solutions

• separate cells or mixtures of cells without destroying them in the process
• spinning fragmented cells at high speeds in the centrifuge will cause their components to sediment at different levels in the test tube on the basis of their respective densities
• denser parts will sink to the bottom

• Monerans
• Protists
• Fungi
• Plants
• Animals

Lack a nucleus

• plasma membrane enclose the cell and exhibits selective permeability
• regulates passage of materials into and out of the cell

• cell membrane consists of a phospholipid bilayer with proteins embedded throughout
• lipids and many of the proteins can move freely within the membrane
• plasma membrane is readily permeable to both small nonpolar molecules, such as oxygen and small polar molecules, such as water
• small charged particles are usually able to cross the membrane through protein channels

Larger charged molecules cross the membrane with their assistance

• controls the activities of the cell, including cell division
• surrounded by a nucleus membrane
• nucleus contains the DNA, which is complexed with structural proteins called histones to form chromosomes
• Nucleolus: dense structure which RIBOSOMAL RNA synthesis occurs

• sites of protein production
• synthesized by the nucleolus
• free ribosomes are found in the cytoplasm whereas bound ribosomes line the outer membrane of the endoplasmic reticulum

network of membrane-enclosed spaces involved in the transport of the materials throughout the cell, particularly those materials destined to be secreted by the cell

• receives vesicles and their contents from the smooth ER
• modifies them
• repackages them into vessicles
• distributes them to the cell surface by exocytosis

• sites of aerobic respiration within the cell
• suppliers of energy
• bounded by an outer and inner phospholipid bilayer

• most of the cell metabolic acitvity occurs here
• cyclosis

• transport within the cytoplasm
• streaming movement within the cell

• and vesicles are membrane bound sacs involved in the transport and storage of materials that are ingested, secreted, processed, or digested by the cell
• larger than vesicles and are more likely to be found in plant than in animal cells

• involved in spindle organization during cell division and are not bound by a membrane
• Animal cells usually have a pair that are oriented at right angles to each other and lie in a region called centrosome
• Plant cells= NONE
• Direct the separation of chromosomes during cell division, are composed of microtubules

• Membrane bound vesicles that contain hydrolytic enzymes involved in intracellular digestion
• breakdown material ingested by the cell

An injured or dying tissue may "commit suicide" by rupturing the lysosome membrane and releasing its hydrolytic enzymes

• supports the cell
• maintains the shape
• functions in cell motility
• composed of: microtubules, microfilaments, and intermediate filaments

• Hollow Rods made up of polymerized tubulin that radiate throughout the cell and provide it with support
• provide a framework for organelle movement within the cell

specialized arrangements of microtubules that extend from certain cells are involved in cell motility and cytoplasmic movement

• solid rod of actin, important in cell movement as well as support, muscle contraction
• move materials across the plasma membrane in the contraction phase of cell division and in amoeboid movement

• No centrosome
• presence of cell wall composed of cellulose
• chloroplasts in many cells of green plants/sites of synthesis of organic compounds
• no lysosomes
• many vacuoles/mature plant cells usually contain one large vacuole

• net movement of dissolved particles down their concentration gradients from a region of higher concentration to a region of lower concentration
• passive process that requires no external source of energy

simple diffusion of water from a region of lower solute concentration to a region of higher solute concentration

• when the cytoplasm of a cell has a lower solute concentration than the extracellular medium
• water will flow out of the cell
• plasmolysis, cause cell to shrivel

• extracellular environment is less concentrated than the cytoplasm of the cell
• water will flow into the cell
• cell swell
• and lyse

• passive transport is the net movement of dissolved particles down their concentration gradient through special channels or carrier proteins in the cell membrane
• not require energy

• Net movement of dissolved particles against their concentration gradient with the help of transport proteins
• require energy
• aid in regulation of the cell's internal content of ions and large molecules
• energy independent carriers
• symporters
• antiporters
• pumps

Facilitate Movement of compounds along a concentration gradient

move 2 or more ions or molecules

exchange 1 or more ions (or molecules) for another ion or molecule

• energy dependent carriers
• require ATP

• cell membrane invaginates
• forming a vesicle that containes extracellular medium

ingestion of fluids or small particles

• engulfing of large particles
• may first bidn to receptors on the cell membrane before being engulfed

• vesicle within the cell fuses with the cell membrane and releases its contents to the outside
• fusion of the vesicle with the cell membrane can play important role incell growth and signaling
• in both exo and endo, material never crosses cell membrane

transportation of material within cells and throughout the body of a multicellular organism

• Move in cell with many ways
• ex. Brownian Movement
• Cyclosis
• Endoplasmic Reticulum

movement of particles because of kinetic energy which spreads small suspended particles throughout the cytoplasm of the cell

circular motion of cytoplasm around the cell transports molecules

provides channels throughout the cytoplasm and provides a direct continuous passageway from the plasma membrane to the nuclear membrane

• movement of materials on a larger scale through the body of an organism
• ex. diffusion and circulatory system

• can serve as a sufficient means of transport for food and oxygen from the environment to the cells
• in larger animals, responsible for transport of materials betwee the cells and interstitial fluids that bathes the cells

• process by which a cell doubles its organelles and cytoplasm
• replicates its DNA
• divides it into two

cell division is a means of reproduction

it is a method of growth, development, and replacement of worn out cells

• division and distribution of the cell's DNA to its two daughter cells such that each cell receives a complete copy of the orginal genome
• Nuclear Division (KARYOKINESIS) is followed by cell division (CYTOKINESIS)
• before initiation, cell undergoes a period of growth and replication of genetic material called interphase

• spends 90% of time
• each chromosome is replicated so that during division, a complete copy of the genome can be distributed to both daughter cells
• after replication, chromosomes consist of two identical sister chromatids held together at a central region : CENTROMERE
• individual chromocomes are not visible
• DNA is uncoiled: CHROMATIN
• Growth period

• 1. G1
• 2. S
• 3. G2
• 4. M

• initiates interphase and is described as active growth phase that can vary in length
• length of the phase dtermines the length of the entire cell cycle

period of DNA synthesis

cell prepares to divide

• Cell division occurs
• MITOSIS

• 1. Prophase
• 2. Metaphase
• 3. Anaphase
• 4. Telophase
• 5. Cytokinesis

• chromosomes condense and the centriole pairs (in animals) separate and move towards the opposite poles of the cell
• spindle apparatus forms between them and the nuclear membrane dissolves allowing the spindle fibers to interact with the chromosomes

• centriole pairs are now at opposite poles of the cell
• fibers of the spindle apparatus attach to each chromatid at the centromere to align the chromosomes at the center of the cell forming metaphase plate

• centromeres split so that each chromatid has its own distinct centromere, thus allowing sister chromatids to separate
• sister chromatids are pulled toward opposite poles of the cell by the shortening of the spindle fibers
• spindle fibers composed of microtubules

• spindle apparatus disappears
• nuclear membrane forms around each set of newlyformed chromosomes
• each nucleus contains the same number of chromosomes (the diploid number) (2n) as the original or parent nucleus
• chromosomes uncoil, resuming their interphase

• near the end of telophase, the cytoplasm divides into two daughter cells, each with a complete nucleus and its own set of organelles
• in animal cells, cleavage furrow: forms and the cell membrane indents along the equator of the cell and finally pinches through the cell, separating two nuclei

• Plant cells lack centrioles
• spindle apparatus synthesized by microtubule organizing centers that are not visible
• Plant cells are rigid; cannot form a cleavage furrow; divide by formation of cell plate an expanding partition that grows outward from the interior of the cell until it reaches the cell membrane

• sexual reproduction occurs via the fusion of two gametes
• process by which these sex cells are produced; similar to mitosis in that a cell duplicates its chromosomes before undergoing the process
• produces haploid number, halving the number of chromosomes
• involves two divisions of primary sex cells resulting in four haploid cells called gametes

• Interphase
• First Meiotic Division
• Second Meiotic Division

specialized sex cells produced by each parent

parent cells chromosomes are replicated during interphase resulting in the 2N number of sister chromatids

• First division produces two intermediate daughter cells with N chromosomes with sister chromatids
• Prophase I
• Metaphase I
• Anaphase I
• Telophase I

• chromatin condenses into chromosomes
• spindle apparatus forms
• nucleoli and nuclear membrane disappear
• Synapsis: Homologous chromosomes come together and intertwine
• Since each chromosome consists oftwo sister chromatids, each synaptic pair contains four chromatids (Tetrad)
• crossing over: chromatidcs of homologous chromosomes break at corresponding points and exchange equivalent DNA; between homologous chormosomes not sister chromatids of the same chromosomes
• Recombination results in incrased genetic diversity within a species
• No longer identical sister chromatids after recombination

Homologous pairs (tetrad) align at the equatorial plane and each pair attaches to a separate spindle fiber by its kinetochore

• homologous pairs separate and pulled to opposite poles of the cell (Disjunction)
• each chromosome of paternal origin separates (or disjoins) from its homologue or maternal origin and either chromosome can end up in either daugher cell
• the distrubution of homologous chromosomes to the two intermediate daughter cells is random with respect to parental origin

• A nuclear membrane forms around each new nucleus
• Each chromosome still consists of sister chromatids joined at the centromere

• not preceded by chromosomal replication
• chromosomes align at the equator, separate, and move to opposite poles surrounded by a reformed nuclear membrane
• new cells have haploid number of chromosomes
• in women, one of these cells becomes a a functional gene

• production of offspring without fertilization
• prokaryotes reproduce asexually

• Fission
• Budding
• Regeneration
• Parthenogenesis

• in prokaryotes
• DNA replicates and a new plasma membrane and cell wall grow inward along the midline of the cell, dividing it into equally-sized cells with equal amounts of cytoplasm, each containing a duplicated of the parent chromosome
• each of the daughter cells must receive an identical set of genetic information

• replication of the nucleus followed by unequal cytokinesis
• membrane pinches inward to form a new cell that is smaller in size but gentically identical to the parent cell, and which grows to adult size
• new cell may separate immediately from the parent, or it may remain attached, develop an outgrowth, and separate at later stage
• occurs in hydra and yeast

• regrowth of a lost or injured body part
• by mitosis
• must contain the central disk
• depends on the severity of the nerve damage

development of an unfertilized egg into an adult organism

• alternation of generations: diploid generation is succeeded by a haploid generation
• sporophyte: diploid, produces haploid spores which develop into the haploid gametophyte generation
• spores: specialized cells with hard coverings that prevent loss of water

• meristems: undifferentiated tissues in plants; provide source of cells that can develop into adult plant
• naturally or human intervention
• no genetic variation
• very quick

• Bulbs split to form several bubls; tulips and daffodils
• Tubers are underground stems and buds; develop into adults plants
• Runners are stems running above and along the ground, extending from the main stem; make new roots and upright stems
• Rhizomes: stolons; woody, underground stems; new upright stems

• A cut piece of stem can develoo new roots in water or moist ground
• auxins: synthetic plant hormones to accelerate root formation
• layering: stems of plants will take root when bent to the ground and covered with soil
• Scion: a stem of one plant; can be attached to the rooted stem of another closely related plant called the stock
• cambium: tissue of both stems must be in contact

• two parents involved
• genetically unique offspring
• fusion of two gametes
• requires:
• production of functional sex cells or gametes by adult organisms
• union of these cells (fertilization or conjugation) to form a zygote
• developmentof the zygote into another adult, completing the cycle

• Gonads
• Spermatogenesis
• Oogenesis
• Fertilization

• specialized organs where gametes produced
• testes: male gonads; produce sperm in the tightly coiled seminiferous tubules
• ovaries: female gonads; produce oocytes (eggs)
• hermaphrodites: both functional male and female gonads

• occurs in seminiferous tubules
• spermatogonia: diploid cells undergo meiosis to produce four haploid sperm of equal size
• sperm is elongatedcell with head, tail, neck and body
• head: entirely of the nucleus that contains paternal genome
• tail: flagellum propels the sperm, whereas mitochondria in the neck and body provide energy for locomotion

• production of female gametes occurs in ovaries
• one diploid female sex cell goes through meiosis to produce single mature egg
• each meiotic division produces a polar body: small cell that contains little more than the nucleus
• mature ovum: large cell containing most of the cytoplasm, RNA, organelles, and nutrients
• polar bodies degenerate

• union of the egg and sperm nuclei to form a zygote with a diploid number of chromosomes
• External and Internal

• occurs in vertebrates that reproduce in water
• lay eggs in water; male deposits sperm near;

practiced by terrestrial vertebrates and provides a direct route for sperm to reach the egg cell

• located in an external pouch: scrotum that maintains testes temperature 2 to 4 celsius lower that body temperature; essential for sperm survival
• sperm pass from testes through the vas deferens to the ejaculatory duct and then to the urethra
• urethra passes throught he penis and opens to the outside at its tips
• site of production of testosterone

regulates secondary male sex characteristics including facial and pubic hair and voice changes

• diploid cells
• differentiate into diploid cells called primary spermatocytes, which undergo the first meiotic division to yield two haploid secondary spermatocytes of equal size
• second meiotic division produces four haploid spermatids of equal size
• after meiosis, spermatids undergo a series of changes leading to the production of mature sperm, or spermatozoa which are specialized for transporting the sperm nucleus to the egg or ovum
• flagella: transpot
• mitochondria in neck and body provide energy for locomotion
• acrosome: caplike structure develops over the anterior half of the head, contains enzymes needed to penetrate the tough outer covering of the ovum

• found in the abdominal cavity
• consists of thousands of follicles
• once a month, an immature ovum is released fromthe ovary into the abdominal cavity and drawn into the nearby oviduct
• each fallopian tube opens into the upper end of a muscular chamber: UTERUS
• all the eggs that a femal will ovulate during her lifetime are already present in the ovaries
• synthesize and secrete femal sex hormones including estrogens and progesterone
• secretion of both estrogens and progesterones regulated by LH and FSH which in turn are regulated by GnRH

• multilayered sac of cells that contains, nourishes and protects an immature ovum
• produce estrogen

site of fetal development

• lower, narrow end of the uterus
• connects with vaginal canal

site of sperm deposition during intercourse and is also the passageway through which a baby is expelled during childbirth

• steroid hormones necessary for female maturation
• stimulate development of the female reproductive tract and contribute to the development of secondary sexual characteristics and sex drive
• responsible for thickening of the endometrium (uterine wall)
• secreted by the ovarian follicles and the corpus luteum

• steroid hormone secreted by the corpus luteum during the luteal phase of the menstrual cycle
• stimulates the development and maintenance of the endometrial walls in preparation for implantation

• hormonal secretions of the ovaries, hypothalamus, and the anterior pituitary play important roles in the femal reproductive cycle
• may be divided into the follicular phase, ovulation, the luteal phase, and menstruation

• Begins with the cessation of the menstrual flow from the previous cycle
• FSH (follicle stimulating hormone) from the anterior pituitary promotes the development of the follicle, which grows and begins secreting estrogen

• mature ovarian follicle burst and releases an ovum
• caused by a surge in LH (lutenizing hormone) that is preceded, caused by peak in estrogen levels

LH induces ruptured follicle to develop into the corpus luteum which secretes estrogen and progesterone

• cause the glands of the endometrium to mature and produce secretions that prepare it for the implantation of an embryo
• along with estrogen, is essential for the maintenance of the endometrium

• IF ovum is not fertilized, corpus luteum atrophies
• resulting in drop in progesterone and estrogen levels causes the endometrium (with its superficial blood vessels) to slough off, giving rise to the menstrual flow (menses)

if fertilization occurs, placenta produces human chorionic gonadotrophin, maintaining the corpus luteum and supply the estrogen and progesterone that maintains the uterus, until the placenta takes over production of these hormones

Production of female gametes, occurs in the ovarian follicles

• at birth, all immature ova
• diploid cells that form by mitosis in the ovary, after menarche (first period), one primary oocyte per month completes meiosis I, yielding two daughter cells of unequal size ----SECONDARY OOCYTE and a small cell known as POLAR BODY
• secondary oocyte is expelled from the follicle during ovulation
• Meiosis II does not occur until fertilization
• surrounded by two laryers of cells: zona pelluciad and corona radiata
• Meiosis II is triggered when these layers are penetrated by a sperm cell, giving two haploid cells-a mature ovum and another polar body(the first may undergo Meiosis II, but will die)

inner layer

outer layer

large cell containing a lot of cytoplasm, RNA, organelles and nutrients needed by a developing embryo

• ovaries become less sensitive to the hormones that stimulate follciel development (FSH and LH) and eventually they atrophy
• remaining follicles disappear, estrogen and progesterone levels greatly decline, and ovulation stops

• Egg can be fertilized during the 12-24 hours after ovulation
• occurs in the lateral widest portion of the fallopian tube
• sperm must travel through the vaginal canal, cervix, uterus, and into the fallopian tubes to reach the ovum
• sperm remain viable for 1-2 after intercourse
• First Barrier: Corona Radiata; enzymes aid in penetration;
• Acrosome responsible for pentrating the zona pelluciada; releases enzymes that digest this layer, allowing the spearm to come into direct contact with the ovum cell membrane;
• Acrosomal Process: once in contact with the membrane, sperm forms tubelike structure, extends to the cell membrane and penetrates it fusing the sperm cell membrane with that of the ovum;
• sperm nucleus now enters the ovum's cytoplasm, ovum completes meiosis II

acrosomal reaction triggers this in the ovum, causing calcium ions to be released into the cytoplasm; initiates reaction to create the fetilization membrane

• hard layer that surrounds the ovum cell membrane and prevents multiple fertilizations
• release of Ca2+ also stimulates changes within ovum, increasing the metabolic rate
• followed by fusion of the sperm nucleus with the ovum nucleus to form a diploid zygote
• first mitotic division of the zygote soon follows

• Identical
• single zygote splits into two embryos
• If split at Two cell stage: embryos will have separate chorions and placentas
• If split at Blastula stage: embryos will have one chorionic sac and share a placenta and possibly an amnion
• If incomplete, resulting in the birth of siamese twins
• same sex, blood type, and so on...

• Fraternal
• when two ova are released in one ovarian cycle and are fertilizaed by two different sperm
• two embryos implant in the uterine wall individually, and each develops its own placenta, amnion, and chorion (placentas may fuse if the embyos implantvery close to each other)

• life cycles of plants are characterized by an alternation of the diploid sprophyte generation and the haploid gametophyte generation
• lengths vary with plants
• evolutinary trends has been towards increased dominance of the sprophyte generation

• Haploid gametophyte generation produces gametes by mitosis
• union of the male and female gametes at fertilization restores the diploid sporophyte generation
• gametophytes reproduce sexually, whereas the sporophyte generation reproduces asexually

• dominant generation
• sporophyte is smaller short lived organism that depends on the gametophyte for energy and nutrients
• sporophytes grow on top of the gametophytes and produce spores that develop into gametophytes

• diploid sporophyte produces haploid(monoploid) spore by meiosis
• spores divide by mitosis to produce the haploid or gametophyte generation

• Sporophytes generation, is the dominant, familiar form
• sporophytes releases spores from the undersides of its leaves that develop into small heart-shaped gametophytes

flowering plants; have gametophytes consisting of a few cells that exist for a very short time; woody plant

• flower is the reproductive structure of angiosperms
• some have flowers that only have stamens(male plants) and others have pistils (femal plants)
• Stamens, Seed Formation

• male organ of the florw and consists of a thin stalk like filament with a terminal sac called the anther
• anther produces monoploid spores that develop into pollen grains

• zygote divides mitotically to form the cells of the mass of cells called embryo
• embryo consists of:
• Epicotyl
• Cotyledons
• Hypocotyl
• Endosperm
• Seed Coat

precurso of the upper stem and leaves

seed leaves, dicots have two seed leaves, whereas monocots have only one

develops into the lower stem and root

• endosperm grows and feeds the embryo
• in dicots, cotyledon absorbs the endosperm

develops from the outer covering of the ovule, embryo and its seed coat together comprise the seed

• the fruit, in which most seeds develip is formed from the ovary walls, base of the flower and other flower pistil components
• fruit serves as a means of seed dispersal
• fruit enables seed to be carried more frequently or effectively by air, water or animals
• seed is released from the ovary and will germinate under proper conditions of temperature, moisture, and oxygen

• Meristem: embryonic cells (undifferentiated); growth for higher plants; active cell reproduction; cells elongate and differentiate
• Apical: found in the tips of roots and stems; growth in lengths at this point
• Lateral: cambium, between xylem and phloem; permits growth in diamter and can differentiate into new xylem and phloem cells; not an active tissue in grasses or alfalfa but predominatnt in woody dicots

• basic unit of heredity
• composed of DNA and located on chromosomes

the alternative forms, when gene exists in more than one form

The genetic makeup of an individual

physical manifestation of the genetic makeup

• Genes exist in alternative forms: Alleles
• Has two alleles for each inherited traits, one inherited from each parent
• Two alleles segregate during meiosis, result in gametes carrying one allel for any given trait
• If two alleles in an individual are different, one will be fully expressed and other silent
• Expressed Allele: Dominant
• Silent Allele: Recessive

The dominant allele is expressed in the phenotype

• Since one trait is being studied
• Parental Generation being crossed; progeny are Filial generation

• tool to determine the genotype of an organism
• only with a recessive phenotype, can genotype be 100% accurate
• with a dominant phenotype of unknown genotype, is crossed with a phenotypically recessive organism

• Dihyrbid Cross: Two traits tested
• Genes are on separate chromosomes and assort independently during meiosis
• Genes on the same chromsomes will stay together unless crossing over occurs

Blends of parental phenotypes

• Occurs when multiple alleles exist for a given gene and more than one of them is dominant
• Ex. is the inheritance of the ABO blood group
• Ab blood group IAIB

• most chromosomes exist as pairs of homologues called autosomes; but sex is determined by a pair of sex chromosomes;
• all humans have 22 pairs of autosomes; additionally women have a pair of homologous X chromosomes, and men have a pair of heterologous chromosomes, and X and a Y chromosome
• Sex Linked: Genes located on the X or Y chromosomes; most located on the X chromosomes

• Recessive phenotype will be much more found in men;
• hemophilia or color blindness genes
• affected men cannot pass the trait to their male offspring
• affected men pass only to daughters
• unless daughter receives from mother,she will be phenotypically normal carrier
• affect only men
• skipping a generation

Interaction between environment and genotype produces the phenotype

• Either the failure of homologous chromosomes to separate properly during meiosis I or the failure of sister chromatid to separate properly during meiosis II
• resulting zygote might either have three copies of that chromosome, trisomy
• or single copy, monosomy
• Trisomy chromosome 21: Down Syndrome

• may occur spontaneously or be induced by environmental factors such as mutagenic agents and X rays
• said to be deficient

• changes in genetic information of a cell coded in the DNA
• In somatic cells: lead to tumors
• In sex cells: transmitted to offspring
• most occur in aread of DNA that do not for proteins and are silent
• that do not change the sequence of amino acids: recessive and deleterious

• induce mutations
• ex. colchicine-inhibits spindle formation, causing polyploidy
• also carcinogenic

• Nitrogen bases are added, deleted or substituted; creating different genes
• genetic error with the wrong base or no base on the DNA at particular position

• -Caused by inability to produce the proper enzyme for the metabolism of phenylalanine
• degradation product accumulates
• unable to consume diet products containing aspartame
• Hyperphenylaninemia: result from an impaired conversion of phenylalanine to tyrosine, characterized by an increased concentration of phenylalanine in blood, increased concentration of phenylalanine and its by products in urine, and mental retardation
• deficiency of phenylalanine hydrolase

• red blood cells become crescent shaped because they contain defective hemoglobin
• carries less oxygen
• caused by a substitution of Valine for Glutamic Acid of a single base pair substitution in the gene coding for hemoglobin

• Deoxyribonucleic Acid contain information coded in the sequence of its base pairs, providing the cell with a blueprint for protein synthesis
• has ability to self replicate; ensures that its coded sequence will be passed onto successive generations
• basis of heredity
• Mutable and can be altered under certain conditions,

• Nucleotide: Basic unit of DNA, which is composed of Deoxyribose (a sugar) bonded to both a phosphate group and a nitrogenous base
• Two types of Bases:
• Purines: Adenine and Guanine
• Pyrimidines: Cytosine and Thymine
• Double Stranded Helix: with the sugar-phosphate chains on the outside of the helix and the bases on the inside;
• T always forms two hydrogen bonds with A
• G always forms three hydrogen bonds with C

• DNA unwinds and separates into two single strands
• Each strand acts as template for complementary base pairing in synthesis of two new daughter helices
• Each new daughter helix contains an intact strand from the parent helix and a newly synthesized strand, DNA replication is semiconservative

• 20 amino acids
• DNA translated by mRNA; triplet code for the amino acid
• Triplets: Codons
• Universal for almost all organisms
• 64 different codons
• has synonyms
• Degeneracy: amino acids have more than one codon specifying them

• ribonucleic acid, a polynucleotide structurally similar to DNA except that its sugar is ribose
• contains uracil instead of thymine, usually single stranded; in nucleus and cytoplasm

• Carries the complement of a DNA sequence
• transports it from the nucleus to the ribosomes, where protein synthesis occurs;
• assembled from ribonucleotides that are complementary to the sense strand of the DNA
• Monocistronic: one polypeptide for one mRNA

• small RNA found in the cytoplasm that aids in the translation of mRNA's nucleotide code into a sequence of amino acids;
• brings amino acids to the ribosomes during protein synthesis
• at least one type of tRNA for each amino acid
• 40 known types of tRNA

• structural componenet of ribosomes and is the most abundant of all RNA types
• rRNA is synthesized in the nucleolus

Process whereby information coded in the base sequence of DNA is transcribed into a strand of mRNA that leaves the nucleus through nuclear pores; remaing events in the cytoplasm

• mRNA codons are translated into a sequence of amino acids
• occurs in the cytoplasm and involves tRNA, ribsomes, mRNA, amino acids, enzymes and other proteins

• tRNA brings amino acids to the ribosomes in the correct sequence for polypeptide synthesis; recognizes both amino acid and mRNA codon; one end contains a three nucleotide sequence, the anticodon: complementary to one of the mRNA codons; other end is site of amino acid attachment;
• Each amino acid has its own aminoacyl-tRNA synthetase: active site that binds to both the amino acid and its corresponding tRNA; catalyzing their attachment to form an aminoacyl-tRNA complex

• Composed of two subunits (consisting of proteins and rRNA)
• One large and one small that bind together only during protein synthesis
• Have three binding sites: one for mRNA and two for tRNA
• The P site: Peptidyl-tRNA binding site
• The A site: Aminoacyl-rRNA complex binding site
• P site binds to the tRNA attached to the growing polypeptide chain
• A site binds to the incoming aminoacyl-tRNA complex

• Into three stages:
• 1. Initiation
• 2. Elongation
• 3. Termination

• When ribosome binds tot he mRNA near its 5' end
• Ribosome scans mRNA until binds to start codon, AUG
• Initiator Aminoacyl-tRNA compleax with anticodon base pairs wiht start codon

• Hydrogen bonds form between mRNA codon in the A site and its complementary anticodon on the incoming aminoacyl-tRNA complex
• Peptide Bond is formed between the amino acid attached to the tRNA in A site and the met attached to the tRNA in the P site
• Ribosome carries uncharged tRNA in the P site and peptidyl-tRNA in the A site
• Translocation: Ribosome advances three nucleotides along the mRNA in the 5' to 3' direction
• uncharged tRNA is discharged from the P site and peptidyl-tRNA from the A site ready for entry of the aminoacyl-tRNA corresponding to the next codon

• when one of the three special mRNA codons: UAA, UGA, or UAG arrives at A site
• Single mRNA molecule translate, forming a polyribosome
• conformation determined by primary sequence of amino acids
• chains can form intramolecular or intermolecular cross bridges with disulfide bonds

• consists of a single circular chromosome located in the nucleoid region of the cell
• contain smaller circular rings of DNA called plasmids, which contain accessory genes
• Replication begins at unique origin of replication and proceeds in both directions simultaneously
• DNA synthesized in the 5' to 3' direction
• Bacterial Cells reproduce by binary fission: proliferate very rapidly under favorable conditions
• Although Binary Fission is an asexual process, have three ways to increase genetic variance:
• 1. Transformation
• 2. Conjugation
• 3. Transduction

A foreign chromosome fragment (plasmid) is incorporated into the bacterial chromosome via recombination, creating new inheritable genetic combinations

• Sexual mating in bacteria, it is the transfer of genetic material between two bacteria that are temporarily joined
• only with plasmids called sex factors capable of conjugation
• F factor in e.coli
• Hfr cells: High Frequency of Recombination

When fragments of the bacterial chromosome accidentally become packaged into viral progency produced during a viral infection

• Occurs when linked genes are separated
• occurs by breakage and rearrangements of adjacent regions of DNA when organism carrying different genes or allels for the same traits are crossed

• Enables prokaryotes to control their metabolism
• Based on accessibility of RNA polymerase to the gens being transcribed and directed by an operon which consists of structural gens, an operator gene and a promoter gene
• Structural Genes: contain sequences of DNA that code for proteins
• Operator Gene: Sequence of nontranscribable DNA that is the repressor binding site
• Promoter Gene: noncoding sequence of DNA that serves as the initial bidng site for RNA polymerase
• Regulator Gene: Codes for the synthesis of a repressor molecule that binds to the operator and blocks RNA polymerase from transcribing the structural genes
• RNA polymerase must move past the operator gene in order to transcribe the structural genes
• Regulation can be via inducible systems or repressible systems

• Require the presence of a substance called an inducer for transcription to occur
• Repressor binds to the operator, forming a barrier that prevents RNA polymerase from transcribing the structural genes
• Must form inducer-repressor complex
• Cannot bind to the operator, thus permitting transcription
• Structural Genes code for an enzyme and the inducer is usually the substrate or a derivative of the substrate, enzyme normally acts on
• When substrate present, enzyme synthesized
• When absent, enzyme is negligible
• Enzymes transcribed when needed

• In a constant state of transcription unless a corepressor is present to inhibit transcription
• Repressor is inactive until it combines with the corepressor
• Repressor can bind to the operator and prevent transcription only when it has formed a repressor-corepressor complex
• Corepressor are the often end products, of the biosynthetic pathways they control
• Proteins are said to be repressible, since they are being synthesized
• Operons containing mutations such as deletions or whose regulator genes code for defective repressors are incapable of being turned off and whose enzymes which are always being synthesized, are referred to as constitutive

• Virus that infects its host bacterium by attaching to it
• Injects its DNA while its protein coat remains attached to the cell wall
• Once inside host, Lytic Cycle or Lysogenic Cycle

• Phage DNA takes control of genetic machinery and manufactures numerous progeny
• Bacterial cell then burst (Lyses), releasing new virions, each capable of infecting other bacteira
• Bacteriophages that replicate by this, killing their host cells: VIRIONS
• If initial infection takes place on a bacterial lawn, then very shortly a plaque or clearing in the lawn occurs corresponding to lysed bacteria

• If Bacteriophage doe not lyse its host cell, becomes integrated into the bacterial genome in a harmless form (provirus), lyring dormant for one or more generations
• Provirus can reemerge and enter a lytic cycle

• Fertilization
• Cleavage
• Gastrulation
• Neurulation
• Development
• Gestation

• Can be fertilized within 12-24 hours afer ovulation
• Occurs in the lateral widest portion of the oviduct when sperm traveling from the vagina encounter an egg
• If more than one egg is fertilized, fraternal twins

• Rapid Mitotic Development
• Results in smaller cells with an increasing ratio of nuclear to cyoplasmic material
• Increases the surface-to-volume ratio of each cell, improving gas and nutrient exchange
• converts zygotes single large cell into a solid ball of cells as the merula then into the blastula
• First Cleavage Occurs 32 hours after fertilization
• Second Cleavage Occurs 60 hours
• Third Cleavage after 72 hours at which point 8-celled embryo reaches the uterus
• Morula forms
• Blastulation

solid ball of embryonic cells

when morula develops a fluid-filled cavity called blastocoel which by the fourth day becomes a hollow sphere of cells called the blastula

• Once implanted in uterus, migrations transforms the single cell layer of the blastula into three layered structure called a gastrula
• Three primary germ layers are responsible for the differential development of tissues, organs, systems of the body at later stages of growth
• Ectoderm
• Endoderm
• Mesoderm

Integument (epidermis, hair, nails, and epithelium of nose)

epithelial linings of the digestive and respiratory tracts

musculoskeletal system, circulatory system

• Regions of the germ layers develop into rudimentary nervous system;
• Notochord: rod of mesodermal cell, develops alongthe longitudinal axis just under the dorsal layer of ectoderm

• inductive effect on the overlying ectoderm, causing it to bend inward and form a groove along the dorsal surface of the embryo
• dorsal ectoderm folds on either side of the groove, neural folds grow upward and finally fuse, forming a closed tube

• gives rise to the brain and spinal cord
• once formed, detaches from the surface ectoderm
• cells at the tip of each neural fold called neural crest cells

migrate laterally and five rise to many components of the peripheral nervous system

Internal and External

• Follows neurulation process
• Organogenesis
• Growth
• Gametogenesis

• Body organs begin to form
• Cells interact, differentiate, change physical shape, proliferate, and migrate

Organs increase in size, which is a continual process from infancy to childhood to adulthood

• Eggs develop in women and sperm develops in men, which results in the possibility of reproduction occurring
• fertilization continues and cleavage begins

• Provides protection for the developing embryo;
• Includes:
• Chorion
• Allantois
• Amnion
• Yolk Sac

Chorion lines the inside of the shell; it is a moist membrane that permits gas exchange

• sac like structure is involved in respiration and excretion and contains numerous blood vessels to transport O2, CO2, water, salt and nitrogenous wastes
• outpocketing of the gut
• allantoic wall enlarges and become umbilical vessels

• Membrane encloses amniotic fluid
• provides an aqueous environment that protects the developing embryo from shock
• Amniotic Fluid acts as shock absorber of external and localized pressur from uterine contractions during labor

• encloses the yolk
• Blood vessels in yolk sac transfer food to the developing embryo
• becomes associated with umbilical vessels

Without a placenta, exchange of food and oxygen between the young and the mother is limited

• receives oxygen from its mother through a specialized circulatory sytem
• removes carbon dioxide and metabolic wastes
• two components: placenta and umbilical cord which both develop in the first few weeks

• Into three trimesters
• 266 days

• major organs begin to develop
• heart begin to beat at 22 days
• cartilaginous skeleton begins to turn into bone by the 7th week
• By end of 8th week, organs have formed, brain failry developed and embryo now a fetus

begins to move around in amniotic fluid, face appears human and its toes and fingers elongate

antibodies are transported by highly selective active transport from the mother to the fetus for protection against foreign matter

Labor into three stages

• Cervix thins out and dilates and the amniotic sac ruptures
• releasing its fluids

• rapid contractions
• resulting in the birth of the baby
• followed by cutting of umbilical cord

• uterus contracts
• expelling placent and the umbilical cord

• Heterotrophic Cells tha consume other cells or food particles
• movement of gases and nurtients by simple diffusion

• walls that are two cells thick
• cells in direct contact with internal or external environments so there is no need for specialized circulatory system

• Have open circulatory systems in which blood is in direct contact with the body tissues
• blood flows through a dorsal vessel and into spaces called sinuses where exchange occurs

• Uses a closed circulatory system to deliver materials to cells that are not in direct contact with the external environment
• blood confined to blood vessels
• blood moves towards the head in the dorsal vessel which functions as the main heart by coordinated contractions
• Five pairs of vessels (aortic lops) connect the dorsal vessel to the ventral vessel and function as additional pumps
• lack any red blood cells

• Blood pumped into the aorta
• Aorta branches into a series of arteries
• Arteries brance into arterioles and then into microscopic capillaries
• Exchange of gases, nutrients and cellular waste products occurs via diffusion across capillary walls
• Capillaries then converge into venules
• leading deoxygenated blood back toward the heart

• Driving Force of the circulatory system
• Right Side Pumps Deoxygenated Blood into pulmonary circulation toward the lungs
• Left Side Pumps Oxygenated Blood into systemic circulation throughout the body
• Two Upper chambers are called atria and the two lower chambers are ventricles
• Atria: Thin-walled
• Ventricles: extremely muscular; left more muscular than right; generating force that propels systemic circulation and pumps against a higher resistance

• Atrioventricular Valves: located between the atria and ventricles on both sides of the heart, prevent backflow of blood into the atria
• Valve on the Right Side: three cusps and called tricuspid valve
• Valve on the Left Side: two cusps, called the mitral valve
• Semilunal Valves: three cusps and are located between the left ventricles and the aorta(aortic valve) and between the right ventricle and the pulmonary artery (the pulmonic valve)

• Divided into two alternating phases
• Systole
• Diastole
• Systole and Diastole makeup the heartbeat

period during which the ventricles contract

period of cardiac muscle relaxation during which blood drains into all four chambers

• defined as the total volume of blood the left ventricle pumps out per minute
• = heart rate (number of beat per volume) X stroke volume (volume of blood pumped out of the left ventricle per contraction)

• Originates in and regulated by Sinoatrial Node (pacemaker): Small mass of specialized tissue located in wall of right atrium
• Spreads impulses in both atria, stimulating them to contract
• Impuse arrives at atrioventricular node, conducts slowly, allowing ventricles to fill with blood,
• Then carried to Bundle of His (AV bundle) which branches into right and left bundle bunches through the Purkinje Fibers and in walls of btoh ventricles

• modifies the rate of heart contraction
• parasympathetic system innervates the heart via the vagus nerve, and causes a decrease in the heart rate
• sympathetic system innervates the heart via the cervical and upper thoracic ganglia and causes an increase in the heart rate
• Adrenal medulla: exerts hormonal control via epinephrine (adrenaline) secretion which causes an increase in heart rate

• Arteries
• Veins
• Capillaries

thick walled muscular, elastic vessels that transport oxygenated blood away from the heart except for the pulmonary arteries, which transport deoxygenated blood from the heart to the lungs

• Thinly walled
• inelastic vessels that conduct deoxygenated blood towards the heart, except for the pulmonary veins, which carry ocygenated blood from the lungs to the heart

• very thin walls composed of a single layer of endothelial cells, across which respiratory gases, nutrients, enzymes, hormones, and wastes can readily diffuse
• smallest diameter of all three types of vessels,

• Lymphatic system if a secondary circulatory system from the cardiovascular circulation
• vessels transport excess interstitial fluid, called lymph thereby keeping fluid levels in the body constant
• Lymph nodes: swelling along lymph vessels containing phagocytic cells (leukocytes) that filter the lymph, removing and destroying foreign particles and pathogens

• liquid portion of the blood
• aqueous mixture of nutrients, salts, respiratory gases, wastes, hormones and blood proteins
• erythrocytes, leukocytes and platelets

• Oxygen carrying components of blood
• hemoglobin binds oxygen, called oxyhemoglobin; primary form of oxygen transport in the blood
• Biconcave, disk like shape, increased surface area, greater flexibility,
• formed from stem cells in the bone marrow, where they lose their nuclei, mitochondria, and membranous organelles
• Once mature, RBCs circulate in the blood for about 120 days, after which they ar phagocytized by special cells in the spleen and liver

• larger than erythrocytes
• protective functions
• some phagocytizeforeign matter and organisms such as bacteria
• Macrophages: When migrate from blood to tissues, mature into stationary cells
• Lymphocytes: involved in immune response and the production of antibodies (B cells) or cytolysis of infected cells (T cells)
• main components of the immune system

• cell fragments that lack nuclei and are involved in clot formation
• injury repair

• Erythrocytes transport O2 throughout the circulatory system
• hemoglobin binds to O2
• Each hemoglobin capable of binding to four molecules of O2
• Hemoglobin bins to CO2

• Amino acids and simple sugars are absorbed into bloodstream at the intestinal capillaries and after processing, are transported throughout the body
• metabolic waste products diffuse into capillaries from surrounding cells
• delivered to the approximate excretory organs

• Platelets come into contact with the exposed collagen of a damaged vessel
• Release chemical that causes neighboring platelets to adhere to one another, form a platelet plug
• Both platelets and the damaged tissue release the clotting factor thromboplastin

• aid of its cofactors calcium and vitamin K, converts the inactive plasma protein prothrombin to its active form, thrombin
• thrombin converts fibrinogen into fibrin
• Threads of fibrin coat the damaged area and trap blood cells to form a clot
• clots prevent extensive blood loss
• fluid left after blood clotting: serum

Non-self entities

• Prodcution of Antibodies
• Specific Defense Mechanism
• Lymphocytes Responsible
• Proliferation of Antibodies after exposure to antigens

• Immunoglobulins
• Complex Proteins that recognize and bind to specific antigens and trigger the immune systemto remove them
• Either attract other cells (such as leukocytes) to phagocytize the antigen or cause the antigens to clump together (agglutinate) and form large insoluble complexes, facilitating their removal by phagocytic cells

• production of antibodies during an immune response
• vaccination: injected with a weakened, inactive, or related form of a particular antigen which stimulates the immune system to produce specific antibodies against it
• may require weeks to build up

• transfer of antibodies produced by another individual or organism
• acquired either passively or by injection
• short lived,
• not specific

• Cells that combat fungal and viral infection
• Specific Defense Mechanism
• Lymphocytes responsible

• Fraction of the blood containing a wide vairety of antibodies
• can be used to confer temporary protection against hepatitis and other diseases by passive immunity

• 1. Skin
• 2. Passages
• 3. Macrophages
• 4. Inflammatory
• 5. Proteins

• Physical Barrier against bacterial invasion
• pores on skin secrete sweat which contains an enzyme that attacks bacterial cell walls

• Respiratory Tract
• Lined with ciliated mucous coated epithelia, which filter and trap foreign particles

engulf and destroy foreign particles

• initiated by the body in response to physical damage
• injure cells release histamine, causes blood vessels to dilate, increasing blood flow to the damaged region
• Granulocytes: attratcted to the site of injury, phagocytize antigenic material
• accompanied by a fever

• Produced by cells under viral attack
• Interferons diffuse to other cells, where they help prevent the spread of the virus

Inappropriate response to certain foods and pollen can cause the body to form antibodies and release histamine

• Detected as foreign bodies by immune system
• can be rejected
• Immuno-suppressing drugs can be used to lower immune response

• Erythrocytes have cell surface Antigens
• Aim to avoid transfusion of red blood cells that will be clumped (rejected) by antibodies present in the recipients plasma
• if donor's antigens are already inthe recipients blood, no clumping occurs
• Type AB: Universal Recipient
• Type O: Universal Donor

• another antigen
• May be Rh+ or Rh-
• Especially during pregnancy
• Rh- woman, canbe sensitized by an Rh+ fetus, if fetal blood cells enter maternal circulation during birth
• If Woman carries another Rh+ fetus, anti-Rh antibodies she produced when sensitized by first birth may cross the placenta and destroy fetal red blood cells; results in severe anemia for the fetus, Erythroblastosis Fetalis

Plant circulation

Primary organ of transport in the plant

• run up and down the stems
• at center of the stem contains xylem, phloem, and cambium cells

• thick walled
• often hollow cells located on the inside of the vascular bundle (toward the center of the stem)
• carry water and minerals up the plant and walls give support
• Outer layer of xylem is alive and called the sapwood
• Two Types: Vessel Cells and Tracheids
• Transpiration Pull
• Capillary Action
• Root Pressure

Water evaporates from the leaves of plants, a vacuum is created that pulls water up the stem

Any liquids in a thin tube will rise because of the surface tension of the liquid and interactions between the liquid and the tube

Water entering the root hairs exers a pressure that pushes water up the stem

• Thin walled cells on outside of vascular bundles
• transport nutrients down the stem
• living cells and include sieve tube cells and companion cells

• two layers thick
• actively dividing
• undifferentiated cells that give rise to xylem and phloem
• found between xylem and phloem cell layers
• as they divide, cells near the phloem differentiate into phloem cells and the cells near the xylem differentiate into xylem cells

• Epidermis (Outer Bark)
• Cortex
• Phloem
• Cambium
• Xylem
• Pith (Tissue involved in storage of nuteirents and plant support)
• Phloem, Cambium, Xylem are fibrovascular Bundle

• Functions to absorb materials through the root hairs, and anchor the plant
• provide storage for energy reserves
• Root hairs: specialized cells of the root epidermis with thin walled projections
• increase surface area for absorption of water and minerals from the soil
• root: epidermis, cortex, phloem, xylem and cambium

actively dividing, undifferentiated cells of a plant

• lying between the phloem and xylem is a type of meristem called lateral meristem
• provides for lateral growth of stem by adding to the phloem or xylem

• located at the tips of roots and stems where division leads to increase in length
• new cells elongate, and finally differentiate into one of the many specialized cells of the plants