What is a nucleotide and what 3 things is it made of?
it is the basic functional unit of dna made of a sugar a phosphate and a nitrogenous base
What kind of bonds connect the bases of dna together on the RUNGS of the ladder?
Hydrogen bonds
____ combinations of bases code for _____ amino acids
64 combos and 20 aas
What is transcription and where does it take place?
DNA is converted to RNA in the nucleus
DNA =________ sugar and RNA=_________ sugar
DNA is deoxyribose and is double stranded
RNA is ribose and is single stranded
DNA has _______ instead of ______, found in RNA.
DNA has thymine
RNA has uracil
What carries the RNA out of the nucleus?
The mRNA brings the RNA out of the nucleus to the ribosome
What allows the RNA to code for protein?
The tRNA has an anticodon that matches with each 3 set of bases on the DNA and has an attached amino acid. The amino acids all together form a protein.
What is rRNA and what makes it?
The rRNA is used to make the large and small subunit of the ribosome and it is made in the nucleolus.
What is added to the rRNA strand after transcription?
A 5' cap and a poly-a tail for signaling in the cell
Where does DNA translation take place?
In the cytoplasm at the RIBOSOME
What occurs in the three stages of translation?
1.Initiation: mRNA attaches itself to the ribosome; the first codon in the mRNA is always AUG (initiation codon-start sequence), which codes for methionine; tRNA brings in the first amino acid (methionine) and places it in its proper place.
2.Elongation: Subsequent amino acids are brought to the ribosome and bonded
together with a peptide bond.
3.Termination: There are three codons which are known as stop codons (UAA, UAG, UGA). These serve as the signal to stop protein synthesis and release the protein from the ribosome.
primary shape of protein is........
unique sequence of amino acids“Beads on a string”
secondary shape of protein.........
Twisting or folding of the polypeptide backbone; hydrogen bonds between the peptide bonds of the backbone stabilize the secondary structure; there are two types of secondary structure: α helix and β pleated sheet.
tertiary structure of protein
interactions between the various kinds of side chains of amino acids
Interactions between the various kinds of side chains of amino acids; hydrogen bonds, ionic bonds, and hydrophobic interactions are weak bonds between side chains that collectively hold the protein in a specific conformation; stronger bonds are the disulfide bridges, covalent bonds between the side chains of cysteine pairs.
quaternary structure of a protein
interaction of two or more polypeptides
Examples: collagen and hemoglobin
missense vs. nonsense mutation
if the substitution changes the amino acid (a mis- sense mutation), the protein may or may not be functional depending on the location of the mutation;
if the substitution produces a premature termination codon (a non- sense mutation), the protein will be prematurely terminated, and will be nonfunctional.
point mutation
Point Mutations: When a single nucleotide base is substituted by another nucleotide base
5 conditions for the Hardy Weinberg to make sure that Hardy Weinberg equation can be used o predict the frequency of alleles
1) Random Mating
2) No natural selection
3) No migration or immigration
4) Large populations
5) No mutations
hardy weinberg equation (just read)
p2+ 2pq + q2= 1 p+q=1
p = frequency of dominant allele
q = frequency of recessive allele
p2 = frequency of homozygous dominant individuals
2pq = frequency of heterozygous individuals
q2 = frequency of homozygous recessive individuals.
Endocrine Vs. Exocrine System
Endocrine secretes hormones directly into the blood, exocrine secretes into a tube or duct (i.e. enzymes)
What are the 3 types of hormones?
steroids, peptides, and amino acid derivatives
What does the hypothalamus secrete
secretes RELEASING HORMONES
connects the nervous system to the endocrine system
also controls hunger, thirst body temp, etc.
i.e.
it secretes TRH (thyrotrypin releasing hormone) which makes the thyroid release thyrotropin
it secretes Gn RH which controls the release of gonotropin hormones
What does the anterior pituitary secrete?
Growth Hormone (somatotropin) Stimulates protein synthesis and promotes growth of bone. ProlactinStimulates secretion of milk and developement of the breasts. TSH (thyroid stimulating hormone) Stimulates the thyroid to secrete thyroxine. ACTH(adrenocorticotropichormone) Stimulatestheadrenalcortextoreleasecortisol.
FSH (follicle stimulating hormone) Stimulates growth of ovarian follicle; promotes formation of sperm in testes.
LH (luteinizing hormone) Stimulates ovulation and formation of corpus luteum; causes secretion of female sex hormones by the ovaries and testos-
terone by the testes.
What does the posterior pituitary secrete?
Two types of hormones: oxytocin accelerates childbirth by increasing uterine contractions during labor and ADH (aka vasopressin) which decreases the water that is excreted by the kidneys
What does the thyroid gland secrete?
Thyroxine which, when released, causes your METABOLISM to increase
Calcitonin which stops calcium from leaving your bones
What happens if you have too much/ not enough thyroxine?
If you have too much thyroxine excreted by your thyroid you get hyperthyroidism and you have trouble sleeping, weight loss, and an increased heart rate
If you do not have enough thyroxine you get HYPOthyroidism and you have fatigue and weight gain
REMEMBER THYROXINE REGULATES METABLOISM
What does the adrenal cortex release?
STEROID HORMONES
Glucocorticoids (i.e. cortisol) which suppresses the immune inflammatory response, and functions well to form glucose from protein and fat
Mineralocorticoids (i.e. aldosterone) which reduces sodium secretion by the kidneys and increases potassium secretion by the kidneys. this makes the body have more sodium and less potassium and is also responsible for an increase in blood pressure.
What does the adrenal medulla secrete?
Adrenaline (epinephrine) and noradrenaline (norepinephrine)
Both are for the "Flight or fight” response Increase metabolic rate, increase heart rate, increase blood pressure, increase glucose concentration in blood (glycogen to glucose), increase blood supply to skeletal muscle, brain and heart, decrease blood supply to kidneys, skin, and digestive system (unessential)
Where are the isles of langerhans and what types of cells (2) do they contain?
in the kidneys and contain alpha and beta cells
What is the funxn of the islets of langerhans?
Beta cells secrete insulin= insulin stimulates the muscles to remove glucose from the blood and stimulates the liver to produce and store glycogen
Alpha cells do the opposite, when blood sugar is too high the alpha cells secrete glucagon which stimulates the conversion of glycogen into glucose to raise blood sugar levels
What are the steps that occur (trace the pathway) after the release of TRH (thyrotropin releasing hormone) by the hypothalamus?
What is the antagonist hormone to parathormone and what is it involved in?
calcitonin and is involved in calcium regulation
What is the antagonist hormone to glycogen and what is it involved in
glycagon and blood sugar regulation
In the pancreas, do the Islets of Langerhans cells produce exocrine or endocrine secretions?
The Islets of Langerhans cells produce insulin and glucagon. These are both hormones and are secreted directly into the blood. Therefore, this is an endocrine secretion. However, the pancreas also produces enzymes, which are used in digestion, which are exocrine secretions.
Endocrine vs. Exocrine system
Exocrine system has ducts that carry the chemical messengers to specific receptors in the body. The endocrine system releases hormones into the body and they are able to travel freely throughout and bind to receptors throughout the body.
What and where are seminiferous tubules?
Located in the testes, seminiferous tubules produce sperm and are all coiled around and covered with tissue
What are interstitial cells and where are they located?
Interstitial cells are located in the testes and they produce testosterone
What is the epididymis and where is it located?
the epididymis is right above the testes and it is where sperm goes after being formed in the seminiferous tubules so the sperm can be stored and mature
What and where are the vas deferens?
The vas deferens are the tubes that sperm travel through in order to go to the urethra
What are the 3 glands that contribute to semen?
seminal vesicles
prostate gland (secretes alkaline fluid)
and bulbourethral glands
What is the follicular phase and what stimulates it?
The follicular phase is part of the female menstrual cycle that occurs when FSH stimulates the follicle to grow and develope white the follicle secrets estrogen. Eventually lutenizing hormone levels surge and this causes the follicle to burst releasing the ovum from the ovary
What happens in the luteal phase?
Part of the menstrual cycle occurs directly after the ovarian follicle has burst and lutein hormone stimulates the ruptured follicle to begin producing estrogen and progesterone
What is progesterone's function in the menstrual cycle?
Progesterone causes the glands of the endometrium to mature and produce secretions that make it ready for the embryo to implant in the endometrium.
What happens when the ovum is not fertilized?
The corpus luteum breaks down and estrogen and progesterone levels drop, the endometrium sloughs off and menstration occurs
What is the corpus luteum?
The structure that forms from the ruptured follicle during the luteal phase of the menstrual cycle.
What is the functional unit of the kidney?
the nephron
Where is the cortex of the kidney located and what is its function?
it contains renal corpuscles, tubules, and ducts
What is the glomerulus and where is it located?
Located in the renal medulla (of the kidneys) glomerulii are like bunches of capilaries that allow for the filter of blood to form urine
How does blood travel IN to the kidneys?
Blood enters the kidney via the renal artery and then travels to afferent arterioles within the kidney which lead to the glomerulii
How does blood leave the kidney?
By way of efferent arterioles which lead to the renal vein
Trace the pathway of fluid through the kidneys
Bowman's capsule (surrounds the glomerulus)------- proximal convoluted tubule---------descending loop of henle---------ascending loop of henle-------------distal convoluted tube----------- collecting duct
What are the fluid and small solutes forced into Bowman's capsule called?
filtrate
The nephron secretes substances from the ___________ ______ into the filtrate by both passive and active transport.
interstitial fluid
After it travels through the collecting duct, where does urine go?
First to the ureter, and then to the urethra
In the kidneys, the ascending/descending limb is permeable to water but completely impermeable to salt, and thus only indirectly contributes to the concentration of the interstitium.
descending
Longer ascending/descending limbs allow more time for water to flow out of the filtrate, so longer limbs make the filtrate more hypertonic than shorter limbs.
descending
the descending/ascending limb of Henle's loop is impermeable to water
ascending
In passing through the ascending limb, the filtrate grows hypotonic since it has lost much of its sodium content. This hypotonic filtrate is passed to the distal convoluted tubule in the renal cortex.
Cells lining the tubule have numerous mitochondria to produce enough energy (ATP) for active transport to take place in the (distal convoluted tube/ proximal convoluted tube)
distal convoluted tube
Much of the ion transport taking place in the distal convoluted tubule is regulated by the _________ system
endocrine
In the presence of parathyroid hormone, the distal convoluted tubule reabsorbs more _____ and excretes more _______
calcium/phosphate making phosphate levels in the urine higher and ca levels in the body higher
When __________ is present, more sodium is reabsorbed and more potassium excreted.
aldosterone
____________, also called the nephron loop, is a U-shaped tube that extends from the proximal tubule
The loop of Henle
The LOOP OF HENLE begins in the _______, receiving filtrate from the proximal straight tubule, extends into the ____ as the descending limb, and then returns to the ______ as the ascending limb to empty into the __________
cortex/medulla/cortex/distal convoluted tubule
The primary role of the loop of Henle is to ...
concentrate the salt in the interstitium, the tissue surrounding the loop
What does ADH do?
anti-dieuretic hormone, ADH, makes the collecting duct permeable to water so water is reabsorbed instead of secreted.
the more ADH, the more concentrated your urine will be
What does urea do (2 things)?
Help us break down nitrogen containing compounds
plays a role in the countercurrent exchange system of the nephrons in the kidneys- the inner medullary collecting ducts of the nephrons will absorb urea and thereby raise the osmolarity of the medullary interstition which causes water to be reabsorbed in the ascending limb of the loop of Henle
Where does pressure filtration occur in the kidneys?
In the glomerulus
What does increasing the permeability of the collecting duct to water result in?
It causes the urine to be more concentrated.
How would a long loop of Henle affect the urine?
Urine would have less water in it because that would mean that more urea and salt would be allowed in the interstitium and the osmotic polarity would mean that more water would therefore be reabsorbed instead of secreted
Animals in the desert would be likely to have a very ______ loop of henle
long loop to conserve water
Alcohol inhibits the secretion of ADH, what does this do to the body?
Increases water loss since ADH is responsible for increasing the permeability of the distal convoluted tubule and collecting duct to water
Aldosterone is not under the control of the anterior pituitary (T or F)
True
Dieuretic drugs cause ________ water loss and _______ blood pressure
increased loss of H2O and lower bp
When bp is low, the _________ secrete renin
afferent arterioles
analogous structures:
these structures have similar functions but have different evolutionary origins and different patterns of development.
The wings of a fly (membranous) and the wings of a bird (bony and covered in feathers) are analogous structures. Analogous organs demonstrate superfi- cial resemblances that cannot be used as a basis for classification.
Vestigial Structures
these are structures that appear to be useless in the context of a particular modern-day organism’s
behavior and environment, but were apparently useful at one time.
_______ pituitary synthesizes own hormones
anterior
(ACTH-causes adrenal gland to secrete corticosteroids) as well as FSH and others
_________ pituitary stores and releases hormones synthesized in the hypothalamus
posterior pituitary (does not make its own hormones)
stores and releases oxytocin (lactation and uterine contractions) and vasopressin (ADH stimulates h2o retention)
What are the 2 principles of Lamarckian Evolution?
(1) Principle of use and disuse : the idea that those organs of the body used extensively to cope with the environment become larger and stronger, while those organs that are not used deteriorate
(2) Inheritance of acquired characteristics: he believed that the modifications an organism acquires dur- ing a lifetime can be passed along to its offspring. An often cited example was that of early giraffes, which stretched their necks to reach for leaves on higher branches. The offspring were believed to inherit the valuable trait of longer necks as a result of their parents’ excessive use of their necks. Modern genet- ics has disproved this concept of acquired characteristics.
It has now been established that changes in the DNA of sex cells are the only types of changes that can be inherited; because acquired changes are changes in the characteristics and organization of somatic cells, they cannot be inherited. This was conclusively proven in an experiment in which the tails of mice were cut off for 20 generations (an example of somatic change), only to find that the twenty-first gener- ation was born with tails of normal length.
Darwin’s Theory of Evolution
survival of the fittest, adaptations, natural selection.
a) Individuals of any population vary from one another in many characteristics (due to mutation).
b) Variations can be inherited.
c) Members of a population produce more offspring than the environment can support (causes competition).
d) Those individuals whose inherited characteristics fit them best to their environment are likely to leave more offspring than less fit individuals.
e) Over many generations of natural selection, the favorable changes (adaptations) are perpetuated in the species. Accumulation of these favorable changes eventually results in speciation.
The theory of natural selection states that pressures in the environment serve to promote “the survival of the fittest;” in other words, certain organisms are better adapted to their environments and are “selected” to survive in greater numbers than less fit organisms. It is these well-adapted organisms that reproduce and multiply, resulting in evolutionary change.
The individuals that survive (those with the favorable variations) live to adulthood, reproduce their own kind, and thus transmit these favorable variations or adaptations to their offspring. These favored genes gradually dominate the gene pool.
The evolution of DDT-resistant insects is an example of this phenomenon. DDT-resistant mutants existed before DDT was introduced into the insect population. The introduction of this insecticide constitutes a favorable environmental change for these mutants, and a fatal environmental change for the rest of the insect population. Now, conditions select for the survival of DDT-resistant organisms, resulting in the evolution of a new DDT-resistant species.
Antibiotic resistance is another example.
Penetrance
the percentage of individuals in the population carrying the allele that actually express the phenotype associated with the allele
Expressivity
the degree to which the phenotype associated with a gene is shown or expressed in an individual (i.e. the crippled hand)
What is enterokinase?
It is an enzyme that turns trypsinogen into trypsin and it is produced in the walls of the duodenum
trypsin also is responsible for activating a lot of the pancreatic enzymes
