biology 2 b

 the spontaneous movement of particles of any kind down a concentration gradient; that is movement of particles from where they are more concentrated to where they are less concentrated.

the diffusion of water across a selectively permeable membrane

 an increase or decrease in the density of a chemical substance within a given region. Cells often maintain concentration gradients of hydrogen ions across their membranes. When a gradient exists, the ions or other chemical substance involved ten to move from where they are more concentrated to where they are less concentrated

, the control of the gain or loss of water and dissolved solutes in an organisms

in comparing two solutions, referring to the one with the greater concentration of solutes

 in comparing two solutions, referring to the one with the lower concentration of solutions

 having the same solute concentration as another solution.

 a membrane protein that helps move substances across a cell membrane.

the movement of a substance across a biological membrane against its concentration gradient, aided by specific transport proteins and requiring the input of energy

cellular “eating”; a type of endocytosis whereby a cell engulfs large molecules, other cells or particles into its cytoplasm.

 the movement of materials from the external environment into the cytoplasm of a cell via vesicle or vacuoles

the movement of materials out of the cytoplasm of a cell via membranous vesicles or vacuoles.

a process leading to chemical changes in matter, involving the making and or breaking of chemical bonds

-a measure of disorder or randomness. One form of disorder is hear, which is random molecular motion

 the total of all the chemical reactions in an organism

a protein that serves as a biological catalyst, changing the rate of a chemical reaction without itself being changed in the process

the egg-producing part of a flower, consisting of a stalk with an ovary at the base and a stigma, which traps pollen, at the tip.

a ripened, thickened ovary of a flower, which protects dormant seeds and aids in their dispersal

a flowering plant whose embryo have two seed leaves or cotyledons

containing two sets of chromosomes(pairs of homologous chromosomes) in each cell, one set inherited from each parent; referring to an 2n cell

containing a single set of chromosomes; referring to an n cell

 a sex cell; a haploid egg or sperm. The union of two gametes of opposite sex (fertilization)produces a zygote.

the union of a haploid sperm cell with a haploid egg cell, producing a zygote

the first leaf that appears on an embryo of a flowering plant; a seed leaf. Monocot embryos have one cotyledon; dicot embryos have two

an energy deposit formed from a the fossilized remains of long-dead plants and animals

 - in flowering plants, a nutrient-rich mass formed by the union of a sperm cell with the diploid central cell of the embryo sac during double fertilization; provides nourishment to the developing embryo in the seed

 -any of a group of seedless vascular plants

 a naked-seed plant. Its seed is said to be naked because its it not enclosed in an ovary

 the part of an enzyme molecule where a substrate molecule attaches ( by means of weak chemical bonds) typically, a pocket or groove on the enzymes, surface

the interaction between a substrate molecule and the active site of an enzyme, which changes shape slightly to embrace the substrate and catalyze the reaction

-the reproduction of a cell

an ordered sequence of events (including interphase and the mitoticpahse) that extends from the time a eukaryotic cell is first formed from a dividing parent cell until its own division into two cells

the combination of DNA and proteins that constitutes chromosomes; often used to refer the diffuse, much extended form taken by the chromosomes when a eukaryotic cell is not dividing

the region of a chromosome where two sister chromatids are joined and where spindle microtubules attach during mitosis and meiosis. The centromere divides at the onset of anaphase during mitosis and anaphase II of meiosis

-the division of the cytoplasm to form two separate daughter cells. Cytokinesis usually occur during telophase of mitosis and the two processes (mitosis and cytokinesis) make up the mitotic (M) phase of the cell cycle

-material in the cytoplasm of a eukaryotic cell that gives rise to microtubules; important in mitosis and meiosis; functions a microtubule-organizing center.

the first sign of cytokinesis during cell division in an animal cell; a shallow groove in the cell surface near the old metaphase plate.

a membranous disk that forms across the midline of a dividing plant cell. During cytokinesis, the cell plate grows outward, accumulating more cell wall material and eventually fusing into a new cell wall.

 a malignant growth or tumor caused by abnormal and uncontrolled cell division               

a display of micrographs of the metaphase chromosomes of a cell, arranged by sized and centromere position.

the exchange of segments between chromatids of homologous chromosomes during prophase I of meiosis

 human genetic disorders resulting from a condition call trisomy 21, the presence of an extra chromosome 21; characterized by heart and respiratory defects and varying degrees of mental retardation-

the phase in the eukaryotic cell cycle when the cell is not actually dividing. During interphase, cellular metabolic activity is high, chromosomes and organelles are duplicated, and cell size may increase. Interphase accounts for 90% of the cell cycle

the division of a single nucleus into two genetically identical daughter nuclei. Mitosis and cytokinesis make up the mitotic phase of the cell cycle.

 the diffusion of a substance across a biological membrane without any input of energy

one of the two identical parts of a duplicated chromosome. While joined, two sister chromatids make up one chromosome; chromatids are eventually separated during mitosis or meiosis II

 energy of motion. Moving matter performs work by transferring its motion to other matter, such as leg muscles pushing bicycles pedals

 the thickest of the three main kinds of fibers making up the cytoskeleton of a eukaryotic cell; a straight, hollow tube made of globular proteins called tubulins. Microtubules form the basis of the structure and movement of cilia and flagella

an abnormal mass of cells that forms within otherwise normal tissue.

an abnormal mass of cells that remains at its original site in the body

 an abnormal tissue mass that spread into neighboring tissue and to other parts of the body; cancerous tumor.

 the spread of cancer cell beyond their original site

 any cell in a multicellular organism except a sperm or egg cell or a cell that develops into a sperm or egg; a body cell

the two chromosomes that make up a matched pair in a diploid cell. Homologous chromosomes are of the same length, centromere position, and staining patterns and possess genes for the same characteristics at corresponding is inherited from the organism’s father, the other from the mother

a chromosome that determines whether an individual is male or female; in mammals, for example, the X or Y chromosome

 A chromosome not directly involved in determining the sex of an organism; in mammals for example, any chromosome other than X or Y

 the fertilized egg, which is diploid, that results from the union of haploid gametes ( sperm and egg) during fertilization

in a sexually reproducing organism, the process of cell division that produces haploid gametes from diploid cells within the reproductive organs

 a human genetic disorder resulting from a condition called trisomy 21, the presence of an extra chromosome 21; characterized by heart and respiratory defects and varying degrees of mental retardation

 an accident of meiosis or mitosis in which a pair of homologous chromosomes or a pair of sister chromatids fail to separate at anaphase

a pore surrounded by guard cells in the epidermis of a leaf. When stomata are open, CO2 enters the leaf, and water and O2 exit a plant conserves water when its stomata are closed.

the underground organ of a plant. Roots anchor the plant in the soil, absorb and transport minerals and water, and store food

main site of photosynthesis in a plant; consists of a flattened blade and a stalk that joins the leaf to the stem.

- plant tissue consisting of cells joined into tubes that transport water and nutrients throughout the plant body

 the portion of a plant’s vascular system that provides support and conveys water and inorganic nutrients from the roots to the rest of the plants. xylem consists mainly of vessel elements and or tracheids, water conducting cells.

 the portion of a plant’s vascular system that conveys sugars nutrients and hormones throughout a plant. Phloem is made up of live food-conducting cells.

a chemical that hardens the cell walls of plants. Lignin makes up most of what we call wood

a plant embryo packaged with a food supply within a protective covering

 in plants and algae, a haploid cell that can develop into a multicellular haploid individual, the gametophyte, without fussing with another cell. 2 in fungi, a haploid cell that germinates to produce a mycelium

 a type of plant that lacks xylem and phloem; a nonvascular plant. Bryophytes include mosses and their close relatives.

 a flowering plant, which forms seeds inside a protective chamber called an ovary

-in a seed plant, the delivery, by wind or animals, or pollen from the male parts of the plant to the stigma of a carpel on the female

 a tough outer covering of a seed, formed from the outer coat of an ovule. In a flowering plant, it encloses and protects the embryo and endosperm

a modified leaf of a flowering plant. A whorl of sepal encloses and protects the flower bud before it opens

 a modified leaf of a flowering plant. Petals are the often colorful parts of a flower that advertise it to insects and other pollinators

 a flowering plant whose embryos have a single seed leaf, or cotyledon