Glossary: Cells

Question 1

Active Transport

Answer 1

The movement of substances across cell membranes against a concentration gradient

Question 2

Apoptosis

Answer 2

Programmed cell death; a normal type of cell death that removes unneeded cells during embryological development, regulates the number of cells in tissues and eliminates potentially dangerous cells

Question 3

Chromatin

Answer 3

Threadlike mass of genetic material, consisting of DNA and histone proteins, present in the nucleus of a nondividing or interphase cell

Question 4

Chromosome

Answer 4

The constricted portion of a chromosome where the two chromatids are
joined; serves as the point of attachment for the microtubules that pull chromatids during anaphase of cell division.

Question 5

Cilia

Answer 5

A hair or hairlike process projecting from a cell that may be used to move the entire cell or to move substances along the surface of the cell. Singular is cilium

Question 6

Crossing over/synapsis

Answer 6

The exchange of a portion of one chromatid with another during meiosis. It permits an exchange of genes among chromatids and is one factor that results in genetic variation of progeny

Question 7

Cytoplasm

Answer 7

Cytosol plus all organelles except the nucleus.

Question 8

Cytoskeleton

Answer 8

Complex internal structure of cytoplasm consisting of microfilaments, microtubules, and intermediate filaments.

Question 9

Cytosol

Answer 9

Semifluid portion of cytoplasm in which organelles and inclusions are suspended
and solutes are dissolved. Also called intracellular fluid.

Question 10

DNA

Answer 10

Deoxyribose nucleic acid. Contains genetic material

Question 11

Diffusion

Answer 11

A passive process in which there is a net or greater movement of molecules or
ions from a region of high concentration to a region of low concentration until equilibrium is reached.

Question 12

Endocytosis

Answer 12

The uptake into a cell of large molecules and particles by vesicles formed from the plasma membrane.

Question 13

Exocytosis

Answer 13

A process in which membrane-enclosed secretory vesicles form inside the
cell, fuse with the plasma membrane, and release their contents into the interstitial fluid; achieves
secretion of materials from a cell.

Question 14

Flagella

Answer 14

Hairlike, motile processes on the extremity of a bacterium, protozoan, or sperm
cell. Singular is flagellum.

Question 15

Gene

Answer 15

Biological units of heredity; a segment of DNA located in a definite position on a
particular chromosome; a sequence of DNA that codes for a particular mRNA, rRNA, or tRNA