Chapter 3 Key Terms Flashcards
form of transport across the cell membrane that requires input of cellular energy
active transport
describes a molecule that exhibits a difference in polarity between its two ends, resulting in a difference in water solubility
amphipathic
third stage of mitosis (and meiosis), during which sister chromatids separate into two new nuclear regions of a dividing cell
anaphase
consecutive sequence of three nucleotides on a tRNA molecule that is complementary to a specific codon on an mRNA molecule
anticodon
breakdown of cells by their own enzymatic action
autolysis
lysosomal breakdown of a cell’s own components
autophagy
life cycle of a single cell, from its birth until its division into two new daughter cells
cell cycle
membrane surrounding all animal cells, composed of a lipid bilayer interspersed with various molecules; also known as plasma membrane
cell membrane
small, self-replicating organelle that provides the origin for microtubule growth and moves DNA during cell division
centriole
region of attachment for two sister chromatids
centromere
cellular structure that organizes microtubules during cell division
centrosome
membrane-spanning protein that has an inner pore which allows the passage of one or more substances
channel protein
progress point in the cell cycle during which certain conditions must be met in order for the cell to proceed to a subsequence phase
checkpoint
substance consisting of DNA and associated proteins
chromatin
condensed version of chromatin
chromosome
small appendage on certain cells formed by microtubules and modified for movement of materials across the cellular surface
cilia
contractile ring that forms around a cell during cytokinesis that pinches the cell into two halves
cleavage furrow
consecutive sequence of three nucleotides on an mRNA molecule that corresponds to a specific amino acid
codon
difference in the concentration of a substance between two regions
concentration gradient
one of a group of proteins that function in the progression of the cell cycle
cyclin
one of a group of enzymes associated with cyclins that help them perform their functions
cyclin-dependent kinase (CDK)
final stage in cell division, where the cytoplasm divides to form two separate daughter cells
cytokinesis
internal material between the cell membrane and nucleus of a cell, mainly consisting of a water-based fluid called cytosol, within which are all the other organelles and cellular solute and suspended materials
cytoplasm
“skeleton” of a cell; formed by rod-like proteins that support the cell’s shape and provide, among other functions, locomotive abilities
cytoskeleton
clear, semi-fluid medium of the cytoplasm, made up mostly of water
cytosol
movement of a substance from an area of higher concentration to one of lower concentration
diffusion
condition marked by the presence of a double complement of genetic material (two sets of chromosomes, one set inherited from each of two parents)
diploid
enzyme that functions in adding new nucleotides to a growing strand of DNA during DNA replication
DNA polymerase
process of duplicating a molecule of DNA
DNA replication
difference in the electrical charge (potential) between two regions
electrical gradient
import of material into the cell by formation of a membrane-bound vesicle
endocytosis
cellular organelle that consists of interconnected membrane-bound tubules, which may or may not be associated with ribosomes (rough type or smooth type, respectively)
endoplasmic reticulum (ER)
export of a substance out of a cell by formation of a membrane-bound vesicle
exocytosis
one of the coding regions of an mRNA molecule that remain after splicing
exon
fluid exterior to cells; includes the interstitial fluid, blood plasma, and fluid found in other reservoirs in the body
extracellular fluid (ECF)
diffusion of a substance with the aid of a membrane protein
facilitated diffusion
appendage on certain cells formed by microtubules and modified for movement
flagellum
phase of the cell cycle, usually entered from the G1 phase; characterized by long or permanent periods where the cell does not move forward into the DNA synthesis phase
G0 phase
first phase of the cell cycle, after a new cell is born
G1 phase
third phase of the cell cycle, after the DNA synthesis phase
G2 phase
functional length of DNA that provides the genetic information necessary to build a protein
gene
active interpretation of the information coded in a gene to produce a functional gene product
gene expression
entire complement of an organism’s DNA; found within virtually every cell
genome
coating of sugar molecules that surrounds the cell membrane
glycocalyx
protein that has one or more carbohydrates attached
glycoprotein
cellular organelle formed by a series of flattened, membrane-bound sacs that functions in protein modification, tagging, packaging, and transport
Golgi apparatus