A&P Chapter 3

active transport

transport across cell membrane that requires energy

amphipathic

molecule with different polarity on each end, resulting in difference in water solubility (how soap removes grease)

anaphase

third stage of mitosis, sister chromatids separate into two new nuclear regions, microtubules shorten, kinetochore “rides along”, pulls them apart

anticodon

3 nucleotides on tRNA, complementary to codon on mRNA

autolysis

breakdown of cells by self, own enzymes, usually lysosomes

autophagy

lysosomal breakdown of cells components (not whole cell)

cell cycle

life cycle of single cell, from birth until division

cell membrane

membrane surrounding all cells, lipid bilayer with various molecules

centriole

small, self replicating organelle, origin for microtubule growth, moves DNA during cell division

aka spindle fibers, 9 groups of 3 microtubules

centromere

region of attachment for 2 sister chromatids

centrosome

cellular structure that organize microtubules during cell division

channel protein

membrane spanning protein, inner pore, allows 1+ substance passage

checkpoint

process point in cell cycle, certain conditions must be met to proceed

chromatin

substance consisting of DNA and associated proteins

chromosome

condensed version of chromatin

cilia

small appendage on certain cells, like little hairs, formed by microtubules, move waste, dust, mucus, eggs in fallopian, etc

cleavage furrow

contractile ring, forms around cell during cytokinesis, pinches cell into two halves

codon

3 nucleotide pairs, on mRNA molecule, corresponds to specific amino acid

concentration gradient

difference in concentration of substance between two regions

cyclin

1 group of proteins, function in the progression of the cell cycle

cyclin-dependent kinase

CDK, one group of enzymes, associated with cyclins, help them perform their functions

cytokinesis

final stage in cell division, cytoplasm divides to form two separate daughter cells

cytoplasm

organelles and cytosol

cytoskeleton

“skeleton” of a cell, formed by rod-like proteins that support cells shape and provide locomotive abilities

3: microtubule, microfilament, intermediate filament

cytosol

clear, semi fluid of cytoplasm

diffusion

passive movement of substance from area of high concentration to lower

diploid

presence of a double complement of genetic material (2 sets of chromosomes

DNA polymerase

enzyme that functions in adding new nucleotides to growing strand of DNA

DNA replication

process of duplicating a molecule of DNA

endocytosis

import of material into cell by formation of membrane bound vesicle

endoplasmic reticulum

ER, cellular organelle, interconnected membrane bound tubules
system of channels, continuous w/ nuclear membrane

overall: provides passage through cell, function in transport, synth, and storing

exocytosis

export of substance out of cell by membrane bound vesicle

ex: hormones from glands

exon

one of the coding regions of an mRNA molecule that remain after splicing

facilitated diffusion

passive diffusion of a substance with aid of an open membrane protein

allows bigger or charged cells

flagella

appendage on certain cells formed by microtubules, only males, move sperm

g0 phase

long or perma period where cell does not move forward into DNA synthesis

g1 phase

after new cell is born, size growth

g2 phase

after DNA synthesis

gene

function length of DNA, provides genetic info to build protein

gene expression

active interpretation of info coded in gene to produce functional gene product

genome

entire complement of organism’s DNA

glycocalyx

fuzzy coating of sugar molecules that surrounds the cell membrane

different for every person

glycoprotein

protein that has one+ carbohydrates attached

golgi apparatus

organelle, series of flattened, membrane bound sacs

the post office
one side receives in vesicles, sorted inside, released other side

helicase

enzyme that functions to separate 2 DNA strands of double helix during DNA replication

histone

family of proteins that associate with DNA in nucleus to form chromatin

homologous

two copies of same chromosome (not identical) one from each parent

hypertonic

solution concentration higher than reference, small

hypotonic

solution concentration lower than reference, big

integral protein

membrane associated protein, spans entire width of bilayer

intermediate filament

cytoskeletal filament, made of keratin, resists cellular tension

interphase

entire life cycle of cell except mitosis

intron

non coding region of pre mRNA transcript, removed during splicing

isotonic

solution concentration same as reference

kinetochore

region of centromere, microtubules attach to pair of sister chromatids

ligand

molecule that binds with specificity to specific receptor molecule

ex: receptors on nerve cells that bind with neurotransmitters

lysosome

membrane bound organelle, originating from GA (vesicle with enzymes) breaks down unneeded things in cell

messenger RNA

nucleotide molecule, intermediate in genetic code between DNA and protein

metaphase

second stage, linear alignment of sister chromatids in center
each chromatid attaches to spindle fiber/microtubules

metaphase plate

linear alignment of sister chromatids in center of cell

microfilament

cytoskeletal filament, made of actin subunits, function in muscle contraction and cellular structural support

microtubule

cytoskeletal filament, made of tubulin subunits, function in cellular movement and structural support

make up cilia and flagella

mitocondrion

organelle bound by double lipid bilayer, production of ATP
inside inner bilayer is the cristae

mitosis

division of genetic material, cell nucleus breaks down and 2 new nuclei are formed

mitotic phase

phase where cell goes under mitosis

mitotic spindle

network of microtubules, originating from centrioles, arranges and pulls apart chromosomes during mitosis

multipotent

being able to differentiate into different types of cells within cell lineage, like red/white blood cell

mutation

change in nucleotide sequence in gene

nuclear envelope

membrane that surrounds nucleus, double lipid bilayer with fluid between

nuclear pore

small, protein lined openings, scattered throughout nuclear envelope

nucleolus

small region of nucleus, functions in ribosome synthesis

nucleosome

a wrapped DNA-histone complex

multiple looks like a beaded necklace

nucleus

contains DNA

oligopotent

able to differentiate into one of a few possible cell types

organelle

membrane bound specialized structure in cell that performs specific function

osmosis

passive diffusion of water down concentration gradient across SPM

passive transport

across cell membrane, does not require cellular energy

peripheral proteins

membrane protein, not all the way through lipid bilayer, attached to integral protein, membrane lipids, or something else

peroxisome

membrane bound organelle, contains enzymes responsible for detoxifying harmful substances

typically create hydrogen peroxide, they remove hydrogen

phagocytosis

endocytosis of large particles

pinocytosis

endocytosis of fluid

pluripotent

able to differentiate into a large variety of cell types, #2

polypeptide

chain of amino acids, linked by peptide bonds

polyribosome

simultaneous translation of a single mRNA transcript by multiple ribosomes

promoter

region of DNA that signals transcription to begin at that site within gene

prophase

breakdown of nuclear envelope, condensing chromatin to chromosomes
microtubules grow from centrosomes

proteome

full complement of proteins produced by cell

reactive oxygen species

ROS, very reactive peroxides and oxygen containing radicals, may contribute to cellular damage

receptor

recognition protein, contains binding site for another specific molecule (ligand)

receptor mediated endocytosis

endocytosis of ligands attached to membrane bound receptors, receptors wait for a certain number before functioning

ribosomal RNA

rRNA, makes up subunits of a ribosome

ribosome

cellular organelle, functions in protein synthesis

RNA polymerase

enzyme that unwinds DNA, adds new nucleotides to growing strand of RNA for the transcription phase of protein synthesis

S phase

DNA replication

selective permeability

allows certain substances (small, nonpolar molecules)
ex: CO2, O2, steroids

sister chromatid

one pair of identical chromosomes

sodium potassium pump

membrane embedded protein pump, uses ATP to move Na+ out and K+ in, helps with electrical gradient, in many nerve cells

somatic cell

all cells except gamete

spliceosome

enzymes that serves to splice out the introns of pre mRNA

splicing

modifying pre mRNA by removing certain, noncoding, regions