AP Biology Vocabulary
Chapters 6-17
Chapter 6 – A Tour of the Cell
organelle
a subcellular structure
cytosol
another word for cytoplasm
plasma membrane
another word for cell membrane
prokaryotic cells
primitive cells with no nuclei; may or may not perform photosynthesis
eukaryotic cells
cells with nuclei; includes both animal and plant cells
chromosome
a discrete structure of DNA and protein in a eukaryotic cell
chromatin
a complex of DNA and proteins; diffused throughout nucleus except during cell
division (do not confuse with chromatid)
nucleolus
dark spot in the nucleus; synthesizes ribosomal RNA
ribosome
organelle composed of two subunits; synthesizes protein; may be free or bound
to the endoplasmic reticulum
endomembrane system various membrane-bound organelles such as the ER, Golgi body, and vesicles
endoplasmic reticulum network of membrane tubules; includes both rough and smooth ER
vesicles
membrane bubbles within the cells; may be used for storage or transport
lysosome
vesicle filled with digestive enzymes
mitochondria
organelles responsible for cellular respiration
chloroplasts
organelles responsible for photosynthesis
cristae
folds in the mitochondrial inner membrane
matrix
interior of the mitochondrial inner membrane
thylakoids
compartments inside the chloroplast
granum
a stack of thylakoids
stroma
fluid outside the thylakoids, inside the chloroplast (do not confuse with stoma)
lumen
interior of the thylakoid
motility
another word for movement
microtubules
relatively thick fibers in the cytoskeleton
microfilaments
thinnest fibers in the cytoskeleton
actin fibers
microfilaments
centrosome
microtubule organizing center; composed of two centrioles
centriole
subunit of centrosome
centromere
attachment point for microtubules in the chromosome (at the kinetochore)
Chapter 7 – Membrane Structure and Function
fluid mosaic model
cell membrane is a fluid with a mosaic of proteins embedded in the phospholipid
bilayer
transport proteins
proteins that span the membrane to transport molecules in or out
passive transport
diffusion across a semipermeable membrane with no expenditure of energy
active transport
diffusion against a concentration gradient; requires energy
electrochemical gradient
the combined effects of a concentration gradient and an electrical charge
Chapter 8 – An Introduction to Metabolism
anabolic
chemical reactions that build up organic molecules
catabolic
chemical reaction that break down organic molecules
exergonic
chemical reaction that releases energy
endergonic
chemical reaction that consumes energy
phosphorylation
transferring a phosphate group from ATP to another molecule to make it more
reactive
activation energy
an initial investment of energy required to start an exergonic reaction
catalyst
speeds up a chemical reaction without being consumed by it; lowers activation
energy
enzyme
a protein that acts as a catalyst
subsrate
the molecule an enzyme acts upon
active site
one area (usually a groove) in an enzyme that binds to the substrate
feedback inhibition
the product of a reaction inhibits the enzyme that promotes that reaction
Chapter 9 – Cellular respiration
oxidation
loss of electrons
reduction
gain of electrons (think of electron’s negative charge; charge is reduced)
redox
chemical reaction involving oxidation of one reagent and reduction of another
glycolysis
first reaction in cellular respiration; glucose is broken into 2 pyruvate molecules
citric acid cycle
another name for the Krebs Cycle
chemiosmosis
diffusion of a chemical usually H+) across a membrane; used to harvest energy in
both cellular respiration and photosynthesis
ATP synthase
an enzyme that works like a turbine engine during chemiosmosis
fermentation
an alternate metabolic pathway for use in the absence of oxygen
anaerobic
without oxygen
aerobic
with oxygen
Chapter 10 – Photosynthesis
autotroph
self-feeder (performs photosynthesis)
heterotrophy
other-feeding (must eat to obtain energy)
chlorophyll
green pigment in chloroplasts; harvests sunlight
stoma
pore in the underside of a leaf (do not confuse with stroma)
Calvin cycle
converts CO2 to sugar using energy from sunlight
Chapter 12 – The Cell Cycle
somatic cells
body cells (not sex cells)
gametes
sex cells (sperm and egg or pollen and seed)
chromatid
when a chromosome has replicated, each copy is called a sister chromatid (do
not confuse with chromatin)
mitosis
cell division; one diploid cell becomes two diploid daughter cells
meiosis
cell division; one diploid cell becomes four haploid daughter cells
cytokinesis
division of the cytoplasm
kinetochore
attachment point for microtubules at the centromere
spindle fibers
microtubules that pull sister chromatids apart and drive cytokinesis
checkpoint
a point in the cell cycle where the cycle is regulated by stop and go signals
cyclin
a cyclically fluctuating protein that regulates the cell cycle
Chapter 13 – Meiosis and Sexual Life Cycles
homologous chromosomes
maternal and paternal versions of the same chromosome in a diploid cell
recombinant chromosome
a single chromosome containing segments of maternal and paternal
versions, after crossing over has occurred
Chapter 14 – Mendel and the Gene Idea
hybrid
a cross between two true-breeding varieties
P generation
parent generation; usually homozygous
F1 generation
first filial generation; usually 100% heterozygous
F2 generation
second filial generation; usually 1:2:1 for homozygous dominant,
heterozygous, and homozygous recessive
alleles
different versions of a gene
law of segregation
different alleles end up in different gametes
homozygous
diploid, with two of the same allele
heterozygous
diploid, with two different alleles
phenotype
an organism’s visible traits
genotype
an organism’s genetic makeup
karyotype
a magnified picture of an organism’s chromosomes arranged in order
law of independent assortment each trait segregates as if it were a monohybrid cross, regardless of how
other traits segregate
monohybrid
heterozygous for one trait; F1 generation will have 1:2:1 ratio
dihybrid
heterozygous for two traits; F1 will have 9:3:3:1 ratio
Chapter 15 – Chromosomal Basis of Inheritance
aneuploidy
abnormal number of chromosomes
trisomy
three copies of a chromosome in a diploid cell
monosomy
only one copy of a chromosome in an otherwise diploid cell
polyploidy
three or four copies of the entire chromosome set
duplication
a kind of chromosomal abnormality
inversion
a kind of chromosomal abnormality
translocation
a kind of chromosomal abnormality
Chapter 16 – Molecular Basis of Inheritance
Hershey-Chase experiment
radioactive phosphorus and sulfur proved DNA carried genetic
information in bacteriophage viruses
Watson & Crick
credited with discovering the double helix form of DNA
Rosalind Franklin
made the X-ray photo used by Watson and Crick
semiconservative
one strand of the original DNA is preserved in each daughter molecule
replication fork
the point where the two strands of DNA are beginning to separate
leading strand
has continuous replication away from the replication fork
lagging strand
replicates in pieces toward the fork
Okazaki fragments
pieces of new DNA in the lagging strand
Chapter 17 – from Gene to Protein
Beadle & Tatum’s experiments one gene-one polypeptide
transcription
DNA → mRNA
translation
mRNA → polypeptide
mRNA
messenger RNA; a long strand; carries info from nucleus to ribosome
tRNA
transfer RNA; cloverleaf shape, connects amino acids to anticodons
rRNA
ribosomal RNA
codon
three-letter word in DNA or mRNA
anticodon
three-letter word in tRNA
reading frame
dictates where codons begin and end
initiation
beginning the transcription process
elongation
continuing the transcription process
termination
ending the transcription process at a stop codon
intron
nonsense mRNA that is edited out before translation
exon
the parts of mRNA that are eventually expressed
point mutation
a change of one letter in a codon
missense mutation
a point mutation that changes an amino acid in the polypeptide
nonsense mutation
a point mutation that terminates an amino acid chain
frameshift mutation
insertion or deletion of a letter, changing all subsequent codons