polypeptide
a long chain of amino acids
peptide
a short sequence of amino acids
peptide bonds
the bonds that join amino acids
transcription
makes a copy of a gene that is an RNA molecule complementary to one strand of the DNA double helix; the copy is taken out of the nucleus and into the cytoplasm so that the genetic info in the nucleus can be used to synthesize proteins
translation
uses the info in RNA to manufacture a protein by aligning and joining the specified amino acids after the RNA copy is taken out of the nucleus and into the cytoplasm
S phase
phase during which cells replicate their DNA
M phase
transcription and translation work continuously except during this phase
central dogma of DNA
the relationship between nucleic acids and proteins as a directional flow of information
template strand
The strand of the double helix that the bases of an RNA sequence are complementary to
RNA polymerase
enzyme that assists the construction of an RNA molecule
coding strand
the strand of the double helix that does not pair with RNA bases during transcription
Uracil
pyrimidine base found in RNA but not in DNA; pairs with adenine
conformation
the shape that RNA folds into as it is synthesized along DNA, determined by complementary base pairing within the same RNA molecule
messenger RNA
carries the information that specifies a particular protein; forms codons that specify amino acids
ribosomal RNA
associates with proteins to form a ribosome and catalyzes the formation of peptide bonds between amino acids, also can help align the ribosome and mRNA
ribozyme
name for an rRNA working as an enzyme to catalyze bond formations between amino acids
transfer RNA
binds mRNA codons at one end and a specific amino acid at the other, holds anticodons, has a cloverleaf shape
operon
a set of genes that is coordinately controlled
transcription factors
groups of proteins that come together to form an apparatus that binds DNA at certain sequences and initiates transcription at different sites on chromosomes. they are activated by signals outside the cell, such as hormones and growth factors, and form a p
binding domains
guide transcription factors to the genes they control
transcription initiation
transcription factors and RNA polymeraser are attracted to a promoter, and signals from outside the cell alter the chromatin structure in a way that exposes the promoter of a gene whose transcription is required under the particular conditions.
promoter
a special sequence that signals the start of a gene
TATA box
the base sequence TATA surrounded by long stretches of G and C; attracts the first transcription factor, the TATA binding protein
transcription elongation
DNA double helix is unwound, free RNA nucleotides bond with exposed complementary bases on the DNA template strand, RNA polymerase adds RNA nucleotides in the DNA specified sequence
transcription termination
a terminator sequence in the DNA indicates where the gene's RNA encoding region ends
methylated cap
added to the 5' end of mRNA after it is transcribed. formed by a backwardly inserted guanine that attracts an enzyme that adds methyl groups to itself and one or two adjacent nucleotides. serves as a recognition site for protein synthesis.
poly-A tail
a sequence of about 200 adenines added to the 3' end of an mRNA by a special polymerase after the mRNA is transcribed. stabilizes the molecule and is necessary for protein synthesis to begin
introns
intervening sequences; parts of mRNAs that are transcribed but not translated
exons
mRNA parts that remain to be translated
pre-mRNA
mRNA prior to intron removal
snurps
when introns associate with certain proteins in order to remove themselves, they are called...
spliceosome
four snurps together; cuts introns out and attaches exons to form the mature mRNA that exists in the nucleus
isoforms
different versions of a protein product formed by different exon combinations of a particular gene
alternate splicing
mechanism of combining exons in different ways
genetic code
the correspondence between the chemical languages of mRNA and protein
twenty
number of amino acids
three
number of RNA bases that specify one amino acid
AUG
start codon
stop codons
UGA, UAA, UAG
synonymous codons
different codons that specify the same amino acid
initiation
mRNA, tRNA molecules carrying amino adics, ribosomes, energy-storing molecules such as ATP and GTP, and various protein factors, meet and are held together by chemical bonds in this stage of translation
methionine
amino acid specified by AUG; signifies the beginning of a polypeptide
translation elongation
A large ribosomal subunit bonds to the initiation complex. The codon adjacent to the initiation codon bonds to its complementary anticodon, which is part of a free tRNA. The two amino acids still attached to their tRNAs align. With the help of rRNA, amino
p-site
part of the ribosome that holds the growing amino acid chain
a-site
holds the next amino acid to be added to the amino acid chain
primary structure
amino acid sequence of a polypeptide chain
secondary structure
loops, coils, barrels, helices, sheets, and other distinctive shapes formed from chemical attractions between amino acids
tertiary structure
formed when more widely separated amino acids attract or repel in response to water molecules
quaternary structure
proteins consisting of more than one polypeptide
chaperone proteins
stabilize partially folded regions in their correct form and prevent a protein from getting stuck in an intermediate form, which would affect its function
ubiquitin
protein that tags misfolded proteins
proteasome
tunnel-like, multi-protein structure that stretches out and chops up misfolded or excess proteins, degrading it into amino acids that are to be re-used