Chapter 9 Flashcards
(23 cards)
primary structure
-sequence of amino acids that form polypeptide chain
secondary structure
- involves hydrogen bonding between AA
- alpha-helices and beta-sheets
tertiary structure
- protein folding
- 3D
- hydrophilic R groups bend towards outer surface
- hyrdophobic R groups bend towards inside
quaternary structure
- complexes of multiple polypeptides
- protein-subunit interactions
eukaryotic translation
- large subunit of ribosome is 60s
- ribosome initially binds 5’ end of mRNA
- occurs in cytoplasm
- mRNA has 5’ cap and poly-A tail
prokaryotic translation
- has multiple ribosome binding sites
- ribsome is 70s and free-floating
three stages of translation
- initiation- ribosomal subunit binds with tRNA to mRNA
- elongation- amino acids are added to polypeptide chain
- termination- ribosome dissociated from mRNA
RNA polymerase role in transcription in eukaryotes
adds RNA nucleotide to growing RNA using a DNA template
nucleus role in transcription in eukaryotes
contains DNA in the cell
promoter role in transcription in eukaryotes
region of DNA that recruits the transcriptional machinery
tRNA role in translation in eukaryotes
carries an amino acid to ribosomes and binds to mRNA
ribosome role in translation in eukaryotes
an organelle where proteins are constructed
2 negatively charged and acidic amino acids
D (asp)
E (Glu)
3 positively charged and basic amino acids
K (Lys)
R (Arg)
H (His)
5 uncharged and polar amino acids
S (Ser) T (Thr) N (Asn) Q (Gln) Y (Tyr)
10 uncharged and nonpolar amino acids
A, V, P, L, I, F, C, G
W (Trp) and M (Met)
roles of the functional domain of proteins
- serves as active site in catalyzing chemical reactions
- anchors the molecule within the plasma membrane
- binds with ligand
number of aminoacyl synthesis
20, one for each AA
what recognizes AUG start codon
n-formyl Met tRNA
shine-dalgarno sequence
aids in ribosome binding to mRNA
2 start codons
Met (M) -> AUG
Trp (W) -> UGG
3 stop codons
UAA, UAG, UGA
wobble hypothesis
3rd position of nucleotide does not have to match tRNA anticodon