Ch8 exam 2

Codon

The basic unit of the genetic code; one of the 64 nucleotide triplets that code for an amino acid or stop sequence.

Anticodon

The nucleotide sequence of transfer RNA that forms complementary base pairs with a codon sequence on messenger RNA

What enzymes attach AA to their corresponding tRNA

aminoacyl tRNA synthatase

Aminoacyl tRNA synthases

An enzyme that joins a specific amino acid to a tRNA molecule carrying the correct anticodon sequence, using ATP.

What do Eukaryotic cells have on their ends of their mRNA that prokaryotic cells do not have

5’ 7methylguanosine cap, 3’- poly A tail

What the sequence that is prior to the initiation site that correctly aligns bacterial mRNAs on ribosomes

Shine-dalgrarno sequence

What do eukaryotic ribosomes need to bind to mRNA

5’- 7methylguanosine cap

three stages of translation

initiation, elongation, and termination

What are internal ribosome entry sites

Nucleotide sequences in the 5′ untranslated regions of some mRNAs that enable translation initiation independent of the 5′ 7-methylguanosine cap.

What are the 3 sites of translation

A, P, E

What is the A site, what does it do

Aminoacyl, The site in which the aminoacyl-tRNAs enter the ribosome during translation elongation.

What is the P site, what does it do

Peptidyl, The site in which the tRNA attached to the elongating polypeptide is located during translation of an mRNA.

What is the E site, what does it do

Exit, The site on the large ribosomal subunit through which tRNAs exit after delivering amino acids to the ribosome during translation.

What are chaperones

A protein that facilitates the correct folding or assembly of other proteins.

What are amyloids

A fibrous aggregate of misfolded protein.

Protein disulfide isomerase (PDI), where does it function?

An enzyme that catalyzes the formation and breakage of disulfide (S–S) linkages, in endoplasmic reticulum

Peptidyl prolyl isomerase (PPI)

An enzyme that facilitates protein folding by catalyzing the cis-trans isomerization of prolyl peptide bonds, compared to other amino acid

What is glycosylation

The addition of sugar to a protein.

glycosylphosphatidylinositol (or GPI) anchors

A glycolipid containing phosphatidylinositol that anchors proteins to the external face of the plasma membrane.

What are the 3 types of lipid addition to proteins

N-myrisoylation, Prenylation, Palmitoylation

What is N-myristoylation

The addition of myristic acid (a 14-carbon fatty acid) to the N-terminal glycine residue of a polypeptide chain.

What is Prenylation

The addition of specific types of lipids (prenyl groups) to C-terminal cysteine residues of a polypeptide chain.

What is Palmitoylation

The addition of palmitic acid (a 16-carbon fatty acid) to cysteine residues of a polypeptide chain.

G proteins

A family of cell signaling proteins, cell regulation, regulated by guanine nucleotide binding.

guanine nucleotide exchange factors (GEFs)?

A protein that acts on small G proteins to stimulate the exchange of bound GDP for GTP. inactive to active

GTPase-activating protein (GAP)

A protein that stimulates GTP hydrolysis by the small GTP-binding proteins, ative to inactive

Allosteric binding

Binding of a molecule at a site other than the active site that changes enzyme activity by altering protein conformation.

Protein kinases

what AAs?

An enzyme that catalyzes the covalent linkage of a phosphate from ATP to, most often, a serine, threonine, or tyrosine residue of a protein substrate.

What are phosphatases

Enzymes that remove phosphates from proteins

What is a protein phosphatases

An enzyme that reverses the action of protein kinases by removing phosphate groups from phosphorylated amino acid residues.