The pathway of protein synthesis is called-

translation

each 3-base codon recognizes specific __________

amino acids

tRNA does what?

brings amino acids

What is an anti-codon

a sequence of three nucleotides in tRNA that binds to a corresponding in an mRNA sequence

a codon is composed of how many nucleotide bases?

3

Nucleotides in RNA are

uracil (U), adenine (A), guanine (G), and cytosine (C)

nucleotide sequences are always written from-

the 5' end to the 3' end

amino acids are coded by an-

mRNA sequence

What is the mRNA start codon?

AUG

What are the stop codons?

UAG, UGA, UAA

UAG, UGA, and UAA are not amino acids but they are-

termination codons

what are the characteristics of the genetic code?

specificity, universality, degeneracy, nonoverlapping and commaless

what is specificity?

each codon is specific to each amino acid

what is universality?

all mammas have the same genetic code

what is degeneracy?

multiple codons code for the same amino acids (redundant)

what is nonoverlapping and commaless?

codons are read in the same direction, in order, 3 codons at a time

What are the types of mutations?

silent, missense, nonsense, tri-nucleotide repeat expansion, splice site mutations, frameshift mutations

What is a silent mutation?

when a base is altered, but still codes for the same amino acid

What is a missense mutation?

when a base is altered and codes for a different amino acid

What is a nonsense mutation?

when a base is altered and codes for a termination codon

Which mutations can alter the amount or structure of the protein produced by translation?

trinucleotide repeat expansion, splice site, and frameshift

What is trinucleotide repeat expansion?

occurs when a sequence of 3 bases that is repeated in tandem will become amplified in number, which results in too many copies of the triplet

What is splice site mutation?

mutations that can alter how introns are removed from pre-mRNA. produce aberrant proteins

What is a frameshift mutation?

when 1 or 2 nucleotides are deleted/added to the coding region of a sequence. alters the reading frame.

what components are required for translation?

all amino acids are found in the finished product, mRNA to be translated, tRNA, functional ribosomes, energy sources, enzymes, and protein factors for initiation, elongation, and termination.

what is the function of tRNA?

carries a specific mRNA

How many species of tRNA are there in humans?

50

Where is the amino acid attachment site of tRNA?

3' end

What does the anticodon of tRNA do?

a three-base nucleotide sequence that recognizes a certain codon on the mRNA

What are aminoacyl-tRNA synthetases?

a group of enzymes that are required for the attachment of amino acids to their corresponding tRNA

Ribosomes consists of how many subunits?

2 (60S and 40S to form 80S) (weird ass math)

The large subunit does what

catalyzes the formation of peptide bonds that link amino acid residues in a protein

The small subunit does what

binds mRNA and is responsible for the accuracy of translation by ensuring correct base-paring between codons in mRNA and the anticodon of the tRNA

What happens at the A site?

binds an incoming aminoacyl tRNA as directed by the codon currently occupying the site (elongation)

What happens at the P site?

a peptide is bound between the amino acids

What happens at the E site?

occupied by the empty tRNA and exits the ribosome

RER associated ribosomes synthesize proteins that can become integrated into the-

plasma, ER, Golgi membranes, lysosomes

cytosolic ribosomes synthesize proteins that are needed in-

the cytosol, nucleus, mitochondria, and peroxisomes

what factors are needed for translation (protein synthesis)

initiation, elongation, and termination

cleavage of ______________________ is required for the addition of one amino acid to the growing polypeptide chain

4 high energy bonds

mRNA is translated from the _____end to the ______ end

5',3'

Proteins are synthesized from the ____________ terminal to its ___________ terminal end

amino, carboxyl

What does a polyribosome consist of?

several ribosomes simultaneously translating one mRNA

elF-2 needs to be ______________ to activate

dephosphorylated