Translation of mRNA

These flashcards cover key concepts related to the translation of mRNA, focusing on processes, historical figures, and significant molecular components in protein synthesis.

What is the primary function of messenger RNA (mRNA)?

To encode the production of cellular proteins.

Who first proposed the relationship between genes and protein production?

Archibald Garrod.

What is alkaptonuria caused by?

A missing enzyme, homogentisic acid oxidase.

What was the one gene-one enzyme hypothesis proposed by Beadle and Tatum?

One gene codes for one enzyme.

What is the start codon for both prokaryotic and eukaryotic translation?

AUG, which codes for methionine.

What are the three stages of translation?

Initiation, Elongation, Termination.

What is the role of tRNA during translation?

Transfer specific amino acids to the growing polypeptide chain based on the codon sequence of mRNA.

What is the purpose of the Shine-Dalgarno sequence in prokaryotic translation?

To facilitate the binding of mRNA to the ribosomal subunit.

What is a key feature of the genetic code?

It is degenerate, meaning that multiple codons can encode the same amino acid.

What factors help initiate translation in eukaryotes?

eIFs (Eukaryotic Initiation Factors) such as eIF4F and eIF2.

What happens during the termination stage of translation?

A release factor binds to the stop codon, triggering the release of the polypeptide.

What are the four levels of protein structure?

Primary, Secondary, Tertiary, and Quaternary.

What is the wobble hypothesis?

It explains how tRNA can pair with more than one codon due to flexibility in the third position of the codon.

What is the role of peptidyl transferase during translation?

It catalyzes the formation of peptide bonds between amino acids.

What are posttranslational modifications?

Events such as phosphorylation, ubiquitination, and proteolytic cleavage that modify proteins after translation.

How do eukaryotic ribosomes differ from bacterial ribosomes?

Eukaryotic ribosomes are larger (80S) and more complex than bacterial ribosomes (70S).

An inborn error of metabolism is cause by

A mutation in a gene that causes an enzyme to be inactive

The reason why Beadle and Tatum observed four different catergoies of mutants that could not grow on media without methionine is because

Four different enzymes are involved in a pathway for methionine biosynthesis

What is the genetic code?

The relationship between a three-base codon sequences and an amino acid or the end of translation

The reading frame begins at a _____ and is read_____

start codon and is read in groups of three bases.

The fourth codon in an mRNA is GGG, which specifies glycine. Assuming that no amino acids are removed from the polypeptide, which of the following statements is correct?

The fourth amino acid from the N-terminus is glycine

A type of secondary structure found in proteins is

Both alpha helix and beta sheet are secondary structures in proteins

Let’s suppose a researcher mixed together nucleotides with the following percentages of bases: 30% G, 30% C, and 40% A. If RNA was made via polynucleotide phosphorylase, What percentage of the codons would be 5’-GGC-3’

2.7%

In the triplet-binding assay carried out by Nirenberg and leder, and an RNA triplet composed of three bases was able to cause the

Binding of a tRNA carrying the appropriate amino acid

if a tRNA has an anticodon with the dequence 3’-GAC-5’, which amino acid does it carry?

Leucine

The anticodon of a tRNA is located in the

Loop of the second stem-loop

An enzyme known as ___attaches an amino acid to the ____ of a tRNA,thereby producting____

aminoacyl-tRNA synthetase,3’ single-stranded region of the acceptor stem, a charged tRNA

Each ribosomal subunit is composed of

Multiple proteins and rRNA

the sits(s) on a ribosome where tRNA molecules may be located include

The A, P, and E sites

During the initiation stage of translation in bacteria, which of the following events occur(s)

IF1 and IF3 bind to the 30s subunit,The mRNA binds to the 30S subunit and tRNA (fMet) binds to the start codon in the mRNA,IF2 hydrolyzes its GTP and is relased;the 50S subunit binds to the 30S subunit

Kozak’s rules determine

the choice of the start codon in complex eukaryotes