Translation

Question 1

What are the two subunits of ribosomes in eukaryotes?

Answer 1

Small (40S) and large (60S) subunits

The intact ribosome in eukaryotes is referred to as 80S.

Question 2

What is the role of ribosomes?

Answer 2

Bind to mRNA and read it 3 base pairs at a time

This process is essential for protein synthesis.

Question 3

What is the structure of Transfer RNA (tRNA)?

Answer 3

Small, single-stranded RNA with a cloverleaf shape

This structure is crucial for its function in protein synthesis.

Question 4

What is the role of tRNA?

Answer 4

Recognizes codons on mRNA with complimentary anticodon and brings the appropriate amino acid

Each tRNA carries only one specific amino acid.

Question 5

How many tRNAs are required for protein synthesis?

Answer 5

20 tRNAs

Each tRNA corresponds to one specific amino acid.

Question 6

What is the redundancy in the genetic code?

Answer 6

Some amino acids are coded for by more than one triplet sequence

This redundancy helps to mitigate the effects of mutations.

Question 7

How many combinations of nucleotide triplets are possible if three nucleotides code for an amino acid?

Answer 7

64 combinations

This is calculated as 4^3, where 4 represents the four nitrogenous bases.

Question 8

Fill in the blank: There are ______ nitrogenous bases in nucleotides.

Answer 8

4

The four nitrogenous bases are adenine, thymine, cytosine, and guanine.

Question 9

How many combinations of nucleotide triplets are possible if one nucleotide codes for an amino acid?

Answer 9

4 combinations

This is calculated as 4^1.

Question 10

How many combinations of nucleotide triplets are possible if two nucleotides code for an amino acid?

Answer 10

16 combinations

This is calculated as 4^2.

Question 11

True or False: Each tRNA can carry multiple amino acids.

Answer 11

False

Each tRNA carries only one specific amino acid.

Question 12

What is the role of the small RNA subunit in translation?

Answer 12

Recognizes the 5’ guanine cap and binds to mRNA

Question 13

Where does the small RNA position itself during translation initiation?

Answer 13

At the start codon AUG

Question 14

What amino acid does tRNA carry during the initiation phase of translation?

Answer 14

Methionine

Question 15

What happens after the tRNA binds to the mRNA complex?

Answer 15

The large subunit clamps into the complex

Question 16

What is sandwiched between the small and large RNA subunits during translation?

Answer 16

mRNA

Question 17

In which direction do ribosomes read mRNA?

Answer 17

5’ to 3’

Question 18

Fill in the blank: The next _______ codon is exposed in the A (AMINO) site during elongation.

Answer 18

mRNA

Question 19

What forms between adjacent amino acids during elongation?

Answer 19

Peptide bond

Question 20

What happens to the tRNAs that are released during translation?

Answer 20

They can be recharged with amino acids

Question 21

What sites are involved in the process of translation?

Answer 21

• P site
• A site

Question 22

True or False: The ribosome shifts over one codon after forming a peptide bond.

Answer 22

True

Question 23

What is the start codon in mRNA?

Answer 23

AUG

Question 24

What is the sequence of tRNA that corresponds to the mRNA codon AUG?

Answer 24

3’ UAC 5’

Question 25

What is the amino acid sequence formed when AUG is followed by GCA?

Answer 25

Met-Ala

Question 26

During elongation, what does the ribosome add for each codon read?

Answer 26

A new amino acid

Question 27

What happens when the ribosome reaches a stop codon?

Answer 27

Translation ceases and the polypeptide chain is released.

Question 28

What are the three stop codons?

Answer 28

* UGA * VAG * UAA

Question 29

Do stop codons code for an amino acid?

Answer 29

No, they do not code for any amino acid.

Question 30

What is the role of the release factor?

Answer 30

It aids in the release of the polypeptide chain from the ribosome.

Question 31

What happens to the ribosomal subunits after translation ceases?

Answer 31

The two subunits fall off the mRNA.

Question 32

What occurs to the polypeptide chain after it is released from the ribosome?

Answer 32

It is modified and folded into a protein.

Question 33

Where is the newly formed protein targeted within the cell?

Answer 33

To the area of the cell where it is required.

Question 34

Fill in the blank: The large subunit of the ribosome is part of the _______.

Answer 34

[ribosome]

Question 35

Fill in the blank: The small subunit of the ribosome is also part of the _______.

Answer 35

[ribosome]