Transcription and Translation

Question 1

What is transcription?

Answer 1

The process of copying a DNA sequence into mRNA

Question 2

What is translation?

Answer 2

The process of converting mRNA into a polypeptide chain (protein)

Question 3

Where does transcription occur in a eukaryotic cell?

Answer 3

In the nucleus

Question 4

What is the role of RNA polymerase?

Answer 4

To synthesize mRNA from a DNA template.

Question 5

What are the three types of RNA?

Answer 5

mRNA (messenger RNA), tRNA (transfer RNA), rRNA (ribosomal RNA)

Question 6

Which RNA carries the genetic code from DNA to the ribosome?

Answer 6

mRNA

Question 7

What is a codon?

Answer 7

A sequence of three mRNA nucleotides that codes for an amino acid

Question 8

What are the base-pairing rules during transcription?

Answer 8

A pairs with U, and C pairs with G.

Question 9

What is the difference between DNA and RNA bases?

Answer 9

RNA has uracil (U) instead of thymine (T)

Question 10

What is a gene?

Answer 10

A segment of DNA that codes for a specific protein or RNA molecule

Question 11

What is the template strand in transcription?

Answer 11

The DNA strand used by RNA polymerase to synthesize mRNA

Question 12

What is the complementary mRNA sequence for this DNA strand: TACGGA?

Answer 12

AUGCCU

Question 13

What happens during the initiation phase of transcription?

Answer 13

RNA polymerase binds to the promoter region of a gene.

Question 14

What role does the promoter region play in transcription?

Answer 14

It signals where RNA polymerase should start transcribing

Question 15

How does RNA polymerase recognize where to bind?

Answer 15

By recognizing specific sequences in the promoter region

Question 16

What occurs during elongation in transcription?

Answer 16

RNA polymerase adds complementary RNA nucleotides to the growing mRNA strand

Question 17

What is the function of the terminator sequence?

Answer 17

It signals RNA polymerase to stop transcription

Question 18

What is pre-mRNA, and how is it processed in eukaryotes?

Answer 18

Pre-mRNA is the initial RNA transcript that is spliced and modified to form mature mRNA

Question 19

Why is the 5’ cap added to mRNA?

Answer 19

To protect mRNA from degradation and help ribosomes recognize it for translation

Question 20

What is the function of the poly-A tail?

Answer 20

To stabilize mRNA and facilitate its export from the nucleus

Question 21

What is the role of introns in mRNA processing?

Answer 21

Introns are removed because they are non-coding regions

Question 22

What are exons?

Answer 22

Coding regions of mRNA that are spliced together

Question 23

What enzyme removes introns during mRNA processing?

Answer 23

Spliceosome

Question 24

What is the difference between the sense and antisense strands of DNA?

Answer 24

The sense strand matches the mRNA sequence (except T for U), while the antisense strand serves as the template

Question 25

How is transcription regulated?

Answer 25

By transcription factors and the availability of promoter sequences

Question 26

Where does translation occur?

Answer 26

In the cytoplasm, at the ribosome

Question 27

What is the role of tRNA?

Answer 27

To bring the correct amino acids to the ribosome based on the codon sequence

Question 28

What is an anticodon?

Answer 28

A sequence of three nucleotides on tRNA that pairs with a codon on mRNA

Question 29

What is the start codon, and what does it code for?

Answer 29

AUG; it codes for methionine

Question 30

What are stop codons?

Answer 30

a sequence of 3 nucleotides in DNA or mRNA that holts the protein synthesis

Question 31

What happens during the initiation phase of translation?

Answer 31

The ribosome assembles around the mRNA and the first tRNA binds to the start codon

Question 32

What occurs during elongation in translation?

Answer 32

tRNA brings amino acids to the ribosome, and peptide bonds form between them

Question 33

What happens during termination in translation?

Answer 33

A stop codon is reached, and the ribosome releases the polypeptide

Question 34

What is the role of the ribosome in translation?

Answer 34

To facilitate the assembly of amino acids into a protein

Question 35

How many binding sites are in a ribosome, and what are they called?

Answer 35

Three: A (aminoacyl), P (peptidyl), and E (exit) sites

Question 36

What molecule provides energy for translation?

Answer 36

GTP

Question 37

What is the role of the release factor in translation?

Answer 37

It binds to the stop codon and triggers the release of the polypeptide

Question 38

What is the relationship between the codon and anticodon?

Answer 38

The codon on mRNA pairs with the complementary anticodon on tRNA

Question 39

How many different codons exist?

Answer 39

64 codons (61 for amino acids and 3 stop codons)

Question 40

What determines the sequence of amino acids in a protein?

Answer 40

The sequence of codons in mRNA

Question 41

Why is the genetic code described as “universal”?

Answer 41

It is used by almost all living organisms

Question 42

Why is the genetic code considered “degenerate”?

Answer 42

Multiple codons can code for the same amino acid

Question 43

How do mutations affect transcription and translation?

Answer 43

Mutations can alter the mRNA sequence and, consequently, the protein structure

Question 44

What is a silent mutation?

Answer 44

A mutation that changes a codon but not the amino acid it codes for.

Question 45

What is a missense mutation?

Answer 45

A mutation that changes a codon to one that codes for a different amino acid

Question 46

What is a nonsense mutation?

Answer 46

A mutation that changes a codon to a stop codon, truncating the protein

Question 47

What is a frameshift mutation?

Answer 47

An insertion or deletion of bases that shifts the reading frame

Question 48

What is the role of ribosomal RNA (rRNA)?

Answer 48

It forms part of the ribosome and helps catalyse peptide bond formation

Question 49

What is polycistronic mRNA, and where is it found?

Answer 49

mRNA that codes for multiple proteins; found in prokaryotes

Question 50

Why are transcription and translation coupled in prokaryotes?

Answer 50

They both occur in the cytoplasm, allowing translation to begin before transcription finishes