DNA 1.2- Protein Synthesis

Question 1

What is a gene, and what does it consist of?

Answer 1

A gene consists of a unique sequence of nucleotides that codes for a functional protein or an RNA molecule

Question 2

What is the primary function of a gene in eukaryotes?

Answer 2

To determine the set of proteins and functional RNAs it contains

Question 3

Describe the characteristics of ribonucleic acid (RNA)

Answer 3

RNA is single-stranded, has Uracil bases instead of Thymine, and has ribose sugar.

Question 4

How many types of RNA are there and what are they?

Answer 4

There are three types: mRNA (messenger RNA), tRNA (transfer RNA), and rRNA (ribosomal RNA)

Question 5

What is the function of mRNA?

Answer 5

Messenger RNA is a complimentary copy of the DNA template strand and carries the code to the ribosomes in the cytoplasm.

Question 6

What is the function of tRNA?

Answer 6

Transfer RNA carries an amino acid during translation. One end of the tRNA attaches to a specific amino acid and the other end has an anticodon which attaches to a codon on the mRNA.

Question 7

What is the function of rRNA?

Answer 7

Ribosomes are made up of rRNA and protein molecules. Ribosomes move along the mRNA, translating the mRNA code into a sequence of amino acids in a polypeptide.

Question 8

Where can mRNA be found

Answer 8

In the nucleus, cytosol, and ribosomes.

Question 9

Where can tRNA be found?

2 marks

Answer 9

In the cytoplasm and ribosomes.

Question 10

Where can rRNA be found?

2 marks

Answer 10

In the ribosomes and the cytoplasm.

Question 11

Differentiate between exons and introns in eukaryotic genes

Answer 11

Exons are coding segments of DNA transcribed into mRNA and translated into a polypeptide. Introns are non-coding segments transcribed into an RNA molecule but do not code for proteins.

Question 12

Do prokaryotic cells contain introns in their DNA?

1 mark

Answer 12

No, prokaryotic cell DNA does not contain introns.

Question 13

What is the role of introns in eukaryotic gene expression?

Answer 13

Introns code for ribosomal RNA (rRNA, involved in translation), transfer RNA (tRNA, involved in translation), micro RNA (miRNA, involved in the regulation of gene expression)

Question 14

What are the two main processes involved in protein synthesis?

four marks

Answer 14

Protein synthesis involves the transcription of a gene into messenger RNA (mRNA) and then the translation of mRNA into an amino acid sequence at the ribosomes

Question 15

Where does transcription occur in eukaryotic cells?

Answer 15

Transcription occurs in the nucleus of eukaryotic cells.

Question 16

In which cellular compartment does protein synthesis take place in prokaryotes?

Answer 16

The Cytosol

Question 17

What is the process of transcription?

involves DNA

Answer 17

Transcription is the process of a DNA molecule being read and rewritten into an mRNA molecule.

Question 18

How are introns and exons processed after transcription?

Answer 18

Introns are spliced out, and exons are joined via ligase enzyme in post-transcriptional processing.

Question 20

What is the relationship between mRNA codons and the DNA template strand, and how do tRNA anticodons interact with mRNA codons during protein synthesis?

two marks

Answer 20

The mRNA codon is a complementary copy of the DNA template strand, and tRNA anticodons bind to mRNA codons.