Unit 1 Topic 3- Gene Expression

Question 1

What does RNA stand for?

Answer 1

Ribonucleic acid

Question 2

What are the 2 stages of gene expression?

Answer 2

Transcription and translation

Question 3

What is RNA made up of?

Answer 3

Nucleotides which consist of a base, a phosphate and a ribose sugar

Question 4

Which bases are present in RNA?

Answer 4

Uracil, adenine, cytosine and guanine

Question 5

Is RNA single stranded or double stranded?

Answer 5

Single stranded

Question 6

What are the 3 types of RNA?

Answer 6

mRNA, tRNA and rRNA

Question 7

What is messenger RNA (mRNA)?

Answer 7

It is transcribed from the DNA in the neucleus and translated into proteins on ribosomes in the cytoplasm (it carries a copy of the DNA code from the neucleus to the ribosome)

Question 8

What is transfer RNA (tRNA) ?

Answer 8

It is found in the cytoplasm and carry a specific amino acid to the ribosome during translation.

Question 9

What is the shape of tRNA?

Answer 9

A clover shape

Question 10

What is ribosomal RNA (rRNA) ?

Answer 10

RNA that combines with proteins to create a ribosome

Question 11

Describe the process of RNA splicing

Answer 11

• Introns are removed from the primary transcript
• exons are joined together to produce a mature transcript

Question 12

Are exons coding or non-coding regions?

Answer 12

Coding regions

Question 13

Are introns coding or non-coding regions?

Answer 13

Non-coding regions

Question 14

What is alternative RNA splicing?

Answer 14

When different mature transcripts are produced due to the difference in sequence of exons

Question 15

How many bases make up a codon?

Answer 15

3

Question 16

Describe the structure of RNA

Answer 16

RNA is a single strand of neuclotides which consist of a phosphate, a ribose sugar and a base which can be adenine, uracil, cytosine or guanine

Question 17

What is the process of transcription?

Answer 17

this process occurs in the neucleus, RNA polymerase moves along the section of DNA and unwinds it, then it adds complimentary RNA neucleotides to the 3’ end of the template strand to create an RNA primary transcript, when the RNA polymerase reaches the terminator at the 5’ end it breaks away from the DNA template strand.

Question 18

what is the process of translation?

Answer 18

mRNA binds to a ribosome at the start codon.
tRNA molecules pick up specific amino acids and line them up according to complimentary base pairing with a section of the mRNA
The ribosome moves along to the next codon and a tRNA brings in the next amino acid.
A peptide bond forms between the two amino acids.
The first tRNA leaves the ribosome.
These steps are repeated until the mRNA stop codon is reached.

Question 19

what is a polypeptide?

Answer 19

a chain of amino acids linked together by peptide bonds