Key Area 1.3 Gene expression

Question 1

What is gene expression?

Answer 1

the activation of only certain genes in a cell to produce a particular protein

Question 2

How many types of RNA are there?

Answer 2

3

Question 3

Name the 3 types of RNA.

Answer 3

mRNA- Messanger
rRNA- Ribosomal
tRNA- Transfer

Question 4

What does mRNA do?

Answer 4

copies the code from the DNA molecule and carries it to the ribosomes

Question 5

What does tRNA do?

Answer 5

binds to specific amino acids and transports them to the ribosomes

Question 6

Where is tRNA found?

Answer 6

in the cytoplasm

Question 7

What does rRNA do?

Answer 7

forms a complex with protein molecules to make the ribosome

Question 8

What are the 3 differences between RNA and DNA?

Answer 8

DNA has deoxyribose sugar- RNA has ribose sugar
DNA has thymine (base) - RNA has uracil (base)
DNA is double stranded- RNA is single stranded

Question 9

What makes up an RNA nucleotide?

Answer 9

phosphate, base, ribose sugar

Question 10

What are the 2 stages of Gene Expression (Protein Synthesis) called?

Answer 10

transcription and translation

Question 11

Where does transcription take place?

Answer 11

in the nucleus

Question 12

Where does translation take place?

Answer 12

in the ribosomes

Question 13

What is stage 1 called?

Answer 13

transcription

Question 14

What enzyme is used in Gene Expression?

Answer 14

RNA polymerase

Question 15

What happens during transcription?

Answer 15

RNA polymerase unwinds DNA into 2 strands breaking the hydrogen bonds.
RNA polymerase joins RNA nucleotides with their complimentary bases.
A primary transcript is formed.

Question 16

What is RNA splicing?

Answer 16

When exons (coding regions) are spliced together and introns (non-coding regions) are removed from the primary transcript to form the mature mRNA transcript

Question 17

What pairs with adenine during Gene Expression?

Answer 17

Uracil

Question 18

What is stage 2 of Gene Expression called?

Answer 18

Translation

Question 19

What happens during translation?

Answer 19

The tRNA anticodon is complimentary to mRNA codon. The tRNA binds to a specific amino acid at its attachment site and carries it to the ribosomes.
Stop and start codons make translation stop and start. Peptide bonds form between the amino acids making a polypeptide chain.

Question 20

What do tRNA molecules have?

Answer 20

Anticodon and amino acid attachment site

Question 21

What do rRNA molecules have?

Answer 21

Codon

Question 22

What is alternative RNA splicing?

Answer 22

When different axons are spliced together to code for a different protein. Different mature transcripts are made from the same primary transcript.

Question 23

What bonds form between the amino acids?

Answer 23

peptide bonds

Question 24

What is phenotype?

Answer 24

phenotype is determined by the portions produced as a result of gene expression, it is the outwards appearance of a molecule

Question 25

What is a string of amino acids called?

Answer 25

Polypeptide chain