Topic 3 - Gene Expression

Question 1

What regulation controls gene expression?

Answer 1

Transcription and Translation

Question 2

Structure of RNA

Answer 2

Single stranded, with nucleotides

Question 3

Bases in RNA and who they’re paired with

Answer 3

Uracil with Adenine, Guanine with Cytosine

Question 4

Difference in nucleotides between RNA and DNA structure

Answer 4

The bases (uracil instead of thymine), the sugar (ribose instead of deoxyribose)

Question 5

What’s the function of mRNA

Answer 5

Carries a copy of the DNA code from the nucleus to the ribosome

Question 6

What’s the function of rRNA

Answer 6

Along with proteins, it forms the ribosome

Question 7

What’s the function of tRNA

Answer 7

Carries a specific amino acid

Question 8

Primary Transcript of DNA into mRNA

Answer 8

A copy of information is made in the nucleus from a DNA molecule on to a RNA molecules called mRNA

Question 9

First stage of Transcription of DNA Into mRNA

Answer 9

RNA polymerase moves along DNA unwinding a section of the double helix

Question 10

What happens to the sugar phosphate bonds during transcription

Answer 10

They form between adjacent RNA nucleotides

Question 11

What is required for transcription?

Answer 11

ATP and RNA polymerase

Question 12

Complementary Base Pairing takes place during Transcription. What does this mean?

Answer 12

Free nucleotides pair with DNA bases, guanine and cytosine, uracil and adenine

Question 13

What happens in RNA splicing? (To the introns)

Answer 13

The introns of the primary transcript of mRNA are non- coding and are removed

Question 14

What happens in RNA Splicing? (To the Exons)

Answer 14

They are coding regions and are joined together to form mature transcript

Question 15

How is gene expression influenced?

Answer 15

By intra and extra - cellular environmental factors

Question 16

A Polypeptide Chain

Answer 16

A short chain of 6 - 8 amino acids joined together

Question 17

What is mRNA translated into and where is it translated?

Answer 17

It’s translated into a polypeptide chain at a ribosome

Question 18

Why does tRNA fold during transcription?

Answer 18

Due to base pairing to form a triplet anticodon site and an attachment site for a specific amino acid

Question 19

What is mRNA transcribed from?

Answer 19

DNA in the nucleus and translated into proteins by ribosomes in the cytoplasm

Question 20

Introns

Answer 20

Non-coding regions of genes

Question 21

Exons

Answer 21

Coding regions of genes

Question 22

What do triplet codons on mRNA and anticodons translate?

Answer 22

They translate the genetic code into a sequence of amino acids

Question 23

Start codon

Answer 23

The first three bases on a mRNA strand (i.e the first codon)

Question 24

Stop Codon

Answer 24

The last codon

Question 25

What happens when the translation reaches the stop codon?

Answer 25

The ribosome releases the newly synthesised polypeptide chain

Question 26

ATP in Translation

Answer 26

It provides energy for the process

Question 27

What will the sequence of the codons in the mRNA strand determine?

Answer 27

The amino acids in the polypeptide that will be synthesised

Question 28

How do anticodons on tRNA relate to the codons on mRNA?

Answer 28

They are complementary to each other

Question 29

Hydrogen bonds form between..

Answer 29

Bases

Question 30

Peptide bonds form between..

Answer 30

Amino acids

Question 31

Where does transcription take place?

Answer 31

The nucleus

Question 32

Where does translation take place?

Answer 32

Ribosome

Question 33

What happens to a protein after translation?

Answer 33

The protein is modified

Question 34

How is the protein modified after translation?

Answer 34

The cutting and joining of polypeptide chains or by the addition of a carbohydrate or a phosphate group to the final protein molecule

Question 35

Structural similarities with mRNA and tRNA

Answer 35

Both contain the bases A,U,C and G

Question 36

Structural differences with mRNA and tRNA

Answer 36

tRNA is folded, when mRNA is not. tRNA has base pairing, mRNA doesn't. mRNA is single-stranded and tRNA is double-stranded

Question 37

Transcription

Answer 37

Copying of the DNA code onto the mRNA

Question 38

Translation

Answer 38

Converting the information given on the mRNA into a sequence of amino acids

Question 39

Triplet

Answer 39

Sequence of bases specifying one amino acid

Question 40

Codon

Answer 40

Triplet of bases on mRNA

Question 41

Anti-Codon

Answer 41

Triplet of bases on tRNA