DNA, Genes and Protein Synthesis

Question 1

What is the name for the position of a gene on a chromosome?

Answer 1

Locus/loci

Question 2

Why is mRNA shorter than pre-mRNA?

Answer 2

Introns have been spliced out

Question 3

Name 3 types of RNA

Answer 3

Messenger RNA (mRNA)
Transfer RNA (tRNA)
Ribosomal RNA (rRNA)

Question 4

Name 4 bases found in RNA

Answer 4

Adenine, guanine, cytosine and uracil

Question 5

What are ribosomes formed from?

Answer 5

Ribosomal RNA and protein

Question 6

Name the parts of a RNA nucleotide

Answer 6

Ribose sugar, phosphate and nitrogenous base

Question 7

What is the function of mRNA

Answer 7

Carry genetic information from DNA in the nucleus to ribosomes in the cytoplasm

Question 8

What similarities do mRNA and tRNA have?

Answer 8

Both single stranded
Both have A, G, C and U bases
Both consist of RNA nucleotides

Question 9

What differences do mRNA and tRNA have?

Answer 9

mRNA is linear, tRNA is folded
tRNA as hydrogen bonds holding the clover leaf shape in place
tRNA has anticodon and amino acid attachment site
tRNA is shorter

Question 10

How many amino acid molecules exist?

Answer 10

20

Question 11

How many bases are there?

Answer 11

5

Thymine, adenine, cytosine, guanine and uracil

Question 12

If one base coded for an amino acid, how many possible sequences would there be?

Answer 12

4

Question 13

If two bases coded for an amino acid, how many possible sequences would there be?

Answer 13

16

Question 14

If three bases coded for an amino acid, how many possible sequences would there be?

Answer 14

64

Question 15

How many bases code for one amino acid?

Answer 15

3

Question 16

What is a triplet of bases called?

Answer 16

Codon

Question 17

Explain what the term degenerate means

Answer 17

Most amino acids are coded for by more than one codon

Question 18

The genetic code is described as being universal. What does this mean?

Answer 18

The same triplet code is used for all amino acids in all organisms

Question 19

The genetic code is described as being non-overlapping. What does this mean?

Answer 19

Each base in the sequence is read only once

Question 20

What are coding sequences called?

Answer 20

Exons

Question 21

What are non-coding sequences called?

Answer 21

Introns

Question 22

How many bases are needed to code for a chain of 8 amino acids?

Answer 22

24

Question 23

What is a gene?

Answer 23

A section of DNA that codes for a polypeptide

Question 24

What is meant by the term genome?

Answer 24

A complete set of genes in a cell

Question 25

What is meant by the term proteome?

Answer 25

The full range of proteins produced by the genome

Question 26

How many different types of tRNA molecules must exist?

Answer 26

64 - one for each of the possible codons

Question 27

What is an advantage of mRNA being broken down quickly?

Answer 27

The correct amount of the protein is synthesised

Question 28

What is the monomer of a protein?

Answer 28

Amino acids

Question 29

Name the two processes in protein synthesis

Answer 29

Transcription | Translation

Question 30

Which process occurs first in protein synthesis?

Answer 30

Transcription

Question 31

What is produced in transcription?

Answer 31

mRNA/pre-mRNA

Question 32

What is produced in translation?

Answer 32

Polypeptide

Question 33

Which enzyme unwinds the DNA helix in transcription?

Answer 33

DNA helicase

Question 34

If the base sequence on the DNA coding strand during transcription is AAGTCGGAT, what is the base sequence on the mRNA strand?

Answer 34

AAGUCGGAU

Question 35

Which enzyme moves along the DNA non-coding/template strand joining RNA nucleotides together to form mRNA?

Answer 35

RNA polymerase

Question 36

What is the role of RNA polymerase in transcription?

Answer 36

Moves along the DNA non-coding/template strand joining RNA nucleotides together to form mRNA

Question 37

If the base sequence of the DNA coding strand in transcription is AATGCTTTC, what is the base sequence on the template/non-coding strand?

Answer 37

TTACGAAAG

Question 38

How does mRNA leave the nucleus?

Answer 38

Via a nuclear pore

Question 39

Where does mRNA attach to in the cytoplasm?

Answer 39

Ribosomes

Question 40

Name the cell organelle involved in translation

Answer 40

Ribosome

Question 41

If a mRNA codon has the base sequence AUC, what would the tRNA anticodon be that attaches to it?

Answer 41

UAG

Question 42

A strand of mRNA has 65 codons but the polypeptide produced has only 63 amino acids. Suggest why.

Answer 42

One codon is the stop codon that does not code for an amino acid