4 DNA, genes and protein synthesis

Question 1

What is a gene?

Answer 1

A section of DNA that contains coded information for making polypeptides and RNA

Question 2

What is a locus?

Answer 2

A section of DNA located at a particular position

Question 3

How many bases code for one Amino Acid

Answer 3

3

Question 4

The term used to describe when an amino acid is coded for by more than one triplet

Answer 4

Degenerate coding

Question 5

Two features of the genetic code?

Answer 5

• Non-Overlapping

- Universal

Question 6

What are exons?

Answer 6

Coding sequences

Question 7

What are introns?

Answer 7

Non-coding sequences

Question 8

Homologous pair

Answer 8

Two chromosomes that carry the same genes

Question 9

Allele

Answer 9

An alternative form of a gene

Question 10

Give examples of different alleles

Answer 10

ones for eye colour, hair colour, blood group etc.

Question 11

Mutation

Answer 11

Changes in the base sequences that results in a different AA being > diff. polypeptide > protein.

Question 12

Genome

Answer 12

Complete set of genes in a cell

Question 13

The function of Messenger RNA

Answer 13

Transfers DNA from nucleus to cytoplasm.

Question 14

What is each nucleotide composed of (three)

Answer 14

• Pentose sugar
• One of the organic bases
• Phosphate group

Question 15

Structure of tRNA

Answer 15

• Small molecule
• Single-stranded chain folded into a clover leaf shape
• One end of the chain extends beyond the other so that the AA can easily attatch

Question 16

Anticodon

Answer 16

Sequence of three opposing organic bases of those at the extended chain

Question 17

In RNA, what does adenine pair up with?

Answer 17

Uracil

Question 18

Transcription is the process of making what?

Answer 18

pre-mRNA

Question 19

Process of Transcription

Answer 19

• Enzyme causes two strands of DNA to seperate to expose the bases
• The bases on one side of the DNA pair with its complemetary base that is within the nucleotide pool
• RNA polymerase moves along the strand and joins them together to form pre mRNA

Question 20

What happens when the RNA polymerase reaches a stop codon?

Answer 20

pre-mRNA detatches and the process is complete

Question 21

In eukaryotic cells what must occur to form mRNA?

Answer 21

Splicing

Question 22

What is splicing?

Answer 22

Formation of mRNA. Introns are removed from the pre-mRNA so that only exons are left.

Question 23

How does mRNA exit the nucleus?

Answer 23

Through the nucleus pore