Topic 4A - DNA, RNA And Proteinsynthesis

Question 1

What is a gene

Answer 1

A sequence of DNA that codes for either a polypeptide or a functional RNA

Question 2

What is an intron

Answer 2

A segment of DNA or RNA molecule which doesn’t code for amino acids

Question 3

What is an exon

Answer 3

The coding bit of a gene that codes for an amino acid

Question 4

What are the 3 components of nucleotides

Answer 4

A pentose sugar, a phosphate group, an organic base

Question 5

Describe the role of DNA

Answer 5

Carries genetic information, determines our inherited characteristics

Question 6

Describe the structure of RNA

Answer 6

Ribose sugar
Phosphate group
A, C, U, G organic base
Single stranded

Question 7

Describe the role of RNA

Answer 7

Transfers genetic information from DNA to ribosomes for Proteinsynthesis

Question 8

What is the genetic code

Answer 8

The order of bases on DNA. Consists of codons.

Question 9

Identify 3 features of the genetic code

Answer 9

Non-overlapping = each triplet is only read once
Degenerate = more than one triplet codes for the same amino acid
Universal = same bases and sequences used by all species

Question 10

What is a gene

Answer 10

A sequence of bases on a DNA molecule that codes for a specific sequence of amino acids to make a polypeptide.

Question 11

What is a locus

Answer 11

The fixed position on a DNA molecule occupied by a gene

Question 12

What is a locus

Answer 12

The fixed position on a DNA molecule occupied by a gene

Question 13

What is an allele

Answer 13

Different versions of the same gene

Question 14

What is the genome

Answer 14

The complete set of genetic information contained in the cells of an organism

Question 15

What is the proteome

Answer 15

The complete set of of proteins that can be produced by a cell

Question 16

Describe the structure of mRNA

Answer 16

A long single strand. It’s base sequence is complementary to the DNA it was transcribed from.

Question 17

Describe the structure of tRNA

Answer 17

Single strand of nucelotides folded into a clover shape. On one end is an anti codon and on the opposite end is an amino acid binding site

Question 18

What is produced by transcription

Answer 18

mRNA

Question 19

Where does transcription take place

Answer 19

In the nucleus

Question 20

Outline the process of transcription

Answer 20

DNA uncoils into 2 strands with exposed bases. One used as a template.
Free nucleotides line up next to their complementary bases, and are joined together by RNA polymerase

Question 21

What happens to mRNA after transcription

Answer 21

Must be spliced to leave the nucleus

Question 22

What is produced by translation

Answer 22

Proteins

Question 23

Where does translation take place

Answer 23

In cytoplasm on the ribosomes

Question 24

Outline the process of translation

Answer 24

The anticodon of tRNA attaches to complementary bases on the mRNA
Amino acids bonded to tRNA to form peptide bonds, continuing to form a polypeptide chain until a stop codon is reached
Process requires ATP

Question 25

What is the genetic code?

Answer 25

Sequence of base triplets in mRNA that code for a specific amino acid
(Base triplets dont share their bases - the code is non overlapping)

Question 26

How can code be degenerate?

Answer 26

More possible combinations of triplets than there are amino acids

Question 27

How can genetic code be universal ?

Answer 27

Same specific base triplets code for the same amino acids in all living things