Features Of Genetic Code

Question 1

What 3 features does genetic code have?

Answer 1

Its degenerate, universal and non-overlapping.

Question 2

What is the start codon?

Answer 2

The 3 bases at the start of every gene.

Question 3

What are the start codons in DNA and mRNA?

Answer 3

TAC and AUG.

Question 4

What is the function of the start codon?

Answer 4

It initiates translation and codes for the amino acid methionine.

Question 5

What is the stop codon?

Answer 5

The final triplet of bases in DNA that signals a halt to protein synthesis.

Question 6

What is the function of the stop codon?

Answer 6

To mark the end of a polypeptide chain, causing the ribosomes to detach and stop translation.

Question 7

How many amino acids does the genetic code have to be able to code for?

Answer 7

20

Question 8

How many bases are needed to make enough combinations to code for at least 20 amino acids in DNA?

Answer 8

3 bases.

Question 9

How many combinations is 4^3?

Answer 9

64

Question 10

What does degenerate mean in genetic code?

Answer 10

Each of the 20 amino acids are coded for by more than one triplet of bases (codon).

Question 11

Why is the genetic code being degenerate an advantage?

Answer 11

If a mutation occurs and a base is changed to another, it could still potentially code for the same amino acid.

Question 12

What is a silent mutation?

Answer 12

A mutation that has no effect on the final protein.

Question 13

What does universal mean in genetic code?

Answer 13

The same triplet of bases codes for the same amino acid in all organisms.

Question 14

Why is genetic code being universal an advantage?

Answer 14

It allows genetic engineering to be possible.

Question 15

What does non-overlapping mean in genetic code?

Answer 15

Each base is only part of one triplet that codes for one amino acid, it reads as a discrete unit.

Question 16

Why is genetic code being non-overlapping an advantage?

Answer 16

If a mutation occurs it will only affect one codon and one amino acid, having a small impact on the final protein structure.

Question 17

What are introns?

Answer 17

Sections of DNA that don’t code for amino acids.

Question 18

How much of DNA is made of introns?

Answer 18

About 98%.

Question 19

Where are introns found?

Answer 19

In eukaryotic DNA but not prokaryotic DNA or mRNA.

Question 20

What happens to introns in mRNA?

Answer 20

They get spliced out.

Question 21

What are exons?

Answer 21

Sections of DNA that do code for amino acids.

Question 22

What is a genome?

Answer 22

An organism’s complete set of DNA in one cell.

Question 23

What is the proteome?

Answer 23

The full range of proteins in one cell.

Question 24

What is the difference between the genome of the cell and the proteome of the cell?

Answer 24

The genome should never change, whereas the proteome of the cell is constantly changing depending on the proteins currently needed.

Question 25

What widely varies between organisms?

Answer 25

The genome.

Question 26

How many base pairs does DNA have?

Answer 26

3 billion.

Question 27

How many base pairs does bacteria have?

Answer 27

600,000