Structure and Replication of DNA (2)

Question 1

What is DNA composed of?

Answer 1

Genes

Question 2

What does DNA code for?

Answer 2

The production of proteins

Question 3

Why is it important for none of the information to be lost from DNA?

Answer 3

It is very important that all of the genetic information remains as the proteins have to be replicated exactly otherwise the protein will not perform its function and the faulty information will be transferred to the next generations

Question 4

Why must DNA replication take place before a cell divides?

Answer 4

This is done to ensure that two identical copies of the DNA are produced and that each daughter cell receives a full set of chromosomes

Question 5

How many chromosomes do gametes contain compared to body cells?

Answer 5

Gametes contain half the mass of DNA when compared to body cells with red blood cells being an exception as they don’t have a nucleus.

Question 6

What structure does DNA have?

Answer 6

Has a double stranded helix structure

Question 7

What is the double helix composed of?

Answer 7

It is composed of two strands/chains of nucleotides.

Question 8

What joins nucleotides together?

Answer 8

The nucleotides are joined together by strong deoxyribose sugar-phosphate bonds.

Question 9

Why do the sugar and phosphates join?

Answer 9

To form the backbone.

Question 10

What is a nucleotide composed of?

Answer 10

A phosphate, base and a sugar (deoxyribose in DNA)

Question 11

How can the carbons in the deoxyribose sugar be numbered?

Answer 11

The end which connects to the phosphate is the 5’ end and the opposite of it is the 3’ end and is where the the other nucleotide would connect via the sugar phosphate bond.

Question 12

What 4 different bases does DNA have?

Answer 12

Adenine, Thymine, Guanine and Cytosine meaning there are four different kinds of nucleotides.

Question 13

In which specific manner do the bases form pairs?

Answer 13

Adenine - Thymine
Guanine - Cytosine

This is known as complementary base pairing.

Question 14

What holds the base pairs?

Answer 14

Hydrogen Bonds.

Question 15

What makes the 3’ end on the deoxyribose sugar distinct?

Answer 15

The chain is only able to grow by adding nucleotides to the 3’ end.

Question 16

What is the arrangement of 2 strands with a sugar phosphate backbone running in opposite directions called?

Answer 16

Antiparallel.

Question 17

What is a group of 3 bases on a DNA strand called?

Answer 17

Triplet.

Question 18

What does a triplet of bases code for?

Answer 18

Amino acids.

Question 19

What is DNA except for the fact that it carries all the genetic data?

Answer 19

It is a molecule of inheritance that has the ability to replicate itself.

Question 20

What must be present for DNA to replicate?

Answer 20

DNA (template)

Primers

Enzymes (polymerase and ligase)

Four different nucleotide types

ATP (energy)

Question 21

Prior to cell division DNA is replicated by?

Answer 21

DNA Polymerase.

Question 22

What does DNA Polymerase need before it can start replicating?

Answer 22

Primers

Question 23

What is a primer?

Answer 23

A primer is a a short strand of nucleotides which bind to the 3’ end of the DNA template, allowing DNA polymerase to add nucleotides.

Question 24

What does the process of DNA replication produce?

Answer 24

Two identical DNA molecules with each double helix containing a newly synthesised strand and an original strand ensuring that the daughter cells have the same genetic information.