Unit 1 DNA Structure and Replication

Question 1

Give 3 descriptions of the structure of a DNA molecule

Answer 1

Double stranded
Double helix
Antiparrallel

Question 2

Name the units that make up a DNA molecule

Answer 2

Deoxyribose sugar
Phosphate group
Nitrogenous base

Question 3

What are the 4 DNA bases

Answer 3

Adenine and Thymine

Guanine and Cytosine

Question 4

What’s the bonds between bases

Answer 4

Hydrogen bonds

Question 5

What do we call the side chains of the DNA molecule

Answer 5

Sugar phosphate backbone

Question 6

Plants cell and the types of DNA

Answer 6

Nucleus - linear DNA
Mitochondria- circular chromosomes (DNA)
Chloroplast- circular chromosomes (DNA)

Question 7

What is a eukaryotic cell

Answer 7

Is a cell with a true membrane bond nucleus

Question 8

What are 3 examples of eukaryotic cells

Answer 8

Plants, animals, fungi

Question 9

How is the DNA organised in the nucleus of eukaryotic cells

Answer 9

In the nucleus cell DNA is linear

Question 10

Which two parts of the eukaryotic cells have circular chromosomes

Answer 10

Mictochondria

Chloroplasts

Question 11

Why is yeast sometimes called a special eukaryotite

Answer 11

As it has plasmids

Question 12

What two parts of bacterial cells are composed of DNA

Answer 12

Plasmids - which contain circular chromosomes

And the main circular chromosome

Question 13

What is a prokaryotic cell

Answer 13

Is a cell with no distinct nucleus

Question 14

Give two examples of prokaryotic cells

Answer 14

Bacteria and archae

Question 15

What is the function of DNA

Answer 15

To store all the genetic information an organism need to develop, function and reproduce

Question 16

When does DNA replication need to occur in cells

Answer 16

For growth and repair of tissues or the replacement of old or worn cells

Question 17

Name 5 things required for DNA required for DNA replication in cells

Answer 17

DNA (to act as a template)
Primers 
Free nucleotides 
Enzymes 
ATP

Question 18

What is a primer

Answer 18

A short strand of nucleotides

Question 19

What has to happen to the DNA helix before replication can begin

Answer 19

DNA helix had to unwind

Question 20

What do we call the part where the helix unwinds

Answer 20

Replication fork

Question 21

What name do we give to the 2 original strands

Answer 21

Template strands

Question 22

What do we called the part which is formed continuously

Answer 22

Leading strand

Question 23

What do we called the short nucleotide strands

Answer 23

Primers

Question 24

What is the strand called that forms discontinously

Answer 24

Lagging strand

Question 25

What do we call the enzyme that seals fragments together

Answer 25

DNA ligase

Question 26

What does PCR

Answer 26

Polymerase chain reaction

Question 27

Why can the leading strand be synthesised continuously

Answer 27

The DNA can be synthesised continuously as the DNA polymerase brings about information between the primer and nucleotides and the individual nucleotides 3’ end going the right way

Question 28

How is the lagging strand formed

Answer 28

Replication of the DNA
Template strand on the 5’ end is discontinuous
Has to be replicated in fragments starting from the 3’ end
DNA polymerase binds nucleotides together
DNA ligase joins fragments together

Question 29

Stages of PCR

Answer 29

• DNA is heated to 92° and 98° to separate DNA stands
• It is the coolest to between 50°-65° to allow primers to bind to the target sequence
• It is the heated to 70°-80° for heat resistant polymerase to replicate the region of DBA by adding nucleotides to the 3’ end

Question 30

List 3 applications of PCR

Answer 30

Diagnosing genetic diseases/ disorders
To solve a crime/ build DNA profiles
To solve paternity disputes

Question 31

What characteristic used in PCR prevents it from becoming denatures during the process

Answer 31

Heat resistant