DNA and the Genome: Key Areas 1.1 - 1.2

Question 1

What three structures make up a DNA nucleotide?

Answer 1

Phosphate, Deoxyribose sugar and base

Question 2

In a nucleotide what are attached to the
Carbon 1 base -
Carbon 5 base -

Answer 2

Carbon 1 base - base

Carbon 5 base - phosphate

Question 3

Describe the structure of the DNA Double Helix

Answer 3

Strong chemical bonds between the phosphate and carbon 3 of deoxyribose. Held by hydrogen bonds and have an antiparallel structure. Also have complementary base pairs.

Question 4

The 4 DNA bases and their complementary pairs

Answer 4

Adenine with thymine

Guanine with cytosine

Question 5

How are nucleotides joined together?

Answer 5

Strong chemical bonds

Question 6

How are the 2 DNA strands held together?

Answer 6

Weak hydrogen bonds

Question 7

Name the three main domains and examples of organisms

Answer 7

Eukaryotes - Plant, animal and fungi cells
Bacteria - E.coli
Archaea - Cells that live in extreme conditions

Question 8

Where are linear chromosomes found?

Answer 8

In the nucleus of Eukaryotes

Question 9

Where are circular chromosomes found?

Answer 9

In the mitochondria and chloroplast of eukaryotes cells but it can also be found in prokaryotes cells

Question 10

Describe the packaging in linear chromosomes?

Answer 10

The DNA is wrapped around bundles of histone protein

Question 11

What are the 4 stages involved in Polymerase Chain Reaction (PCR)?

Answer 11

1. DNA is Heated between 92 and 98c* to separate the DNA strands
2. Its then Cooled to 50 and 65* to allow primers to bind to a specific target sequence
3. PCR uses primers which are complementary to a specific target sequence
4. Then heated from 70 to 80* for heat-tolerant DNA polymerase to replicate

Question 12

Why must heat tolerant DNA polymerase be used in PCR?

Answer 12

So that it is not denatured by the temperature used in the first step

Question 13

Give a use of amplified DNA from PCR

Answer 13

Diagnose a disease

Question 14

How many more molecules of DNA are there after each PCR Procedure Cycle?

Answer 14

Twice as many e.g.
1 - 2 - 4 - 8 - 16 - 32 - 64 - 128 - 256

(There are 8 cycles in this since 1 is not included)

Question 15

What type of cell is true nucleus bound by double membrane?

Answer 15

Eukaryotic cells

Question 16

What organisms can be found in both Prokaryotic and Eukaryotic Cells?

Answer 16

Ribosomes and Plasmids