2.1.3

Question 1

What is the structure of a nucleotide?

Answer 1

phosphate group
pentose sugar
nitrogenous base

Question 2

What is DNA?

Answer 2

a polymer / polynucleotide
made of many nucleotides joined together

Question 3

How are 2 nucleotides joined together?

Answer 3

condensation reaction
between sugar of 1 nucleotide and phosphate group of another

Question 4

What is the difference in the pentose sugars in DNA and RNA?

Answer 4

RNA has ribose sugar
DNA has deoxyribose

Question 5

What are the purine bases?

Answer 5

Adenine
Guanine

Question 6

What are the pyrimidine bases?

Answer 6

Cytosine
Uracil
Guanine

Question 7

How is the phosphodiester bond formed between 2 nucleotides?

Answer 7

condensation reaction
carbon 3 on sugar and carbon 5 on another sugar

Question 8

What is the structure of ATP?

Answer 8

pentose sugar
nitrogenous base
at least 1 phosphate group

Question 9

What is the base called in ATP?

Answer 9

Adenine

Question 10

Atp and water

Answer 10

ADP and inorganic phosphate and energy

Question 11

What reaction is ATP and water?

Answer 11

hydrolysis

Question 12

What is the reaction to make ATP from ADP

Answer 12

condensation

Question 13

What are antiparallel DNA strands

Answer 13

2 polynucleotide strands running in opposite directions
starnds are held by hydrogen bonds between bases

Question 14

how many hydrogen bonds between C and G?

Answer 14

3

Question 15

How many hydrogen bonds between A and T?

Answer 15

2

Question 16

What does a purine always bind to?

Answer 16

pyrimidine

Question 17

What is a double helix?

Answer 17

2 strands of DNA twist around eachover to form a double helix

Question 18

When does DNA replication happen?

Answer 18

during interphase

Question 19

Outline semi-conservative DNA replication?

Answer 19

1)DNA helicase breaks the hydrogen bonds between the bases
Dpouble helix unwinds
each strand acts as a template
2) Free nucleotides from the cytoplasm assemble on the template DNA in complimentary base pairs
3) Hydrogen bonds reform between bases
DNA polymerase joins nucleotides forming a new sugar-phosphate backbone
2 identical DNA molecules have been produced

Question 20

What does semi-conservative DNA replication mean>?

Answer 20

each new DNA molecule contains 1 new strand and 1 old strand

Question 21

What happened in the Mesleon and Stahl experiment?

Answer 21

the more replications, the darker the band of nitrogen-14 formed in the testtube

Question 22

What is a gene?

Answer 22

Section of DNA that codes for a sequence of amino acids in a polypeptide

Question 23

What are alleles?

Answer 23

different versions of a gene

Question 24

What is non-overlapping code?

Answer 24

each sequence of 3 bases determines 1 amino acid
triplet code

Question 25

What is the degenerate nature of DNA?

Answer 25

some amino acids have more than 1 triplet code

Question 26

What is the universal nature of genetic code?

Answer 26

universal and used across all organisms

Question 27

Outline the practical to extract DNA from fruit?

Answer 27

1) Crush piece of fruity using pestle and mortar 2) Add detergent 3) Add protease enzyme 4) Filter to remove any solids 5) Add salt 6)Pour ice-cold alcohol into mixture

Question 28

Why do we crush the piece of fruit?

Answer 28

to help break down celluose cell wall

Question 29

Why do we add detergent?>

Answer 29

dissolve the cell surface / plasma membrane

Question 30

Why do we add protease?

Answer 30

break down the histones / proteins associated with DNA

Question 31

Why do we add salt?

Answer 31

to clump the DNA together

Question 32

Why do we add ice-cold alcohol?

Answer 32

DNA is insoluble in alcohol and should float on top

Question 33

Outline transcription?

Answer 33

1) split the hydrogen bonds that hold the double helix together with DNA helicase 2)Free nucleotides in the nucleoplasm form a complimentary mRNA strand. mRNA is a copy of the DNA sense coding strand 3) RNA helps form phosphodiester bonds in between RNA nucleotides 4) mRNA peels away from DNA and leaves through a nuclear pore and DNA helix reforms

Question 34

Outline translation

Answer 34

5) mRNA attaches to the ribosome and this is made of 2 subunits of rRNA 6) anti-codon on tRNA will find the complimentary codon on mRNA bringing a specific amino acid with it 7) amino acids are joined together by peptide bonds , primary structure -> secondary -> tertiary