2.3 Nucleic Acids

Question 1

What does DNA stand for?

Answer 1

Deoxyribose nucleic acid

Question 2

How many chromosomes are there in the human body?

Answer 2

23 pairs, 46 total

Question 3

How many chromosomes do the egg and sperm have?

Answer 3

23

Question 4

What are genes?

Answer 4

sections of DNA

Question 5

What do genes do?

Answer 5

code for specific characteristics

Question 6

What are genes that come in different forms called?

Answer 6

alleles

Question 7

What are the nitrogenous bases?

Answer 7

Adenine - Thymine
Cytosine - Guanine

Question 8

What are the parts of a nucleotide?

Answer 8

• Phosphate
• Pentose sugar
• Nitrogenous base

Question 9

How many hydrogen bonds do A + T have?

Answer 9

2

Question 10

How many hydrogen bonds do C + G have?

Answer 10

3

Question 11

How do the base and sugar join?

Answer 11

Glycosidic bond

Question 12

How do the phosphate and sugar join?

Answer 12

Phosphodiester bond

Question 13

What sort of reaction do the bonds require?

Answer 13

Condensation reaction

Question 14

What are the purines and what are their structure?

Answer 14

• Adenine + Guanine
• double ringed structure

Question 15

What are the pyrimidines and what is their structure?

Answer 15

• Thymine + Cytosine
• Single ringed structure

Question 16

What does semi-conservation mean?

Answer 16

one parent DNA strand and one new daughter strand

Question 17

What does Gyrase do?

Answer 17

Unwinds DNA

Question 18

What does Helicase do?

Answer 18

Unzips DNA

Question 19

What does Primase do?

Answer 19

Signals where the nucleotides are added

Question 20

What does DNA polymerase do?

Answer 20

adds the nucleotides

Question 21

What does DNA ligase do?

Answer 21

sticks the lagging strand fragments

Question 22

What are okazaki fragments?

Answer 22

short sequences of DNA nucleotides for lagging strands

Question 23

What is the lagging strand?

Answer 23

the new strand of DNA whose direction is opposite to the direction of the old strand

Question 24

When does DNA replication happen?

Answer 24

In the interphase before cell division

Question 25

Why does DNA replication happen?

Answer 25

Because when cells divide, they need the same amount of DNA

Question 26

What are the products of DNA replication?

Answer 26

2 semi conservative DNA strands

Question 27

What does RNA stand for?

Answer 27

Ribonucleic acid

Question 28

What are the 3 types of RNA?

Answer 28

- mRNA - tRNA - rRNA

Question 29

In RNA, what does Adenine pair with?

Answer 29

Uracil

Question 30

How do the sugar phosphate backbones run?

Answer 30

In opposite directions

Question 31

What do hydrogen bonds between the bases do?

Answer 31

stabilise the structure

Question 32

How do the bases pair?

Answer 32

Purine to pyrimidine

Question 33

What do RNA molecules do?

Answer 33

Convert the instructions in DNA

Question 34

What sort of sugar does RNA have?

Answer 34

ribose

Question 35

What is a protein?

Answer 35

- Polymer of units linked by peptide bonds - built up from 20 amino acids

Question 36

What is transcription?

Answer 36

When DNA is read to produce a strand of mRNA

Question 37

What does RNA polymerase do?

Answer 37

binds to DNA strand and unwinds small section to travel along building an RNA molecule from the template strand.

Question 38

What is translation?

Answer 38

Where mRNA is read to produce a strand of protein chain

Question 39

What is tRNA?

Answer 39

Short strand of RNA which carries anti codon

Question 40

What does tRNA attach to?

Answer 40

mRNA strand

Question 41

What do anticodon molecules have?

Answer 41

area with 3 bare bases which match to corresponding bases on mRNA

Question 42

How can you describe the arrangement of the DNA molecule?

Answer 42

antiparallel