Chapter 3- Biological molecules 3.8, 3.9, 3.10, 3.11

Question 1

What is the role of DNA helicase?

Answer 1

It catalysis the reaction that breaks down hydrogen bonds between complementary base pairs.

Question 2

What is the role of DNA polymerase?

Answer 2

It catalysis the formation of phosphodiester bonds between free nucleotieds and exposed bases on the tenplate strand of DNA.

Question 3

What is meant by semi-conservatice replication?

Answer 3

DNA replication that ends in oe old strand and one new strand present in each daughter DNA molecule.

Question 4

What are the main 3 stages of semi-conservative replication? (summarised)

Answer 4

1. DNA helicase causes DNA strands to seperate
2. free nucleotides will pair with complementary bases exposed strands
3. these bases are then joined together by DNA polymerase

Question 5

What directions does DNA polymerase travel in?

Answer 5

3’ to 5’ direction

Question 6

What is the genetic code?

Answer 6

Sequences of bases in DNA are code for the sequence of amino acids in the production of proteins?.

Question 7

What is a codon?

Answer 7

Sequence of three bases

Question 8

A codon codes for an ……

Answer 8

amino acid

Question 9

What is the start codon?

Answer 9

ATG

Question 9

What are the two parts of protein synthesis?

Answer 9

TRanscription (DNA copied into mRNA) and translation (mRNA is decoded by tRNA into amino acids to make a protein)

Question 10

What are the stages of transcription?

Question 11

what are the stages of translation?

Question 12

What do cells need energy for?

Answer 12

synthesis, transport, and movement

Question 13

What does ATP stand for?

Answer 13

Adenosine triphosphate

Question 14

What makes up an ATP molecule?

Answer 14

a nitrogenous base (adenine_, a pentose sugar, and three phosphate groups

Question 15

How does ATP release energy? (reaction and equation)

Answer 15

hydrolysis reaction-
although small amount of energy is needed to break weak bond between last phosphate, a large amount of energy is released when bond is broken
ATP + H20 ———-> ADP + Pi (inorganic phosphate) + energy

Question 16

How is energy stored as ATP?

Answer 16

Condenstation reaction happens which turns ADP + P into ATP.
This procces is called phosphorylation

Question 17

Why is ATP a good energy source?

Answer 17

• small- moves eaily in and out of cells
• water soluble
• realises energy in small quantaties- heat not watsed
  easily regenerated

Question 18

What are some example of nucleic acids?

Answer 18

DNA and RNA (Large molecules discovered in cell nuclei)

Question 19

What elements do nucleic acids contain?

Answer 19

Carbon, hydrogen, oxygen, nitrogen and phosphorus

Question 20

What components make up nucleic acids?

Answer 20

a pentose sugar, a phosphate group, and a nitrogenous base

Question 21

What are the names of the 4 bases?

Answer 21

Thymine
Adenine
Cytosine
Guanine

Question 22

What are pyrimidines?
(Structure and name of bases)

Answer 22

Smaller bases, contain single carbon structures
Thymine and cytosine

Question 23

What are purines?
(Structure and name of bases)

Answer 23

Larger bases, contain double carbon ring structures
Adenine and Guanine

Question 24

What base will Adenine pair with?

Answer 24

Thymine

Question 25

What base will Cytosine pair with?

Answer 25

Guanine

Question 26

How many hydrogen bonds will form when C and G join?

Answer 26

2 hydrogen bonds

Question 27

how many hydrogen bonds will form when A and T join?

Answer 27

3 hydrogen bonds