2 nucleic acids

Question 1

give an example of a nucleic acid

Answer 1

RNA
DNA

Question 2

what does DNA stand for?

Answer 2

deixyribonucleic acid

Question 3

what does DNA carry?

Answer 3

genetic information

Question 4

what do nucleotides contain?

Answer 4

• pentose sugar
• nitrogen containing organic base
• phosphate group

Question 5

what bond is made in a condensation reaction of 2 nucleotides?

Answer 5

phosphodiester bond

Question 6

what organic bases does RNA have?

Answer 6

adenine
uracil
guanine
cytosine

Question 7

is RNA single or double stranded?

Answer 7

single

Question 8

is DNA single or double stranded?

Answer 8

double helix

Question 9

what is the pentose sugar in DNA?

Answer 9

deoxyribose

Question 10

what are the bases for DNA

Answer 10

adenine
thymine
guanine
cytosine

Question 11

what are the 2 strands held together by?

Answer 11

H bonds

Question 12

where do the H bonds form?

Answer 12

between base pairs

Question 13

why is DNA a stable molecule?

Answer 13

the phosphodiester backbone protects the chemically reactive bases
H bonds link base pairs

Question 14

which base pairs are specifically complementary to eachother?

Answer 14

adenine and thymine/uracil
guanine and cytosine

Question 15

how many H bonds link both base pairs?

Answer 15

A-T 2 H bonds
G-C 3 H bonds

Question 16

give the functions of DNA

Answer 16

to pass genetic information from cell to cell and generation to generation

Question 17

how does DNA carry out it’s function?

Answer 17

• very stable
• extremely large so can carry lots of genetic information
• base pairing leads to DNA being able to replicate

Question 18

when does semi conservative replication occur?

Answer 18

before mitosis

Question 19

what does semi conservative replication form?

Answer 19

two copies of DNA each with one strand of original DNA and one strand of newly formed DNA

Question 20

what are the 2 enzymes in semi conservative replication?

Answer 20

DNA helicase
DNA polymerase

Question 21

what is the role of DNA helicase in semi conservative replication?

Answer 21

to break the hydrogen bonds that link the base pairs so the double helix separates into two strands and unwinds

Question 22

what happens after DNA helicase breaks the hydrogen bonds in semi conservative replication?

Answer 22

both strands act as a template for free nucleotides to bind to specific base pairs

Question 23

what is the role in DNA polymerase in semi conservative replication?

Answer 23

it joins nucleotides together in a condensation reaction

Question 24

what do each of the new DNA molecules contain in semi conservative replication?

Answer 24

they contain one of the original DNA strands each

Question 25

what does ATP stand for?

Answer 25

adenosine triphosphate

Question 26

what is the structure of ATP?

Answer 26

adenine ribose sugar three phosphate groups

Question 27

how does ATP release energy?

Answer 27

bond between phosphate groups break

Question 28

why can the bonds between phosphate groups break so easily on ATP?

Answer 28

unstable due to low activation energy

Question 29

what is the equation for the hydrolysis of ATP?

Answer 29

ATP -> ADP + Pi

Question 30

what enzyme catalyses the hydrolysis of ATP

Answer 30

ATP hydrolase

Question 31

what enzyme catalyses the synthesis of ATP?

Answer 31

ATP synthase

Question 32

what is a use of ATP?

Answer 32

phosphorylation provides energy

Question 33

what processes can ATP provide energy for?

Answer 33

muscle contraction active transport protein synthesis

Question 34

why is ATP useful?(6)

Answer 34

1. phosphorylation 2. releases energy in small amounts 3. can be made again 4. makes phosphorylated substances more reactive 5. energy is rapidly available 6. broken down in single step process

Question 35

why is water a dipolar molecule?

Answer 35

oxygen and hydrogen molecules have opposite charges

Question 36

describe how ATP is resynthesised in cells

Answer 36

1. ADP + Pi 2. enzyme ATP synthase 3. in respiration

Question 37

give 5 properties of water

Answer 37

1. polar 2. metabolite 3. has strong cohesion between molecules 4. high specific heat capacity 5. high latent heat of vaporisation

Question 38

what happens due to water being polar?

Answer 38

it acts as a universal solvent

Question 39

what happens due to water being a metabolite?

Answer 39

it is involved in processes like condensation and hydrolysis

Question 40

what happens due to water having strong cohesion between molecules?

Answer 40

it provides surface tension/ stops columns of water from breaking

Question 41

what happens due to water having a high specific heat capacity?

Answer 41

reduces fluctuations of temperature

Question 42

what happens due to water having a high latent heat of vaporisation?

Answer 42

evaporation of small amounts of water can cool organisms

Question 43

what does being a solvent mean?

Answer 43

to be able to dissolve substances and molecules

Question 44

what does being metabolite mean?

Answer 44

to be used and produced in many chemical reactions in cells

Question 45

what does having strong cohesion between molecules mean?

Answer 45

molecules are stuck together due to weak hydrogen bonding

Question 46

what does having a high specific heat capacity mean?

Answer 46

that it takes a lot of heat for the temperature to change

Question 47

what does having a high latent heat of vaporisation mean?

Answer 47

takes a lot of energy to break H bonds which increase the energy required to evaporate water

Question 48

why is water so important for life to occur?

Answer 48

1. life evolved in water 2. water provides support for organisms 3. water a major component of cytoplasm 4. water is a universal solvent 5. water is a metabolite 6. water stabilises temperature 7. water important in stabilising temperature of organisms

Question 49

why does water become lighter as it expands/freezes?

Answer 49

1. density = mass ÷ volume 2. ice has same mass of water but greater volume

Question 50

suggest 3 biological advantages of ice