Topic 1B - More Biological Molecules

Question 1

What is the name of the bond that forms between two nucleotides?

Answer 1

Ester bond

Question 2

What is a phosphodiester bond?

Answer 2

Consists of the phosphate group and two ester bonds

Question 3

Describe what would be seen during semi conservative replication.

Answer 3

The strand of DNA would settle between where the light nitrogen and heavy nitrogen have settled out

Question 4

Describe what would be seen during conservative replication.

Answer 4

The DNA containing heavy nitrogen would settle at the bottom and the DNA containing light nitrogen would settle closer to the top

Question 5

What does DNA helicase do

Answer 5

Breaks the hydrogen bonds between bases

Question 6

What does DNA polymerase do

Answer 6

Catalyses the reaction and joins together nucleotides via condensation
Hydrogen bonds from between the complimentary bases

Question 7

What is ATP made up from

Answer 7

One adenine
One ribose sugar
3 phosphates

Question 8

What are the 5 properties of water

Answer 8

Good solvent
Important metabolite
Can buffer changes in temperature
High latent heat of vaporisation
Cohesive

Question 9

Why is water an important metabolite

Answer 9

Many metabolic reactions involve condensation and hydrolysis.
Condensation - water is released to form a new bond
Hydrolysis - water is required to help break a bond

Question 10

Why is water a good solvent

Answer 10

Because water is polar, the slightly positively charged end of a water
molecule will be attracted to the negative ion, and the slightly negatively
charged end of a water molecule will be attracted to the positive ion.
This means the ions will get totally surrounded by water molecules

Question 11

Why does water have a high latent heat of vaporisation

Answer 11

Water evaporates when the hydrogen bonds holding water molecules are broken. It takes a lot of energy to break the hydrogen bonds between the water molecules, so a lot of energy is used up when water evaporates

Question 12

Why can water buffer changes in temperature

Answer 12

Hydrogen bonds give water a high specific heat capacity - this is the energy needed to raises the temperature of 1 gram of a substance by 1 degrees Celsius.
Water has a high specific heat capacity as it requires a lot of energy to heat it up

Question 13

Why is water cohesive

Answer 13

Water is cohesive because it’s polar
Strong cohesion helps water to flow, making it great for transporting substances

Question 14

State the structure of a nucleotide

Answer 14

Phosphate group
Pentose sugar
Nitrogenous base

Question 15

What’s the role of DNA in living cells

Answer 15

Contains genetic information for a persons characteristics

Question 16

What’s the role of mRNA

Answer 16

To splice out introns and keep exons

Question 17

What’s the role of tRNA

Answer 17

Supplies complementary amino acid to mRNA codons during translation

Question 18

How do polynucleotides form

Answer 18

Condensation reactions between nucleotides form phosphodiester bonds and create a sugar phosphate backbone

Question 19

Describe the structure of DNA

Answer 19

Double helix of 2 polynucleotide strands

Question 20

Explain the process of DNA replication? (3)

Answer 20

1. DNA helicase breaks hydrogen bonds between the bases
2. Each original strand acts as a template for a new strand. Complimentary base pairing occurs.
3. Condensation reaction occurs between free floating nucleotides and the original strand. Catalysed by the enzyme DNA polymerase

Question 21

What is ATP used for?

Answer 21

Respiration

Question 22

What enzyme hydrolyses ATP?

Answer 22

ATP hydrolase

Question 23

What enzyme catalyses the reaction between ADP and Pi?

Answer 23

ATP synthase

Question 24

What is an ion?

Answer 24

An atom that has an electrical charge