C5

Question 1

What is the Allosteric Site of an enzyme

Answer 1

The rest of the enzyme (outside) does nothing

Question 2

What are enzymes?

Answer 2

Biological Catalysts which remain unchanged after chemical reactions

Question 3

When Enzymes are present, what are the effects? (2)

Answer 3

• Less energy is needed to start the chemical reaction
• reaction rates are higher

Question 4

Draw up a diagram of the induced fit model of enzyme function

Answer 4

Check the enzymes PowerPoint in the google classroom.
This image must include:
- Active site and change
- Substrate
- Substrate enzyme complex
- Products produced and leaving the enzyme unchanged

Question 5

What are the different types of reactions that enzymes catalyse? (2)

Answer 5

Anabolic reactions and Catabolic reactions.

Question 6

What factors affect enzyme activity? (4)

Answer 6

• Temperature
• pH
• Enzyme concentration
• Substrate concentration

Question 7

Draw the graph for the effect of changing temperatures on the reaction rate when enzymes are added

Answer 7

Check enzymes PowerPoint

Question 8

Draw the graph for the effect of changing pH on the reaction rate when enzymes are added

Answer 8

Check enzymes PowerPoint

Question 9

Draw the graph for the effect of changing the concentration of substrate/enzyme on the reaction rate when enzymes are added

Answer 9

Check enzymes PowerPoint

Question 10

What are Co-factors and Co-enzymes?

Answer 10

Any non-protein chemical needed for an enzyme reaction to proceed

Organic molecules are called co-enzymes, and inorganic molecules are called co-factors

Question 11

What is competitive inhibition?

Answer 11

This is when a non-substrate molecule binds to the active site of an enzyme. This blocks the substrate from reaching the active site, stopping reactions.

Question 12

What is non-competitive inhibition?

Answer 12

This is when a non-substrate molecule binds to an allosteric site on the enzyme. This changes the shape of the active site and stops the substrate from binding to the enzyme

Question 13

Each nucleotide in DNA is made of… (3)

Answer 13

• deoxyribose sugar
• phosphate group
• one of four nitrogenous bases

Question 14

How is each backbone chemically bonded?

Answer 14

Each Pentose sugar is connected to the phosphate above and below it in the chain.

Question 15

How many hydrogen bonds do adenine and thymene create between them?

Answer 15

2

Question 16

What are the differences between RNA and DNA

Answer 16

RNA is:
- Short
- single-stranded
- ribose sugar
- has uracil
DNA is:
- Long
- Double Stranded
- Deoxyribose sugar
- Has thymene

Question 17

What are the enzymes involved in DNA replication? (4)

Answer 17

• Helicase
• Primase
• Polymerase
• Ligase

Question 18

Draw up a diagram of DNA replication

Answer 18

Check on Google Drive notes from Nicola

Question 19

Define Gene regulation

Answer 19

The process used to control the timing, location and amount in which genes are expressed

Question 20

What is a Mutation

Answer 20

A mutation is simply a change in the sequence of the nucleotides of a
genome.

Question 21

What are the causes of mutations (2)

Answer 21

Mutations can occur in several ways:
* Induced - consequence of exposure to mutagens (chemicals, UV rays,
X-rays, environment etc)
* Spontaneous - not environment, occur as a result of reactions in body.

Question 22

What are the 3 types of mutations

Answer 22

1. Point mutations - Substitution - Insertion / deletion (frameshift)
2. Block mutations
3. Chromosomal mutations

Question 23

What are point mutations?

Answer 23

a substitution in a single nucleotide (base) in the original DNA code. They are also called substitution mutations.

Question 24

What are the three types of point mutation?

Answer 24

silent mutations
missense mutations
nonsense mutations

Question 25

What are silent mutations?

Answer 25

Silent mutations occur when the DNA base change does not alter the amino acid sequence of the polypeptide.

Question 26

What are missense mutations?

Answer 26

Missense mutations occur when the DNA base change alters a single amino acid in the polypeptide chain

Question 27

What are missense mutations?

Answer 27

Nonsense mutations occur when the DNA base change leads to a premature STOP codon which stops the formation of the rest of the polypeptide.

Question 28

What are Frameshift mutations (2)

Answer 28

Frameshift mutations occur when the addition (insertion) or removal (deletion) of a base alters the entire reading frame (sequence of bases/codons between START – STOP codons) of the gene, thereafter. This change will affect every codon beyond the point of mutation and can dramatically change the remaining amino acid sequence.

Question 29

What are the 4 types of block mutations and what do they do?

Answer 29

Duplications - Part of the chromosome is copied, resulting in duplicate sections. This can cause extra gene expression due to the duplicates. Deletions - A portion of the chromosome is removed, along with any of the genes in that chromosome. Potentially catastrophic if those genes are not expressed and are critical for life Inversions - A segment of the chromosome is removed and then replaced with a chromosome in the reverse order. DNA is reversed with its orientation within the chromosome Translocations - A portion of one chromosome is transferred to another chromosome, possibly interrupting gene sequences

Question 30

What are the two stages of photosynthesis?

Answer 30

The light dependent phase: - First stage of photosynthesis - Requires the input of light energy to occur - Occurs in thylakoid membranes - Involves splitting of 12 water molecules using light - energy (photolysis) - oxygen is released from the chloroplast by diffusion - ATP molecules are transported from the thylakoid membrane to the stroma The light independent phase - Second stage of photosynthesis - Requires certain outputs of the light dependent stage to occur - Occurs in the stroma of the chloroplast - Involves the use of CO2 to create glucose; also called the Calvin cycle or carbon fixation

Question 31

Chloroplasts:

Answer 31

Chloroplast - membrane bound organelle Contains stacks of thylakoids: a pancake-shaped compartment made of a thylakoid membrane around a lumen (like cytosol); each stack of thylakoids is called a granum (plural grana) Chlorophyll is embedded in the thylakoid membranes and absorbs light energy. The more thylakoid membranes there are, the more surface area available for capturing light energy and for exchange of other requirements/waste products in the light dependent stage of photosynthesis (occurs here). Remaining space in chloroplast is filled with stroma (gel-like fluid); contains a large number of ribosomes due to the large number of enzymes needed for the reactions that occur during the light independent stage of photosynthesis (occurs here

Question 32

What are the limiting factors of photosynthesis?

Answer 32

- Carbon dioxide or water concentration - Light intensity - Temperature

Question 33

What are the parts of the mitochondria in cellular respiration and their functions?

Answer 33

Matrix: fluid component of mitochondria, site of Krebs cycle Cristae: folds of inner membrane that project into matrix, site of electron transport chain reactions More cristae = more surface area More surface area = more reactions in electron transport chain ∴ more ATP able to be produced