Test 3

Question 1

describe primary polypeptide structure

Answer 1

linear structure is dictated by order of amino acids

Question 2

What are the two structures of secondary shapes?

Answer 2

Alpha helix (Pasta)
Beta sheets (waves)

Question 3

What dictates secondary structure

Answer 3

The reaction between hydrogen bonds

Question 4

What dictates tertiary structure?

Can polypeptides be biologically active?

Answer 4

Interaction between amino acids

Yes they can be called proteins if they are at the final shape

Question 5

What dictates Quaternary structure?

Answer 5

Interactions between two or more polypeptides

Question 6

What are four types of proteins

Answer 6

1.receptor proteins
2.hormones
3. antibodies
4.enzymes

Question 7

What is the function of receptor proteins?

Answer 7

The function is that they are embedded within the cell membrane and are complementary binding sites for messenger molecules like hormones

Question 8

What is the function of hormones?

Answer 8

Bind to receptor proteins are regulate processes e.g. puberty

Question 9

What is the function of antibodies

Answer 9

Involved in the immune response binds to and deactivates antigens

Question 10

What is the function of enzymes

Answer 10

They are biological catalyst

Question 11

Why is the 3D shape important for function?

Answer 11

Shape dictates function
commonly proteins are complementary in shape to substrate molecules

Question 12

discuss benefits and harms of chemicals that humans use

Answer 12

Caffeine is a positive- it gives you more energy

Panadol as a positive it reduces pain by binding to pain receptors.

Arsenic- stop oxygen

Question 13

Describe the relationship between the enzymes active site and its substrate.

Answer 13

The enzyme active site is complementary to the shape of the substrate.

Question 14

Describe the induced fit model

Answer 14

The active site changes shape until the substrate is completely bound to it. This change in shape weakens the bonds of, and correctly orientates the substrate, thus reducing the activation energy and speeding up the reaction.

Question 15

How are enzymes affected by temperature

Answer 15

They work best at the optimal temperature
too cold =inactive, meaning don’t work until temp increases
too hot= denatured->Dead/cannot catalyse reactions

Question 16

How are enzymes affected by pH

Answer 16

They work best at optimal pH
too high= denatured
too low=denatured

Question 17

What does the presence of inhibitors do to the reaction rate

Answer 17

decreases reaction rate

Question 18

Describe competitive inhibitors

Answer 18

Same shape as a substrate meaning they are complementary to the active site. can reversible (leaves the active site) or be irreversible (does not leave).

Question 19

Describe noncompetitive inhibitors

Answer 19

Bind to the binding site, which is not an active site. Distort the shape of the active site so nothing can bind to it-meaning the enzyme is useless it reversibly binds.

Question 20

Describe reasons for regulating metabolic pathways

Answer 20

Lose small amounts of heat at each stage instead of all at the end. Also, collect intermediate products (Doritos). that have specific enzymes for specific substrates at each stage.

Question 21

What is gene expression?

Answer 21

Gene expression is the amount of protein being made of a specific gene.

Question 22

What is methylation

Answer 22

Way of controlling gene expression.

Increase methylation = decrease gene expression.

Decreased methylation= increased gene expression.

Question 23

What is CANCER?

Answer 23

Rapid uncontrolled cell division

Question 24

What is the function of a proto-oncogenes

Answer 24

They increase cell division

Question 25

What is the function of a tumor suppressor gene

Answer 25

Suppress tumours by decreasing cell division/preventing uncontrolled division

Question 26

Describe the changes of methylation that lead to CANCER

Answer 26

The Increase in the methylation of the tumour suppressor gene.

The decrease in methylation of the proto-oncogenes. higher gene expression leads to increased cell division.

This all leads to Rapid Uncontrolled Cell Division (CANCER)

Question 27

Is Tahlia annoying?

Answer 27

Yes on certain days.

Question 28

Describe a breakdown / exergonic reaction

Answer 28

One reactant into two plus products overall gain energy. (start high end low)

Question 29

Describe a synthesis / endergonic reaction

Answer 29

From two products into one. Were you require energy (starts low and ends high)

Question 30

what is the difference between phenotype and genotype

Answer 30

physical vs genetic

Question 31

what is a mutation

Answer 31

change to genetic code

Question 32

reasons for mutation

Answer 32

DNA replication error
cell division error
or damage from environment (physical/chemical)

Question 33

what factors can increase mutation

Answer 33

ionising radiation
mutagenic chemicals
viruses

Question 34

what are the 3 potential outcomes from mutation

Answer 34

• not harmful (creation of new gene that is not harmful eg new eye colour)
• harmful
• no change (change in codon sequence codes for the same amino acid)

Question 35

can you pass on mutations that occur to somatic cells? (somatic = anything except sex cells)

Answer 35

no, only can pass on mutations to germ cells (sex cells)