Enzymes and Genetics

Question 1

What is a catalyst?

Answer 1

A catalyst is a substance which increases the speed of reaction without being changed or used up in the reaction.

Question 2

State three functions of proteins in living cells, other than acting as a catalyst?

Answer 2

G

Question 3

Why does an enzyme-catalysed reaction stop when a mixture is heated about a certain heat?

Answer 3

Some of the bonds holding the enzymes together break, this destroys the enzymes special shape and so it won’t work anymore. It is said to be denatured.

Question 4

In which three places in the body is amylase produced?

Answer 4

Salivary glands

Small intestine

Pancreas

Question 5

Where in the body is bile produced?

Answer 5

Liver

Question 6

Where in the body is bile stored?

Answer 6

Gall bladder

Question 7

Where in the body is bile used?

Answer 7

Small intestine

Question 8

Why does the stomach produce hydrochloric acid?

Answer 8

1) to kill bacteria

2) to give the right ph for the protease enzyme to work

Question 9

What is the word equation for aerobic respiration?

Answer 9

Glucose + Oxygen —> Carbon Dioxide + water + energy

Question 10

Give two examples of how an animal used the energy released by aerobic respiration?

Answer 10

• To allow muscles to contract

- In mammals and birds the energy is used to keep their body temperature steady.

Question 11

What is anaerobic respiration?

Answer 11

When your body can’t supply enough oxygen to your muscles, they start doing anaerobic (without oxygen) respiration. It’s the incomplete breakdown of glucose.

Question 12

How do you repay an oxygen debt?

Answer 12

You have to keep breathing hard to get more oxygen into your blood. Blood flows through your muscles to remove the lactic acid by oxidising it to harmless Carbon dioxide and water.

Question 13

Name two types of enzymes that would be useful in a biological washing powder?

Answer 13

Protease

Lipases

Question 14

Advantages of using enzymes in industry’s?

Answer 14

• There specific, so they only catalyse the reaction you want them to.
• Using lower temperatures and pressures means a lower dose as it saves energy.
• Enzymes work for a long time, so after the initial cost of busting them you can continually use them.
• They are biodegradable and therefore cause less environmental pollution

Question 15

Name disadvantages of using enzymes in industry?

Answer 15

• Some people can develop allergies to the enzymes.
• Enzymes can be denatured by even a small increase in temperature. There are also susceptible to poisons and changes in pH. Conditions must be tightly controlled.
• Enzymes can be expensive to produce
• Contamination of the enzyme with other substances can affect the reaction.

Question 16

How does DNA control the activities of a cell?

Answer 16

It contains all the instructions to put an organism together and make it work, found in the nucleus

Question 17

How is DNA fingerprinting used in forensic science?

Answer 17

DNA is taken from a crime scene is compared with a DNA sample from a suspect. Each person has a unique genetic pattern (other than identical twins) the DNA Samples are then composed.

Question 18

What is mitosis used for in the human body?

Answer 18

Mitosis makes new cells for growth and repair. When a body cell divided it needs to make new cells identical to the original cell with the same number of chromosomes. This type of division is known as mitosis.

Question 19

What are the four steps in mitosis?

Answer 19

If the cell gets a signal to divide it needs to duplicate its DNA.

The chromosomes then line up at the centre of the cell and livers pull them sparer. The two arms of each chromosomes do to opposite ends of the cells.

Membranes form around each of the sets of chromosomes. These become the nuclei of the two new cells

Lastly the cytoplasm divides.

Question 20

What is meiosis?

Answer 20

Making of new cells which only have half the Number of chromosomes. In humans it only happens in the reproductive organs.

Question 21

What is the differentiation in a cell?

Answer 21

Is the process by which a cell changes to become specialised for its job.

Question 22

Give three ways that an embryonic stem cells could be used to cure diseases?

Answer 22

B

Question 23

Which chromosome in the human body causes male characteristics?

Answer 23

H

Question 24

List three important conclusions that Mendel reached following his experiments with pea plants?

Answer 24

H

Question 25

Why was Mendel work not understood at the time it was released?

Answer 25

F

Question 26

What is an allele?

Answer 26

H

Question 27

What is meant by an organism being heterozygous?

Answer 27

F

Question 28

Briefly describe the difference beteeen a recessive allele and a dominant one?

Answer 28

B

Question 29

If both parents carry recessive allele for cystic fibrosis m, what is the probability of their child being a carrier?

Answer 29

H

Question 30

What is polydactyly?

Answer 30

H

Question 31

Describe three ways fossils can form?

Answer 31

H

Question 32

Give three reasons why some species become extinct?

Answer 32

H

Question 33

What is speciation? Explain how geographical isolation can lead to speciation?

Answer 33

H

Question 34

Name the four stages of meiosis division?

Answer 34

Before the cell starts to divide it duplicated its DNA.

In the first division in meiosis the chromosome pairs line up in the centre of the cell.

The parts are then pulled aparet ski each new cell had only one copy of each chromosome.

In the second division the chromosomes line up again in the centre of the cell. The arms of the chromosomes are pulled apart.
You get four gametes each with only a single set of chromosomes in it.