B1

Question 1

Give 2 differences between a
light microscope and electron
microscope.

Answer 1

• Electron microscopes have better
  resolution and magnification.
• So you can see the specimen in
  more detail.

Question 2

How do you calculate total
magnification?

Answer 2

Total magnification = eyepiece lens
magnification x objective lens
magnification

Question 3

What is the function of a
mitochondria?

Answer 3

To release energy

Question 4

What is the function of a
ribosome?

Answer 4

To make protein for growth and repair.

Question 5

What is the function of the cell
membrane?

Answer 5

This controls the substances which can move in and out of the cell.

Question 6

What is the function of the cell
wall in a plant cell?

Answer 6

This is made of cellulose. It provides support and protects the cell.

Question 7

How is a bacterial cell different
from a plant or animal cell?

Answer 7

Bacterial cells don’t have a nucleus.

Question 8

Where in a plant cell does
photosynthesis take place?

Answer 8

In the chloroplast

Question 9

Give the steps you would use to
prepare a microscope slide.

Answer 9

1.Place specimen (cells on the slide).
2.Specimen must be thin to allow light
through.
3.Add stain.
4.Add cover slide on top at an angle.

Question 10

Give an example of a prokaryotic cell.

Answer 10

Bacteria cell

Question 11

Why must the specimen be thin
when preparing a slide?

Answer 11

To allow the light to pass through.

Question 12

Give 2 adaptations of a sperm cell.

Answer 12

1.Have an acrosome to release
enzymes to break through jelly coat of
the egg.
2.Have a tail to swim.
3.Has mitochondria to release energy.

Question 13

Give 2 adaptations of an egg cell.

Answer 13

Has a jelly coat which hardens to
prevent more than one sperm from
entering.
- Has nutrients in the cytoplasm.
- Has a haploid nucleus.

Question 14

Give 2 adaptations of a ciliated
cell in the oviduct.

Answer 14

• Has cilia to move the egg.
• Has mitochondria to release energy.

Question 15

Give 2 adaptations of a ciliated
cell in the digestive system.

Answer 15

• Has villi to increase surface area.
• Has mitochondria to release energy
  for active transport.

Question 16

What are the two types of DNA in a bacterial cell?

Answer 16

Chromosomal DNA
plasmid

Question 17

What do you call the pigment
(chemical) found inside chloroplasts
which helps to trap light for
photosynthesis?

Answer 17

Chlorophyll

Question 18

When preparing a microscope
slide, what is the purpose of the cover
slip?

Answer 18

• It protects the specimen.
• It helps to hold the specimen in
  place.

Question 19

Sperm and egg cells are haploid.
What does this mean?

Answer 19

Haploid means that the cell only has
half the genetic information (23
chromosomes).

Question 20

What is meant by the ‘optimum’
temperature?

Answer 20

The optimum temperature is the
temperature at which the rate of
reaction for a particular enzyme is the
fastest.

Question 21

What forms when an enzyme and substrate combine?

Answer 21

When an enzyme and substrate
combine, we call it an
enzyme-substrate complex.

Question 22

What does ‘denature’ mean?

Answer 22

This is when the active site of the enzyme changes shape.

Question 23

What two main conditions could cause an enzyme to denature?

Answer 23

Temperature
pH

Question 24

What substrate does protease
break down?

Answer 24

Protein

Question 25

What is produced when protease breaks down protein?

Answer 25

Amino acids

Question 26

What substrate does amylase break down?

Answer 26

starch

Question 27

What is produced when amylase breaks down starch?

Answer 27

glucose

Question 28

What substrate does lipase break down?

Answer 28

fats

Question 29

What two things are produced when lipase breaks down lipids?

Answer 29

fatty acids glucose

Question 30

What do you call the molecule which fits into the active site of the enzyme?

Answer 30

Substrate

Question 31

Enzymes are biological catalysts. What does this mean?

Answer 31

Biological catalysts speed up the rate of reactions, like digestion, without being used up themselves.

Question 32

What term is used to describe the fact that the shape of the substrate allows it to fit into the active site of the enzyme?

Answer 32

Complementary

Question 33

What do enzymes do?

Answer 33

Enzymes often break down large insoluble molecules into smaller soluble molecules. .

Question 34

Why do larger molecules need to be broken down into smaller molecules?

Answer 34

Larger molecules need to be broken down into smaller molecules so that they can be absorbed through the small intestine.

Question 35

How can the lock and key model be used to help understand enzymes and substrates?

Answer 35

Lock = enzyme Key = substrate The lock and key model shows that only one substrate molecule (key) has the correct shape to fit into the active site of the enzyme (lock).

Question 36

How does temperature affect the rate of an enzyme-controlled reaction?

Answer 36

As the temperature increases the rate of an enzyme driven reaction increases as the enzyme and substrate molecules have more kinetic energy so collide more often so more enzyme-substrate complexes are formed.

Question 37

When we increase substrate concentration, the rate of reaction increases and then levels off. Why

Answer 37

It levels off because all of the enzymes are already bound to substrates.

Question 38

What is ‘diffusion’?

Answer 38

Diffusion is the random movement of particles from a high concentration to a low concentration.

Question 39

What is ‘osmosis’?

Answer 39

Osmosis is: - The movement of water. - From a high concentration of water to a low concentration of water. - Through a partially permeable membrane.

Question 40

What is ‘active transport’?

Answer 40

Active transport is: - The movement of particles from a low concentration to a high concentration. - It requires energy. - Movement is up the concentration gradient.

Question 41

In what two transport processes do substances move down their concentration gradient?

Answer 41

1. Osmosis 2. Diffusion

Question 42

Water moves through a partially permeable membrane by what process?

Answer 42

Omosis

Question 43

What is meant by ‘partially permeable’ membrane?

Answer 43

Partially permeable means that some substances can pass through the membrane, but other substances can’t.

Question 44

Why is active transport referred to as an ‘active’ process?

Answer 44

It is an active process because it requires energy.

Question 45

Why does active transport require energy?

Answer 45

Active transport requires energy because substances are moved against the concentration gradient.

Question 46

What is meant by ‘concentration gradient’?

Answer 46

This is the difference between two concentrations.

Question 47

What is the equation to work out % change in mass?

Answer 47

% change = change in mass/starting mass x 100

Question 48

In an experiment, what is meant by the independent variable?

Answer 48

The independent variable is the thing we are changing.

Question 49

In an experiment, what is meant by the dependent variable?

Answer 49

The dependent variable is the thing we are measuring.

Question 50

In an experiment, what is meant by the control variable?

Answer 50

The control variable is the thing we keep the same.

Question 51

Why is it important that we have control variables?

Answer 51

It is important because: - we should only be changing one variable (independent variable) - so we can compare results

Question 52

Why do we repeat experiments?

Answer 52

We repeat experiments: - to identify anomalies - so we can calculate a mean/average

Question 53

What is meant by ananomalous result?

Answer 53

An anomalous result is one which doesn’t follow a trend or pattern in results.