Chapter One - Cells

Question 1

Function of a cell wall

Answer 1

Rigid structure providing structural integrity - fully permeable

Question 2

Function of cytoplasm

Answer 2

Site of chemical reaction, jelly-like fluid

Question 3

Function of a nucleus

Answer 3

Contains genetic information in the form of chromosomes

Question 4

Function of nuclear membrane

Answer 4

Surrounds nucleus

Question 5

Function of chloroplast

Answer 5

Site of photosynthesis,contains chlorophyll

Question 6

Function of a permanent vacuole

Answer 6

Storage of salts and sugars and provides turgor

Question 7

Label an animal cell

Answer 7

• cell membrane
• Cytoplasm
• nuclear membrane
• chromosomes

Question 8

Label a plant cell

Answer 8

• cell membrane
• cytoplasm
• chloroplast
• nuclear membrane
• chromosomes
• vacuole
• cellulose cell wall

Question 9

Label a bacterial cell

Answer 9

• plasmid
• loop of DNA
• cytoplasm
• non-cellulose cell wall

Question 10

Cell structure exam tips

Answer 10

• plant and animal cells are much larger than bacterial cells
• plant cells tend to have a regular shape because of their cell walls
• bacterial cells contain a large loop of DNA in addition to many small rings of DNA called plasmids.

Question 11

Equation to work out actual size from a magnification

Answer 11

Action size = observed size / (divided by) magnification

Question 12

Equation for magnification

Answer 12

Magnification = observed size / actual size

Question 13

Function of a cell membrane

Answer 13

Controls entry and exit of substances - selectively permeable

Question 14

Levels of organisation

Answer 14

Cell - tissue - organ - organ system - organism

Question 15

Explain the process of growth in animals compared to plants

Answer 15

Animal growth involves growth all over their bodies whereas plants tend to grow only at the tips of their roots and shoots (apices)

Question 16

Explain growth in plants

Answer 16

Plants grow only at the tips of their roots and shoots (apices). The reason for this is only certain areas of the plant have the ability to grow. These areas are called meristem. Meristematic tissues are made up of unspecialised cells that have the ability to become any type of plant cell. Plants have these cells for the duration of their life. This is why gardeners can take cuttings (a selected section cut from a plant) and grow whole new plants from the cuttings.

Question 17

Three major sources of stem cells

Answer 17

• umbilical cord blood
• embryos
• adult cells

Question 18

Why is stem cell research considered controversial?

Answer 18

Some groups believe that the types of procedures used to harvest stem cells are controversial as life can be created artificially. Others have concerns that people seek to have so-called ‘designer babies’. For example, in order to provide stem cells for the treatment of illnesses in other family members.

Question 19

What is the use of stem cells being investigated for?

Answer 19

A way of producing meat in a cheaper and more efficient way. It is possible to grow muscle tissue from a cow, pig or chicken which could then be used as a food source. It is hoped that this would be cheaper as the costs of feeding and keeping animals would be greatly reduced.

Question 20

Exam tip on stem cell research

Answer 20

It is important to keep your answer balanced, consider both the positive and negative arguments.

Question 21

Definition of diffusion?

Answer 21

Diffusion is the random molecular movement of molecules from a region of high concentration to a region of lower concentration along a concentration gradient.

Question 22

How can diffusion be demonstrated?

Answer 22

A sugar solution in visking tubing immersed in a beaker of water.

Question 23

Why is diffusion important for photosynthesis?

Answer 23

Diffusion is important in the movement of gases into and out of leaves.