S

Question 1

Sclerotic

Answer 1

The tough, white outer layer of the eye which keeps it in shape.

Question 2

Secretion

Answer 2

The release of useful substances by cells.

Question 3

Selective breeding

Answer 3

see artificial selection

Question 4

Self-pollination

Answer 4

The transfer of pollen grains from the anther of a flower to the stigma of the same flower or a different flower on the same plant.

Question 5

Sense organs

Answer 5

A receptor organ that is sensitive to a particular stimulus or stimuli, e.g. touch, light, sound, temperature and chemicals.

Question 6

Sensitivity

Answer 6

The ability to detect changes in the environment and make responses.

Question 7

Sensory neurones

Answer 7

A neurone that transmits impulses from receptors to the brain or spinal cord.

Question 8

Sex chromosomes

Answer 8

The pair of chromosomes that determine a person’s sex chromosome, In humans, XX is female and XY is male.

Question 9

Sex linkage

Answer 9

The location of a gene on a sex chromosome, usually the X chromosome.

Question 10

Sexual reproduction

Answer 10

The process involving fusion of haploid nuclei to form a diploid zygote and the production of genetically dissimilar offspring.

Question 11

Sexually transmitted infection

Answer 11

A disease that is transmitted through body fluids during sexual activity, e.g. HIV.

Question 12

Sickle cell anaemia

Answer 12

An inherited disease affecting haemoglobin, which alters the shape of the red blood cells and results in severe anaemia.

Question 13

Small intestine

Answer 13

The region of alimentary canal that completes digestion and absorbs digested food.

Question 14

Solute

Answer 14

A substance that dissolved in a solvent.

Question 15

Solvent

Answer 15

A liquid that dissolved substances.

Question 16

Species

Answer 16

A group of organisms with similar characteristics which are capable of interbreeding and producing fertile offspring.

Question 17

Sperm

Answer 17

the male sex cell or gamete.

Question 18

Starch

Answer 18

An insoluble carbohydrate made from glucose molecules. An energy store in plant cells and an important component of the human diet.

Question 19

Stem

Answer 19

The organ that supports the leaves, flowers and fruits of a plant. It contains xylem tissue to transport water and mineral salts and phloem tissue to transport sugars and amino acids.

Question 20

Stem cells

Answer 20

Unspecialised cells that divide by mitosis to produce daughter calls that can become specialised for specific functions.

Question 21

Stimulus

Answer 21

A change in the environment that is detected by a sense organs.

Question 22

Stoma (Stomata)

Answer 22

a small hole in the epidermis of leaves that allows gases to diffuse in and out. The size of the hole is controlled by the guard cell.

Question 23

Stomach

Answer 23

A muscular sac at the end of the oesophagus that mixes food with gastric juice. The chemical digestion of protein begins in the stomach.

Question 24

Suspensory ligaments

Answer 24

Fibres that hold the lens in the eye in place and alter its shape when the ciliary muscles contract and relax.

Question 25

Sustainable development

Answer 25

Development that is able to conserve natural resources so that they are available in the future.

Question 26

Sustainable resource

Answer 26

A resource (timber, fish) which is produced as rapidly as it is removed from the environment so that it does not run out.

Question 27

Sweat glands

Answer 27

Coiled glands found in the dermis of the skin which secrete sweat to lose heat by evaporation.

Question 28

Synapse

Answer 28

Gap between two neurones across which a chemical transmitter is released to stimulate an impulse in the second neurone.