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N5 Biology > Unit 2 > Flashcards

Unit 2 Flashcards

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1
Q

What word is used to describe cells that have an adapted structure to carry out a particular function?

A

Specialised

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2
Q

What is

a) a tissue
b) an organ
c) a system

A

a) a group of cells that are specialised to perform a particular function
b) a group of tissues that perform the same function
c) a group of organs

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3
Q

What are stem cells and what do they do?

A

They are non-specialised animal cells that can divide and become specialised.
They carry out growth and repair

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4
Q

What name is given to the part of a plant that produces non-specialised cells?

A

meristem

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5
Q

Why is internal communication needed for a multicellular organism to survive

A

Cells in a multicellular organism don’t work independently

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6
Q

What makes up the nervous system?

A

1) CNS ( central nervous system)

2) nerves

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7
Q

What is central nervous system?

A

brain and spinal cord

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8
Q

What are the three main parts of the brain and what do they do?

A

cerebellum - controls balance and coordination
cerebrum - controls thought and personality
medulla - controls breathing and heart rate

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9
Q

What are the three types of neurons and what do they do?

A

sensory neurons - carry an electrical impulse from sensory receptors to the spinal cord and brain
inter neurons - carry electrical impulses from one part of the CNS to another
motor neuron - carry electrical impulses from one part of the CNS to make a response happen eg. muscle move.

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10
Q

How do electrical impulses get transferred from one neuron to another?

A

By chemical messages travelling across synapses

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11
Q

List the three types of neuron in a reflex arc

A

sensory neuron
relay neuron
motor neuron

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12
Q

What is a reflex arc?

A

a rapid pathway that goes through the spinal cord but does not pass through the brain

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13
Q

What is a reflex?

A

A rapid response that happens without conscious thought

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14
Q

Give two examples of reflexes

A

Any 2 from:

blinking, response to pain, iris response to light, response to touching something hot, sneeze and knee-jerk.

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15
Q

What name is given to chemical messengers in the blood?

A

hormones

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16
Q

Where do hormones come from?

A

endocrine glands

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17
Q

Why do some hormones only work on certain tissues?

A

Hormones only work on tissues that have receptors for them

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18
Q

Which hormone is released when blood glucose levels are higher than normal?

A

insulin

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19
Q

Which hormone is released when blood glucose levels are lower than normal?

A

glucagon

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20
Q

How is glucose stored in the liver?

A

As glycogen. This is long chains of glucose molecules joined together.

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21
Q

How does insulin lower the blood glucose level?

A

It causes glucose to be converted into glycogen in the liver

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22
Q

How does glucagon raise the blood glucose level?

A

It causes glycogen to be converted into glucose in the liver

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23
Q

Which organ releases insulin and glucagon?

A

pancreas

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24
Q

Which two hormones control blood glucose levels?

A

insulin and glucagon

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25
Q

What name is given to cells that contain two copies of each chromosome?

A

diploid

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26
Q

What name is given to cells that contain only one copy of each chromosome?
Where are these found?

A

Haploid

The gametes are haploid cells so found in ovaries or testes

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27
Q

What are the gametes?

a) in animals
b) in plants

A

a) egg and sperm cells

b) pollen and ovule cells

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28
Q

Where are gametes made in animals?

A

male - testes

female - ovary

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29
Q

Where are gametes made in plants?

A

Male - pollen made in anther

female - ovule made in ovary

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30
Q

What is fertilisation?

A

Fusion of two haploid gametes to make a diploid zygote

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31
Q

What is a zygote?

A

The new cell with 2 copies of each chromosome made by fertilisation.
or
The cell made when male and female gametes join.

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32
Q

What is discrete variation?

A

Differences caused by the presence or absence of a gene or group of genes

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33
Q

What is continuous variation?

A

Differences caused by complex interactions of genes and the environment

34
Q

Give an example of discrete variation in humans

A

tongue rolling (you can either do it or you can’t)

blood group - A, B, AB r O

35
Q

Give an example of continuous variation in humans

A

height (can take a range of values)
weight
hand span or any other body dimension

36
Q

What causes genetic variation?

A

The combination of genes from two parents (sexual reproduction)

37
Q

What is the phenotype of an organism?

A

Its physical appearance and characteristics

38
Q

What is the genotype of an organism?

A

The set of alleles it has inherited

39
Q

What are alleles?

A

Different forms of the same gene

E.g. the gene for eye colour has an allele for blue and an allele for brown

40
Q

What does homozygous mean?

A

Has the same two alleles of a gene e.g. RR or rr

41
Q

What does heterozygous mean?

A

Has two different alleles of a gene e.g. Rr

42
Q

What name is given to an allele that will only to be expressed if it is homozygous?

A

recessive

43
Q

What name is given to allele that is expressed when heterozygous?

A

dominant

44
Q

In genetics, what are P1, F1 and F2?

A

P1 - the parents
F1 - the offspring from the P1 parents (children)
F2 - the offspring from F1 generation (grandchildren)

45
Q

How can some people have the allele of a gene that causes disease yet not get the disease?

A

The disease allele may be recessive. It is therefore possible to have the allele but it is not expressed - the person would be a carrier.

46
Q

Why are the predicted ratios of genetic inheritance not always achieved?

A

The combination of genes is a random event.

With big enough samples the statistical ratios are usually achieved but with small samples this is not the case.

47
Q

List seven structural parts of a plant leaf.

A

upper epidermis, palisade mesophyll, spongy mesophyll, vein, lower epidermis, guard cells, stomata

48
Q

What are the tiny holes in leaves that allow water to evaporate out called?

A

Stomata

49
Q

What do the guard cells on a leaf do?

A

Open and close the stomata to prevent water loss at night.

50
Q

How does water travel up through a plant?

A

Transpiration.

Water evaporating from the leaves pulls the column of water up through the xylem.

51
Q

What do xylem vessels do?

A

transport water and minerals

52
Q

How does water enter plants?

A

Through the roots. Root hairs increase the surface area so they can absorb lots of water.

53
Q

Describe the structure of xylem

A

It is long tubes of dead cells that contain lignin.

54
Q

What is the role of lignin in xylem cells?

A

It makes the xylem strong and waterproof

55
Q

Why do leaves need water?

A

For the mesophyll cells to carry out photosynthesis

56
Q

How is sugar transported around a plant?

A

In phloem cells

57
Q

List two differences between xylem and phloem

A

xylem carries water
phloem carries sugar

xylem cells are dead
phloem cells are alive

58
Q

How do phloem cells stay alive when they don’t have much cytoplasm?

A

They have companion cells which carry out many of the activities the phloem needs to stay alive.

59
Q

How are nutrients, oxygen and carbon dioxide transported around the body in mammals?

A

In blood

60
Q

Describe the flow of blood through the heart

A

From body to right atrium, to right ventricle, to lungs.

From lungs to left atrium to left ventricle to body.

61
Q

What do the valves in the heart do?

A

Prevent the blood flowing backwards

62
Q

Which blood vessel delivers blood from the body to heart?

A

vena cava

63
Q

Which blood vessel carries blood away from heart to the lungs?

A

pulmonary artery

64
Q

Which blood vessel carries blood from the lungs back to the heart?

A

pulmonary vein

65
Q

Which blood vessel carries blood from the heart to the body?

A

aorta

66
Q

Describe where the valves in the heart are.

A

On both sides of the heart

1) between the atrium and ventricle
2) between the ventricle and blood vessel

67
Q

Which blood vessels supply the muscle of heart with blood so it can keep beating?

A

coronary arteries

68
Q

Describe four differences between arteries and veins.

A

Arteries - thick muscular walls
veins - thinner walls

arteries - high pressure
veins - low pressure

arteries - narrow central channel
veins - wide central channel with valves

arteries - carry blood away from the heart
veins - carry blood towards the heart

69
Q

Which characteristics of capillaries allows them to exchange materials with tissues and organs?

A

They have a large surface area from forming networks.

They are very thin walled to allow substances in and out.

70
Q

How is oxygen carried in the blood?

A

In red blood cells.

Oxygen attaches to haemaglobin to make oxyhaemaglobin

71
Q

How are red blood cells specialised to carry oxygen?

A

They have no nucleus, have a biconcave shape and contain haemoglobin.

72
Q

Which part of the lungs carries out gas exchange?

A

alveoli

73
Q

What three factors make alveoli good at gas exchange?

A

large surface area
thin walls
good blood supply

74
Q

How are the main airways kept open?

A

Rings of cartilage

75
Q

How are the lungs kept clean?

A

Mucus traps dirt and microorgansims then cilia (little hairs) move this up and out of the lungs

76
Q

What name is given to the way food is moved through the gut by a wave of muscle contractions?

A

peristalsis

77
Q

What makes the small intestine good at absorbing and amino acids?

A

It has villi (finger-like bits sticking out) that increase the surface area. It has thin walls and a good blood supply.

78
Q

Which part of the digestive system absorbs fatty acids and glycerol?

A

Lacteals which are inside each villi in the small intestine.

79
Q

What do fatty acids and glycerol get taken to from the small intestine?

A

the lymphastic system

80
Q

Which cells in the blood are involved in destroying pathogens?

A

White blood cells

81
Q

What are the two types of white blood cells and what do they do?

A
  1. Phagocytes - engulf pathogens

2. Lymphocytes - produce antibodies which destroy pathogens.

N5 Biology (3 decks)

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