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Flashcards in Biology Paper 2 Deck (67):
1

What is homeostasis?

The regulation of internal conditions of a cell or organism in response to internal or external changes

2

What does homeostasis control?

Blood glucose concentration
Body temperature
Water an ion levels

3

What is the order of the negative feedback system of control system?

Stimulus
Receptor
Sensory neurone
Relay neurone
Motor neurone
Effector
Response

4

What controls body temperature?

The thermoregulatory centre

5

If temperature is too high?

Vasodilation

6

If temperature too low?

Vasoconstriction

7

What does the cerebral cortex control?

Consciousness, intelligence, memory and language

8

What does the cerebellum control?

Coordination

9

What does the medulla control?

Automatic action

10

What does the retina do?

Contains reception cells that are sensitive to light

11

Optic nerve

Carries impulses from retina to the brain

12

Sclera

Tough outer layer with transparent region called cornea

13

Iris

Controls size of pupils and amount of light reaching retina

14

Ciliary muscled and suspensory ligaments

Change shape of lens to focus light

15

What is Accommodation?

Process of changing shape of lens to focus on objects

16

What is myopia?

Short sightedness

17

What’s hyperopia?

Long sightedness

18

Which system is faster?

The effects of the hormones are slower and act for longer

19

What does Thyroxine do?

Increase metabolic rate
Controls growth and development in young
Controlled by negative feedback

20

What happens in blood glucose is too low?

Release glucagon
Glucagon stimulates glycogen to convert back to glucose

21

What controls the balance of water?

Kidneys

22

What is urea?

Produced by liver from breakdown of proteins and contains nitrogen

23

What are excess amino acids converted to?

Ammonia in process called deamination

24

Urine produced by

Filtering blood
Selective reabsorption
Urea and excess water and ions

25

Where does production of urine take place?

Tubules

26

What is ADH?

Released by pituitary gland when blood con. too high
Cause more water to be reabsorbed

27

What does a dialysis machine do?

Takes over role of kidneys

28

What is FSH?

Produced by pituitary gland
Causes eggs to mature
Stimulates ovaries to produce oestrogen

29

What is Oestrogen?

Produced by ovaries
Inhibits FSH
Stimulates LH
Makes lining grow

30

What is LH?

Produced by pituitary gland
Stimulates release of egg

31

What is Progesterone?

Produced by empty follicle in ovaries
Maintains lining
Inhibits FSH and LH

32

What does the combines pill contain?

Oestrogen and progesterone

33

What does a implant contain?

Progesterone

34

What is IVF?

Gives a woman LH and FSH to grow many eggs
Collect eggs
Fertilise eggs with sperm
Insert embryos into womb

35

What is a tropism?

Response involving growth in a direction

36

Gravitropism in shoots

Away=negatively

37

Gravitropism in toots

Towards=positively

38

Phototropism I’m shoots

Towards=positivity

39

Phototropism in roots

Away=negatively

40

What are gibberellins?

Plant hormone important in germination

41

What is ethane?

Gas and hormone controls cell division and ripening of fruits

42

Auxins are used as

Weed killers, grow too fast
Rooting powders
Promoting tissue culture

43

Gibberellins are used for

End seed dormancy
Promote flowering
Increase fruit size

44

Advantages of sexual reproduction

Variation
If environment changes, survive
Selective breeding

45

Advantages of asexual reproduction

One parent
More time and energy efficient
Faster
Identical offspring

46

What is a genome

Organisms entire genetic material

47

What is DNA

Polymer made up of nucleotides

48

What does a nucleotide contain?

A sugar
A phosphate
One of 4 base; A, C, G or T

49

What bases attract

C links with a G
T links with an A

50

How is a protein made?

Proteins synthesised
Carrier molecules bring amino acids in correct order
Chain down, folds
Unique shape to do jobs

51

Who was Gregor Mendel?

Originally, blend of characteristics
Breeding on pea plants
Units called genes
Not recognised though

52

What is an allele?

Different forms of genes

53

What is a genotype?

Combination of alleles present in a gene

54

What is a phenotype?

How the alleles are expressed

55

What is homozygous

Same alleles

56

What is heterozygous

Different alleles

57

What is monohybrid inheritance

Only one gene involved

58

What is polydactyl

Extra fingers or toes caused by dominant alleles

59

What is cystic fibrosis

Disorder of cell membranes cause by recessive alleles

60

How are fossils formed?

Hard parts of animals that do not decay easily
Parts of organisms that have not decayed
Parts of organisms replaced by other materials
Preserved traces of organisms

61

What is selective breeding?

Choose parents by characteristics
Breed together
Offspring choose desired and breed
Continue and repeat

62

What is genetic engineering?

Enzymes used to isolate gene
Gene inserted into vector
Vector used to insert gene into cells

63

Cloning

Remove nucleus from unfertilised egg cell
Insert nucleus into adult body cell
Stimulate egg to divide
Allow embryo to develop
Insert embryo into surrogate

64

Principles of classification

Kingdom-phylum-class-order-family-genus-species

65

What is the binomial system

First part=genus
Second part=species

66

Three domain system is divided into

Archaea
Bacteria
Eukaryota

67

What is speciation?

Populations physically isolated
Variation present
Natural selection operates differently
Populations so different inter breeding not possible