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Biology Paper 2 > Homeostasis And Response > Flashcards

Homeostasis And Response Flashcards

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1
Q

What is homeostasis?

A

The regulation of internal conditions of a cell / organism to maintain optimum conditions for function in response to internal / external changes

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2
Q

What does homeostasis maintain inside a plant cell?

A

Maintains optimum conditions for enzymes action and all cell functions

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3
Q

What does homeostasis maintain in a human body?

A

Body temperature and water levels

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4
Q

What two types of responses are there?

A

Nervous and chemical

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5
Q

What does a control system include?

A

Cells called receptors, co-ordination centres that receive and process info from receptors, effectors which bring out responses that restore optimum levels

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6
Q

What does the brain do?

A

It controls the blood temperature so enzymes can work at their optimum temp and not denature

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7
Q

What do the lungs do?

A

Controls amount of water lost when we breathe out

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8
Q

What does skin do?

A

It controls skin temperature through sweat, controls how much water and ions are lost in the sweat

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9
Q

What do the kidneys do?

A

Controls amount of water lost in urine and ions lost in urine

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10
Q

What does the pancreas do?

A

Controls the blood sugar by producing insulin and glucagon

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11
Q

Where does the impulse come from in the sensory neurone?

A

Receptors

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12
Q

Where does the impulse come from in the relay neurone?

A

Sensory neurone

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13
Q

Where does the impulse come from in the motor neurone?

A

Relay neurone

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14
Q

Where does the sensory neurone send the impulse?

A

Relay neurone

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15
Q

What does the relay neurone send the impulse?

A

Motor neurone

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16
Q

Where does the motor neurone send the impulse?

A

Effector

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17
Q

What does the chain for the nervous system look like?

A

stimulus -> receptor -> sensory neurone -> cns -> motor neurone -> effector

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18
Q

What is a dominant allele?

A

Something that is always expressed even if one allele is present

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19
Q

What is a recessive allele?

A

Something that is only expressed if two alleles are present

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20
Q

What is a genotype?

A

Combination of alleles

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21
Q

What is a phenotype?

A

Feature that is expressed

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22
Q

What is homozygous dominant?

A

2 dominant alleles present, dominant trait seen in the phenotype

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23
Q

What is homozygous recessive?

A

2 recessive alleles present, recessive trait seen in phenotype

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24
Q

What is heterozygous?

A

2 dominant and 2 recessive alleles are present, dominant trait seen in phenotype

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25
How many pairs of chromosomes do humans have?
23
26
Is cystic fibrosis dominant or recessive?
Recessive
27
Is polydactyl recessive or dominant?
Dominant
28
How are messages sent in the endocrine system?
Messages are sent using chemicals called hormones
29
Where are hormones made?
They are made by glands in the blood
30
How are hormones transported?
They are transported through the plasma to their target organ
31
How do target organs trigger a response?
They have receptors which detect the hormone and trigger the response
32
Where is FSH made?
In the pituitary gland
33
What does FSH do?
It stimulates the maturing of eggs in the ovary , stimulates the ovary to make oestrogen
34
Where is oestrogen produced?
Ovary
35
What does oestrogen do?
Stimulates thickening of the uterus, inhibits production of FSH and stimulates the pituitary to make LH
36
Where is LH produced?
In the pituitary gland
37
What does LH do?
Stimulates the release of an egg which is also known as ovulation
38
Where is progesterone produced?
Ovary
39
What does progesterone do?
Maintains the thickness of the uterus lining
40
How are blood sugar levels regulated in the body? (High blood sugar)
If blood sugar is too high, insulin is released and converts glucose into glycogen then it’s stored in the liver
41
How are blood sugar levels regulated in the body? (Low blood sugar)
Glucagon is released, it converts glycogen back into glucose , glucose is in the blood
42
What are some ways to control fertility?
Oral contraceptives - contain hormones to inhibit FSH production so that no eggs mature Barrier methods - prevent sperm reaching the egg Abstaining from intercourse - no egg can be fertilised
43
What s involved in asexual reproduction?
Involves no joining of sex cells, only one parent is involved, offspring are genetically identical
44
Whats involved in sexual reproduction?
Involves joining of gametes, two parents are involved leading to a variation in offspring
45
What is an allele?
Contains two copies of each gene
46
What type of cell division are gametes made from?
Meiosis
47
What is the structure of DNA?
DNA is a polymer made up of the same repeating units of nucleotides, double helix
48
What do genes code for?
Particular amino acids
49
What is the process to genetically modify something?
You need to cut out a gene by using an enzyme then transfer it to a different organism’s genome to give it a specific characteristic using a vector
50
What can genetic engineering be used for?
Plant crops to make them more resistant to diseases or to make crops bigger
51
What are genetically modified crops modified for?
To make them resistant to herbicides or insect attacks, make them resistant to diseases, produce bigger and better fruits
52
What are some concerns to genetically modified crops?
The effect on population of wild flowers and insects, effects of eating genetically modified crops on human health haven’t been fully explored
53
What is genetic screening?
It involves an analysis of a person’s DNA to see if they carry alleles that cause genetic disorders
54
What is embryo screening?
Scientists carry out IVF and then once the embryos have reached the 8 cell stage one cell is removed and the cells are tested for the disorder causing alleles, embryos that dont contain the disorder allele are then implanted back into the uterus
55
What is antenatal?
DNA or chromosome of a foetus are analysed before they are born
56
What is neonatal?
DNA is analysed when the baby is born to detect genetic disorders in order to treat them early
57
What can selective breeding lead to?
Inbreeding
58
What are fossils?
Fossils are the remains of organisms from millions of years ago which are found in rocks
59
How may fossils be formed?
- from parts of organisms that have not decayed because one or more conditions for decay are absent - when parts of organisms are replaced by minerals as they decay - are preserved traces of organisms such as footprints, burrows and rootlet traces
60
What is extinction?
Where there are no remaining individuals of species still alive
61
What are some causes of extinction?
- changes to the environment over geological time - new predators - new diseases - new , more successful competition - single catastrophic event
62
What is evolution?
The gradual change in the inherited characteristics of a population over time through a process of natural selection which may result in the formation of a new species
63
what is a sound and balance receptor?
ears
64
what is a chemical receptor?
nose and mouth
65
what is a pressure and temperature receptor?
hand
66
what happens at a synapse when an impulse arrives?
- electrical impulse travels down neurone - neurotransmitters are released - neurotransmitters diffuse across the synapse
67
what neurones are involved in a reflex?
sensory relay and motor
68
what is the independent variable of the reaction practical?
hand use, gender, age, caffeinated drinks vs water
69
what is the dependent variable of the reaction practical?
distance ruler fell - cm
70
what are some control variables in the reaction practical?
distance between thumb and first finger, height ruler was dropped from
71
What are the stages to evolution?
- variation - survival - breeding - genes are passed on
72
What is some evidence for evolution?
Fossils, antibiotic resistance in bacteria
73
What happens in antibiotic resistance in bacteria?
- mutations of bacterial pathogens produce new strains - some strains might be resistant to antibiotics so theyre not killed - they then survive and reproduce so the population of the new strain increases - new strain spreads because people are not immune to it
74
What are the 3 domains in the three domain system?
Bacteria, archaea and eukaryota
75
How are bacteria classified?
Prokaryotic cells
76
How are archaea classified?
- prokaryotic cells - live in extreme environments
77
How are eukaryota classified?
Eukaryotic cells
78
What are the classification groups?
-kingdom -phylum -class -order -family -genus -species
79
What is the binomial system?
Organisms are named genus then species
80
What is used to classify organisms?
Structural features, modern classification uses
81
Why is the binomial system so useful?
Organisms which have the same genus are related to each other, this shows they had a common ancestor at the time
82

Biology Paper 2 (1 decks)

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