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GCSE Science > Biology Paper 2-Major Focus Of Exam > Flashcards

Biology Paper 2-Major Focus Of Exam Flashcards

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1
Q

What is homeostasis?

A

Regulation of internal body conditions

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2
Q

What is your body temperature monitored and controlled by?

A

The brain

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3
Q

What is the part of the brain that monitors and controls body temperature?

A

Thermoregulatory centre

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4
Q

How can the thermoregulatory system control blood temperature?

A

It contains receptors which are sensitive to the temperature of the blood

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5
Q

Besides the thermoregulatory centre containing receptors sensitive to blood, what is another way the thermoregulatory centre can control temperature?

A

The skin contains receptors, that send electrical impulses down sensory neurones to the thermoregulatory centre

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6
Q

Give 3 ways that body temperature can be returned to normal when it has gone too high

A

Sweating
Flushing
Hairs lie flat

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7
Q

How does sweating cool the body down?

A

Releases water on surface of the skin

Water evaporates, taking energy

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8
Q

What is flushing a result of ?

A

Vasodilation of blood capillaries

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9
Q

How does vasodilation of blood capillaries cool the body down?

A

More blood follows to surface of skin
Heat can transfer out of
Blood to surroundings

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10
Q

Give 3 ways body temperature can be returned to normal when too low

A

Vasoconstriction
Shivering
Hairs stand up

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11
Q

How does vasoconstriction warm the body up?

A

Less blood flow to surface of skin

Less heat lost to surroundings

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12
Q

How does shivering warm the body up?

A

Causes our skeletal muscles to contract
Increases rate of respiration to generate needy for the contraction
Releases heat

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13
Q

What is the control of body temperature an example of?

A

Homeostasis

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14
Q

What are 2 comparisons of the nervous system and the endocrine system?

A

The nervous system is faster

The effects of the nervous system are more short lived

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15
Q

What does the endocrine system consist of?

A

A number of glands

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16
Q

What do glands secrete?

A

Hormones directly into the blood

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17
Q

What is a hormone(3)

A

A chemical messenger that passes through the bloodstream to a target organ

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18
Q

Besides the endocrine system have a slower, but more long-lasting effect, what’s another key difference between the NS and the ES?

A

The nervous system uses electrical impulses, whereas the endocrine system uses hormones

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19
Q

What is the role of the pancreas?

A

Releases hormones- eg insulin - control blood glucose concentration

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20
Q

What do the ovaries and testes release?

A

Hormones involved in puberty and reproduction

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21
Q

What does the thyroid gland produce?

A

Hormones involved in growth and regulating the body’s basal metabolic rate

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22
Q

What does the adrenal gland release?

A

The hormone adrenaline

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23
Q

When is adrenaline produced?

A

In times of fear or stress

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24
Q

Where is the pituitary gland located?

A

In the brain

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25
Q

What is another word for the pituitary gland?

A

The master gland

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26
Q

What does the pituitary gland release?

A

A number of different hormones depending on the conditions

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27
Q

What do pituitary hormones cause?

A

Other hormones to be released

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28
Q

What do pituitary hormones act on?

A

Other glands

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29
Q

When does the pancreas produce insulin?

A

After a meal, when blood glucose concentration is high

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30
Q

Where does insulin travel and what does it trigger?

A

Travels in the bloodstream
And triggers body cells to take up
Glucose

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31
Q

Besides triggering cells to

Uptake glucose, what else can insulin trigger?

A

Liver and muscle cells to store excess glucose as glycogen

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32
Q

What is wrong with person with type 1 diabetes?

A

Their pancreas doesn’t produce enough insulin

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33
Q

What do people with type 1 diabetes do to counteract their problem?

A

Inject themselves with insulin

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34
Q

What’s wrong with people who have type 2 diabetes?

A

Cells stop responding to insulin

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35
Q

How can type 2 diabetes be treated?

A

A controlled carb diet

Take exercise

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36
Q

What is a major risk factor for type 2 diabetes?

A

Obesity

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37
Q

If the blood glucose concentration is too low, what hormone does the pancreas release?

A

Glucagon

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38
Q

What does glucagon trigger?

A

Liver cells to convert glycogen back to glucose

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39
Q

In a graph of blood glucose concentration against time, what does the line fluctuate?

A

The balance between the releasing of insulin and glucagon

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40
Q

What type of cycle do insulin and insulin form?

A

Negative feedback

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41
Q

What are 3 ways we can lose water?

A

Exhaling
Sweat
Urination

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42
Q

What substances can sweat contain?

A

Sodium ion and urea

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43
Q

How is urea removed from the kidney?

A

Blood enters kidney through an artery
Contains urea
Kidney removes this and excess substances
Leave kidney as urine and store in bladder

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44
Q

How does the kidneys adjust the level of molecules in the blood?

A

Blood passes through capillaries
Small molecules filtered out- eg urea and water and glucose
Pass into tube
All of glucose, some water and ions are reabsorbed back into the blood
Urea, excess water and ions are excreted as urine

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45
Q

How do we deal with excess amino acids?

A

Liver breaks down the amino acids to produce ammonia
Desmond room
Ammonia is converted to urea and excreted

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46
Q

What hormone does the pituitary gland release when the level

Of water in the blood falls?

A

ADH

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47
Q

What does ADH cause?

A

The kidney tubules to become more permeable to water

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48
Q

Increased ADH=

Less____ produced

A

Urine

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49
Q

What does the ADH cause the kidneys to?

A

Reabsorb more water into the blood

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50
Q

If blood becomes too dilute, what does the pituitary gland stop releasing?

A

ADH

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51
Q

When the pituitary gland stops releasing ADH, is more or less
Water reabsorbed back in the blood by the kidneys?

A

Less

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52
Q

If a person has kidney failureX what will their blood contain?

A

A higher concentration of water, ions and urea

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53
Q

In kidney dialysis, where does the patients blood pass over?

A

A semi permeable membrane

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54
Q

What will the semi permeable membrane not allow through?

A

Large molecules like proteins

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55
Q

What’s on the other side of the semi permeable membrane?

A

Dialysis fluid

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56
Q

What does the dialysis fluid contain ?

A

Normal

Concentration of water and ions, and no urea

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57
Q

Why does the urea diffuse from the blood into the dialysis fluid ?

A

Because of the concentration gradient

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58
Q

Why is the dialysis fluid constantly refreshed?

A

To
Maintain a steep
Concentration gradient

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59
Q

What’s some disadvantage of kidney dialysis?

A

Inconvenient- visit hospital regularly

Controlled diet- low protein

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60
Q

What’s an alternative to kidney dialysis?

A

Kidney transplant

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61
Q

What is an advantage of dialysis?

A

No shortage of machines

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62
Q

What’s 2 advantages of a kidney transplant?

A

Allow for normal life

Only expensive initially

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63
Q

What are 2 disadvantages of kidney transplants?

A

Shortage of donors

Patients need to take anti rejection drugs for rest of their life

64
Q

What is phototropism?

A

A response of a plant to light

65
Q

How did scientists first suggest plant tips produced a hormone?

A

They removed the tips of shoots and found they didn’t grow towards the light
Then they put foil
Over the tip and found it didn’t grow towards the light either

66
Q

What did scientists do to tell us that the lower parts of shoots aren’t sensitive to light?

A

They covered the lower parts of the shoot the shoot grew towards light

67
Q

In shoots, what does auxin trigger?

A

Cell growth

68
Q

Where does the light cause auxin to concentrate on?

A

The darker side of the shoot tip

69
Q

Because of auxin, when plants are shone with light, does the darker side
Grow faster?

A

Yes

70
Q

What do plant roots grow towards?

A

The force of gravity

71
Q

What is gravitropism or geotropism?

A

Plant response to gravity

72
Q

What does gravity cause the auxin to

Do?

A

Concentrate on the lower side

73
Q

In roots, does auxin promote
Or inhibit
Cell growth?

A

Inhibit

74
Q

In the roots due to auxin, does the lower side grow faster or slower than the upper side?

A

Slower

75
Q

What are giberellins

Important for?

A

Seed germination
Flower
Production

76
Q

What does Ethene control?

A

Cell division and ripening of fruits

77
Q

What are producers important?

A

They are the source of biomass

78
Q

What do scientists call molecules such as glucose?

A

Biomass

79
Q

What type of consumer eats the producer?

A

Primary consumer

80
Q

What type of consumers eat primary consumers?

A

Secondary consumers

81
Q

What organisms eats a secondary consumer?

A

Tertiary consumer

82
Q

What are predators?

A

Consumers that kill other animals

83
Q

What’s the prey?

A

The animal being eaten

84
Q

Describe the predator prey cycle using an example

A 
Warm summer- lots of grass
More of rabbits offspring survive 
Rabbit population increases 
Fox population increases- more prey 
Rabbit population falls- more predators 
Fox population falls- less prey 
Rabbit population increases- less predators
Cycle
85
Q

What is the predator and prey cycle only true in ?

A

A stable community

86
Q

What is a stable community?

A

A community where all biotic and abiotic factors are balanced

87
Q

What a couple of examples of abiotic factors?

A

Wind direction
Temperature
Levels of moisture

88
Q

What is random sampling used to compare?

A

Numbers of organisms in different areas

89
Q

What do we use to carry out random sampling?

A

A quadrat

90
Q

How do we use a quadrat?

A

Place it on the ground

Count number of organisms inside it

91
Q

In random sampling, where is the quadrat placed?

A

At random locations across the area - could use random numbers To select location

92
Q

Describe how we can compare to areas, one with light conditions, one with dark conditions

A

Place quadrat randomly
Count number of organisms inside it

Move quadrat to different location
Count number of organisms

Repeat until we sample a large number of random locations
Dark conditions
Repeat the same steps and compare

93
Q

Why do we place the quadrat down a large number of times ?

A

More likely to get valid results

94
Q

Why don’t we use a quadrat in one area?

A

Won’t give sample that accurately represents the whole area

95
Q

What’s the equation for total population size?

A

Total area/area sampled x number of organisms of specifies in sample

96
Q

When do we use sampling along a transect?

A

How number of species change as we move across a habitat

97
Q

What is a transect?

A

A line

98
Q

How do we use a transect?

A

Place so it runs across the habitat

99
Q

After placing the transect across the habitat, what do we do next?

A

Use a quadratic to count number of organisms at intervals on the transect

100
Q

When using a transect and quadrats on sand dunes inland from the sea, how can we get valid results?

A

Repeat the whole process with the line shifting along

101
Q

Describe how to measure the population size of a common species in a habitat

A

Use 2 tape measures to lay out an area(eg 10 by 10m)
Use a random number generator to create a set of co ordinates(4,5)
Count number of species within it
Record number and repeat none more times to get a 10 time sample
Estimate whole population using an equation

102
Q

If we thinks there’s a big difference in the percentage of daisies within an area, what should we do?

A

Throw more quadrats- cover a higher percentage of the area

103
Q

Describe how we use transects and quadrats to see how number of daisies changes from the tree outwards

A

Place tape measure at tree
Use quadrat to count daisies at start
Record light intensity - light meter
Move transect 1m down transect and repeat

104
Q

How does carbon enter the carbon cycle?

A

By photosynthesis

105
Q

How does carbon dioxide return back to the atmosphere?

A

By aerobic respiration

106
Q

Describe the steps in the carbon cycle

A 
CO2 in atmosphere 
Plants gain it by photosynthesis 
Return it by respiration
Organisms eat plants and gain carbon 
They respire
Carbon in waste
Broken down by decomposerss
They respire- co2 returned
Combustion of fossil fuels- release
107
Q

If decomposes can’t function effectively, what happens?

A

Carbon is dead remains is converted to fossil fuels

108
Q

Why are decomposers important?

A

They cycle materials
Return co2 and release mineral
Ions

109
Q

Describe the steps in the water cycle

A

Energy from sun causes water to evaporate from surface of the sea
Water vapour condenses in air, forming clouds
Transpiration and exhalation
Water in clouds fall as precipitation
Some water reevaporates, some
Passes in rocks to make aquifers

110
Q

What role do organisms play in the water cycle?

A

Animals- exhalation

Plants- transpiration

111
Q

What are examples of decomposers?

A

Bacteria and fungi

112
Q

What do gardeners use compost as natural fertilisers?

A

Compost is rich in minerals

113
Q

What are some conditions for decomposers?

A

Temperature
Water
Oxygen

114
Q

Why does decomposition take place at warmer temperatures?

A

Enzymes work faster

115
Q

Why is compost usually quite warm?

A

Decomposers release energy when they respire

116
Q

Why is it important that the compost isn’t too hot?

A

Enzymes in decomposers denature and die

117
Q

Why do decomposers work faster if compost is moist?

A

Many chemical reactions in decay require water

118
Q

Why is a plentiful supply of oxygen important for decomposers?

A

They carry out aerobic respiration

119
Q

What’s an adaptation of compost bins?

A

Holes

120
Q

Why do some compost bins have holes?

A

Allow oxygen in for decomposition

121
Q

Why do gardeners mix up the compost?

A

Allow oxygen to distribute evenly

Break up large clumps/ increase surface sea for decomposition

122
Q

In the absence of oxygen, what do decomposers carry out?

A

Anaerobic decay

123
Q

What does anaerobic decay mainly produce?

A

Methane- biogas

124
Q

What are biogas generators used to provide?

A

Fuels for homes

125
Q

Explain what goes wrong on the regulation of blood sugar levels in a person with type 1 diabetes

A

Pancreas produces little insulin
Liver is unable to remove glucose from blood
This causes levels to rise to a dangerous level

126
Q

Hypopituitsrism is a condition in which the pituitary gland stops secreting hormones, why could people have certain symptoms of all are linked to low Thyroid hormone levels?

A

Pituitary gland releases hormones that act on other glands, directing them to release hormones
Oof a pituitary gland hormone that acts in the thyroid gland isn’t released, the thyroid gland may stop releasing hormones, causing the symptoms

127
Q

Why after exercise does your urine go a dark colour?(6)

A

Sweat while running=water loss
Receptors in brain detect decreased water content in bloor
Coordination centre in brain receives this and coordinates a response- pituitary gland
Pituitary gland released ADH
ADH caused kidneys to reabsorbed more water, resulting in less water being released in urine

128
Q

Explain how toxic waste substances are removed from the bloodstream during dialysis

A

There’s a partially permeable membrane between fluid and machine
Fluid contains normal conc of glucose and ions so glucose didn’t lost
Urea sissies into fluid and released into good then excreted
Protein molecules are too large so can’t diffuse

129
Q

Describe the role of kidneys in selective reabsorption to produce urine

A

Kidneys act as filters and filter blood
All of glucose is selectively reabsorbed
Some water and ions are reabsorbed
Waste produces like excess water and urea are released through urine

130
Q

What’s meant by a positive gravitropic response?

A

Plants grow upwards, against gravity

131
Q

Explain how some of shoots from seedlings bend towards light

A

Unequal distribution of auxin
More aux in on darker side
Causes elongation of darker sode

132
Q

Why does asexual reproduction lead to genetically identical offspring?

A

No mixing of genetic information as there’s no fusion of gamete’s

133
Q

Similarities and differences between meiosis and mitosis

A

Mitosis- 1 parent, produces genetically identical offspring
Meiosis- 2 parents , produce variant offspring
Both involve the replication of dna

134
Q

Describe the structure of dna

A

Polymer made up of repeating sun units
It’s 2 strands form a double helix structure
Consists of sequences of nucleotides
Nucleotides contains a sugar phosphate and base
T pairs with A and c with g as complementary base pairs

135
Q

How can cystic fibrosis lead to damage if the lungs

A

Produces mucus
Trapped in respiratory pathways
Affects cell membranes and can lead to death

136
Q

Why do many compost heaps have air holes?

A

Rate of decay is faster because it slows oxygen in so microorganisms can respire aerobically

137
Q

Explain how carbon form desd organisms is recycled

A

Decomposers break down dead organic matter through the use of enzymes
As they respire aerobically, they releases carbon dioxide
This carbon dioxide is returned to atmosphere and absorbed by plants for photosynthetic

138
Q

Similarities and differences between quadrats and transects

A

Both used with each other
Quadrats- used in random sampling to avoid bias+ count number of organisms in specific area
Transects- used in systematic sampling and show distribution in an area

139
Q

Independent variable for required practical 8- effect of light on seedling

A

Conditions - light/dark

Direction of light

140
Q

Dependent variable for required practical 8

A

Mean height of seedlings

141
Q

Control variables of seedling practical

A

Number of seeds
Temperature
Volume of water seedlings are given

142
Q

What can you do to decide where you place your first quadrat?

A

Use a random number generator to generate a set of coordinates

143
Q

Describe the negative feedback lol that takes place when blood glucose levels are too low

A

Stimulates pancreas to release glucagon
Causes glycogen in liver to be converted to glucose
Blood sugar Returns to normal
Glucagon no longer released

144
Q

Explain how the brain is altered to changes in external temperature

A

Temperature reflected in skin and thermoregulatory centre has receptors that detects blood temp
Send impulse to brain

145
Q

Suggest what effect replacing a cotton wool pad with a ball of cotton wall has

A

Hall is uneven so can change volume and distribution of water

146
Q

Describe the plant hormones practical

A

Put cotton wool into 3 Petri dishes and add same vol of water
Add 10Seeds to each dish and place them in warm place
Allow seeds to germinate and add water if cotton wool dries out
Once seeds have germinated, ensure dishes contain same number of seeds
1 dish sits in full light , 1 sits in dark cupboard , 1 sits in partial light
Every day for a week, measure height of each seedling and record results
Calculate mean of seedlings each day and compare mean heights in different locations

147
Q

State some control variables and how they can be controlled

A

Number of seeds- use same number of seeds in each dish and remove any if need be
Type of seeds- use seeds that come from same packet
Vol of water- use measuring cylinder to add same vol of water
Temperature- keep dishes in place where temp is stable

148
Q

Explain why more water is lost by breathing during a race

A

More energy needed
More respiration
Increased breathing rate to supply oxygen

149
Q

What’s the end 2 marks for the question explain how carbon is recyclables into the growth of new leaves ?

A

Glucose is produced in photosynthesis and used to make amino acids and proteins , required for growth of new leaves

150
Q

Explain how can a mutation could cause the enzyme not to work

A 
Changes from c to t- changes in bases
Changes amino acid
Change protein
Shape  if active site changes 
Enzyme no longer fits substrate
151
Q

Disadvantage of factory farming

A

Disease spreads rapidly

Antibiotics can build up on food chain

152
Q

Explain how effiecincu of factor farming can be increased

A

Kept in temp controlled and restrict environment
Less energy lost in movement and less energy lost in regulating temp
More muscle
Mass
On each pig

153
Q

Suggest what would happen in the body of a person that has a disorder due to an overactive thyroid gland

A

Too much thyroxine released into blood
Raises BMR
Increase in respiration

154
Q

2 biological reasons why kidney transplant is better than dialysis

A

Blood ain’t in contact with machine, so lower risk of infection
Changes in concentrations of minerals are minimised , so less chance of causing damage to crlls

155
Q

3 differences between mitosis and meiosis

A

Mitosis produces 2 daughter cells, whereas meiosis produces 4
One cell division in mitosis, but 2 in meiosis
Mitosis produces genetically identical offspring, meiosis produces variant

GCSE Science (8 decks)

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