Biology Flashcards

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1
Q

How do dissolved substances move

A

Through diffusion and active transport

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2
Q

How does water move across borders

A

Osmosis

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3
Q

What is osmosis

A

Diffusion of water from a dilute to more concentrated solution through a partially permeable membrane that allows the passage of water molecules

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4
Q

What causes water to move in and out of the cells by osmosis

A

Difference in concentration inside and outside the cell

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5
Q

What do most soft drinks contain

A

Water
Sugar
Ions

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6
Q

Why do sports drinks contain sugar

A

To replace the sugar used in energy release during the activity

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7
Q

Why do sports drinks contain water and ions

A

To replace the water and ions lost through sweat

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8
Q

What happens if water and ions are not replaced

A

The ion/water balance is disturbed and the cells do not work as efficiently

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9
Q

What is active transport

A

When substances are absorbed against a concentration gradient using the energy from respiration

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10
Q

Many organisms are specialised for exchanging materials. How can the effectiveness of an exchange surface increase

A

Having a large surface area
Being thin - to create a short diffusion path
Having an efficient blood supply (in animals)
Being ventilated (in animals, for gaseous exchange)

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11
Q

Why are gas and solute exchange surfaces in humans and other organisms adapted

A

To maximise effectiveness

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12
Q

The size and complexity increases …

A

… The difficulty of exchanging materials

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13
Q

The surface area of the lungs are increased by…

A

… Alveoli

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14
Q

The surface area of the small intestine is increased by…

A

… Villi

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15
Q

How do villi absorb the products of digestion

A

By diffusion and active transport

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16
Q

What are the adaptations of villi

A

Large surface area

Extensive network of capillaries for absorption

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17
Q

Where are the lungs

A

In the upper part of the body (thorax)
Protected by the ribcage
Separated from the lower part of the body (abdomen) by the diaphragm

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18
Q

Why does the breathing system take air into and out of our system

A

So that oxygen can be diffused into the bloodstream

So that carbon dioxide can be diffused from the bloodstream into the air

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19
Q

How does air move into the lungs

A

The ribcage moves down and out

The diaphragm become flatter

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20
Q

What is ventilation

A

The movement of air in and out of the lungs

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21
Q

What do the roots absorb

A

Water and mineral ions

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22
Q

How does carbon dioxide enter plants

A

Through leaves

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23
Q

How is the surface area of leaves increased

A

It’s flattened shape and internal air spaces

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24
Q

What do stomata do

A

Obtain carbon dioxide from the atmosphere

Remove oxygen through respiration

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25
Q

Where is the main water loss in plants

A

In the stomata, in the leaves

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26
Q

When is evaporation faster

A

In hot, dry or windy conditions

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27
Q

How can the stomata help with excessive water loss

A

Close to prevent wilting as water is being lost faster than replaced by the roots

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28
Q

How is the size of stomata controlled

A

Guard cells that surround them

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29
Q

What does the circulatory system do

A

Transport substances around the body

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30
Q

What is the heart

A

An organ, mostly made up of muscle tissue that pumps blood around the body

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31
Q

What are the main chambers in the heart

A

Left atrium
Left ventricle
Right atrium
Right ventricle

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32
Q

Properties of arteries

A

Thick walls compared to the lumen
Thick layers of muscle to make them strong
Elastic fibres to allow them to stretch and bounce back
These carry blood away from the heart

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33
Q

Properties of veins

A

Thinner walls and often have valves to prevent back-flow of blood
These carry blood to the heart

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34
Q

When are stents used

A

When the arteries begin to narrow and restrict blood flow

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35
Q

What are capillaries

A

Thin-walled blood vessels that are involved in the exchange of materials at the tissues
Have permeable walls so substances can diffuse
Supply food and oxygen and take away CO2

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36
Q

Substances needed by the cell in body tissues pass …

A

…out of the blood

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37
Q

Substances produced in the cells pass …

A

… Into the blood, through the capillary walls

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38
Q

What is blood

A

A tissue

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39
Q

What does blood consist of

A

A fluid called plasma in which red blood cells, white blood cells and platelets are suspended

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40
Q

What does blood plasma transport

A

Carbon dioxide from the organs to the lungs
Soluble products of digestion from the small intestine to other organs
Urea from the liver to the kidneys
Hormones
Antibodies and antitoxins produced by white blood cells

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41
Q

What do red blood cells transport

A

Oxygen from the lungs to the organs

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42
Q

In the lungs, oxygen and haemoglobin come together to make

A

Oxyhaemoglobin

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43
Q

Where does oxyhaemoglobin split up

A

Organs (excluding the lungs) into oxygen and haemoglobin

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44
Q

What are white blood cells part of

A

The body’s defence system against microorganisms

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45
Q

What are platelets

A

Small fragments of cells

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46
Q

What do platelets help with

A

Blood to clot at the site of the wound

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47
Q

What are the separate transport systems in flowering plants

A

Xylem tissue
Transpiration stream
Phloem tissue

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48
Q

Xylem tissue

A

Transports water and mineral ions from the roots to the stem and leaves

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49
Q

Phloem

A

Carries dissolved sugars from the leaves to the rest of the plant, including the growing regions and storage organs

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50
Q

Waste products that have to be removed

A

Carbon dioxide

Urea

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51
Q

How is carbon dioxide produced and removed

A

Respiration

Via the lungs when we breathe out

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52
Q

How is urea produced and removed

A

In the liver by the breakdown of amino acids

In the kidneys, in urine which is temporarily stored in the bladder

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53
Q

What happens if the water and ion content is wrong

A

Too much water may move in and out of the cell and damage it

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54
Q

How do water and ions enter the body

A

When we eat and drink

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55
Q

How does a healthy kidney produce urine

A

Filtering the blood
Reabsorbing all the sugar
Reabsorbing the dissolved ions needed by the body
Reabsorbing as much water as the body needs
Releasing urea, excess ions and water as urine

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56
Q

How are people who suffer from kidney failure treated

A

Using a kidney dialysis machine

Having a healthy kidney transplanted

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57
Q

What does treatment by dialysis restore

A

The concentration of dissolved substances in the blood and has to be carried out at regular intervals

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58
Q

In a dialysis machine, a person’s blood flows through a …

A

… Partially permeable membrane

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59
Q

The dialysis fluid contains the same concentration of …

A

… Of useful substances in the blood. This ensures that glucose and mineral ions aren’t lost

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60
Q

What passes out of the blood and into the dialysis fluid

A

Urea

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61
Q

What happens in a kidney transplant

A

A diseased kidney is replaced with a healthy one by a donor

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62
Q

What is a problem with kidney transplants

A

The donor kidney may be rejected by the immune system unless precautions are taken

63
Q

What are antigens

A

Proteins on the surface of cells

64
Q

Why might the donor kidney be rejected

A

The recipient’s antibodies may attack the antigens on the donor organ as they do not recognise them as part of the recipient’s body

65
Q

How do you prevent rejection of the transplanted kidney

A

Use a donor kidney with a ‘tissue-type’ similar to that of the recipient
Treat the recipient with drugs that suppress the immune system

66
Q

What does sweating help to do

A

Cool the body

67
Q

Why does more water have to be taken in as drink or in food when it’s hot

A

To balance the loss of water as when it is hot, more water is lost

68
Q

What is body temperature controlled and monitored by

A

The thermoregulatory centre in the brain (hypothalamus)

69
Q

How is the thermoregulatory centre of the brain adapted

A

By having receptors sensitive to the temperature of blood flowing through the brain

70
Q

How is information about skin temperature given

A

Temperature receptors in the skin send information to the thermoregulatory centre

71
Q

What is the blood glucose monitored and controlled by

A

The pancreas

72
Q

What hormone does the pancreas produce

A

Insulin which allows the glucose to move from the blood into the cells

73
Q

What is glucagon

A

Another hormone produced in the pancreas when blood glucose levels fall.

74
Q

What does glucagon do

A

Converts glycogen into glucose and be released into the blood

75
Q

What is Type 1 diabetes

A

A disease in which a person’s blood glucose concentration may rise to a high level because the pancreas does not produce enough insulin

76
Q

How can Type 1 diabetes be controlled

A

Careful attention to diet, exercise and by injecting insulin

77
Q

Why is more waste produced

A

Rapid growth in the human population and increase in standard living means

78
Q

Waste may pollute

A

Water, with sewage, fertiliser or toxic chemicals
Air, with smoke and gases e.g. sulphur dioxide (acid rain)
Land, with toxic chemicals e.g. pesticides and herbicides, which may be washed from the land into the waterways

79
Q

How do humans reduce the land available for other animals and plants

A

Farming
Building
Quarrying
Dumping waste

80
Q

Effects of large-scale deforestation in tropical areas

A

Increased the release of carbon dioxide into the atmosphere (burning and activities of microorganisms)
More methane in the atmosphere from rice farms and cattle
Reduced the rate at which carbon dioxide is removed from the atmosphere and ‘locked up’ for many years as wood
Less biodiversity due to extinction

81
Q

Deforestation has occurred so that

A

Crops can be grown from which biofuels, based on ethanol, can be produced
There can be increases in cattle and in rice fields to provide more food

82
Q

What does the destruction of peat bogs and other areas of peat release

A

Carbon dioxide into the atmosphere

83
Q

How can the efficiency of food production be improved

A

Reducing the number of stages in a food chain. At each stage in a food chain, less material and energy are contained in the biomass of the organisms

Restricting energy loss from food animals by limiting their movement and controlling the temperature of their surrounding

84
Q

Why is it important to maintain fish stocks at a level where breeding continues

A

Certain species may disappear altogether in some areas

85
Q

What play an important role in conservation of fish stocks

A

Net size and fishing quotas

86
Q

Why is Fusarium useful

A

It helps produce mycoptotein

87
Q

What is mycoptotein

A

A protein-rich food suitable for vegetarians

88
Q

How is the fungus, Fusarium, grown

A

It’s grown on glucose syrup, in aerobic conditions and the biomass is harvested and purified

89
Q

How is the heart a double pump

A

The blood goes around the body twice through the heart:
From the heart to the lungs (deliver CO2 and pick up O2/ gas exchange)
From the heart to the rest of the body

90
Q

Left Atrium

A

Receives oxygenated blood from the lungs and pumps the blood to the left ventricle

91
Q

Left Ventricle

A

Pumps oxygenated blood to the rest of the body

92
Q

Right Atrium

A

Receives deoxygenated blood from the body and pumps this to the right ventricle

93
Q

Right ventricle

A

Pumps deoxygenated blood to the lungs

94
Q

Vena Cava

A

The main vein that carries deoxygenated blood from the body to the right atrium

95
Q

Aorta

A

The main artery that carries oxygenated blood from the heart’s left ventricle away to the body

96
Q

Pulmonary Vein

A

Carries oxygenated blood from the lungs to the left atrium

97
Q

Pulmonary Artery

A

Carries deoxygenated blood away to the lungs from the right ventricle

98
Q

Coronary artery

A

Supplies heart muscle cells with blood rich in oxygen and nutrient

99
Q

How are blood vessels narrowed

A

Fatty deposits can be deposited and restrict the flow of blood

100
Q

What can be done to widen blood vessels

A

Stents

Bypass

101
Q

What are stents

A

Narrow mesh tubes inserted into blood vessels

102
Q

How do stents work

A

Balloons inside the mesh tube are blown up, which expands the mesh tube
This restores blood flow

103
Q

Transpiration

A

Movement of water from the roots (osmosis) through the xylem and out of the leaves (stoma)

104
Q

What do vascular bundles consist of

A

Xylem tissue

Phloem tissue

105
Q

Adaptations of alveoli

A
Increased surface area (for gas exchange) - maximises rate of diffusion
Thin wall (1 cell thick) - flattened cell (even thinner), shortens diffusion pathway
Dense blood supply - Take away the absorbed gases; maintains the concentration gradient 
Moist lining - Allows dissolved gases to diffuse
106
Q

What happens when we inhale

A
Intercostal muscles contract 
Ribcage lifts up and out 
Diaphragm contracts 
Lung volume increases 
Pressure decreases 
Air flows into lungs
107
Q

What happens when we exhale

A
Intercostal muscles relax
Ribcage lowers and goes in 
Diaphragm relaxes 
Lung volume decreases 
Pressure increases 
Air flows out of lungs
108
Q

How does light intensity affect the rate of transpiration

A

They’re in direct proportion until a certain point because by then all the stomata have opened

109
Q

How does temperature affect the rate of transpiration

A

They’re in direct proportion.

The higher the temperature, the faster the water particles move -> evaporate faster -> increased rate of transpiration

110
Q

How does wind speed affect the rate of transpiration

A

When air moves over a leaf, evaporated water molecules are removed.
Faster the air moves, more water removed
Increased diffusion of water out of the leaf
Increased rate of transpiration (high concentration gradient)

111
Q

How does humidity affect the rate of transpiration

A

The more humid the air is, the more water there is in it

Water molecules will diffuse out less quickly, decreasing the rate of transpiration (low concentration gradient)

112
Q

6 reasons why water and ions are important

A

Fluids protect organs (liquid buffer)
Fluids keep skin, mouth, lining of nose and lungs moist
Needed to regulate body temperature
Fluids lubricate joints
Reactants of respiration are dissolved in water and carried to muscle cells
Mineral ions cannot be used as they need to be dissolved in water

113
Q

What changes happen in a cell during respiration

A
Oxygen (in)
Nutrients (in)
Water (in and out)
Carbon dioxide (out)
Energy creates heat in the cell
114
Q

Factors that need to be controlled in the body

A
Body temperature 
Salt levels 
Amounts of nutrients 
Oxygen 
Waste (CO2 and urea)
Water
115
Q

Urea

A

Product of breakdown of protein
Excess amino acids cannot be stored -> amino acids broken down by liver -> urea
Removed by kidneys from the blood

116
Q

Receptor cells

A

Cells that detect change in temperature

117
Q

If the body temperature is too high

A

More sweat is produced by sweat glands

Blood vessels supplying capillaries of the skin dilate

118
Q

How does sweat cool the body

A

Evaporation

119
Q

Vasodilation

A

More blood flows through skin capillaries -> more heat is lost

120
Q

If the body temperature is too low

A

Muscles contract quickly

Blood vessels supplying capillaries of the skin constrict

121
Q

How does shivering warm us up

A

Increases rate of respiration -> some energy is transferred in respiration warming the surrounding tissue

122
Q

Vasoconstriction

A

Less blood flows through the skin capillaries less heat is lost

123
Q

Health risks associated with an unhealthy diet

A
Heart disease 
Diabetes (Type 2)
Obesity 
Tooth decay 
Cancers (Bowel cancer)
Eating disorders (anorexia)
124
Q

Risk factor

A

Things that increase your chance of being ill

125
Q

Identification of risk factors

A
Epidemiological studies (large sample of population studied)
Looks for links between diet and health
126
Q

Why do processed foods have high glucose levels

A

To improve the taste

Quickly absorbed into the blood stream

127
Q

How does the body respond to the sugar high

A

Pancreas releases insulin

Glucose quickly removed from blood and absorbed by cells

128
Q

Result of sugar highs

A

Energy boost becomes sugar low
Lack of concentration
Mood swings
Lack of concentration

129
Q

Symptoms of diabetes

A
Feeling very thirsty 
Urinating frequently 
Feeling very tired 
Weight loss
Muscle loss
130
Q

Reasons behind fast increase in population after 1900

A

Improved diet
Better hygiene
Better healthcare
Lower infant mortality rate

131
Q

What is biofuel made from

A

Natural products by anaerobic fermentation of the products or waste material by decomposers

132
Q

Advantages of biofuel

A

Reduces use of fossil fuels
Carbon neutral
(Biogas/ alcohol) - produce no particulates

133
Q

Disadvantages of biofuel

A

Destroys habitats

Extinction of species

134
Q

Advantages of energy-efficient farming

A

Less energy is transferred out of the food chain, more energy available for humans to consume
Less labour intensive since animals are contained in a reduced area
Less risk of attack by predators
Low production costs

135
Q

Disadvantages of energy-efficient farming

A

Inhumane technique
Greater risk of disease spreading through the animals (close together)
Lower quality of product

136
Q

Tissue fluid

A

Water with dissolved oxygen and glucose surrounding the cells in our body
It’s squeezed out of the blood capillaries to supply the cells with everything they need

137
Q

Why is exchanging substances harder in more complex substances

A

The place where the substances are needed ends up being a long way away from the exchange surfaces

138
Q

Where are the alveoli

A

In the bronchioles, in the bronchi, in the lungs

139
Q

Ventilators

A

Machines that move air into or out of the lungs

They help people who can’t breathe by themselves e.g. if they’re under anaesthetics, or have a lung injury or disease

140
Q

‘Iron lung’

A

Giant cases from the neck to the abdomen, with only the patient’s head out

141
Q

How did ‘iron lungs’ work

A

Air was pumped out of the case
Pressure dropped
The lungs expanded
Air was drawn into the lungs

Air pumped into the case had an opposite effect, forcing air out of the lungs

142
Q

Problem with ‘iron lungs’

A

They could interfere with blood flow to the lower body

143
Q

How do modern ventilators work

A

By pumping air into the lungs

This expands the ribcage - when they stop pumping, the ribcage relaxed and pushes back out of the lungs

144
Q

Problem with modern ventilators

A

Can occasionally cause damage (e.g. burst alveoli) if the lungs can’t cope with the artificial air flow

145
Q

What are phloem tubes made of

A

Columns of living cells with small holes in the ends to allow food to flow through

146
Q

What are xylem tubes made from

A

Made of dead cells joined end to end with no end walls between them and a hole down the middle

147
Q

Where do xylem tubes carry water and minerals

A

To the stem and leaves in the transpiration stream

148
Q

What is transpiration caused by

A

The evaporation and diffusion of water from inside the leaves

149
Q

Why is there a constant transpiration stream

A

Transpiration causes a slight shortage of water in the leaf so more water has to be drawn up from the rest of the plant to replace it
Therefore more water is drawn up from the roots

150
Q

What are nephrons

A

Filtration units in the kidneys

151
Q

What are bogs

A

Areas of land that are acidic and waterlogged

152
Q

How is peat formed

A

Plants that live in bogs don’t decay when they die because of the lack of oxygen
The partly-rotted plans gradually build up to form peat

153
Q

How are root hairs specialised

A

The cells on the surface of plant roots grow into long ‘hairs’ which stick out into the soil -> larger surface area