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GCSE Science > Biology (section 1) > Flashcards

Biology (section 1) Flashcards

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1
Q

What are the 5 senses?

A 
Smell
Sight
Taste
Touch
Hearing
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2
Q

What are the different sense organs, and what do they sense?

A

Eye – light

Skin – touch, temperature, pressure, pain

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3
Q

What is the job of the nervous system?

A

To sense and respond to the outside environment

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4
Q

What is the nervous system made up of?

A

Nerves (sensory, motor and relay neurons), spine & brain

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5
Q

What is a receptor? Give some examples

A

A receptor receives information from the outside environment

Eye – light
Nose – smell
Skin – pressure & temperature

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6
Q

What is the job of a sensory neurone?

A

To take information from the receptor to the CNS

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7
Q

What is the job of a motor neurone?

A

To take information from the CNS to the effector (muscle / gland)

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8
Q

What is the job of a relay neurone?

A

A relay neurone passes information within the CNS – these are used in reflex reactions to pass information straight from a sensory neurone to a motor neurone, bypassing the brain

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9
Q

What is a synapse and how does it work?

A

A synapse is the gap between 2 nerves – chemicals called neurotransmitters pass across the gap

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10
Q

What is an effector?

Give an example of an effector in a reflex reaction?

A

An effector is the muscle or gland that is targeted in a nervous response (e.g. you blink because you have dust in your eye (the effector is the muscle in the eye lid))

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11
Q

What happens in a reflex action?

A

Receptor → sensory neurone → relay neurone → CNS → motor neurone → effector

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12
Q

What conditions within the body need to be controlled?

A 
Temperature (37°C)
Water level
Ion level
Glucose level
Carbon dioxide
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13
Q

How does water leave the body?

A

Sweat

Urine (via kidneys)

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14
Q

How are ions lost from the body?

A

Sweat
Breath
Urine (via kidneys)
Faeces

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15
Q

Why is it important to control temperature & how is this controlled?

A

Temperature must be controlled as enzymes work best at 37°C – temperature is controlled by skin and blood vessels

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16
Q

What is a hormone, and where are they secreted from?

A

Hormones are chemical substances that control processes within the body – they are secreted by glands (e.g. the adrenal and pituitary gland)

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17
Q

How do hormones travel around the body?

A

In the blood

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18
Q

What are the main differences between a hormonal and nervous reaction?

A

Hormonal control: -
• Slow
• Travel within blood
• Go to whole body

Nervous control: -
• Fast
• Travel via nerves
• Go to a specific organ

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19
Q

Why is it important that blood sugar levels are controlled?

A

To maintain a constant energy supply

Too high or too low blood sugar levels can result in a coma / death

Blood sugar is controlled by the hormone insulin

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20
Q

What is the function of the hormone oestrogen and where is it secreted from?

A

Oestrogen, secreted from the ovaries, inhibits (stops) FSH production and increases LH production

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21
Q

What controls the menstrual cycle?

A

Hormones control the menstrual cycle (oestrogen; progesterone; LH; and FSH)

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22
Q

What are the 4 hormones involved in maintaining the menstrual cycle?

A

Oestrogen
Progesterone
LH
FSH

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23
Q

What is the function of the hormone FSH, and where is it secreted from?

A

FSH, secreted by the pituitary gland, causes the egg to mature and stimulates the ovaries to produce oestrogen

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24
Q

How are hormones used to control fertility?

A

FSH is used to increase fertility

The ‘pill’ prevents FSH (so preventing pregnancy)

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25
Q

How can FSH be used to control fertility?

A

FSH can be given to women who want to get pregnant but are having difficulty

FSH increases the number of mature eggs, increasing the likelihood of becoming pregnant and mature eggs can be collected for IVF

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26
Q

How does the contraceptive pill work?

A

Oestrogen and progesterone are used to stop FSH production, stopping any eggs maturing, preventing pregnancy

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27
Q

What are the possible problems with using FSH for fertility treatment?

A

FSH can lead to multiple eggs being released, resulting in multiple offspring

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28
Q

What does a healthy diet consist of?

A 
A balance of: -
•	Carbohydrate
•	Protein
•	Fat
•	Vitamins
•	Minerals
•	Fibre
•	Water
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29
Q

What does malnourished mean and what can this lead to?

A

If you do not eat a healthy balanced diet you will be malnourished – this can lead to deficiency diseases as well as weight problems (too fat / thin

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30
Q

What deficiency diseases are caused by a lack of: -

  • Iron
  • Vitamin C
  • Vitamin D
A

Iron  anaemia

Vitamin C  scurvy

Vitamin D  rickets

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31
Q

What health problems are linked to a lack of food?

A

Reduced resistance to infection / irregular periods

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32
Q

What is metabolic rate and what affects it?

A

Metabolic rate is the rate at which the chemical reactions occur within the cells – this is affected by exercise, proportion of muscle to fat and genetic makeup

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33
Q

What may cause people to need less food?

A

Less exercise / warmer climate

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34
Q

How does exercise affect your metabolic rate?

A

Metabolic rates stay high for some time after exercise

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35
Q

What diseases are linked to obesity?

A

Arthritis
Diabetes (type II)
High blood pressure
Heart disease

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36
Q

What is arthritis?

What is diabetes?

A

Arthritis – wearing of the joints

Diabetes – high blood sugar

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37
Q

What type of lipoproteins are ‘bad’ cholesterol?

A

LDLs – low-density lipoproteins

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38
Q

Where is cholesterol made?

A

Liver

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39
Q

What affects the level of cholesterol in the blood?

A

Diet and inherited features

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40
Q

What are the health risks associated with too much cholesterol?

A

Diseases of the heart and blood vessels

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41
Q

What are the 2 types of lipoprotein that carry cholesterol in the blood?

A

LDLs – low-density lipoproteins

HDLs – high-density lipoproteins

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42
Q

How is cholesterol carried in the blood?

A

As lipoproteins

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43
Q

Which type of fat increases the level of cholesterol in your blood?

A

Saturated fats

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44
Q

Which type of fat can reduce the blood cholesterol levels and improve the balance of LDLs and HDLs?

A

Monounsaturated and polyunsaturated fats

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45
Q

Why is too much salt bad for you?

A

Increased blood pressure for ~30% of the population

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46
Q

Which types of food contain high levels of fat and salt?

A

Processed foods

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47
Q

What are statins used for?

A

Lowering the risk of cardio-vascular disease

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48
Q

What is a drug?

A

A substance, which affects the way the body or mind functions – the affects can be positive or negative

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49
Q

How are drugs tested before they are prescribed to patients?

A

Tested in labs on cells and tissues / on animals and human volunteers / in clinical trials with a small dose

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50
Q

What was thalidomide developed to treat, what were its side effects and what is it now used to treat?

A

Developed as a sleeping pill but not tested during pregnancy – leads to offspring with limb abnormalities. Now affective treatment for leprosy

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51
Q

What are withdrawal symptoms and why do people suffer from these?

A

Withdrawal symptoms are experiences when an individual stops taking a drug – these are suffered as the body has become dependent on the drug (the drug has affected the body chemistry of the individual)

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52
Q

What dangerous substances are found in cigarettes?

A

Nicotine  addictive

Carcinogens  cancer causing

Tar  coats lungs

Carbon monoxide  reduces oxygen carried within blood

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53
Q

What is a carcinogen and where are these found?

A

Carcinogens are chemicals, which cause cancer – found within cigarettes

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54
Q

How can smoking when pregnant affect the baby?

A

Smoking can deprive the foetus of oxygen and lead to a low birth weight

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55
Q

What is carbon monoxide and what affect does it have on the body?

A

Carbon monoxide is a poisonous gas, which reduces the ability for the red blood cells to carry oxygen around the blood

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56
Q

How does alcohol affect the body and what are the long-term effects?

A

Alcohol affects the nervous system and slows reaction times

Long-term effects include sclerosis of the liver and brain damage

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57
Q

What did Semmelweiss do to help prevent the spread of disease in hospitals?

A

Semmelweiss realised the link between hygiene and infection rates – he prevented many deaths by insisting hospital workers washed their hands

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58
Q

What is a pathogen and what are the 3 main types?

A

A pathogen is a microbe, which causes infectious diseases: bacteria, viruses and fungi

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59
Q

How do bacteria make you ill?

A

They reproduce rapidly inside the body and may produce toxins (poisons) making us feel ill

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60
Q

How do viruses make you ill?

A

They reproduce inside our body cells, causing damage to the cells they reproduce in

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61
Q

How do white blood cells help to protect you against disease?

A

White blood cells ingest pathogens (produce antibodies which destroy bacteria and produce antitoxins to counteract the toxins)

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62
Q

What is an antibody and how do they help fight infections?

A

Antibodies are produced by the white blood cells – they clump pathogens together (they also ‘remember’ the pathogens so they can fight them much quicker if an infection occurs again)

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63
Q

How can painkillers help during an infection?

A

Painkillers treat the symptoms (i.e. a headache) but do not kill the pathogen

64
Q

How may a viral infection be treated by a doctor?

A

Antiviral medications (hard to develop) and painkillers are prescribed

65
Q

What are antibiotics used to treat?

Give an example of an antibiotic

A

Antibiotics treat bacterial infections

Penicillin

66
Q

Why are antibiotics not used to treat the flu?

A

Flu is a virus – antibiotics have no affect (they only treat bacterial infections)

67
Q

Why are antiviral drugs hard to develop?

A

Viruses mutate (change) resulting in the antiviral medication no longer working

68
Q

How have antibiotic resistant bacteria evolved?

Give an example

A

Natural selection – antibiotics kill most bacteria, but some survive and reproduce into antibiotic resistant bacteria, e.g. MRSA

69
Q

What are we doing to prevent the evolution of more antibiotic resistant bacteria?

A

Prescribing less antibiotics / improving hygiene within hospitals

70
Q

How does a vaccination work?

A

A small amount of dead or weakened microbe is injected – white blood cells make antibodies and the individual is now immune

71
Q

What is immunity?

A

Immunity means you cannot ‘catch’ a disease

72
Q

Give an example of a vaccination

A

MMR

Polio

Tetanus

73
Q

What does the MMR vaccination protect against?

A

Measles, mumps and rubella

74
Q

How may you become immune to a disease?

A

Catching the disease (and surviving) / vaccinations

75
Q

In the menstrual cycle what happens at day 1-5 and then at day 14?

A

Day 1-5 – lining of the uterus breaks down (period)

Day 14 – ovulation (egg released)

76
Q

What is insulin used to treat?

A

Diabetes

77
Q

Which hormone controls the maturation of the egg?

A

FSH

78
Q

Which hormone stimulates the lining of the uterus to thicken?

A

Oestrogen

79
Q

What is homeostasis?

A

Controlling the bodies internal environment

80
Q

What 7 nutrients are needed for a healthy diet and what are they used for?

A 
Carbohydrate – energy
Protein – growth and repair
Fat – insulation
Vitamins – chemical reactions
Minerals – chemical reactions
Fibre – aid digestion
Water – chemical reactions
81
Q

What is the normal body temperature?

A

37C

82
Q

What is the difference between saturated and unsaturated fat?

A

Saturated – fat saturated with hydrogen

Unsaturated – fat not saturated with hydrogen

83
Q

What diseases are associated with smoking?

A

Lung cancer
Throat cancer
Emphysema
Heart disease

84
Q

What is meant by a ‘gateway’ drug?

Give an example

A

A drug, which may lead to the use of harder drugs – e.g. cannabis

85
Q

What is the addictive substance in a cigarette?

A

Nicotine

86
Q

What is an epidemic?

What is a pandemic?

A

Epidemic – a disease spread around a local area

Pandemic – a disease spread around the world

87
Q

Why are viral infections often more contagious than bacterial infections?

A

Viruses are small enough to be transferred in water droplets within the air

88
Q

How does smoking affect the ciliated cells and what affects can this have on health?

A

Cells become damaged, causing smokers to cough regularly

89
Q

What is the definition for the following symbol (yellow triangle with black circles)

A

Biohazard - (biological hazard) – a biological substance which poses a threat to the health of living organisms, primarily that of humans

90
Q

How are micro-organisms grown?

A
  1. Sterilise the culture medium and petri-dish (done in an autoclave)
  2. Use sterile inoculating loops (pass through a flame) to transfer micro-organisms
  3. Seal the dish with adhesive tape to prevent micro-organisms from the air contaminating the sample / culture
91
Q

Why are micro-organisms not grown at temperatures above 25oC in school laboratories?

A

To reduce the risk of pathogens growing which might harm humans

92
Q

Why does industry grow micro-organisms above 25oC

A

In industrial conditions higher temperatures can produce more rapid growth (although the risks are increased of growing pathogens potentially harmful to humans

93
Q

What is a tropism and what are geotropism, hydrotropism and phototropism?

A

Plants respond to stimuli by growing to or away from them – a growth movement in response to a stimulus is a tropism (towards stimulus = positive tropism, away from stimulus = negative tropism)

Geotropism – gravity
Hydrotropism – water
Phototropism - light

94
Q

What do auxins do?

A

Auxins are plant hormones that make some parts of a plant stem grow faster than others (controlling geotropism and phototropism)

95
Q

What is rooting powder?

A

Rooting powder contains plant growth hormones – dip a cutting into rooting powder and the plant hormones stimulate the cutting to grow new roots

96
Q

What are statins?

A

Statins are drugs which potentially reduce the risk of heart attacks and strokes – they do this by lowering the level of cholesterol in the blood

97
Q

What is doping?

A

Athletes who use performance enhancing drugs

98
Q

What do stimulants do?

A

They make athletes more alert and mask fatigue

99
Q

What do steroids do?

A

They help athletes train harder and build up muscles

100
Q

What do beta blockers do?

A

They help athletes keep their heart rate low and reduce tremble in the hand

101
Q

What is the function of the hormone LH in the menstrual cycle?

A

LH stimulates the release of an egg from the ovary

102
Q

What is cannabis?

A

Cannabis is an illegal drug which contains chemicals which may cause mental illness

103
Q

What is the first step in the carbon cycle?

A

Carbon enters the atmosphere as carbon dioxide from respiration and combustion.

104
Q

What is the second step in the carbon cycle?

A

Carbon dioxide is absorbed by producers to make carbohydrates in photosynthesis.

105
Q

What is the third step in the carbon cycle?

A

Animals feed on the plant passing the carbon compounds along the food chain. Most of the carbon they consume is exhaled as carbon dioxide formed during respiration. The animals and plants eventually die.

106
Q

What is the fourth step in the carbon cycle?

A

The dead organisms are eaten by decomposers and the carbon in their bodies is returned to the atmosphere as carbon dioxide. The plant and animal material may then be available as fossil fuel in the future for combustion.

107
Q

What factors affects the rate of decay?

A

moisture
temperature
amount of available oxygen.

108
Q

What are the main groups of decomposers?

A

Bacteria and fungi

109
Q

What is the decay cycle?

A

A process that digests food or waste matter and recycles materials.

110
Q

What happens in the decay cycle?

A

Materials from living things decay because they are digested (broken down) by microorganisms. These microorganisms cause decay by releasing enzymes that break down compounds to be absorbed by their cells.

111
Q

What are some adaptations for the cold climate? (i.e. Polar Bears)

A
  • a white appearance, as camouflage from prey on the snow and ice
  • thick layers of fat and fur, for insulation against the cold
  • a small surface area to volume ratio, to minimise heat loss
  • a greasy coat, which sheds water after swimming.
112
Q

What are some adaptations for a desert climate? (i.e. Cactus)

A
  • spines which let out less water during transpirations then leaves.
  • enlarged stems which carry out photosynthesis and store water.
  • long roots which allow the plant to reach water from far away.
113
Q

Give an example of variation within humans.

A

Your friends and classmates may have different eye colour and hair colour. Some will be boys and some will be girls. Some will be tall and some will be shorter. The presence of differences between living things of the same species is called

114
Q

Give an example of variation within animals.

A

animals called ligers are produced when a male lion and a female tiger reproduce. But a liger cannot have offspring. This means that lions and tigers are different species.

115
Q

What are extremophiles

A

Extremophiles are organisms that live in very extreme environments and can survive conditions that would kill most other organisms.

116
Q

What are some environments that extremophiles live in?

A

high temperatures (volcano)
high concentrations of salt in water (salt marshes)
high pressures. (bottom of the sea)

117
Q

What animals are extremophiles

A

Herons (Salt marshes)
Shark (bottom of the sea)
Bacteria (volcano)

118
Q

What is environmental change?

A

a change or disturbance of the environment most often caused by human influences and natural ecological processes. (e.g. including natural disasters, human interference, or animal interaction.)

119
Q

explain food chains.

A

Animals get energy from the food they eat, and all living things get energy from food. Plants use sunlight, water and nutrients to get energy (in a process called photosynthesis). Energy is necessary for living beings to grow.

120
Q

What is DNA?

A

They carry the genetic code that determines the characteristics of a living thing. Except for identical twins, each person’s DNA is unique. This is why people can be identified using DNA fingerprinting. DNA can be cut up and separated, forming a sort of ‘bar code’ that is different from one person to the next.

121
Q

What are chromosomes?

A

The cell’s nucleus contains chromosomes made from long DNA molecules. The diagram shows the relationship between the cell, its nucleus, chromosomes in the nucleus, and genes.

122
Q

What are genes.

A

A gene is a short section of DNA. Each gene codes for a specific protein by specifying the order in which amino acids must be joined together.

123
Q

Explain sexual reproduction.

A

Genetically identical cells are produced by a type of cell division called mitosis. In sexual reproduction, a male gamete fuses with a female gamete to produce a new cell. This is called fertilisation. Gametes are produced by a type of cell division called meiosis.

124
Q

Explain asexual reproduction.

A

offspring arise from a single organism, and inherit the genes of that parent only; it does not involve the fusion of gametes and almost never changes the number of chromosomes.
Asexual reproduction can also be a type of cloning.

125
Q

What are two types of cloning?

A

Embryo transplants and fusion cell cloning

126
Q

Explain the process of embryo transplants.

A

A developing embryo is removed from a pregnant animal at an early stage, before the embryo’s cells have had time to become specialised. The cells are separated, grown for a while in a laboratory, and then transplanted into host mothers. When the offspring are born, they are identical to each other. They are not identical to their host mothers, because they contain different genetic information

127
Q

Explain the process of fusion cell cloning

A

Fusion cell cloning involves replacing the nucleus of an unfertilised egg with the nucleus from a different cell. The replacement nucleus can come from an embryo, but if it comes from an adult cell, it is called adult cell cloning.

128
Q

What do plants compete for?

What do animals compete for?

A

Plants – light; water; nutrients (from soil); space

Animals – food; mates; territory

129
Q

What is a gamete and what do they carry?

A

Gametes are the sex cells (e.g. sperm and egg), which carry genetic information

130
Q

Where is DNA carried in most cells?

A

In the nucleus

131
Q

How can plants be cloned?

A

Plants can be cloned by taking cuttings (small section of plant is cut off and placed in rooting powder – plant grown is genetically identical to the parent)

132
Q

How can cells be cloned using tissue cultures?

A

A small group of cells are removed and grown in a growth medium (such as agar)

133
Q

What are the ethical implications of genetic engineering?

A

Should we be playing God?

There has been no long-term testing

134
Q

What are the ethical considerations involved in cloning?

A

we may become more susceptible to diseases

Should we be allowed to clone organs / whole organisms?

135
Q

What are GM crops and what concerns are associated with them?

A

GM crops have been genetically engineered to have the best genetic makeup (e.g. resistant to specific diseases) increasing yields

There is concern on the effect of wild flowers and insects as well as uncertainty on human health when GM crops are consumed

136
Q

Why can scientists not be certain how life began on Earth?

A

We were not there / we cannot reproduce spontaneous life

137
Q

What evidence is there for the theory of evolution?

A

Fossil records show how animals have changed over time

DNA and physiological similarities

138
Q

What is the theory of evolution?

A

That all organisms on Earth have evolved from simple single celled organisms millions of years ago

139
Q

How does natural selection lead to evolution?

A

Organisms evolved through natural selection: -

  • Variation where one organism has an advantage (mutation / change in environment)
  • Organism now more likely to survive
  • Organism more likely to breed and pass on their advantageous genes
140
Q

What is a mutation and what can it lead to?

A

A mutation is a change in DNA – this can lead to a negative change / neutral change / positive change (leading to evolution)

141
Q

What are the impacts caused by our rapidly increasing population?

A

Raw materials are being used up (including non-renewable energy resources); more waste; and more pollution

142
Q

How does the rapidly increasing human population reduce the land available for animals?

A

Building / quarrying / farming / waste

143
Q

How can an increase in human waste pollute the Earth?

A

Water: sewage; fertilisers and toxic chemicals

Air: smoke; gases (sulfur dioxide (acid rain))

Land: toxic chemical (pesticides and herbicides which can be washed from land to water)

144
Q

Which organisms can be used as indicators of pollution?

A

Lichens: air pollution indicators (particularly SO2)

Invertebrates: water pollution indicators varying in species found due to differing amounts of O2 in the water

145
Q

What is the equation for photosynthesis?

A

6CO2 + 6H2O —-> C6H12O6 + 602

146
Q

Why is energy needed for photosynthesis and how does a plant obtain this energy?

A

Energy is needed to convert carbon dioxide and water into sugar (glucose)

The energy is light energy – this is trapped by the chlorophyll in the chloroplasts

147
Q

What happens to the mass of living material (biomass) as you go up the stages of a food chain?

A

It is reduced

148
Q

What is a pyramid of biomass?

A

The biomass at each stage is drawn to scale and shown as a pyramid. The thing with the most energy is at the bottom, and the animal with the least is at the top.

149
Q

What happens to the energy as you move up the stages of a food chain?

A

It is reduced

150
Q

How can food production be made more energy efficient?

A

If the stages in the food chain are reduced less energy is lost

151
Q

Why is the energy and biomass reduced as you move up the stages of a food chain?

A

Energy is lost due to: -

  • Some materials and energy are lost by the organism as waste
  • Energy is used for movement etc… (lost to the surroundings)
  • Mammals and birds maintain a constant temperature, which is usually higher than the surroundings
152
Q

Why do materials decay?

A

They are broken down (digested) by microorganisms and returned to the environment

153
Q

What conditions do materials decay fastest in?

A

Warm

Moist

Oxygen rich

154
Q

What is eutrophication, how is it caused and what are the associated dangers?

A

Eutrophication occurs when excess nitrates may their way into rivers causing algae growth

Some plants then start dying due to increased competition for light which result in micro-organisms decomposing them (which respiring, using oxygen)

The lack of oxygen causes larger organisms such as fish to die

155
Q

Why was the theory of natural selection only gradually accepted?

A

Natural selection challenged the idea of God – initially there was thought to be insufficient evidence (this was subsequently found ~50 years after publication)

GCSE Science (2 decks)

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