Science A (Core): Biology Flashcards
1
Q
What are the 5 senses?
A
Smell
Sight
Taste
Touch
Hearing
2
Q
What are the different sense organs, and what do they sense?
A
Eye – light
Skin – touch, temperature, pressure, pain
3
Q
What is the job of the nervous system?
A
To sense and respond to the outside environment
4
Q
What is the nervous system made up of?
A
Nerves (sensory, motor and relay neurons), spine & brain
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
6
Q
What is the job of a sensory neurone?
A
To take information from the receptor to the CNS
7
Q
What is the job of a motor neurone?
A
To take information from the CNS to the effector (muscle / gland)
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
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
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))
11
Q
What happens in a reflex action?
A
Receptor → sensory neurone → relay neurone → CNS → motor neurone → effector
12
Q
What conditions within the body need to be controlled?
A
Temperature (37°C)
Water level
Ion level
Glucose level
Carbon dioxide
13
Q
How does water leave the body?
A
Sweat
Breath
Urine (via kidneys)
Faeces
14
Q
How are ions lost from the body?
A
Sweat
Urine (via kidneys)
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
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)
17
Q
How do hormones travel around the body?
A
In the blood
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
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
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
21
Q
What controls the menstrual cycle?
A
Hormones control the menstrual cycle (oestrogen; progesterone; LH; and FSH)
22
Q
What are the 4 hormones involved in maintaining the menstrual cycle?
A
Oestrogen
Progesterone
LH
FSH
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
24
Q
How are hormones used to control fertility?
A
FSH is used to increase fertility
The ‘pill’ prevents FSH (so preventing pregnancy)
25
How can FSH be used to control fertility?
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
26
How does the contraceptive pill work?
Oestrogen and progesterone are used to stop FSH production, stopping any eggs maturing, preventing pregnancy
27
What are the possible problems with using FSH for fertility treatment?
FSH can lead to multiple eggs being released, resulting in multiple offspring
28
What does a healthy diet consist of?
A balance of: -
Carbohydrate
Protein
Fat
Vitamins
Minerals
Fibre
Water
29
What does malnourished mean and what can this lead to?
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)
30
What deficiency diseases are caused by a lack of: -
Iron
Vitamin C
Vitamin D
Iron → anaemia
Vitamin C → scurvy
Vitamin D → rickets
31
What health problems are linked to a lack of food?
Reduced resistance to infection / irregular periods
32
What is metabolic rate and what affects it?
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
33
What may cause people to need less food?
Less exercise / warmer climate
34
How does exercise affect your metabolic rate?
Metabolic rates stay high for some time after exercise
35
What diseases are linked to obesity?
Arthritis
Diabetes (type II)
High blood pressure
Heart disease
36
What is arthritis?
What is diabetes?
Arthritis – wearing of the joints
Diabetes – high blood sugar
37
What type of lipoproteins are ‘bad’ cholesterol?
LDLs – low-density lipoproteins
38
Where is cholesterol made?
Liver
39
What affects the level of cholesterol in the blood?
Diet and inherited features
40
What are the health risks associated with too much cholesterol?
Diseases of the heart and blood vessels
41
What are the 2 types of lipoprotein that carry cholesterol in the blood?
LDLs – low-density lipoproteins
HDLs – high-density lipoproteins
42
How is cholesterol carried in the blood?
As lipoproteins
43
Which type of fat increases the level of cholesterol in your blood?
Saturated fats
44
Which type of fat can reduce the blood cholesterol levels and improve the balance of LDLs and HDLs?
Monounsaturated and polyunsaturated fats
45
Why is too much salt bad for you?
Increased blood pressure for ~30% of the population
46
Which types of food contain high levels of fat and salt?
Processed foods
47
What are statins used for?
Lowering the risk of cardio-vascular disease
48
What is a drug?
A substance, which affects the way the body or mind functions – the affects can be positive or negative
49
How are drugs tested before they are prescribed to patients?
Tested in labs on cells and tissues / on animals and human volunteers / in clinical trials with a small dose
50
What was thalidomide developed to treat, what were its side effects and what is it now used to treat?
Developed as a sleeping pill but not tested during pregnancy – leads to offspring with limb abnormalities. Now affective treatment for leprosy
51
What are withdrawal symptoms and why do people suffer from these?
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)
52
What dangerous substances are found in cigarettes?
Nicotine → addictive
Carcinogens → cancer causing
Tar → coats lungs
Carbon monoxide → reduces oxygen carried within blood
53
What is a carcinogen and where are these found?
Carcinogens are chemicals, which cause cancer – found within cigarettes
54
How can smoking when pregnant affect the baby?
Smoking can deprive the foetus of oxygen and lead to a low birth weight
55
What is carbon monoxide and what affect does it have on the body?
Carbon monoxide is a poisonous gas, which reduces the ability for the red blood cells to carry oxygen around the blood
56
How does alcohol affect the body and what are the long-term effects?
Alcohol affects the nervous system and slows reaction times
Long-term effects include sclerosis of the liver and brain damage
57
What did Semmelweiss do to help prevent the spread of disease in hospitals?
Semmelweiss realised the link between hygiene and infection rates – he prevented many deaths by insisting hospital workers washed their hands
58
What is a pathogen and what are the 3 main types?
A pathogen is a microbe, which causes infectious diseases: bacteria, viruses and fungi
59
How do bacteria make you ill?
They reproduce rapidly inside the body and may produce toxins (poisons) making us feel ill
60
How do viruses make you ill?
They reproduce inside our body cells, causing damage to the cells they reproduce in
61
How do white blood cells help to protect you against disease?
White blood cells ingest pathogens (produce antibodies which destroy bacteria and produce antitoxins to counteract the toxins)
62
What is an antibody and how do they help fight infections?
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)
63
How can painkillers help during an infection?
Painkillers treat the symptoms (i.e. a headache) but do not kill the pathogen
64
How may a viral infection be treated by a doctor?
Antiviral medications (hard to develop) and painkillers are prescribed
65
What are antibiotics used to treat?
Give an example of an antibiotic
Antibiotics treat bacterial infections
Penicillin
66
Why are antibiotics not used to treat the flu?
Flu is a virus – antibiotics have no affect (they only treat bacterial infections)
67
Why are antiviral drugs hard to develop?
Viruses mutate (change) resulting in the antiviral medication no longer working
68
How have antibiotic resistant bacteria evolved?
Give an example
Natural selection – antibiotics kill most bacteria, but some survive and reproduce into antibiotic resistant bacteria, e.g. MRSA
69
What are we doing to prevent the evolution of more antibiotic resistant bacteria?
Prescribing less antibiotics / improving hygiene within hospitals
70
How does a vaccination work?
A small amount of dead or weakened microbe is injected – white blood cells make antibodies and the individual is now immune
71
What is immunity?
Immunity means you cannot ‘catch’ a disease
72
Give an example of a vaccination
MMR
Polio
Tetanus
73
What does the MMR vaccination protect against?
Measles, mumps and rubella
74
How may you become immune to a disease?
Catching the disease (and surviving) / vaccinations
75
In the menstrual cycle what happens at day 1-5 and then at day 14?
Day 1-5 – lining of the uterus breaks down (period)
Day 14 – ovulation (egg released)
76
What is insulin used to treat?
Diabetes
77
Which hormone controls the maturation of the egg?
FSH
78
Which hormone stimulates the lining of the uterus to thicken?
Oestrogen
79
What is homeostasis?
Controlling the bodies internal environment
80
What 7 nutrients are needed for a healthy diet and what are they used for?
Carbohydrate – energy
Protein – growth and repair
Fat – insulation
Vitamins – chemical reactions
Minerals – chemical reactions
Fibre – aid digestion
Water – chemical reactions
81
What is the normal body temperature?
37°C
82
What is the difference between saturated and unsaturated fat?
Saturated – fat saturated with hydrogen
Unsaturated – fat not saturated with hydrogen
83
What diseases are associated with smoking?
Lung cancer
Throat cancer
Emphysema
Heart disease
84
What is meant by a ‘gateway’ drug?
Give an example
A drug, which may lead to the use of harder drugs – e.g. cannabis
85
What is the addictive substance in a cigarette?
Nicotine
86
What is an epidemic?
What is a pandemic?
Epidemic – a disease spread around a local area
Pandemic – a disease spread around the world
87
Why are viral infections often more contagious than bacterial infections?
Viruses are small enough to be transferred in water droplets within the air
88
How does smoking affect the ciliated cells and what affects can this have on health?
Cells become damaged, causing smokers to cough regularly
89
What is the definition for the following symbol: -
Biohazard - (biological hazard) – a biological substance which poses a threat to the health of living organisms, primarily that of humans
90
How are micro-organisms grown?
Sterilise the culture medium and petri-dish (done in an autoclave)
Use sterile inoculating loops (pass through a flame) to transfer micro-organisms
Seal the dish with adhesive tape to prevent micro-organisms from the air contaminating the sample / culture
91
Why are micro-organisms not grown at temperatures above 25oC in school laboratories?
To reduce the risk of pathogens growing which might harm humans
92
Why does industry grow micro-organisms above 25oC
In industrial conditions higher temperatures can produce more rapid growth (although the risks are increased of growing pathogens potentially harmful to humans)
93
What is a tropism and what are geotropism, hydrotropism and phototropism?
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
What do auxins do?
Auxins are plant hormones that make some parts of a plant stem grow faster than others (controlling geotropism and phototropism)
95
What is rooting powder?
Rooting powder contains plant growth hormones – dip a cutting into rooting powder and the plant hormones stimulate the cutting to grow new roots
96
What are statins?
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
What is doping?
Athletes who use performance enhancing drugs
98
What do stimulants do?
They make athletes more alert and mask fatigue
99
What do steroids do?
They help athletes train harder and build up muscles
100
What do beta blockers do?
They help athletes keep their heart rate low and reduce tremble in the hand
101
What is the function of the hormone LH in the menstrual cycle?
LH stimulates the release of an egg from the ovary
102
What is cannabis?
Cannabis is an illegal drug which contains chemicals which may cause mental illness
103
How are these animals adapted to their surroundings: -
Polar bear
Camel
Cactus
Polar bear: white coat (camouflage); thick coat & small SA: volume (warmth); high body fat levels
Camel: hump (fat store); wide feet (reduce sinking into sand)
Cactus: spines (protection & reduced transpiration); long roots (increase water uptake); low leaf surface area
104
What do plants compete for?
What do animals compete for?
Plants – light; water; nutrients (from soil); space
Animals – food; mates; territory
105
What is a gamete and what do they carry?
Gametes are the sex cells (e.g. sperm and egg), which carry genetic information
106
What is a gene?
A gene is a section of DNA, coding for the development of one characteristic
107
Where is DNA carried in most cells?
In the nucleus
108
What is sexual and asexual reproduction?
Sexual reproduction – require 2x parents producing similar, but not identical offspring (fusing of male and female gametes)
Asexual reproduction – only 1x parent needed producing genetically identical offspring (no gametes so no mixing of genes)
109
How can plants be cloned?
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)
110
How can cells be cloned using tissue cultures?
A small group of cells are removed and grown in a growth medium (such as agar)
111
How can animals be cloned using embryo transplants?
Chosen embryo is split into small bundles of cells at an early stage – bundles are placed into host mother resulting in genetically identical offspring to original embryo
112
How can adult cells be cloned?
Nucleus of adult cell removed, and nucleus of ovum removed – original nucleus then inserted into ovum resulting in clone of adult
113
What is genetic engineering and how is it done?
Genetic engineering is when the genes of one animal are inserted into another – e.g. human gene cut using enzymes and placed within DNA of bacterium
114
What are the ethical implications of genetic engineering?
Should we be playing God?
There has been no long-term testing
115
What are the ethical considerations involved in cloning?
If we reduce the gene pool we may become more susceptible to diseases
Should we be allowed to clone organs / whole organisms?
116
What are GM crops and what concerns are associated with them?
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
117
Why can scientists not be certain how life began on Earth?
We were not there / we cannot reproduce spontaneous life
118
How did Darwin suggest animals and plants evolved from simple organisms?
Simple organisms evolved through natural selection (more than 3 billion years ago): -
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
119
What are the differences between the ideas suggested by Darwin and Lamarck?
Darwin suggested genetic information was passed from parent to offspring
Lamarck suggested environmental factors (causing changed in an organisms lifetime) were passed on, e.g. a giraffe stretches for food so their offspring’s necks and bodies become larger
120
What evidence is there for the theory of evolution?
Fossil records show how animals have changed over time
DNA and physiological similarities
121
What is the theory of evolution?
That all organisms on Earth have evolved from simple single celled organisms millions of years ago
122
What may cause an organism to become extinct?
New diseases
Changes to the environment
New predators
New competitors
123
How does natural selection lead to evolution?
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
124
What is a mutation and what can it lead to?
A mutation is a change in DNA – this can lead to a negative change / neutral change / positive change (leading to evolution)
125
What are the impacts caused by our rapidly increasing population?
Raw materials are being used up (including non-renewable energy resources); more waste; and more pollution
126
How does the rapidly increasing human population reduce the land available for animals?
Building / quarrying / farming / waste
127
How can an increase in human waste pollute the Earth?
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)
128
Which organisms can be used as indicators of pollution?
Lichens: air pollution indicators (particularly SO2)
Invertebrates: water pollution indicators varying in species found due to differing amounts of O2 in the water
129
What is the equation for photosynthesis?
light
6CO2 + 6H2O → C6H12O6 + 602
130
Why is energy needed for photosynthesis and how does a plant obtain this energy?
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
131
What happens to the mass of living material (biomass) as you go up the stages of a food chain?
It is reduced
132
What is a pyramid of biomass?
The biomass at each stage is drawn to scale and shown as a pyramid
133
What happens to the energy as you move up the stages of a food chain?
It is reduced
134
How can food production be made more energy efficient?
If the stages in the food chain are reduced less energy is lost
135
Why is the energy and biomass reduced as you move up the stages of a food chain?
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
136
Why do materials decay?
They are broken down (digested) by microorganisms and returned to the environment
137
What conditions do materials decay fastest in?
Warm
Moist
Oxygen rich
138
Draw a diagram of the carbon cycle
Carbon Cycle
139
Why is the decay process so important to food chains?
Decay releases substances, which plants need to grow
140
Explain the carbon cycle
CO2 is removed by photosynthesis (used to make carbohydrates, fats and proteins)
Some CO2 is returned by respiration of the plants
Animals eat plants, and the carbon becomes part of the fats and proteins, which make up the animal
Plants and animals die – microorganisms feed on them, respiring as they do, returning some carbon
141
Plants remove carbon dioxide from the environment during photosynthesis – what do they use this to make?
Carbon dioxide is needed for carbohydrates, fats and proteins (which make up the plant bodies)
142
What are extremophiles?
Organisms that live in very extreme environments, e.g. high temperature / pH / pressure / salinity
143
What is eutrophication, how is it caused and what are the associated dangers?
Eutrophication occurs when excess nitrates make 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
144
Why was the theory of natural selection only gradually accepted?
Natural selection challenged the idea of God – initially there was thought to be insufficient evidence (this was subsequently found ~50 years after publication)
