Further biology Flashcards
(428 cards)
1
Q
What are the functions of the skeleton?
A
Support; protection; blood production; movement
2
Q
How does the skeleton keep us upright?
A
The bones are held together with joints and muscles.
3
Q
How does the skeleton protect us?
A
The rigid bones can protect our soft tissues, eg the skull protects our brain.
4
Q
How does the skeleton make blood?
A
The bone marrow inside the larger bones make blood.
5
Q
How does the skeleton enable us to move?
A
The long bones can act as levers.
6
Q
What makes our bones move?
A
We rely on muscles
7
Q
How does a muscle make a bone move?
A
It contracts and pulls on the bone.
8
Q
How can you move a bone back to the original position?
A
A second muscle has to pull is back into the original position.
9
Q
How do muscles contract?
A
Proteins in their cells react together,
10
Q
What happens to the muscle when it contracts?
A
It becomes shorter.
11
Q
What has more force, a large muscle or a small muscle?
A
A large muscle.
12
Q
What happens when an athlete trains?
A
The muscles can be increased in size, and therefore strength.
13
Q
What do you call the two muscles involved in the movement of one bone?
A
An antagonistic pair.
14
Q
What does antagonist mean?
A
Something that actively fights against or opposes something.
15
Q
What happens when one muscle of the antagonistic pair contracts?
A
The other has to relax.
16
Q
How much can muscles contract?
A
About 10% of their length
17
Q
How is the movement of muscles magnified?
A
By using the bones as levers.
18
Q
What can’t muscles do?
A
Push, muscles can only PULL
19
Q
What is a joint?
A
The connection between two bones
20
Q
What are most of our joints called?
A
Synovial joints
21
Q
Give some examples of synovial joints
A
Shoulders, hips, elbows
22
Q
What do synovial joints permit?
A
Relatively free movement.
23
Q
What lines the inside of a synovial joint?
A
The synovial membrane.
24
Q
What does the synovial membrane produce?
A
Synovial fluid.
25
What is between the two bones, acting like a cushion?
Articular cartilage
26
What stops the ends of the bones being worn away in the joint?
Articular cartilage
27
What does to articulate mean?
To introduce a joint (or to speak fluently)
28
What joins bone to bone?
Ligaments
29
What joins muscle to bone?
Tendons.
30
What are tendons like?
They are transmitting the pull of a muscle, so they are not stretchy.
31
What are ligaments like?
They need to allow the movement of the bones, so they are stretchy,
32
What could happen without ligaments?
The bones could come away from the joint
33
What can ligaments do when you jump?
They absorb some of the energy of the impact.
34
What sort of joint is the knee, or a finger?
A hinge joint.
35
What sort of movement does a hinge joint permit?
Movement in one plane, like a door hinge.
36
What sort of joint is the shoulder, or the hip?
Ball and socket joints
37
What sort of movement do ball and socket joints permit?
A wider range than hinge joints.
38
How can you assess the risk and the benefits of a sport?
The risks are what could happen, and how likely it is; the benefits are the know benefits to health of taking exercise.
39
Name some risks and benefits associated with the trampoline?
Risks - broken neck, broken leg, waffle face, sprains, cuts, bruises. Broken neck - unlikely, I have only heard of 2. Waffle face - almost inevitable. Health benefits - lower blood pressure, stronger heart, stronger bones etc
40
What can happen if you have problems with joints and still do sports?
You could injure the joint.
41
How severe are sports injuries?
They vary
42
Which sports are more likely to cause injury?
Contact sports (like rugby)
43
How can you get an idea of how healthy your weight is?
BMI
44
What BMI counts as seriously underweight?
17.5 or under
45
What BMI is underweight?
17.5 - 19
46
What BMI is ideal?
19 - 25
47
What BMI is overweight?
25 - 30
48
What BMI is obese?
30 +
49
Why is BMI by itself not enough to tell whether someone has a healthy weight?
Proportion of muscle and fat could be different in an individual. Sports people often have a BMI in the overweight range as they have so much muscle.
50
What do you need to do if your BMI, and your body fat percentage, are too high?
Lose weight.
51
How can you lose weight?
An exercise programme is one way.
52
What should you consider before starting an exercise programme?
Symptoms; medication; alcohol and tobacco consumption; current level of physical activity; family medical history; previous treatments.
53
If you consider all possible factors before starting an exercise programme, it would enable the exercise programme to be?
Effective.
54
If there are factors that could have an affect, what should you do?
Address them before starting to exercise.
55
Why should an exercise programme be started slowly?
To prevent excessive strain on heart, joints, muscles.
56
How could we see whether the exercise programme is working?
Take measurements of weight.
57
What does the accuracy of data depend on?
The accuracy of the monitoring technique.
58
What would you need in order to see whether there has been progress?
Multiple readings, as the individual reading will fluctuate.
59
How could you reduce the fluctuations if you wanted to show the data?
Present the data as averages.
60
How does exercise affect the heart and the blood pressure (at the time of the exercise)
An increase in heart rate, and an increase in blood pressure
61
What does the increased pulse rate, and the increased blood pressure, do?
More blood is supplied to muscles.
62
What is the blood going to the muscles needed for?
It delivers oxygen and glucose for respiration, and removes waste product such as carbon dioxide.
63
What does respiration do?
Converts glucose and oxygen to carbon dioxide and water, and gives out energy that the cells use.
64
What can muscle cells do with the energy?
Contract
65
What can happen if the heart rate is too high during exercise?
Muscles become strained, and blood pressure can increase.
66
What can happen if blood pressure goes too high?
Delicate blood vessels, eg in the eye or heart, can burst.
67
What is the safe heart rate for exercise?
About 70-90% of the maximum rate your heart can actually achieve.
68
What is the formula for the maximum safe heart rate?
220 - your age in years.
69
What is the time for the heart to return to normal after exercise called?
Recovery period.
70
When do injuries take place?
If you exercise more than your body can physically take
71
What happens when ligaments overstretch?
You get a sprain, and the joint can be more wobbly.
72
Torn ligaments or tendons are...
when ligaments or tendons become disconnected
73
What is a dislocation?
When a bone comes out of the socket
74
How do you treat a sprain?
Protect; Rest; Ice; Compression; Elevation
75
What must you do before treating a sprain?
Make sure that it is a sprain, and not something more serious.
76
What does a physiotherapist do?
Helps the injured person strengthen any damaged joints by providing a suitable exercise programme
77
How many chambers in the human heart?
Four
78
What does the heart do?
Collect deoxygenated blood at low pressure from the body; pump deoxygenated blood to the lungs; collect oxygenated blood at low pressure from the lungs; pump oxygenated blood at high pressure to the body
79
Humans have a ........ circulation system?
Double
80
What is meant by a double circulation system?
Blood is pumped twice for each entire trip around the body
81
Where does deoxygenated blood enter the heart?
On the right hand side. (So on the left as you look at a picture)
82
What vessel takes deoxygenated blood to the heart?
Vena cava
83
What is the route taken through the heart by deoxygenated blood?
Right atrium, right ventricle
84
What vessel take deoxygenated blood from the heart?
Pulmonary artery
85
Where does the pulmonary artery lead from the heart?
The lungs
86
What vessel leads back to the heart from the lungs?
Pulmonary vein
87
What route does oxygenated blood take through the heart?
Left atrium, left ventricle
88
What vessel takes the oxygenated blood to the body?
The aorta (at high pressure)
89
What does the blood do in the lungs that enables gas transfer?
Slows down.
90
What gas transfer takes place in the lungs?
Carbon dioxide leaves the blood and oxygen enters the blood.
91
By what process does the gas transfer take place?
Diffusion
92
What system is the heart part of?
Circulatory system
93
What forms the circulatory system?
heart; arteries; veins; capillaries
94
What is an artery wall like?
Thick, with layers of muscle and elastic fibres.
95
What is a capillary wall like?
Thin, a single cell
96
What is a vein wall like?
Thin, no muscles.
97
What is the direction of blood flow in an artery?
Away from the heart.
98
What is the direction of blood flow in capillaries?
Through tissues
99
What is the direction of blood flow in veins?
Back to the heart
100
What is the blood like in an artery?
Oxygenated - except pulmonary
101
What is the blood like in a vein?
Deoxygenated - except pulmonary
102
What is the blood like in capillaries?
Oxygenated at the start, deoxygenated by the end
103
Which blood vessels contain valves?
Veins; aorta; pulmonary artery
104
What do valves in the heart and veins prevent?
Backflow of blood.
105
How can the closing of the heart valve be detected?
There is an audible noise, which can be detected using a microphone.
106
What can a faulty heart valve cause?
The blood may not reach the lungs in sufficient quantities to pick up enough oxygen to enable the person to keep the body going.
107
What do valves in the vein do?
Stop gravity from allowing the blood to pool at the lower end of the body.
108
What are varicose veins?
When a valve in the leg veins fails and blood pools at the next valve down.
109
What is blood made of?
Red blood cells; white blood cells; platelets; plasma
110
What do red blood cells contain?
Haemoglobin, to bind with oxygen.
111
What is very unusual about red blood cells?
They have no nucleus, giving maximum space for haemoglobin
112
Why can't red blood cells be used for DNA tests?
They have no nucleus, so no DNA
113
What is the function of red blood cells?
To carry oxygen around the blood.
114
Why does the body need oxygen?
For respiration
115
What is the shape of a red blood cell?
Smooth, to allow them to slide along narrow capillaries.
116
Are all white blood cells alike?
No
117
What do white blood cells do?
Some recognise invading organisms and swallow them, others produce antibodies.
118
What do platelets do?
Help blood to form a clot at the site of an injury.
119
What is plasma?
The liquid part of blood, containing nutrients, antibodies, proteins, waste, salt.
120
What is 90% of plasma?
Water
121
What is 10% of plasma?
Glucose; proteins; salts; hormones; waste substances.
122
What is the glucose in the plasma for?
To provide energy in body cells through respiration.
123
What are the proteins in the plasma?
Some are antibodies that help protect the body.
124
Why is there salt in the plasma?
To keep the osmotic pressure of the blood equal to the body cells - otherwise cells will expand or shrink due to water crossing the semi-permeable membrane.
125
What are the hormones in the plasma for?
To help control a range of functions in the body, eg growth
126
What wastes are found in the plasma?
Carbon dioxide, on the way to the lungs;urea, going to the kidney.
127
How do platelets react to an injury?
They start a series of reactions that ends up producing a protein called fibrin, which helps to produce the clot.
128
What happens to plasma in the capillaries?
Some leaks out.
129
What is the name for the spaces between the capillaries and the cells?
The capillary bed.
130
How does dissolved oxygen, and glucose, move into the cells?
By diffusion.
131
What can white cells also do through the walls of capillaries?
Escape into the tissues.
132
What happens to most of the fluid?
It passes into tubes called lymph vessels.
133
What red chemical is found in red blood cells?
haemoglobin
134
What metal is part of the haemoglobin molecule?
Iron (Fe)
135
What is the job of haemoglobin?
To carry oxygen
136
What compound is formed with haemoglobin and oxygen?
Oxyhaemoglobin
137
How does the oxygen get into the blood?
It diffuses.
138
What happens when the red blood cell containing oxyhaemoglobin passes through an area of low oxygen?
The oxygen detaches from the haemoglobin and diffuses into the cells.
139
What happens to the carbon dioxide in the tissues?
It passes into the plasma by diffusion
140
What other waste enters the blood plasma?
Urea
141
How is the carbon dioxide removed from the blood?
It diffuses out of the blood plasma in the lungs, and can be breathed out.
142
What else does blood transport, other than gases?
eg white blood cells, glucose, hormones, salt, urea, red blood cells, platelets
143
Why do some white blood cells travel in the blood?
To protect against infection.
144
What can some white blood cells do to remove micro-organisms?
Engulf them
145
What do some white blood cells release to "mark" micro-organisms as foreign for other cells to destroy?
Antibodies.
146
Why is glucose transported in the blood plasma?
It is needed for respiration
147
How are waste products transported around the body?
In the blood plasma
148
Where is urea made?
In the liver
149
What is urea made from?
Waste amino acids
150
What removes urea from the blood?
The kidneys
151
Where do the kidneys move the urea to?
Into the urine.
152
What are hormones?
Chemical messengers, chemicals that affect the functions of cells in the body.
153
What is insulin?
A hormone that controls blood sugar
154
Where is insulin made?
In the pancreas
155
How is insulin transported?
In the blood plasma.
156
What does insulin do?
It influences the take up of blood glucose by the bodies cells.
157
What is adrenaline?
A hormone that prepares the body for vigorous exercise, the "fight or flight" hormone.
158
Where is adrenaline made?
By the adrenal glands, which are near the kidneys
159
What is special about red blood cells as compared to all other body cells?
They don't have a nucleus.
160
Why does the red blood cell not have a nucleus?
It gives extra space for haemoglobin.
161
What shape are red blood cells?
Biconcave - both sides are dish shaped.
162
Why do red blood cells have such an odd shape?
It gives extra surface area without having any parts that could catch in the capillaries. The large surface area gives the best chance for oxygen take up.
163
What does the disorder sickle cell anemia lead to?
Sickle shaped (new moon shaped) red blood cells. One sickle gene gives and advantage against malaria, two gives disadvantage as sickle blood cells are more likely to clump together and block blood vessels.
164
What is normal human body temperature?
Around 36.9C
165
What does an increase in temperature cause?
Body reaction could go faster - or stop, as enzymes are denatured. This could cause death
166
Why would it be hard to keep cool if you are working hard in hot temperatures?
Muscles produce heat when they do work.
167
How do we cool down?
Blood is diverted to the skin surface, to enable heat to be lost; sweat is produced which cools the body as it evaporates.
168
What is the disadvantage of sweating?
The body loses water and salts (and urea, which is not a problem)
169
What would happen if you don't replace water and salts lost by sweating?
You would become dehydrated.
170
What happens to sweating as you become dehydrated?
The body stops sweating as it tries to conserve water.
171
What is the implication of the body not sweating due to dehydration?
The body cannot cool itself.
172
What happens as the body heats up?
Heat stroke, which can be fatal
173
What must you do if your friend is complaining of being hot but is not even sweating?
Get medical help as they could be suffering from heat exhaustion.
174
How does the body detect external temperatures?
Sensors in the skin.
175
How does the body detect internal temperature?
A sensor deep in the brain
176
What does the brain do with the information from the various sensors?
It controls the response - so you can sweat on a very cold day, if your body temperature goes too high.
177
What does the brain do if the internal body temperature rises?
Send signals to the swear glands, telling them to release sweat; it send signals to the blood vessels that supply the skin capillaries telling them to dilate.
178
Why is sweating so effective?
The water evaporates, and the latent heat of vaporisation is taken from the body.
179
What is the process of losing heat through the surface capillaries called?
Vasodilation.
180
What happens during vasodilation?
Blood is shunted to the outer layers of the skin; the small blood vessels that supply capillaries of the skin become wider, increasing blood flow through the capillaries; the skin turns red, and feels hot.
181
What happens during vasoconstriction?
Small blood vessels leading to the capillaries in the skin get narrower; this restricts the blood flowing to the surface; skin appears paler/bluer and feels cold to the touch
182
What does your core body temperature need to stay at?
36.9C
183
What is the normal temperature for the shell of the body, including arms and legs?
Anything down to about 32C
184
What can skin drop to?
25C with little, or no, damage.
185
What do sensors in the skin do when the skin temperature drops?
Pass impulses to the brain,the brain also checks the core temperature and then starts shivering; stops sweating; diverts blood to the core, away from the shell which cools it.
186
What controls the bodies response to low temperature?
The brain
187
Where is the part of the brain involved in temperature regulation located?
Near the centre of the brain.
188
What does the brain do if it decides the temperature is too cold?
It send a message to effectors, sweat glands (switching sweating off) and muscles (starting shivering)
189
What can the core body temperature fall to before hypothermia sets in?
35C
190
Why must someone suffering from hypothermia be warmed up slowly?
If the person is warmed too quickly the warmer blood can leave the core, and be replaced with cooler blood from the shell, which can cause organ failure and death
191
What is the part of the brain responsible for monitoring blood temperature called?
Hypothalmus.
192
Effectors like muscles and sweat glands work against each other to change body temperature. This means they work....
antagonistically.
193
If hot and cold comes up in the exam...
you need to mention taking clothes off or putting a jumper on, and moving to a warmer/cooler place. DUH
194
What are carbohydrates broken down to in the gut?
Sugars
195
What is the sugar that is the final product of digestion?
Glucose
196
What happens to the glucose in the gut?
It passes in to the blood.
197
What happens to the blood sugar level when glucose passes into the blood from the gut?
It rises.
198
If the rise in blood sugar is not corrected, what can it cause?
increased blood pressure; glucose leaking into the urine
199
What can a long term rise in blood pressure cause?
Problems with the kidneys, eyes, and the circulation.
200
Why is it a bad idea to lose glucose in the urine?
It is a waste of energy; increased risk of fungal infections.
201
How can highly processed foods affect the blood sugar level?
It can rise suddenly after eating them.
202
How does the body react to a rise in blood sugar?
It releases insulin
203
How does insulin drop the blood sugar?
It allows the bodies cells to take up glucose.
204
What do the cells do with glucose?
Either use it for respiration,or convert it to other substances for storage,
205
What happens if the insulin level in the blood drops?
Cells cannot absorb glucose into the cells.
206
If someone has diabetes, what can't their body do?
Regulate the blood sugar level properly
207
What happens when the blood sugar falls too low?
The person can go into a coma, then death
208
How many types of diabetes are there?
2; type 1 and type 2
209
How common is type 1 diabetes?
About 10% of diabetes cases are type 1.
210
When does diabetes start?
Type 1 often in childhood; type 2 usually after age 40
211
What causes diabetes?
Type 1 unknown, possible genetic component; type 2 high sugar diet or being overweight.
212
How is diabetes treated?
Type 1 - insulin injections. Type 2 - improve diet, exercise, tablets, insulin injections if no other way of controlling blood sugar
213
What are the risk factors for type 2 diabetes?
Being overweight; taking little or no exercise; being over 40 years old; high blood pressure; unhealthy diet (high fat and sugar, low fibre)
214
What are the control of body temperature and blood sugar examples of?
Negative feedback.
215
What is negative feedback?
When the body responds to a change by trying to reduce the change.
216
What does negative feedback allow?
Very accurate control by a very fine-tuned response.
217
What is an open loop system?
One where the waste cannot be used again - eg oil is made into plastic which cannot be recycled.
218
What is a closed loop system?
One where the waste can be used again to keep the loop going round for ever - eg paper, which can either be processed to make more paper, or composted into soil to produce nutrients for more trees
219
Give some examples of closed loops in the natural world.
The carbon cycle.
220
Describe the carbon cycle.
Plants take in carbon dioxide, and use sunlight. (Described as sustainable?!); Make sugar and other organic matter; waste product is oxygen; animals take oxygen and organic matter to produce CO2. (Expand if needed, look at number of marks!)
221
What are the outputs from animals?
CO2; faeces (used by microorganisms and returned to the soil)
222
What happens to the carbon and other materials in the organism when plants and animals die?
Their organic matter is broken down by micro-organisms for energy and CO2 is produced.
223
How can microorganisms break down complex materials, such as cellulose (plant cell walls) and lignin (wood)
They use enzymes
224
Why is using fossil fuels considered an open loop system?
On a human time scale, it is
225
Over what time scale is the fossil fuel loop actually a closed loop?
Over a million years.
226
Why do we say that fossil fuels cannot be replaced?
Because we are using them much faster than the earth can replenish them.
227
What is a fruit?
A structure that grows from a fertilised flower.
228
What does a fruit contain?
Seeds that can grow into a new plant
229
What do seeds usually contain?
An energy store to help the seed to germinate
230
Why do we eat fruits?
They hold a lot of energy, more than eg leaves.
231
What are the reproductive structures of plants?
eg - eggs; sperm; pollen; flowers; fruit
232
Why is overproduction of reproductive structures necessary?
To ensure that enough survive to be a sexually mature adult of the species
233
Take the Brazil nut tree in Amazonia (South America), what losses does it face to the reproductive structures?
Failure of seed germination; damage by fungal or insect attacks; animal feeding; death of tree before reproductive age
234
Do animals overproduce reproductive structures?
Yes.
235
What losses do animals face to their reproductive structures?
Failures of eggs and sperm; animal feeding; death of the animal before reproductive age.
236
What is the the cost to the organism of producing excess reproductive structures?
The energetic cost of production.
237
What is the cost to the ecosystem of producing excess reproductive structures?
None, the structures that are not used are recycled.
238
How do the materials in a rainforest get used?
In a number of closed loop systems.
239
What do the closed loop systems of the rainforest produce all together?
A stable system.
240
What is the implication of a stable system?
The inputs broadly match the outputs.
241
What losses could there be from a stable rainforest ecosystem?
eg Animal migration; rivers washing some soil nutrients into the sea.
242
How can the rainforest systems be disrupted?
eg Climate change; human logging; human removing fruits and other resources; human manufacturing products; human building houses.
243
How can we balance the needs of the local population with the need to conserve the rainforest?
It is an ethical dilemma, and do we have the right to say anything when our lands are almost totally deforested?
244
What do you call a type of land degradation in which a relatively dry land region becomes increasingly arid, typically losing its bodies of water as well as vegetation and wildlife.
Desertification
245
What medium do most plants need to grow in?
Soil
246
What is soil a mixture of?
Minerals; organic matter; air spaces; water
247
What does good soil offer?
The right minerals; good drainage so that roots are not waterlogged and can still access oxygen
248
How do plants affect soil?
The roots hold the soil together; the leaves slow down the rain so it hits the soil with less force; water is removed from the soil by plant roots.
249
What does healthy soil do to the risk of floods?
Reduces it, as it can take up the water.
250
How does healthy soil release water?
Slowly, and therefore rivers and streams are less likely to flood.
251
What is likely to happen to soil if the vegetation is removed?
Erosion - blown away by wind; washed away by water
252
What happens when the topsoil is eroded away?
The land is no longer fertile, and it is no longer possible to grow crops.
253
What can happen to the whole area if plants are removed?
It can become a desert, as the transpiration of trees can be an important source of water vapour.
254
What type of ecosystem is a rainforest?
Complex.
255
How do rainforests enrich the soil?
They cover it with layers of leaves, and bind it together with large root systems.
256
What is the water like that flows out of a rainforest?
Clear
257
What does the clear water draining out of a rainforest tell you?
The rainforest is very good at retaining nutrients and minerals.
258
What happens to the soil when logging occurs in a rainforest?
It is washed away
259
What happens to a river that is carrying a lot of soil as a result of logging?
It can become blocked downstream, as the soil settles; this makes flooding more likely, which can wash away the river banks.
260
How does the water taken up by the plant leave it?
Transpiration through the leaves
261
What is transpiration?
Water evaporates from the leaves, and re-enters the atmosphere
262
What can happen as a result of many trees' transpiration?
Rain clouds can form
263
If you remove rainforests, what can this do to the weather?
The weather patterns become more unpredictable
264
What are ecological services?
Functions of the ecosystem that the ecosystem provides for all members
265
What are the four areas of ecological service?
Supporting services; provisioning services; regulating services; cultural services
266
What are the supporting services of an ecological system?
eg Nutrient cycling; oxygen production; pollination; soil production
267
What are the provisioning services of an ecological system?
eg Food, fibre, fuel, water
268
What are the regulating services of an ecological system?
eg Climate regulation; water purification; flood prevention
269
What are the cultural services of an ecological system?
eg Education and recreation
270
How are the ecosystem services provided?
By different parts of the ecosystem working together
271
How do humans interact with ecosystems?
We take advantage of the services they provide, eg removing water, using wood for building and fuel, using resources for food.
272
How must we use ecosystems?
We must not damage them so much that the service becomes unavailable.
273
What do organisms depend on to survive (ecology)
Ecological services.
274
What happens in the provision of ecological services?
They are often provided by the actions of other organisms
275
Give some examples of ecological services
A plant relying on an insect for pollination, without the insect, the plants cannot live; Plants rely on microorganisms to break down dead organic matter so that it can be absorbed by the roots; Bees rely on plants for nectar to feed the colony, and the plants rely on bees for pollination.
276
What is the environment in the tropics like?
Warm, wet, sunny
277
What does the environment of the tropics do to plant growth?
It helps them grow very quickly, the extra sunshine also allows a greater density of vegetation.
278
If the plants grow very quickly, what happens to nutrients in the soil?
They are taken up very quickly, even though microorganisms work faster in the warm
279
What is the implication of the quick absorption of nutrients by plants in the tropics?
The soil is depleted of nutrients in the tropics,
280
What is a temperate climate?
The climate is cool, drier and has less sunshine
281
What is the implication of temperate climate on soil nutrients?
There are more available as plants take them much more slowly.
282
What can we say about inputs and outputs in tropical and temperate ecosystems?
They are balanced.
283
What is the slash and burn method of exploiting an ecosystem?
Cut everything down and burn it, then start farming.
284
What does slash and burn do to soil nutrients?
For the first year, there will be many available due to the burning. After the minerals have been removed (by crops of livestock) the land becomes barren.
285
What happens when the land turns barren due to slash and burn?
Either a simple grasslands ecosystem develops, or desertification can happen if the soil is lost.
286
What is the measure of the number of organisms in a given area called?
Biodiversity
287
What are the most biodiverse ecosystems on the planet?
Rainforests
288
What do we believe are the implications of losing the rain forest?
Once it is gone it is gone forever, we cannot preserve the biodiversity and recreate it.
289
What is sustainable forestry?
Planning the steady replacement of resources removed from the ecosystem so that the system is only minimally affected. (Done here, and throughout a lot of Europe)
290
What happens to waste that is not recycled?
Landfill; faeces removed in sewage works and remains go into rivers; waste gases go into the atmosphere and are diluted to safe levels.
291
What happens to waste, long term?
It will be broken down, or diluted to such a level that it becomes safe
292
What does the damage done by waste depend on?
How much has been produced; how dangerous it is; how quickly the environment can deal with it.
293
What happens if the environment cannot deal with waste quickly enough?
The waste will build up to harmful levels.
294
What is sewage?
Anything flushed down the loo
295
What happened to sewage in historical times?
It went straight into rivers - if people were lucky.
296
What happened to the river as the amount of sewage increased?
The fish died (bacteria built up and deoxygenated the water)
297
What can happen with drinking water if sewage is not treated carefully?
It can get contaminated
298
Name some diseases that are spread by faecal contamination of drinking water.
Cholera and typhoid
299
What element is human faeces high in that causes a problem to rivers?
Nitrogen
300
What problem does nitrogen in water cause?
It causes growth of microorganisms, who take up oxygen as they respire, so fish die and start decaying, so the oxygen goes down further due to those microorganisms.
301
What happens to nitrogen levels in the water as a result of the death of the organisms that live in the water?
It goes up further (remember protein contains nitrogen)
302
What is the final result of the high level of nitrogen in the river?
The river is only suitable for anaerobes. (Oh, and that makes it smelly!)
303
What can happen when fields next to rivers are fertilised?
Nitrates in the river go up after rain, as the fertiliser is washed off the fields.
304
What is the name given to the process where water receives excessive nutrients that stimulate plant growth?
Eutrophication
305
What happens as a result of eutrophication?
Bacteria and algae show sudden growth (algal bloom)
306
What uses up the oxygen in the water?
Decay of dead algae/bacteria; respiration
307
What do some algae produce that causes big problems for other organisms using the water?
Toxins
308
What happens when there is too much nutrient being brought into the sea by a river?
Parts of the sea can suffer algal blooms
309
What is the name for a chemical that builds up in organisms in the food chain?
Bioaccumulation
310
Which organisms are most affected by bioaccumulation?
The ones at the top of the food chain.
311
What is the effect of bioaccumulation?
It depends on the chemical, but potentially very harmful if the chemical is toxic.
312
How is it possible to eat fish while not harming wild fish stocks?
Fish farming.
313
How do you grow fish?
In ponds, or enclosed in giant net "cages" in the sea.
314
How can fish farms in ponds fertilise their ponds?
They use run off from fields, which contains fertilisers not used by plants.
315
What is the effect of adding carefully controlled amounts of run off to ponds?
The pond weeds grow faster
316
What happens to pond weeds in fish farm ponds?
They are eaten by fish, which then grow
317
How are the numbers of fish kept constant?
The fish farmers add new fish every year.
318
How do the farmers/fishermen know how many fish they can take out of the pond?
They know how many are added every year.
319
What is the total dry weight of fish in the pond called?
Biomass
320
How does the biomass of fish in a farmed pond compare to the biomass of fish in a wild pond?
The farmed pond supports much greater biomass.
321
What is a Scottish lake called?
Loch (can also be an inlet of the sea - called a sea loch)
322
How are salmon farmed in lochs?
They are kept in giant tanks made of netting
323
How is the farm stocked?
Eggs and sperm are removed from adult fish and mixed in the laboratory.
324
What happens to wild salmon after spawning? (breeding)
They all die.
325
Where are the fertilised fish hatched?
In tanks of gently running water.
326
What happens to the young fish?
They go into the giant tanks and are fed.
327
What are young fish called?
Fry
328
What is the name for the amount of fish harvested each year?
Yield.
329
What are the disease implications of keeping so many fish so close together?
Pesticides are used.
330
What can happen with the pesticides used in fish farming?
They can enter the ecosystem if they move from the ponds/tanks.
331
What happens to the waste that the fish produce when farmed?
In lock fishing, the waste drains away naturally. In pond fishing, it is necessary to empty the ponds, clean them, and refill
332
What is stock biomass?
The amount of fish old enough to produce eggs.
333
Why are wild fish numbers declining?
Often due to overfishing, but changing sea currents/temperatures can have a massive impact as well.
334
What is overfishing?
Taking more fish than the system can replenish
335
What do governments do to prevent overfishing?
They set quotas.
336
What do quotas do?
Limit the number of days that fleets can fish; limit the size of the nets to only catch bigger fish; throw smaller fish back into the sea; only allow certain species to be kept, others are thrown back.
337
What is the problem with throwing fish back due to quotas?
They are often dead/dieing anyway.
338
Why do we farm microorganisms?
To take advantage of their ability to produce useful products/
339
What makes microorganisms useful for farming?
Simple biochemistry; reproduce quickly; can be farmed large scale to produce complex molecules; can be genetically engineered; few ethical concerns.
340
What feature of bacterial DNA makes it easier to genetically engineer them?
They have plasmids (rings of DNA in the cytoplasm)
341
What common foodstuffs are produced with microorganisms?
Yoghurt; cheese
342
Why are people worried by the thought of bacteria being farmed for food?
They are associated with disease
343
Why are bacteria hard to harvest?
The cells are very small
344
Why are yeasts easier to harvest?
Larger cells
345
Why are yeasts not as good for food production as bacteria?
They produce lower quality protein
346
What is quorn?
A protein produced by a fungus that is marketed as as vegetarian "meat" in sausages etc.
347
What makes quorn very versatile?
It can look like mince, or pieces of meat, so is an easy replacement for meat.
348
Where do we get penicillin?
From the fungus Penicillium Crysogenum
349
What other products do we make by farming microorganisms?
Vitamin B12; Chymosin (an enzyme for veggie cheese); Ethanol; pectinases (to increase the amount of juice extracted from fruit); protease (for enzyme washing powder)
350
How does the efficiency of bacterial protein production compare with cows?
They are much more efficient.
351
How are large quantities of eg penicillin produced?
A fermenter is used.
352
What sort of system is a fermenter?
A closed system, all inputs and outputs are controlled.
353
What sort of variables can be controlled in the fermenter?
Temperature; pH; oxygen levels; nutrients
354
Why are fermenters used?
Fermenters can produce large amounts of products cheaply and quickly.
355
What can weeds do to the yield of a crop?
Reduce it, between 35% and 100%
356
What is a chemical that kills some plants but not others?
A selective herbicide
357
What is happening with weed species that have been targeted by selective herbicides?
They are developing herbicide resistance
358
What happens to crop yield when weeds develop pesticide resistance?
They go down as the weeds are not killed.
359
What can some insect species do to crop yield?
Reduce it, as they eat part of the plant.
360
What do we call insects (and other animals) that compete with us for the food we are farming?
Pests
361
What happens when we spray our crops with pesticides?
The pests die, but so do other, innocent insects. Bees are a big concern!
362
What is happening to fungi that have been targeted by antifungal crop sprays?
They are developing resistance.
363
How are we genetically engineering crop species?
We are giving them characteristics that were not previously present.
364
What desirable characteristics are we adding to crop species with genetic engineering?
The crop species can produce chemicals that act as herbicides, pesticides or fungicides; the crop can be engineered with resistance to new chemicals that can be used as pesticides, fungicides or herbicides
365
Name a human hormone that is produced by farming bacteria?
Insulin
366
How did we get insulin before we could farm bacteria?
It was extracted from the pancreas of cows and pigs.
367
What had to be done to the animal insulin before it could be used on humans?
It had to be purified very carefully.
368
What ethical issues were there with animal insulin?
Cows are sacred to certain religious groups; pigs are unclean by certain religious groups; if you were vegetarian or vegan you still had to use animal insulin (or die)
369
When was human insulin first made using genetically engineered bacteria?
1982
370
How were the bacteria modified to make them produce human insulin?
They had the human insulin gene inserted.
371
What technique is used to genetically engineer bacteria and crop plants?
Recombinant DNA
372
What is recombinant DNA?
DNA from more than one source.
373
What is used to transfer the gene from one organism to another?
A vector, either a plasmid or a virus.
374
What are plasmids?
Circular DNA molecules found in the cytoplasm of some bacteria.
375
Why are viruses good as a vector?
They naturally "hijack" the cell and get it to produce more viruses, this ability can be used to get the protein we want.
376
How is a person tested for a specific gene?
Fluorescence In Situ Hybridisation (FISH)
377
What cells are tested?
White blood cells, red blood cells have no nucleus; foetal cells
378
What are the two strands of DNA?
Opposites of each other.
379
What is a gene probe like?
A gene probe has the opposite base sequence as the gene that is being looked for
380
What is a DNA probe?
A length of DNA that is the opposite of the gene being looked for.
381
How does the process work?
Make your gene probe; add a fluorescent chemical; mix the DNA probe with white blood cells; look under the microscope, if the probe has matched with the DNA it will fluoresce in UV light.
382
What does evidence suggest about genes and cancer?
Cancer is not caused by a single gene, more needs to go wrong in the cell to allow cancer to start,
383
What are BRCA1 and BRCA2
Two genes that greatly increase the chance of one type of breast cancer.
384
What ethical issues are raised with genetic testing for genes that merely raise the risk of a disease?
If the tests are done before birth, is it reasonable to abort the fetus as there is increased risk?
385
What ethical issues are raised about genetic testing of fetuses?
Already being abused in some parts of the world to select for boy babies (but may be better than killing babies); is it OK to select for blue eyes? Who decides whether a "disorder" makes life not worth living?
386
What are the ethical issues of genetic testing after birth?
It could affect life chances, difficulty getting job/insurance if have genes that mean an increased risk of disease.
387
What is the positive implication of knowing your genetic risk of certain diseases?
You can potentially change your lifestyle to reduce the risk; screening could be done more often for higher risk groups; some people choose to have breasts removed if they find their genetic risk of breast cancer unacceptable.
388
What is nanotechnology?
Technology that works on the scale of atoms and molecules.
389
How large are materials on the nanoscale?
Between 0.1 and 100 nm in size.
390
What is a nanometre (nm)?
10^-9 metres.
391
How big is an atom?
Between 0.1 and 0.2 nm
392
How wide is DNA?
About 2nm
393
How large is a red blood cell?
About 7,000nm
394
How wide is a human hair?
About 80,000nm
395
How much of the food we buy is wasted?
About 20%
396
What makes food "go bad"?
Much goes off because of oxygen in the air.
397
How can nanotechnology stop the problem of food spoiling in the packet?
It can make the packaging air tight, also stopping water getting in or out.
398
What else could be done with nanoparticles to reduce food waste?
They could be designed to change colour if the packaging is damaged, or if the temperature has gone too high, or if bacteria and fungi are detected.
399
What will colour changing nanoparticles mean for food waste?
It will be reduced as people will know that the feed is safe to eat.
400
What can nanoparticles do in wound dressings?
Silver nanoparticles are used, when exposed to water they have antibacterial properties, which means less infection.
401
What can be done with gold nanoparticles?
They are attached to antibodies which attach to cancer cells, then infrared light is passed into the body and the gold nanoparticles heat up, destroying the cancer.
402
Why is using nanoparticles for cancer treatment a good idea?
It makes it possible to target only the cancer cells, no healthy tissue will be affected (except maybe a few cells adjacent to the cancer)
403
What does the heart do?
Pumps blood around the body
404
What are the implications of anything that interferes with the function of the heart?
Very serious, potentially fatal
405
What happens when the heart valves become damaged?
Backflow of blood reduced the efficiency of the heart, so the heart has to work very much harder.
406
What can be done surgically to replace damaged heart valves?
Use human heart valves (donor organs); pig heart valves; artificial heart valves.
407
What is the problem with using human donors?
Not enough; immune system recognises the donor heart as "foreign" and attacks it, so immunosuppressant drugs need to be taken.
408
What has been done to reduce the problem of rejection?
Pigs have been specially bread to have heart valves that are less likely to be attacked by the human immune system.
409
What controls the heartbeat?
Specialised cells
410
What happens if the specialised cells that control the heart beat are damaged?
A pacemaker is needed.
411
What is a pacemaker?
A device that monitors the heartbeat, and if it is not beating correctly it will give a small shock.
412
What can be done when the whole heart is damaged?
A heart transplant (donor heart)
413
What do we see the future of heart transplantation being?
Mechanical hearts that remove the problems of rejection, and also the problem of limited supply.
414
What are your options currently if an organ becomes faulty?
Transplantation of donor organ, or an artificial organ (if available)
415
What alternatives could there be to donor organs, or artificial organs?
Stem cells.
416
What types of stem cell are there?
Embryonic; fetal; somatic; amniotic; IPS
417
What are embryonic stem cells?
Harvested from embryos (four or five days old -8 cell stage)
418
What are fetal stem cells?
Stem cells that are harvested from an aborted fetus.
419
What are somatic stem cells?
Another word for adult stem cells.
420
What are amniotic stem cells?
Stem cells harvested from the amniotic fluid surrounding the fetus.
421
What are IPS stem cells?
Stem cells formed by forcing an adult cell back to the embryonic stem cell.
422
Why are stem cells controversial?
Some people don't like killing embryos of fetuses; some people afraid of stem cells becoming cancerous and being more dangerous than the disease corrected.
423
Why would stem cells be at greater risk of cancer?
They are using genes that can also be switched on in cancer.
424
What has the government done about stem cells?
An ethics committee has been set up to make decisions about whether a treatment should be allowed.
425
How are stem cells used in leukaemia?
Bone marrow transplant
426
How does the bone marrow transplant work?
The patients own bone marrow is destroyed by chemotherapy and radiotherapy, so no more leukaemic cells are made; stem cells from a bone marrow donor are infused into the patients blood stream; the stem cells colonise the bone marrow and start making blood cells.
427
How might stem cells treat nerve damage?
They are being trialled to see whether they can help reconnect the broken nerve tissue in spinal injury.
428
Why are you a wonderful person?
You got to the end of unit 7!!!!!
