Biology Flashcards
1
Q
What’s the heart?
A
A muscular organ which pumps blood sound the body, it’s actually 2 pumps held together.
2
Q
How does the heart work?
A
The right pump forces deoxygenated blood to the lungs where it picks up oxygen and loses carbon dioxide.
After returning to the heart, the oxygenated blood is then pumped to the rest of the body by the left pump.
The heart has four chambers.
The upper ones, called atria, receive blood from the vena cava on the right and the pulmonary vein on the left.
The atria contract to move blood into their lower chambers - the ventricles.
When the ventricles contract, they force blood into the pulmonary artery from the right side and into the aorta on the left side.
Valves in the heart prevent the blood from flowing in the wrong direction. The heart muscle is supplied with oxygenated blood via the coronary arteries.
The action of the 2 sides of the heart result in a double circulation.
3
Q
What are the 3 types of blood vessel?
A
Arteries
Veins
Capillaries
4
Q
What are properties of arteries?
A
They carry blood away from the heart
They have thick walls containing muscle and elastic tissue
5
Q
What are properties of veins?
A
They have thinner walls than arteries
They often have valves along their length to prevent the back flow of blood
6
Q
What are properties of capillaries?
A
They’re narrow, thin-walled vessels
They carry the blood through the organs and allow the exchange of substances with all the living cells in the body.
7
Q
What happens if blood vessels are blocked or too narrow?
A
Blood can’t flow through effectively so the organs will be deprived of nutrients and oxygen.
Equipment e.g. Stents have to be used.
8
Q
What’s a stent?
A
A method to widen and keep blood vessels open.
They are inserted into blood vessels and a balloon is then inflated to open the stent before being removed and leaving the stent in place.
This is beneficial when coronary arteries become narrowed due to fatty deposits and are cutting off blood supply to the heart muscle.
9
Q
What’s the issue with a leaky valve?
A
Leaky valves mean the blood could flow in the wrong direction.
Artificial or animal valves can be inserted in the heart to replace damaged valves.
10
Q
What’s blood?
A
Blood’s a tissue.
The fluid plasma contains red blood cells, white blood cells and platelets.
11
Q
What does blood plasma transport?
A
Many substances including:
CO2 from the organs to the lungs
Soluble products of digestion from the small intestine to other organs
Urea from the liver to the kidneys where ur one is made
12
Q
Properties and functions of red blood cells:
A
Are biconcave discs which don’t have a nucleus
Contain the red pigment haemoglobin
Use their haemoglobin which combines with oxygen to form oxyhemoglobin in the lungs
Carry the oxygen to all the organs where the oxyhemoglobin splits into haemoglobin and oxygen
13
Q
Properties and functions of white blood cells:
A
Have a nucleus
Form part if the body’s defence system against microorganisms
14
Q
What are the properties and functions of platelets:
A
They’re small fragments of cells
Don’t have a nucleus
Help blood to clot at the site of a wound.
15
Q
Why is plasma given to patients?
A
The plasma can be given to patients in a transfusion to increase blood volume.
Blood from donors can be separated into plasma and cells. Donated blood mist be refrigerated. Some blood products can be frozen.
16
Q
What’s artificial blood?
A
Artificial blood e.g. Perfluorocarbons (PFCs) can be used which doesn’t have to be refrigerated. It doesn’t contain cells so blood matching is not necessary.
Artificial blood is expensive and doesn’t carry as much oxygen as whole blood. Some types are insoluble in water therefore they don’t mix well with blood.
Some also cause unpleasant side-effects.
17
Q
What are the advantages and disadvantages of artificial hearts?
A
Adv:
They don’t need to match the persons tissue
There’s no need for immunosuppressant drugs.
Dis:
Problems with blood clotting
Long stays at the hospital
It’s expensive
18
Q
What are the transport tissues within plants?
A
Xylem tissue - transports water and mineral ions from the roots to the stem, leaves and flowers.
Phloem tissue - carries dissolved sugars from the leaves to the rest of the plant, including the growing regions and the storage organs.
19
Q
What’s the transpiration stream?
A
The movement of water from the roots through the xylem and out of the leaves.
20
Q
What’s the circulatory system?
A
The double circulation system in humans which consists of blood, blood vessels and the heart.
21
Q
What’s osmosis?
A
The movement of water - it is the diffusion of water across a partially permeable membrane e.g. In and out of cells via the cell membrane.
The water moves from a region of high water concentration (dilute solution) to an area of low water concentration (more concentrated solution).
Just like diffusion, movement of water molecules requires no energy from the cell.
22
Q
What does active transport allow?
A
It allows cells to take in substances against a concentration gradient. (It uses energy from respiration).
Cells may need to absorb substances which are in short supply i.e. Against the c’ gradient.
They use active transport to absorb substances across partially permeable membranes against the c’ gradient.
23
Q
What can be absorbed from active transport?
A
Cells are able to absorb ions from dilute solutions e.g. Root cells absorb mineral ions from the dilute solutions in the soil by active transport.
Glucose can be re-absorbed in the kidney tubules by active transport.
24
Q
What happens during active transport?
A
- the transport protein absorbs the useful molecule from outside the cell.
- the transport protein rotates to release the molecule inside the cell using energy.
- the transport protein then rotates again so it’s facing the outside if the cell.
25
What do most sports drinks contain and why?
They're solutions of sugar and mineral ions.
- water helps replace the water lost when sweating
- sugar helps replace sugar and glucose used for respiration and energy release
- mineral ions help replace those lost in sweating
26
What are sports drinks used for?
They're designed to help balance the the concentration of body fluids and the concentrations inside cells.
If the drink concentration matches the body fluids the solution is called isotonic.
27
What are exchange surfaces?
Large, complex organisms have special exchange surfaces to obtain all the food and oxygen they need.
Soluble food materials (solutes) are absorbed by the intestine. Oxygen is absorbed by the lungs and CO2 is removed from them.
28
What makes efficient exchanging surfaces?
A large surface area, thin walls or a short diffusion path.
29
How are the lungs efficient exchanging materials?
Lungs contain gaseous exchange surfaces.
- Surface area is increased by the alveoli (air sacs)
- Alveoli have thin walls, a large surface area and good air supply
- The lungs are ventilated to keep. Steep diffusion gradient
- Oxygen can easily diffuse into the many capillaries surrounding the alveoli and CO2 can diffuse out
Air goes in
Oxygen moves into the blood via diffusion
CO2 passes out of the blood by diffusion
Air out
30
Where are the lungs situated?
In the thorax, inside the rib age above the diaphragm separating the lungs from the abdomen
31
What happens when we breathe in?
- the intercostal muscles between the ribs and diaphragm contract
- the rib age moves up and out and the diaphragm flattens
- the volume of the thorax is increased
- pressure in the thorax decreases and air is drawn in
32
What happens when we breathe out?
- the intercostal muscles between the ribs and diaphragm relax
- the rib age moves down and in and the diaphragm becomes domed
- the volume of the thorax is decreased
- pressure in the thorax increases and air is forced out
33
What's ventilation?
Movement of air in and out of the lungs
34
Why would you not be able to get enough oxygen into the blood stream?
Damaged alveoli - smaller surface area for gas exchange
Narrow tubes leading to the lungs - less air can move through
Paralysis - their muscles won't work to pull their rib age up and out
35
Hat are the various breathing aids?
Iron lung - for paralysed people (chest sealed in large metal cylinder, when air was drawn out the cylinder the persons chest moved out and they breathed in and vise versa) (negative pressure)
Breathing aids force measured amounts of air into the lungs using positive pressure. Bags of air linked to masks can force air down the trachea.
Positive pressure aids are often smaller and easier to manage at home and can be linked to computers for control
36
What are villi?
Finger-like projections from the lining of the small intestine which increases the surface area for the absorption of digested food and soluble molecules into the blood
37
What makes gillie such efficient exchange surfaces?
Large surface area for diffusion
Very thin (only one cell think) so there is only a short distance across which diffusion takes place
Lots of capillaries close to the wall of the villus so there's a rich blood supply which enables efficient diffusion
38
How do materials exchange within plants and what materials are exchanged?
Gases diffuse in and out of leaves through tiny holes called 'stomata', the size of which is controlled by guard cells.
Gases exchanged include:
- Oxygen for respiration and is a waste product of photosynthesis
- Carbon dioxide needed for photosynthesis and waste of respiration
- Plants also lose water vapour due to evaporation
- Water and mineral ions are taken up by the roots (root hair cells increase surface area)
39
What increases exchange efficiency in plants?
The leaves are flat and thin with internal air spaces to increase the surface area for diffusion of gases.
40
What's the structure of a leaf?
| With features
1) Upper epidermis
waxy cuticle - waterproof layer stops water loss
2) Palisade layer
Air spaces
3) Spongey layer
Cells not tightly packed - large surface area for gas exchange
4) Lower epidermis
Guard cells open and close stomata to control water loss
41
What's transpiration?
Movement of water through a plant is known as the transpiration stream.
Plants take up water from the roots which passes through the plant to the leaves. It then evaporates from the leaves and water vapour diffuses from the stomata.
If the rate of evaporation is greater Han water uptake, the plants dehydrate. Evaporation is quicker in dry, hot, windy or bright conditions.
42
Ow is water loss in plants reduced?
Guard cells can close the stomata to prevent excessive water loss
Wilting results in the leaves collapsing and hanging down which reduces the surface area
43
What's homeostasis?
Internal conditions of the body must be controlled. keeping conditions within a narrow range is called homeostasis.
44
What must be controlled for homeostasis?
```
Temperature
Blood glucose levels
Water
Ion content
Levels of waste products
```
45
What waste products are removed?
CO2 when produced from respiration removed from the lungs when we breath out
Urea from the liver from the breakdown of amino acids, removed by the kidneys in the urine and temporarily stored in the bladder
46
What is the purpose of the kidney?
The body has two kidneys. They filter the blood, excreting substances you dont want and keep those you need.
It's an important part of homeostasis.
A healthy kidney produces urine by:
First filtering the blood
Re absorbing all the sugar
Re absorbing dissolved ions needed by the body
Re absorbing as much water necessary
Releasing urea, excess ions and water on the urine
47
If a person suffers from a kidney failure, how can a dialysis be used?
A dialysis machine carries out the same jobs as a kidney - blood flows between partially permeable membranes - and is used until the patient receives a successful kidney transplant.
Dialysis fluid contains the same concentration of useful substances that the patient's blood does e.g. Glucose and mineral ions, meaning they don't diffuse out the blood so don't need to be reabsorbed.
Urea diffuses out from the blood and into the dialysis fluid.
It restores the concentration of substances in the blood but must be done regularly.
48
How does a dialysis work?
1) Arterial blood leaves the arm and is pumped through tubes (where blood thinners are added to prevent clotting).
2) The blood then enters the dialysis machine where dialysis fluid is entered and the dialysis fluid carrying waste and urea is removed.
- Within the dialysis machine, blood cells and large proteins cannot pass through the partially permeable dialysis membrane.
- Urea diffuses out
- There is not net movement of sugar or other substances. The dialysis fluid has no urea and is a concentration of sugar and mineral ions.
- Excess salt diffuses out of the blood
3) Clean blood flows through a bubble trap to remove any bubbles
4) Clean blood returns to a vein in the arm
49
Why does the dialysis fluid contain glucose and minerals ions?
If the fluid was water only, all the useful solutes would diffuse out of the blood as well as the urea
50
What happens during a kidney transplant?
(Perhaps a better option than dialysis)
A donor is found (either living or a victim of a fatal accident)
There are proteins called antigens on the surface of cells - the recipients antigens may attack the antigens on the donor organ as they don't recognise it / it's 'foreign'
Following the transplant, the recipient must take drugs to suppress the immune response to prevent rejection - immunosuppressant drugs
The new kidney is usually place in the groin and attached to the blood vessels and bladder
Despite advantages, there are some risks e.g. Suppressing the immune system leaves them vulnerable to common infections
51
How is body temperature controlled?
Human body temperature should be around 37°C so that enzymes will work efficiently.
- Body temperature is regulated by the thermoregulatory centre in the brain where there are receptors that detect the temperature of blood flowing through the brain
- Temperature receptors in the skin also send impulses to the brain to give info on skin temp'
- Skin looks red when hot due to increased blood flow
- Sweating helps cool the body. When hot, more water is lost from skin so more water must be taken in
52
What happens if the core body temperature rises?
- Blood vessels near the surface of the skin dilate so more blood can flow through the skin capillaries. Energy is transferred by radiation and the skin cools
- Sweat glands produce more sweat. The water evaporates from the skins surface. Energy required for the evaporation comes from the skins surface so we cool down.
- Hairs lie flat so less air is trapped as insulation
53
Hat happens if the core body temperature falls?
- Blood vessels near the surface of the skin constrict and less blood flows through the skin capillaries so less energy is radiated.
- We 'shiver' - muscles contract quickly. This requires respiration and some of the energy released warms the blood
- No sweat is produced
- Muscles pull hairs erect so can trap an insulating layer of air
54
What must doctors consider when discussing the suitability of dialysis or kidney transplants?
```
Patients general health
Length of time of dialysis received
Cost (no more dialysis, more immunosuppressants)
Risks (anaesthetics, infections etc)
Availability of donors
```
55
What are the ethical issues with kidney donors?
Should everyone be on a transplant register or should they opt in?
Should people be paid to be donors?
Should people pay for a new kidney to jump the queue
56
What happens to the body during extreme temperatures?
Can be dangerous for survival as the body's enzymes don't work properly
Small children have a large SA:V ratio so they transfer energy to their surroundings quickly in cold conditions and dehydrate quickly in heat.
If the body temperature is too low the respiratory enzymes work to slows
If the child dehydrates they can't cool and overheat meaning their enzymes have denatured
Elderly people suffer from hypothermia as they don't move around much so little energy is released.
57
How is blood glucose controlled?
Levels of glucose are monitored and controlled by the pancreas
If there is too much glucose in our blood, the pancreas produces the hormone insulin.
Insulin causes the glucose to move from the blood into cells.
In the liver, excess glucose is converted to glycogen
If no or too little insulin is produced by the pancreas, the blood glucose level may become very high. This is called Type 1 diabetes which can be controlled by injections of insulin and careful attention to diet and levels of exercise.
58
What does insulin do?
- Insulin causes the blood glucose levels to fall
- If the level gets too low receptors in the pancreas detect the low level
- The pancreas released glucagon, another hormone
- The glucagon causes the glycogen in the liver to change back to glucose
- The glucose is released back into the blood
59
How is diabetes treated?
Type 1 is commonly treated with insulin produced by genetically engineered bacteria
It must be injected before every meal of their life although some use pumps
Doctors and scientists are trying to develop new methods of treating and possibly crying type 1 diabetes
This includes:
- Pancreas transplants
- Transplanting pancreas cells
- Using embryonic stem cells to produce insulin secreting cells
- Using adult stem cells from diabetic patients
- Genetically engineering pancreas cells to make them work properly
60
What is meant by 'against a concentration gradient'?
When particles move from an area of low concentration to an area of high concentration
61
Why is the rate of transpiration higher on a bright day?
The plant is photosynthesising at a faster rate and needs more CO2 so the stomata will be open as wide as possible
62
What is occurring with the human population?
It's rapidly increasing.
Many want a better standard of living.
We are using up non renewable raw materials.
Production of goods results in industrial waste.
This effects the ecology of the Earth.
63
What are the ways in which humans pollute the earth?
Sewage, fertilisers and toxic chemicals pollute waterways and lakes
Smoke and gases e.g. SO2 pollute the air and contribute to acid rain or the greenhouse effect
Pesticides and herbicides can pollute land and wash into water
64
How do humans pollute land?
Sewage contains human body waste and waste water from homes - sewage must be treated properly to remove gut parasites
Household and industrial waste go to landfill and toxic chemicals leak out.
Farming
Herbicides and pesticides are poisons which are sprayed onto crops and can get into soil and the food chaining washed into rivers.
Chemical fertilisers may also be washed into rivers and lakes - this can cause eutrophication.
65
How do humans pollute water?
Herbicides, pesticides and chemical fertilisers all get washed into rivers and streams.
Fertilisers and untreated sewage can cause high levels of nitrates in the water.
Toxic chemicals from landfill leak into waterways and pollute the water, causing eutrophication and killing fish.
66
What causes air pollution?
Power stations, cars and burning fuels produce sulphur dioxide and other acidic gases e.g. NO2
SO2 dissolves in water in the air forming acidic solutions.
These solutions fall as acid rain - it can be a long way from where the gases were produced.
Acid rain kills organisms and trees can be damaged if the leaves are soaked in acid rain for long periods of time.
It can also change the soil pH which damages the roots and may release toxic minerals. E.g. Aluminium ions are released which damage organisms in the soil and waterways.
Enzymes which control reactions are sensitive to pH.
When trees are damaged, food and habitats are lost.
67
What are the impacts of deforestation?
It has increased the release of CO2 into the atmosphere due to the burning of trees and decay of the wood by microorganisms.
It has reduced the rate which CO2 is removed from the atmosphere by photosynthesis.
It has reduced biodiversity due to loss of food and habitats.
Cattle and rice growing produce methane which has led to an increase of methane in the atmosphere.
The destruction of peat bogs and other areas of peat result in the increase of CO2 which occurs because the peat is removed from the bogs and used in compost for gardens. The compost is decayed by microorganisms.
Using peat-free composts means the peat boys will not be destroyed.
68
Why does deforestation occur?
So that crops can be grown to produce ethanol-based biofuels.
So that there can be an increase in cattle and rice fields for food.
69
How is carbon dioxide sequestered?
It is removed from the air by plants in photosynthesis and by dissolving in oceans, rivers and lakes.
70
What is the result of an increase in the Earth's temperature by only a few °C?
It can cause big changes in the Earth's climate
It can cause a rise in sea level due to melting of ice caps and glaciers
It reduces biodiversity
It can cause changes in migration patterns e.g. Of birds
It may result in changes in the distribution of species.
71
What are biofuels and what the the two types of biofuel?
A fuel produced from biological materials and waste which is renewable and sustainable.
There's:
- Ethanol-based fuels (produced by anaerobic fermentation of sugars from plants)
- Biogas (mainly methane produced by the fermentation of biological materials)
72
How are ethanol-based biofuels produced?
By anaerobic fermentation of sugars from plants.
Microorganisms respire anaerobic ally to produce ethanol using sugars from crops as an energy source.
Glucose is produced from maize starch by the action of a carbohydrase.
The glucose and sugar cane juices can be fermented by yeast to produce ethanol.
The ethanol is extracted by the process of distillation and can then be used as a fuel in motor vehicles.
Using ethanol as a fuel could replace fossil fuels in the future. In terms of the greenhouse effect, ethanol fuel is more carbon-friendly.
Ethanol is described as carbon neutral because only the CO2 used for photosynthesis by the crops is returned to the atmosphere when the ethanol is burned.
73
How is biogas produced?
Biogas, mainly methane, can be produced by anaerobic fermentation involving bacteria.
Plants and any waste material containing carbohydrate e.g. Cattle dung can be broken down in biogas generators.
The generators provide the ideal conditions for bacteria to reproduce and ferment the carbohydrates. They must be maintained at a suitable temperature in oxygen-free conditions.
Some generators are designed to mix the contents.
They're either buried in the ground for insulation or have insulating jackets.
Large scale commercial generators use waste from sugar factories or sewage works.
Small scale generators can be used by a home or farm.
The gas produced is a fuel and provides energy for heating etc. The more methane in the gas mixture the better the quality of biogas.
The remaining material (slurry) is also removed and used as fertilisers.
74
What makes food production efficient?
The shorter the food chain, the less energy will be wasted therefore shorter food chains make food production more efficient.
It's more efficient for us to eat plants than it is to eat animals.
75
How can we produce meat more efficiently?
- By preventing the animal from moving so it doesn't waste energy on movement (however this is seen as cruelty by many and so is controversial).
- By keeping the animal in warm sheds so it doesn't use as much energy from food to maintain its body temperature.
76
What does sustainable food production involve?
- Managing resources
- Finding new types of food e.g. Mycoprotein (the fungus Fusarium is grown to produce this. It's a protein rich food suitable for vegetarians. It's grown aerobically on cheap sugar syrup made from waste starch and the mycoprotein harvested).
- Monitoring fish stocks (fisherman can only remove a strict allocation of fish and certain sized nets must be used to not catch small, young fish)
77
How are microorganisms grown on a large scale?
By using industrial fermenters
The conditions must be controlled to ensure maximum growth e.g. of the fusarium fungus.
Industrial fermenters are large vessels which have:
- an air supply providing oxygen for respiration
- stirrer or gas bubbles to keep the microorganisms spread out and provide an even temperature
- a water-cooled jacket around the outside as the respiring microorganisms release energy which heats the contents
- sensors to monitor both pH and temperature
78
What human activities affect the global environment?
Deforestation which causes increased levels of CO2
Increases in rice growing and rearing cattle resulting in more methane being released
Building dams to store water in reservoirs causing loss of habitats, drying out rivers below the dam and reduction in fertile land to grow crops
79
Why are opinions of global warming divided?
Some believe the Earth's temperature has increased due to increases in greenhouse gases.
Others say the increase is part of a natural cycle.
80
What's a hypertonic solution?
A solution that has a greater concentration of solutes outside the cell in comparison to inside the cell.
When the solution is more concentrated than the cell/cytoplasm
(Osmosis occurs by water moving OUT OF the cell)
81
What's a hypotonic solution?
A solution that has a lower concentration of solutes outside the cell in comparison to inside the cell.
When the inside of the cell is more concentrated than the solution outside.
(Osmosis occurs by water moving INTO the cell)
82
What processes occur in the kidney to make urine?
Filtration and reabsorption.
They filter the blood, excreting substances you don't want and keeping those you need.
A healthy kidney produces urine by:
- first filtering the blood
- re absorbing all the sugar
- re absorbing the dissolved ions needed by the body
- re absorbing as much water as the body needs
- releasing urea, excess ions and water in the urine
83
What is the function of glucagon?
It causes glycogen to be turned into glucose which enters the blood and raises the blood glucose level.
84
Suggest two possible advantages of getting more food from mycoprotein:
• quicker
• suitable for vegetarians
• cheaper
• more efficient or less land / methane
85
What substances does the blood transport around the body?
* carbon dioxide / CO2
• urea
• protein
• water / H2O
• hormones / insulin
* glucose
* oxygen
86
What are the effects if global warming?
* reduce biodiversity or
extinction
• change in migration patterns
• change in species distribution
• change in climate
* rising sea levels
accept correct examples of climate change eg storms, flooding, drought
references to weather changing is insufficient
allow ice caps melting or habitat destruction
87
Describe how the body measures body temperature:
any three from:
• thermoregulatory centre
• (has temperature) receptors
• (which) monitor blood temperature (as it flows through the brain)
• (temperature) receptors in the skin
• (receptors) send impulses to the brain
88
How does a healthy kidney produce urine?
(the kidney) filters the blood
(and then)
reabsorbs all of the glucose
reabsorbs some of the ions
reabsorbs some of the water
releases urea (in urine)
