Biology Unit 3 - Life Processes

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  • Created by: Susie
  • Created on: 05-04-13 18:02
What is Osmosis?
the net movement of water molecules across a partially permiable membrane
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What is the difference between Diffusion and Osmosis?
Diffusion is the movement of particles from an area of high concentration to an area of low concentration, Osmosis is the movemant of water molecules across a partially permiable membrane
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What is active transport? Give examples of active transport in the body and in plants.
The movement of particles against a concentration gradient where the cells physicly move the particle. In plants it is used to absorb ions in the root hairs and in the gut to move nutrients into the blood
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How is the Diaphragm used in ventilation?
It flattens, increasing the volume of the thorax and thereby decreaseing the pressure around the lungs causing them to inflate. It then moves up, decreasing the volume, increasing the pressure and deflating the lungs
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What is the Thorax?
The upper part of the torso where the lungs and heart are located. It is separated from the abdomen (the lower part of the torso) by the diaphragm
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How did an iron lung work? Why were they replaced?
An iron lung was a case from the neck to the abdomen that changed the pressure around the thorax thereby causing the lungs to inflate and deflate alternatly. They restricted the user's movements alot and interfered with blood flow to the lower body
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How do the new artificial lungs work? What Problems can they cause?
They pump air into the lungs. They can occasionally burst alveoli if the lungs cannot cope with the artificial air flow however they do allow the user to live a more normal life than an iron lung
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What are Alveoli?
Millions of tiny "air sacks" in the lungs where gas exchange takes place
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How are alveoli specialised for gas exchange?
They have: a very large surface area to maximise diffusion; a moist lining to dissolve gases; very thin walls (1 cell thick) and a large blood supply to maintain a large concentration gradient
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What are Villi? Where are they found? And what do they do?
They are tiny "projections" in the small intestine, they increase the suface area so digested food is absorbed quickly. Their walls are 1 cell thick and they have a good blood supply to assist fast absorbtion
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How are root hairs cells specialised for absrobing water and minerals?
They have a long "Hair" which sticks out into the soil this increases the surface area of the root to increase absorbtion
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What are Phloem tubes made of? What do they do? And which way do they flow?
Phloem tubes are made of columns of living cells with holes between them to allow the food substances they transport from the leaves to the growing areas and storage organs in the plant, the transport in them flows in both directions
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What are Xylem tubes made of? What do they do? And which way do they flow?
They are made of dead cells joined end to end to form a column that transports water and mineral ions from the roots to the rest of the plant, because of this the transport in them only flows up
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Name the Chambers and blood vessels in the heart.
Form the body in the Vena Cava (vein) into the Right Atrium into the Right Ventricle out in the Pulmonary Artery to the lungs back in through the Pulmonary Vein into the Left Atrium into the Left Vetricle out through the Aorta (artery) to the body
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Humans have a double circulatory system. What does this mean?
The human circulatory system is 2 circuits joined together. One consisting of the heart and lungs and the blood vessels between them and the other consists of the heart and the rest of the body and all the other blood vessels in the body
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What are valves and where can they be found in the circulatory system?
Valves prevent blood flowing the wrong way in the circulatory system and can be found in the heart between the atria and the ventricles on both sides and between the ventricles and the arterys again on both sides and also in veins.
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What are arteries? What do they do? And discribe their structure.
Arteries are blood vessels that carry blood away from the heart. The blood they carry is at a high pressure so they have think, strong and elastic walls (made of muscle and elastic fibres). They have a small lumen (centre) to maintain blood pressure
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What are Veins? What do they do? And discribe their structure.
Veins are blood vessels that carry blood towards the heart. The blood is at a low pressure so the walls are thiner than artery walls (still made of muscle and elastic fibres). They have a large lumen and valves to stop the blood flowing backwards
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What are Capillaries? What do they do? And discribe their structure.
Blood vessels between Arteries and Veins. Their walls are only 1 cell think and they have a very small lumen. They are where substances and gases are exchanged
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Name the 4 parts of the blood and what they do.
Red blood cells, carry oxygen (oxygen reacts with haemoglobin). White blood cells defend against disease. Platelets are dead bits of cells that help clot wounds. Plasma is the liquid that carries everything else in the blood including hormones
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What is artificial blood?
When someone loses alot of blood their body is still able to pump what's left around if the volume of liquid is increased so artificial blood such as saline (a salt solution) is used to give the body time to make new blood
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What can go wrong with using artificial blood?
If air bubbles get into the blood it can lower the blood pressure to dangerous levels. Also Artificial Blood cannot carry oxygen so lower levels of oxygen are getting to the cells in the body, therefore it cannot be used as a long term solution.
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What is the alternative to artificial blood?
Blood transfusions consist of replacing lost blood with blood from a donner, however blood groups have to match, some people will refuse them for religous reasons and donnated blood can only be stored for a short time
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What are artificial hearts? What are they made of?
Mechanical hearts are made of plastics or metal so that the body doesn't reject them. They can be temporary or perminant and they replace the heart in the body
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What are the pros and cons of an artificial heart?
Pros: because they are made of metal or plastic there is no chance of rejection from the body. Cons: major surgery is needed to fit it which can lead to infection, not as good as a natural heart, parts can break or wear out can cause blood clots
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What can be done if the heart valves are defective but the rest of the heart is fine?
Mechanical valves can replace them but major surgery is needed to replace them and they can cause blood clots which can lead to strokes so the patient must take drugs to thin the blood which can be dangerous
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What are Stents? What do they do? And when are they used?
Stents are used to treat Cononary Heart Disease, when fat deposits shrink the lumen in arteries. They are tubes that are inserted into the artery to keep the lumen open
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What are the disadvantages of stents?
The stent can irritate the artery and cause scar tissue to grow which can narrow the artery again. Drugs must be taken to prevent blood clotting on the stent
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What is Homeostasis?
The maintenance of a constant internal enviroment
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Name the 6 things that need to be controlled in homeostasis.
Temperature, Water, Ion content and Blood sugar all need to be kept at the right level. Carbon dioxide and Urea both.have to be removed from the body.
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What is body temerature? And how does the body maintain it?
The enzymes in the body work best at about 37 C. If you get too hot you produce sweat and blood supply to the skin is increased. If you are too cold the blood supply is shut off and the hairs on the body erect to trap an insulting layer of air
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How do the kidneys help with homeostasis?
The kidneys remove the poison urea and any excess ions from the blood and mix them with the excess water (also removed from the blood) to produce urine
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What is a Nephron? What does it do?
Found in the kidney. It absorbs all the water, urea and ions out of the blood then keeps the urea and excess ions and water and allows the rest to reabsrob back into the blood. All the sugar is reabsorbed.
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What happens inside the body when a kidney fails? What are the treatments?
There is a build up of waste substances such as urea and excess ions. The treatments are dialysis or a kidney transplant
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What is in dialysis fluid? And why?
The same concentration of ions and glucose as healthy blood and no urea, this means that any excess ions and glucose and all the urea diffuse out across a concentration gradient
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How does Dialysis work?
Blood is pumped through a dialysis machine. through a tube with a selectively permeable barrier surrounded by dialysis fluid. The blood is then pumped back into the body.
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Which direction does the dialysis fluid flow in relation to the flow of blood? Why?
They flow in opposite directions to maintain the concentration gradient.
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What are the disadvantages of dialysis?
It has to take place up to 3 times a week and it takes 3-4 hours. Between dialysis sessions the patient must flow a strict diet. Dialysis can cause blood clots and/or infections
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What are the advantages and disadvantages of a kidney transplant?
No more dialysis sessions and patient can eat what they like. The body can reject the donor kidney and attack it. To prevent this the patient take immunosupressants but this can mean that the catch something else as the immune system is weakened
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What are the two hormones used to control blood glucose level? What produces them?
Insulin is secreted if the blood glucose level is too high. Glucagon is secreted if the blood glucose level is too low. Both are made and secreted by the pancreas.
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What do insulin and glucagon do to control the blood glucose level?
They are carried in the blood stream to the liver where they are absorbed. Depending on the hormone the liver is stimulated to either removes glucose (insulin) or adds glucose (glucagon) into the blood stream
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What can changed the blood glucose level (BGL- (this is not a scientific term it just makes it easier to write))?
What you eat, foods like carbohydrates cause BGL to rise. How much you exercise, vigorous exercise will decrease BGL. When you last ate, the BGL will rise after a meal but will gradually fall during the day.
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What is type 1 diabetes? How can it be treated?
A condition where the pancreas produces little or no insulin. Treatments: controlling diet, injecting insulin, pancreas transplant or pancreatic cells transplant
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What are the pros and cons of insulin injections?
No chance of rejection as the insulin has been genetically engineered in bacteria. It has to be taken every day for the rest of the patient's life. Not as accurate as a working pancreas so there may be long term health issues
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What are the pros and cons of a pancreas transplant?
No more insulin injections. Possible rejection so immunosuppessants need to be taken (swap 1 medication (insulin) for another) these can leave the body expossed to other diseases and can have serious side-effects. Major sergery for the transplant.
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Other cards in this set

Card 2

Front

What is the difference between Diffusion and Osmosis?

Back

Diffusion is the movement of particles from an area of high concentration to an area of low concentration, Osmosis is the movemant of water molecules across a partially permiable membrane

Card 3

Front

What is active transport? Give examples of active transport in the body and in plants.

Back

Preview of the front of card 3

Card 4

Front

How is the Diaphragm used in ventilation?

Back

Preview of the front of card 4

Card 5

Front

What is the Thorax?

Back

Preview of the front of card 5
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