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Science - Biology - GCSE > P1 - Organisation > Flashcards

P1 - Organisation Flashcards

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1
Q

How are organ systems formed ?

A

Specialised cells carry particular functions, and groups of similar cells form tissues, which form organs made up of different tissues which then form organ systems.

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2
Q

The digestive system is an example of what ?

A

A complex organ system. It is found in humans and other mammals and breaks down and absorbs food.

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3
Q

What makes up the digestive system ?

A

Glands (pancreas and salivary glands), stomach and small intestine, liver and large intestine.

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4
Q

What are the jobs of the organs in the digestive system ?

A

The stomach digests food, liver produces bile, pancreas produces digestive juices, small intestine digest food further and absorbs soluble food molecules and the large intestine absorbs water from undigested food leaving faeces.

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5
Q

What are enzymes ?

A

An enzyme is a type of catalyst, something that increases the speed of a reaction without being changed or used up. They control reactions in the body and are large proteins.

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6
Q

What is a catalyst ?

A

A substance which increases the speed of a reaction, without being changed or used up in the reaction.

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7
Q

What happens in chemical reactions ?

A

Things are either being split apart or joined together.

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8
Q

How does an enzyme work ?

A

Each enzyme has an active site, with a unique shape - and the substrate has to fit into the active site for the reaction to work.

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9
Q

How can you represent how enzymes work ?

A

The lock and key model.

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10
Q

How does temperature affect the rate of reaction ?

A

A higher temperature increases the rate at first, but too hot can denature the active site by breaking bonds in the enzyme. All enzymes have an optimum temperature.

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11
Q

How does pH affect the rate of reaction ?

A

All enzymes also have an optimum pH - above or below this it can denature the enzymes active site.

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12
Q

How can you work out the rate of reaction ?

A

Rate = 1000 ÷ time

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13
Q

Why are big molecules broken down into smaller ones ?

A

Starch, proteins and fats are big molecules that need to be broken down because they’re too big to pass through the walls of the digestive system. And smaller soluble molecules can be easily absorbed into he bloodstream.

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14
Q

What are carbohydrases ?

A

Enzymes to break down carbohydrates, like amylase which is made in the salivary glands, pancreas and small intestine - which breaks down starch (a carbohydrate) into sugars.

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15
Q

What are proteases ?

A

Enzymes to break down proteins, made in the stomach, pancreas and small intestine - breaking down proteins into amino acids.

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16
Q

What are lipases ?

A

Enzymes to break down lipids, made in the pancreas and small intestine - breaking down lipids into glycerol and fatty acids.

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17
Q

What is bile ?

A

Produced in liver and stored in gall bladder before released into the small intestine. It’s also alkaline.

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18
Q

What does bile do ?

A

It neutralises hydrochloric acid from stomach and then makes conditions alkaline. It also emulsifies fats - breaking them down into tiny droplets, giving a larger surface area for lipase to work on.

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19
Q

Why does bile make stomach acid alkaline ?

A

Enzymes in small intestine work best in alkaline conditions.

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20
Q

How do you prepare a food sample ?

A

Get a piece of food and break it up using a pestle and mortar, transfer to a beaker and add distilled water, stir with a stirring rod to dissolve food and then filter out the solid using a funnel and filter paper.

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21
Q

What is the test for sugars ?

A

The benedict’s test. Transfer 5cm^3 food sample to test tube, prep. water bath to 75C. Add 10 drops benedict’s solution to test tube using pipette - place in water bath and leave for 5 minutes. If there’s sugar, solution will go from blue to green, yellow or brick-red depending on concentration of sugar.

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22
Q

What is the test for starch ?

A

Use iodine solution - transfer 5cm^3 food sample to test tube, add a few drops iodine solution and gently shake to mix contents. If there’s starch, solution will change from browny-orange to black or blue.

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23
Q

What is the test for proteins ?

A

The biuret test - transfer 2cm^3 food sample to test tube and add 2cm^3 biuret solution, mix contents by gently shaking. If there’s protein, solution will change from blue to pink or purple.

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24
Q

What is the test for lipids ?

A

The sudan III test - prepare food sample without filtering it and transfer 5cm^3 to test tube and add 3 drops sudan III stain solution and gently shake. If there’re lipids, mixture will separate into two layers - top layer being bright red.

25
Q

How does air move into the lungs ?

A

The air breathed in goes through the trachea, passes through the bronchi, then the bronchioles and then ends in the alveoli - small air sacks.

26
Q

What do alveoli do ?

A

They carry out gas exchange - surrounded by blood capillaries, blood comes to lungs through capillaries, containing lots of carbon dioxide and little oxygen. Oxygen diffuses from air in the alveolus into blood. While carbon dioxide diffuses out of blood into air in alveolus. Breathing rate: breaths per minute = number of breaths ÷ number of minutes.

27
Q

Where are the lungs located ?

A

In the thorax(top part of the body) separated from the lower part of the body by the diaphragm. Big pink sponges protected by the rib cage surrounded by pleural membranes.

28
Q

What is the double circulatory system ?

A

Two circuits joined together, in the first circuit the right ventricle pumps deoxygenated blood to the lungs, where it picks up oxygen and returns to the heart. In the second, oxygenated blood pumped, by the left ventricle, around all other organs.

29
Q

How does blood flow through the heart ?

A

Blood flows into the two atria from the vena cava and pulmonary vein, from the atria into the ventricles and out of the heart. Right through pulmonary artery to lungs, left through aorta to the body. Blood flows to organs through arteries and returns through veins.

30
Q

Why are valves necessary ?

A

Stops blood flowing backwards in the double circulatory system.

31
Q

How do the heart muscles work ?

A

The heart needs it’s own supply of oxygenated blood, it gets this through arteries called coronary arteries - which branch off the aorta and surround the heart.

32
Q

What is a pacemaker ?

A

Group of cells in the right atrium wall, they control resting heart rate and tell the heart when to pump blood.

33
Q

What if the pacemaker doesn’t work properly ?

A

Causes an irregular heartbeat, an artificial pacemaker can be used to make heart beat regularly.

34
Q

What are arteries ?

A

Blood vessel that carries blood under pressure away from the heart, strong and elastic, with thick walls relative to the lumen.

35
Q

What are capillaries ?

A

Branch of arteries, very small and carry blood close to every cell in the body to exchange substances. Walls one cell thick to allow for fast diffusion.

36
Q

What are veins ?

A

Capillaries join up to form veins, lower pressure blood so not as thick walls as arteries - although bigger lumen helping blood flow. Also have valves to keep blood flow in right direction.

37
Q

How can you calculate rate of blood flow ?

A

Rate of blood flow = volume of blood ÷ number of minutes

38
Q

What do red blood cells do ?

A

Carry oxygen from the lungs, their shape (biconcave disk) gives large surface area to absorb oxygen.Without a nucleus to store more oxygen. They contain haemoglobin - which binds to oxygen in the lungs to form oxyhaemoglobin. In body tissues oxyhaemoglobin splints into haemoglobin and oxygen to release oxygen into the cells.

39
Q

What do white blood cells do ?

A

Defend against infection, they’re part of the immune system, some change shape to engulf microorganisms(phagocytosis), some produce molecules called antibodies or antitoxins to defend against them. These have a nucleus.

40
Q

What are platelets ?

A

Small fragments of cells, without any nucleus - help blood to clot to stop blood pouring out and microorganisms getting in.

41
Q

What is plasma ?

A

Pale straw coloured liquid that carries everything in the blood - red and white blood cells and platelets, food molecules, carbon dioxide - form organs to lungs, urea from liver to kidneys, hormones and antibodies and antitoxins produced by white blood cells.

42
Q

What are coronary arteries ?

A

Arteries that supply the heart muscle with blood.

43
Q

What is coronary heart disease ?

A

When layers of fatty material (fatty deposits) build up in the coronary arteries causing them to become narrow - reducing blood flow to the heart muscle, causing less oxygen to be carried there which can result in a heart attack.

44
Q

What are stents ?

A

Tubes put inside coronary arteries through surgery to keep them open, reducing risk of a heart attack. They’re effective for a long time, and recovery time from surgery is quick. Risks involve heart attack during operation, or infection or development of a blood clot near stent.

45
Q

What is cholesterol ?

A

A lipid that your body needs, too much of a bad type of cholesterol (LDL) can however cause fatty deposits to form in arteries.

46
Q

What are statins ?

A

Drugs to reduce the amount of cholesterol in blood slowing down formation of fatty deposits.

47
Q

What are advantages of statins ?

A

They reduce the risk of strokes, coronary heart disease and heart attacks. Some studies also suggest prevention of other diseases. Increase amount of good cholesterol (HDL) in the bloodstream.

48
Q

What are disadvantages of statins ?

A

Must be taken regularly over a long time, unwanted side effects include headaches, kidney failure, liver damage and memory loss. Their effect isn’t instant.

49
Q

What is a heart transplant ?

A

When a person’s heart is replaced by a donor heart - this can happen if someone has heart failure - where the heart can’t pump blood.

50
Q

What is an artificial heart ?

A

When a donor heart isn’t available these can keep the person alive, sometimes can be permanent however.

51
Q

What are some advantages of an artificial heart ?

A

Made from metals or plastics - less likely to be attacked by the body’s immune system.

52
Q

What are some disadvantages ?

A

Surgery to fit one can cause bleeding and infection, they don’t work as well as natural ones, blood doesn’t flow as smoothly - potentially causing blood clots and strokes. Patients also need to take medication to thin blood. Parts can also wear out and the electrical motor could fail.

53
Q

How can valves in the heart be damaged ?

A

By heart attacks, infection or old age - causing them to stiffen and not open properly, or become leaky allowing blood to flow in both directions.

54
Q

Can you replace heart valves ?

A

Yes, with biological valves or mechanical valves, this is less risky than a heart transplant however can still cause blood clots.

55
Q

What is the definition of health ?

A

The state of physical and mental well being, diseases can however cause ill health.

56
Q

What is a communicable disease ?

A

One that can spread from person(/animals) to person - and are caused by bacteria, viruses, parasites and fungi.

57
Q

What are non-communicable diseases ?

A

Ones that cannot spread between people and/or animals, generally last for a long time and slowly get worse i.e coronary heart disease.

58
Q

What is artificial blood ?

A

A blood substitute - salt solution (saline) used to replace a lost volume of blood. Can keep someone alive even if they lose up to 2/3 of their red blood cells. Gives patient enough time to make new red blood cells, if not they’d need a blood transfusion.

59
Q

P

A

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Science - Biology - GCSE (7 decks)

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