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GCSE Biology (AQA) > Topic 2: Organisation (Paper 1) > Flashcards

Topic 2: Organisation (Paper 1) Flashcards

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1
Q

What is a tissue?

A

A tissue is a group of cells with a similar structure and function.

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2
Q

What is an organ?

A

An organ is a group of tissues working together for a specifc function.

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3
Q

What are organ systems?

A

Organ systems are groups of organs which work together to form organisms.

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4
Q

What is the function of the digestive system?

A

To break down large molecules of food into smaller, soluble ones so that they can be absorbed into the bloodstream

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5
Q

What is the function of the mouth in the digestive system?

A
  • Food is chewed
  • Amylase enzymes released by the salivary glands begin to digest starch.
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6
Q

What is the function of the stomach in the digestive system?

A
  • Protease enzymes begin the digestion of proteins
  • Contains hydrocloric acid which provides optimal conditions for the protease.
  • Chruning turns the food into a fluid which increases the SA for enzymes to digest.
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7
Q

What is the function of the pancrease in the digestive system?

A

Pancrease releases amylase and protease enzymes into the SI (small intestine) which continues the digestion of starch and protein, and begin the digestion of lipids.

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8
Q

What is the function of the liver and gall bladder in the digestive system?

A
  • Releases bile into the SI
  • gall bladder store bile
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9
Q

What is the function of the SI in the digestive system?

A
  • Walls of the SI release enzymes to continue the digestion of protein and lipids
  • Small food molecules are absorbed into the bloodstream
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10
Q

What is the function of the LI (large intestine) in the digestive system?

A

Water is absorbed into bloodstream
(Remember: L for lake)

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11
Q

What is the function of the rectum and anus on the digestive system?

A
  • rectum stores faeces
  • faeces is released from anus
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12
Q

What happens to the products (absorbed materials) of digestion after?

A
  • Products used by the body to build new carbohydrates, lipids and proteins
  • Some of the glucose produced is used in respiration
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13
Q

What is the function of enzymes?
What are enzymes?

A

Enzymes catalyse (speed up) chemical reactions.
Enzymes are protein molecules

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14
Q

How do enzymes work?

A

Enzymes have an active site where only a complementry substate fits into. The enzyme then breaks down the substrate into products. Enzymes lower the activation energy.

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15
Q

What is the enzyme and substrate theory called?

A

The ‘lock and key theory’ shows that enzymes are specific and the substrate must fit perfectly into the active site.

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16
Q

What are proteins broken down into?
What happens after the products are absorbed into the bloodstream?

A

Proteins (chains of amino acids) are broken dowin into amino acids by protease.
When amino acids are absorbed by the body cells, they are joined together in a different order to make human proteins.

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17
Q

What are carbohydrates broken down into?
What is the specific case for starch?

A

Carbohydrates (chair of simple sugars) are broken down by carbohydrase into simple sugars.
Starch is broken down by amylase.

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18
Q

What is the strucutre of lipids/fats?
What are lipids broken down into?

A

A lipid molecule consists of a glycerol molecule attached to 3 fatty acid molecules.
Lipids are broken down by lipase enzymes into glycerol and fatty acids.

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19
Q

What are the 2 functions of bile?

A
  • Bile emulsifies lipids (increase SA –> increase rate of lipid breakdown)
  • the alkaline bile also neutralises the HCl in the stomach, to provide the optimum conditions for lipase enzymes –> increases rate of lipid digestion.
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20
Q

What happens if we increase the temperaure for enzymes?
Why?

A

Activity of the enzyme increases and the reaction is faster because the enzyme and the substare are moving faster, colliding more frequently

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21
Q

What happens at the optimim temperature?

A

Enzymatic recations occuring at maximum possible rate –> maximum frequency of sucessful colisions

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22
Q

What happens if we increase the temperature past the optimum? Why?

A
  • Enzyme activity rapidly decreases to zero and active site is denatured
  • At high temperatures, enzyme vibrates and the shape of the active site changes so the substate no longer fits
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23
Q

How can we test for starch?

A

Tke the food sample and grid it with distilled water using a mortar and psetle; transfer paste to a beaker, add more distilled water, stir to dissolve; filter
1. Add 2cm3 of food solution to test tube.
2. Add a few drops of iodine solution.
3. If starch, iodine: black –> blue/black

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24
Q

How can we test for reducing sugars?

A
  1. Add 2cm3 of food solition to a test tube.
  2. Add 10 drops of Benedict’s solution.
  3. Place tube into beaker and half-fill with hot water from kettle, leave for 5 min
  4. If sugar, Benedict’s solution: blue –> green/yellow/red
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25
Q

How can we test for proteins?

A
  1. Add 2cm3 of food solution to a test tube.
  2. Add 2cm3 of Biuret solution.
  3. If protient, Biruet solution: blue –> purple/pink
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26
Q

How can we test for lipids?

A
  1. Add 2cm3 of food solution to a test tube.
  2. Add 3 drops of Sundan III.
  3. Shake test tube gently to mix
  4. If lipids: red-stained oil layer will separate out and float on the surface
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27
Q

Why should no naked flames be present when testing for lipids?

A

Sudan III contains ethanol ehich is flammable.

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28
Q

RP: Describe a method to investigate the effect of pH on amylase.

A
  1. Place 1 drop of iodine solution into each well of a spotting tile.
  2. In the first test tube, add 2cm3 of starch solution.
  3. In the second tube, add 2cm3 of amylase solution.
  4. In the thrid solution, add 2cm3 of pH5 buffer solution.
  5. Place all 3 test tubes in a water bath (30°C) for 10 min to allow the solutions to reach the correct temperature.
  6. Combine the 3 solutions into 1 test tube and mix with a stirring rod. Return test tube to the waterbath and start a stopwatch.
  7. Ater every 30sec, use the stirring rod to transfer 1 drop of solution into a spotting well.
  8. Iodine should turn blue-black if starch is present.
  9. Stop transferring when the iodine remains orange (Reaction complete). Record this time.
  10. Repeat whole experiment with different pH buffers.
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29
Q

What are some problems with this method and how could we solve this issue.

A
  • Samples takesn every 30secs (only have approximate time for when the reaction is complete) –> take samples every 10sec
  • Not obvious when iodine doesn’t turn black/blue –> ask several people to look at the sporring tile to decide the time –> mean
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30
Q

How is the small intestine adapted for absorption of food molecules?

A
  • length of 5m –> large SA
  • interior covered with millions of villi –> increase SA
  • microvilli on surface of the villi
  • very goof blood supply from capillaries –> rapidly removes the products of digestions (maintains a high concentration gradient)
  • thin membrane (short diffusion pathway)
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31
Q

What is the problem of having a single circulatory system?

A

Blood loses a lot of pressure, so blood reaches organs relatively slowly –> can’t deliver a grat deal of oxygen

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32
Q

What is advantageous about a double circulatory system?

A

Blood passes through the heart twice which repressures it so it reaches organs quickly

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33
Q

What is and what is the function of the heart?

A

The heart is an organ, consisting mainly of muscle tissue, that pumps blood around the body.

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34
Q

What is the order of the 4 chambers in the heart (left to right on a diagram)

A

right atrium –> left atrium –> right ventricle –> left ventricle

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35
Q

How are the atria separated from the ventricles?

A

By atrioventricular valves

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36
Q

What is the flow of blood through the heart?

A
  • The vena cava brings in deoxygenated blood from the body.
  • The blood passes from the heart to the lungs in the pulmonary artery, where the blood becomes oygenated.
  • Oygenated blood passes from the lungs to the heart in the pulmonary vein
  • Oxxygenated blood is pumped from the heart to the body in the aorta.
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37
Q

What is the role of valves?

A

To prevent the backflow of blood.

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38
Q

Why does the left side of the septum have a thicker muscular wall than the right side?

A

The left ventricle has to pump to the entire body so it requires a grater force from the thicker muscular wall.

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39
Q

What is the function of coronary arteries?

A

The coronary arteries branch out of the aorta to supply the heart muscle with oxygen so it can be used in respiration to provide the energy for contraction.

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40
Q

How is the natural resting heart rate controlled?
What happens if this stops working correctly?

A

By a group of cells located in the right atrium that act as a pacemaker.
If the pacemaker becomes faulty, doctors can implant an artificial pacemaker to correct irregularities in the heart rate

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41
Q

What do arteries do?
How are thet adapted for this?

A

Arteries carry very high blood pressure blood away from the heart to the organs in the body.
* Very thick muscular walls to withstand the very high pressure
* Elastic fibres which stretch to cope with the blood surges passing through (then recoil in between to keep the blood moving)

42
Q

What do capillaries do?
How are they adapted for this?

A

Capillaries are where substances, such as glucose and oxygen, diffuse out to the cell in the organs (carbon dioxide diffuses back into the blood)
* very thin walls (short diffusion pathway for rapid substance diffusion)

43
Q

What do veins do?
How are they adpated to this?

A

Veins carry a low pressure, slow-moving blood back to the heart
* have valves to prevent backflow of slow-moving blood
* thin wall (Thick = unecessary)

44
Q

What is the plasma?
What is its function?

A

The plasma is the liquid part of the blood. The blood plasma transports dissolved substances around the body, such as:
* soluble digestion produces (Small intetine –> other organs)
* Carbon dioxide (organs –> lungs)
* urea (liver –> kidneys)

45
Q

What is the function of red blood cells?

A

Red blood cells transport oxygen from the lungs to the body cells.

46
Q

How are red blood cells adapted to their function?

A
  • contain heamoglobin which binds to oxygen in the lungs
  • no organelles –> more room for haemoglobin
  • binocave disc shape –> increase SA –> oxygen diffuses in and out rapidly
47
Q

What is the function of white blood cells?

A

White blood cells form part of the immune system

48
Q

What features help white blood cells to carry out their function?

A

Have a nucleus (contains DNA which encodes the instructions for their job)

49
Q

What is the function of the plateles?

A

Platelets are tiny fragments of cells that help the blood to clot

50
Q

What can donated blood be used for in medicine?

A
  • To replace blood that has been lost during an injury
  • Platelets are extracted to help pateint with blood clotting
  • Proteins that are extracted from blood can be useful, e.g. antibodies
51
Q

What are some problems with donating blood?

A
  • In a blood transfusion, the dontated blood has to be the same blood type as the patient’s (otherwise the pateint’s immune system could reject the blood)
  • risk of infection (Different disease could be transmitted via blood)
52
Q

What are cardiovascular diseases?

A

Diseases of the heart and blood vessels.

53
Q

What does it mean if cardiovascular diseases are non-communicable?

A

They aren’t infectious (can’t be passed from person to person)

54
Q

What happens if someone has coronary heart disease?

A

Layers of fatty material build up inside the coronary arteries, narrowing them, and therfore, reduce the flow of blood through the coronary arteries
* heart muscle recieves less oxygen to use in respiration
* muscle can’t contract efficiently

54
Q

What are statins?
Pros?
Cons?

A

Statins are drugs which reduce the levels of colesterol in the blood
* Pros: they slow down the rate the fatty materials build up; reduce the risk of coronary heat disease
* Cons: have some unwanted side effects, e.g. liver problems

55
Q

What are stents?
Pros?
Cons?

A

A stent is a tube which can be inserted into the coronary artery to keep it open.
* Pros: blood can flow normally through the coronary artery
* Cons: Stents won’t prevent other regions of the coronary arteries from narrowing, dosen’t treat the underlying causes of the disease.

56
Q

What happens if heart valves are faultyu and don’t fully open?
What happens if heart valves are leaky?

A

The heart has to pump extra hard to force the blood through –> causes the heart to enlargen
If the heart valves are leaky, the patient can feel weak and tired

57
Q

What are 2 treatemnts used for faulty heart valves?

A
  • replacement with an artificialy mechanical valve (made from metal)
  • replacement with a biological valve from an animal (e.g. pig)
58
Q

What are the pros and cons of mechanical valves?

A
  • Pros: can last a lifetime
  • cons: may increase the risk of bloodclots –> patients have ti take anticlotting drugs
59
Q

What are the pros and cons of biological valves?

A
  • Don’t need to take drugs
  • Don’t last as long and may need to be replaced
60
Q

What is heart failure?

A

Heart failure is the inability of the heart to pump sufficient blood to meet the needs for oxygen and nutrients.

61
Q

What are the 2 problems associated with a donated heart to treat heart failure?

A
  • Not enought donated hearts available
  • Patient must take drugs to stop the donated heart from being rejected by the immune system
62
Q

What is an artificial heart used for?
What are the disadvantages of using an artificial heart?

A

tempoary solution to heart failure while waiting for a heart transplant, allows the damaged heart to rest
Increases the risk of blood clotting, not a long-term solution to heart failure.

63
Q

What is the pathway of air in the gas exchange system?

A

Air passes into the lungs through the trachea –> trachea now splits into two smaller bronchi (one bronchus to each lung) –> bronchi subdivide into many smaller bronchioles –> alveoli

64
Q

What is one key feature of the trachea?

A

Contains rings or cartilage, prevents the trachea from collapsing during inhalation

65
Q

What is the function of the alveoli?

A

Alveoli are the tiny air sacs within our lungs where oxygen diffuses in and carbon dioxide diffuses out from the bloodstream

66
Q

How are alveoli adapted for gas exchange?

A
  • millions of alveoli - huge SA
  • very thin walls (short diffusion pathway)
  • very good blood supply (maintains a steep concentration gradient)
  • moist (gases have to be dissolved to diffuse)
  • ventilation brings in fresh oxygen and removes carbon dioxide (maintains steep concentration gradient)
    –> rapid rate of gas diffusion
67
Q

What is key about the control of mitosis?

A

Extremely tightly controlled (genes tell cells when to divide and when to stop dividing)

68
Q

How are cancers formed?

A

Changes take place in the genes –> uncrontrolled growth and division –> produces a tumour

69
Q

What is the different between benign and malignant tumours?

A
  • benign tumours are growths of abnormal cells found in one area (usually contained within the membrane), they lack the ablility to invade other parts of the body, they stay in one place
  • malignant cells invade neighbouring tissues and move into the bloodstream and spread to form new, secondary tumours - cancer
    (Rembmer = Malignant - Malicious (MM))
70
Q

What are the risk factors linked to cancers?

A
  • genetics
  • lifestyle
  • exposure to carcinogens
71
Q

Why is radon a carcinogen?

A

Radon releases ionising radiation which damages the DNA in oue cells (Causes cells to undergo uncontrolled cell division) –> increases risk of developing lung cancer

72
Q

What is a communicable disease? Give an example.
What is a non-communicable disease? Give an example.

A

A communicable disease can be spread form person to person (e.g. measles) - spread by pathogens
A non-communicable disease can’t be spread from person to person (e.g. Coronary heart disease)

73
Q

What is health?
What can ill health be caused by?

A

Health is the state of physical and mental well-being.
Ill health can be caused by:
* both communicable and non-communicable diseases
* poor diet
* high levels of stress
* life situations

74
Q

What is TB?
Why may some people be unable to fight off bacteria that cause TB?

A

Turbercolosis (TB) is a fatal, communicable lung disease.
Some people have a defective immune system, e.g. people with AIDs (caused by HIV), so they are more likely to suffer from infectious diseases like TB

75
Q

How can cervical cancer be caused by another disease?

A

The human papilloma virus (HPV) infects the cells of the cervix, triggering cancer

76
Q

How can allergies be caused by a pathogen?

A

Allergies, such as asthma or dermatitis, can be triggered by immune reactions initially caused by a pathogen, which the immune system fights off, but is left with an allergy.

77
Q

Give an example where a mental illness can be caused by a physical illness (E.g. arthritis)?

A

Depression can be caused by arthritis

78
Q

What is epidemiology?

A

The study of the patterns of disease to determine risk factors

79
Q

Why dosen’t a correlation prove a cause?

A

A correlation dosen’t prove that a disease is caused by a risk factor, it only suggests that they may be linked

80
Q

What is a casual mechanism?
What is the correlation between cigarette smoking and lung cancer?
What is the casual mechanism between cigarette smoking and lung cancer?

A

A casual mechanism is evidence that a risk factor definitely leads to a particular disease.
Cigarette smoking and lung cancer have a positive correlation - they may be linked
Cigarette smoke contains carcinogens which damage DNA and increase the risk of cancer

81
Q

What is the probelm of only sampling a group of people?
How can we avoid bias when sampling?

A

You can’t try to draw conclusions from this small group of people to the whole population
To avoid bias
* take a sample as large as possible
* take a sample as random as possible

82
Q

What are the risk factors for cardiovascular diseases?

A
  • a diet high in fat and low in vegtables ==> increases certain types of cholesterol in the blood –> increases rate that fatty material build up in the arteries
  • a diet high in salt –> increases blood pressure
  • smoking –> increases risk
  • regular exercise –> decreases risk
83
Q

What are the risk factors for lung cancer and other diseases of the lungs?

A

smoking increases risk of lung cancer (contains carcinogens) but also other lung diseaes like emphysema

84
Q

Whar is the effect of smoking during pregnancy?
What is the effect of drinking alcohol on an unborn baby?

A

smoking when pregnant increaeses risk of miscarrage and premature birth
drinking alcohl can cause fetal alcohol syndrome (children may have learning difficulties and other mental/physical problems)

85
Q

What other diseaes are aslo caused by drinking alcohol?

A
  • Adults who drink alcohol excessively increase their risk of liver cirrhosis and liver cancer
  • can also affect the brain: addition, memory loss
86
Q

What are the risk factors of type 2 diabetes?

A

obesity increases risk

87
Q

What is the risk factor of lung cancer that isn’t linked to lifestyle?

A

radon is a radioactive gas which damages the DNA in cells

88
Q

What is the top and bottom of the leaf covered with?
What is the function of both these layers?

A

Top and bottom of the leaf are covered with a layer of very thin epidermal cells which form epidermal tissue (upper and lower epidermis)
The epidermises protect the top and bottom surfaces of the leaf

89
Q

What is the key adaptation of the upper epidermis?

A
  • transparent –> allows light to pass through to the photosynthetic cells below
90
Q

What is the function of the waxy cuticle?

A

The thin, oily waxy cuticle reduces the evaportation of water from the surface of the leaf –> help prevent the leaf from drying out

91
Q

What is the function of the stomata?

A
  • Stomata allow carbon dioxide to diffuse into the leaf and oxygen to diffuse out
  • stomata also help to control the amount of water vapour that can pass out of the leaf (when water is lost, gaurd cells become flaccid, stomata closes)
92
Q

What is the palisade mesophyll?

A

The palisade mesophyll is a layer that consists of palisade cells.

93
Q

What is the function of the palisade cells?

A

The palisade cells chloroplasts (containing chlorophyll) that absorb the light energy needed for photosynthesis

94
Q

What is the function of the spongey mesophyll?

A

The spongey mesophyll is full of air spaces which allow CO2 to diffuse from the stomat through the spongey mesophyll to the palisafe cells to be used in photosynthesis (vice versa for O2)

95
Q

What is the function of the xylem?

A

Xylem tissue transports water and dissolved minerals from the roots to the stem and leaves

96
Q

What is the function of the phloem?

A

Phloem tissue transports dissolved sugars produced by photosynthesis from the leaves to the rest of the plant - translocation

97
Q

Where can meristem tissue be found?
What is the function of the meristem tissue?

A

We find meristem tissue at growing tips in roots and shoots
The meristem tissue contains stem cells which can differentiate into different types of plant tissue at any point in the plants life

98
Q

What is transpiration?
What is the transpirtation stream?
Why is the transpiration stream important?

A

Transpiration is the constant evaportation of water from the surfaces of the leaves
Evaporation of water from cells . water vapour diffuses through air spaces and out of the leaf through the stomata . water passes from the xylem into the leaf to replace the lost water . water is drawn into the root hair cells and up the xylem vessels to the leaf

The transpiration stream is important because:
* water is needed for photosynthesis
* dissolved mineral ions (Such as magnesium) are required in the plant
* evaporation of water cools the leaf down

99
Q

What factors lead to a high rate of transpiration?

A
  • higher temperatures –> molecules moving faster
  • dry conditions (not humid) (maintain a steep concentration gradient outside the leaf)
  • higher wind speed –> water is removed awat outside the leaf quickly (maintain steep concnetration gradient)
  • higher light intensity –> increases the rate of photosynthesis –> stomata open to allow CO to enter (Water can then pass out)
100
Q

What factors lead to a high rate of transpiration?

A
  • higher temperatures –> molecules moving faster
  • dry conditions (not humid) (maintain a steep concentration gradient outside the leaf)
  • higher wind speed –> water is removed awat outside the leaf quickly (maintain steep concnetration gradient)
  • higher light intensity –> increases the rate of photosynthesis –> stomata open to allow CO to enter (Water can then pass out)

GCSE Biology (AQA) (4 decks)

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