Chapter 2: B2 core questions
1 What is the order in which food passes through the digestive system? Mouth->oesophagus-> stomach-> small intestine->large intestine->rectum->anus
2 What is the function of the mouth in digestion? To mechanically break up food into smaller pieces to increase surface area.
3 What are two functions of saliva in digestion? 1. To moisten food to allow easier swallowing, 2. To start chemical digestion by containing salivary amylase.
4 What is the function of stomach acid? To kill potentially pathogenic microorganisms in food.
5 What is the function of the small intestine? To absorb carbohydrates, lipids, amino acids, vitamins and mineral ions from digested food.
6 Give an adaptation of a) the small intestine and b) cells lining the small intestine to aid absorption of digested molecules. a) Small intestine has structures called villi which increase surface area, b) Epithelial cells lining the villi have microvilli on their surface which further increase surface area.
7 What is the function of the large intestine? To absorb water from digested food.
8 What is the function of the liver in digestion? To produce bile, an emulsifying and neutralising substance.
9 What is the function of the gall bladder? To store bile until it can be released into the small intestine.
10 What is the function of the rectum? To store undigested material before excretion.
11 What is an enzyme? A protein which can catalyse a reaction (speed it up) without being used up itself.
12 What is a substrate? A molecule or atom which is acted upon by an enzyme.
13 How does an enzyme "recognise" its specific substrate? A complementarily-shaped "active site" – a region on the enzyme which fits the substrate.
14 Name two environmental conditions that can change an enzyme's active site. 1. pH (either higher or lower than optimum), 2. Higher than optimal temperature
15 Name where carbohydrase is made in the body. Salivary glands, pancreas and small intestine.
16 What do carbohydrases break down and what is produced? Carbohydrates to simple sugars (e.g. amylase breaks down starch to glucose).
17 Name where protease is made in the body. Stomach, pancreas and small intestine.
18 What do proteases break down and what is produced? Proteins to amino acids.
19 Name where lipase is made in the body. Stomach, pancreas and small intestine.
20 What do lipases break down and what is produced? Lipids (fats) to fatty acids and glycerol.
21 What are the products of digestion used for? To build new carbohydrates, lipids and proteins.
22 How does bile help the action of lipase? (2) 1. Provides alkaline conditions by neutralising acid from the stomach, 2. Emulsifies fat to form small droplets with a larger surface area.
23 What is the Benedict's test and how do you carry it out? For testing if there is sugar in food samples. Add Benedict's reagent (blue liquid, leave in a hot water bath for 5 minutes, if it turns orange/brick red, it contains sugar.
24 What is the Biuret test and how do you carry it out? For testing if there is protein in food samples. Add Biuret reagent (blue liquid). If it turns lilac, protein is present.
25 Which food test can be carried out with iodine? Testing for the presence of starch. Add iodine (reddish brown) drops to food sample. If it turns blue/black, it contains starch.
26 Which system transports substances around the body? The circulatory system.
27 What is the heart? An organ.
28 What does the heart do? Pump blood around the body.
29 What are the walls of the heart made from? Muscle tissue.
30 Name the two types of chambers in the heart Atria and ventricles.
31 Which are the upper chambers of the heart? Atria.
32 Which are the lower chambers of the heart? Ventricles.
33 Where do the atria force blood upon contraction? To the ventricles.
34 Where do the ventricles force blood upon contraction? Out of the heart.
35 What is the job of the heart valves? To prevent backflow of blood in the heart.
36 To where does blood flow after leaving the right hand side of the heart? The lungs.
37 To where does blood flow after leaving the left hand side of the heart? The rest of the body.
38 Through which blood vessel does blood flow away from the heart? Arteries.
39 Through which blood vessel does blood flow back into the heart? Veins.
40 Name the blood vessel by which blood leaves to the rest of the body. Aorta.
41 Name the blood vessel by which blood arrives back from the rest of the body. Vena cava.
42 Name the blood vessel by which blood leaves the heart to the lungs. Pulmonary artery.
43 Name the blood vessel by which blood leaves the lungs to go back to the heart. Pulmonary vein.
44 Which blood vessels have thick walls containing muscle tissue and elastic fibres? Arteries.
45 Which blood vessels have thinner walls and contain valves? Veins.
46 Name two key adaptations of capillaries. 1. Very thin (only one cell thick) to reduce distance diffusion has to occur across.
2. Very narrow to reduce distance diffusion has to occur across.
47 Where is the "natural" pacemaker of the heart located? The right atrium.
48 Where are the lungs located? The upper part of the body (thorax).
49 What protects the lungs? The ribcage.
50 What separates the lungs from the abdomen (lower part of body)? The diaphragm.
51 Which gas diffuses into the bloodstream? Oxygen.
52 Which gas diffuses out of the bloodstream? Carbon dioxide.
53 Name the structure which carries air from the nose/mouth. Trachea.
54 Name the two structures which branch off from the trachea. Bronchi (singular: bronchus).
55 Name the structure which branch off from the bronchi. Bronchiole(s).
56 What are the small gas exchange structures in the lungs called? Alveoli (singular: alveolus).
57 Describe four adaptations alveoli have to make them well suited for gas exchange. 1. Thin walls (one cell thick).
2. Extensive capillary network covering the surface of each alveolus.
3. Efficient movement of blood through capillaries to maintain a concentration gradient for diffusion of oxygen & carbon dioxide.
4. Folded inner surface to give a large surface area.
58 What is the liquid part of blood called? Plasma.
59 What are the three main cell types found in blood? Red blood cells, white blood cells, platelets.
60 What does blood plasma transport from the organs to the lungs? Carbon dioxide.
61 What does blood plasma transport from the small intestine to other organs? Soluble products of digestion.
62 What does blood plasma transport from the liver to the kidneys? Urea.
63 What do red blood cells transport? Oxygen.
64 What do red blood cells lack? A nucleus.
65 In the lungs, which reversible reaction occurs? Haemoglobin + oxygen ó oxyhaemoglobin.
66 What do white blood cells do? Defend the body against microorganisms.
67 What do platelets do? Help clot the blood at wound sites.
68 What are the coronary arteries? Blood vessels that supply the heart muscle tissue.
69 What occurs in Coronary Heart Disease (CHD)? The coronary arteries become blocked with fatty deposits, narrowing them.
70 Why is this a problem? Reduces flow of blood to the heart, therefore reducing supply of oxygen, glucose and pickup of carbon dioxide.
71 How do stents treat Coronary Heart Disease (CHD)? Re-opens the blocked coronary artery, restoring blood flow.
72 How do statins treat Coronary Heart Disease (CHD)? Decreases the blood concentration of cholesterol, which reduces build-up of fatty deposits in the coronary arteries.
73 Why are faulty heart valves life-threatening? Allows backflow of blood.
74 Name two sources of replacement heart valves. 1. Mechanical.
2. Biological (e.g. pigs or sheep).
75 Describe a treatment used in the case of total heart failure. Heart transplant.
76 Name a risk of surgical intervention in heart disease. Infection.
77 When would an artificial heart be used? 1. To allow the heart to rest and recover.
2. To keep the patient alive whilst they wait for a transplant.
78 What is "health"? The state of physical and mental well-being.
79 What are the two types of disease? Communicable (caused by a pathogen) and non-communicable.
80 Give an example of how different diseases can interact. • Defects in the immune system mean that an individual is more likely to suffer from infectious diseases.
• Viruses living in cells can be the trigger for cancers.
• Immune reactions initially caused by a pathogen can trigger allergies such as skin rashes and asthma.
• Severe physical ill health can lead to depression and other mental illness.
81 Name three factors, other than pathogens, which can influence health. 1. Diet
2. Stress
3. Life situations
82 What is a risk factor? A factor linked to an increased rate of disease.
83 Give two general examples of a risk factor. 1. The lifestyle of a person
2. Substances in the person's body or environment
84 What is meant by "correllation does not imply causation"? Just because two variables are correllated (one increases as the other increases), doesn't mean that one causes the other e.g. ice cream sales and number of sunburnt people
85 Some risk factors have had a causal mechanisms proven for some diseases. Name three examples. • The effects of diet, smoking and exercise on cardiovascular disease.
• Obesity as a risk factor for Type 2 diabetes.
• The effect of alcohol on the liver and brain function.
• Carcinogens, including ionising radiation, as risk factors in cancer.
• The effects of smoking and alcohol on unborn babies.
• The effect of smoking on lung disease and lung cancer.
86 Most diseases are termed "multi-factorial". What does this mean? Multiple risk factors contributing to the person developing the disease.
87 What is cancer? The uncontrolled growth and division of cells.
88 How do cancers develop? DNA in cells is changed (mutated)
89 What is a benign tumour? A growth of abnormal cells which is contained in one area within the body and will not invade other body parts.
90 What is a malignant tumour? A growth of abnormal cells which invade neighbouring tissues and spread to different parts of the body in the blood where they form secondary tumours.
91 Name two main lifestyle risk factors for cancer. 1. Smoking
2. Excessive alcohol use
3. Obesity
92 Name another risk factor in the development of cancer. Genetic.
93 Name six plant tissues. Epidermal, palisade mesophyll, spongy mesophyll, xylem, phloem, meristem.
94 For each of the following tissues, describe their function:
epidermis, palisade mesophyll, spongy mesophyll, xylem, phloem, guard cells. 1. Epidermis: To cover and protect
2. Palisade mesophyll: The site of photosynthesis
3. Spongy mesophyll: Gas exchange (although also happens in #2)
4. Xylem: Transport of water and dissolved ions
5. Phloem: Transport of sugars made in photosynthesis
6. Guard cells: To allow gas exchange and control water loss
95 Name three plant tissues. The epidermis, the palisade mesophyll, the spongy mesophyll, the xylem, the phloem, guard cells.
96 What is transpiration? The movement of water from the roots to the leaves, eventually leaving the leaves via evaporation.
97 Name four factors which affect the rate of transpiration in plants. 1. Temperature
2. Humidity
3. Air movement
4. Light intensity
98 How does temperature affect rate of transpiration? Higher temp increases transpiration rate
99 How does humidity affect rate of transpiration? Higher humidity decreases transpiration rate
100 How does wind or air flow affect rate of transpiration? More wind increases transpiration rate (as maintains steep conc gradient)
101 How does light intensity affect rate of transpiration? More light increases transpiration rate
102 Name the equipment used to estimate transpiration rate. Potometer: a device that measures the volume of water uptake in a plant shoot
103 Name three plant organs. Leaves, stems and roots.
104 What is translocation? The movement of sugars from the leaves to the rest of the plant.
105 Describe the adaptations of xylem tissue. Hollow tubes strengthened by lignin.
106 Describe the adaptations of phloem tissue. Elongated cells with pores in the end cell walls to aid the movement of dissolved sugars.
107 What is the role of stomata and guard cells? To allow gas exchange and contol water loss.
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