2. Organisation Flashcards
1
Q
What are cells?
A
The basic building blocks that make up all living organisms.
2
Q
What is a tissue?
A
A group of similar cells that work together to carry out a particular function. Can include more than one type of cell.
3
Q
List some examples of tissues in mammals.
A
- Muscular tissue: contracts to move whatever it’s attached to.
- Glandular tissue: makes and secretes chemicals like enzymes and hormones.
- Epithelial tissue: covers some parts of the body, eg. gut.
4
Q
What is an organ?
A
A group of different tissues that work together to perform a certain function.
5
Q
What tissues is the stomach made out of?
A
- Muscular tissue: moves the stomach wall to churn up the food.
- Glandular tissue: makes digestive juices to digest food.
- Epithelial tissue: covers the outside and inside of the stomach.
6
Q
What is an organ system?
A
A group of organs working together to perform a particular function.
7
Q
What organs is the digestive system made up of?
A
- Glands (eg. pancreas and salivary glands): which produce digestive juices.
- Stomach and small intestine: digest food.
- Liver: produces bile.
- Small intestine: absorbs soluble food molecules.
- Large intestine, absorbs water from undigested food, leaving faeces.
8
Q
What are enzymes?
A
A protien which is a biological catalyst. Increases the speed of a reaction, without being changed or used up in the reaction.
9
Q
Why are enzymes useful?
A
Reduces the need for high temperatures.
10
Q
What is the substrate?
A
The substance that the enzyme acts upon.
11
Q
How does an enzyme “recognise” its specific substrate?
A
A complementarily-shaped “active site” – a region on the enzyme which fits the substrate.
12
Q
What two factors affect enzyme activity?
A
- Temperature
2. pH
13
Q
How does changing the temperature affect the rate of enzyme activity?
A
Higher temperature increases the rate at first. But if it gets too hot some of the bonds holding the enzyme together will break, changing the shape of the enzymes active site, so the substrate won’t fit anymore. It is not ‘denatured’.
14
Q
What is the optimum temperature for enzymes?
A
45°C.
15
Q
How does pH affect enzyme activity?
A
If it’s too high or too low it interferes with the bonds holding the enzymes together changing the shape of the active site and denatures the enzyme.
16
Q
What is the optimum pH for an enzyme?
A
Often pH 7. But pepsin works best at pH 2 to be well suited for the acidic conditions of the stomach.
17
Q
Describe how you would investigate the effect of pH on enzyme activity.
A
- Put a drop of iodine solution into every well of a spotting tile.
- Place a bunsen burner on a heat-proof mat, and a tripod and gauze over the bunsen burner. Put a beaker of water on top of the tripod and gauze over the bunsen burner. Heat the water until it’s 35°C (use a thermometer). The temp should be kept constant.
- Use a syringe to add 1cm³ of amylase solution and 1cm³ of buffer solution with a pH of 5 to a boiling tube. Using test tube holders, put the tube into the beaker of water and wait for five minutes.
- Next use different syringes to add 5cm³ of starch solution to the boiling tube.
- Immediately mix the contents and start a stop clock.
- Use continuous sampling to record how long it takes for the amylase to break down all the starch. Use a dropping pipette to take a fresh sample from the boiling tube every 30 seconds and put a drop into a well. When the iodine remains browny-orange, starch is no longer present.
- Repeat the experiment with buffer solutions of different pH values to see how pH affects the time taken for the starch to be broken down.
- Control any variables each time to keep it a fair test.
18
Q
How do you calculate rate of reaction?
A
1000/time or change/time.
19
Q
Where is amylase made in the body?
A
- Salivary glands.
- The pancreas.
- The small intestine.
20
Q
What does amylase break down and what is produced?
A
Starch to maltose and other sugars.
21
Q
What does carbohydrase break down and what is produced?
A
Carbohydrates to simple sugars.
22
Q
Where is protease made in the body?
A
- The stomach (called pepsin there).
- The pancreas.
- The small intestine.
23
Q
What does protease break down and what is produced?
A
Protiens to amino acids.
24
Q
Where is lipase made in the body?
A
- The pancreas.
2. The small intestine.
25
What does lipase break down and what is produced?
Lipids to fatty acids and glycerol.
26
What is the use of the products of digestion?
To make new carbohydrates, proteins and lipids. Some of the glucose that is made can be used in respiration.
27
Where is bile produced and stored?
Bile is produced in the liver and stored in the gall bladder before it's released into the small intestine.
28
How does bile help the action of lipase?
1. Provides alkaline conditions by neutralising acid from the stomach.
2. Emulsifies fat to form small droplets with a larger surface area making digestion faster.
29
What is the function of the mouth in digestion?
To mechanically break up food into smaller pieces to increase surface area.
30
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.
31
What is the function of stomach acid?
To kill potentially pathogenic microorganisms in food.
32
What is the function of the small intestine?
To absorb carbohydrates, lipids, amino acids, vitamins and mineral ions from digested food.
33
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.
34
What is the function of the large intestine?
To absorb water from digested food.
35
What is the function of the liver in digestion?
To produce bile, an emulsifying and neutralising substance.
36
What is the function of the gall bladder?
To store bile until it can be released into the small intestine.
37
What is the function of the rectum?
To store undigested material before excretion.
38
Describe how you would prepare a food sample for a food test.
1. Get a piece of food and break it up using pestle and mortar.
2. Transfer ground up food to a beaker and add some distilled water.
3. Give the mixture a good stir with a glass rod to dissolve some of the food.
4. Filter the solution using a funnel lined with filter paper to get rid of the solid bits of food.
39
What would you use to test for sugars?
Benedict's solution.
40
How would you use benedict's solution to test for sugars?
1. Prepare a food sample and transfer 5cm³ to a test tube.
2. Prepare a water bath so that it's set to 75°C.
3. Add some benedict's solution to the test tube (about 10 drops) using a pipette.
4. Place the test tube in the water bath using a test tube holder and leave it in there for 5 minutes. Making sure the test tube is pointing away from you.
5. If the food sample contains reducing sugar, the solution in the test tube will change from the blue colour to green, yellow or brick-red depending on how much sugar is in the food.
41
What would you use to test for starch?
Iodine solution.
42
How would you use iodine solution to test for starch?
1. Make a food sample and transfer 5cm³ of your smaple to the test tube.
2. Then add a few drops of iodine solution and gently shake the test tube to mix the contents.
3. If the sample contains starch, the colour of the solution will change from browny-orange to black or blue-black.
43
What would you use to test for proteins?
Biuret solution.
44
How would you use biuret solution to test for proteins?
1. Prepare food sample and transfer 2cm³ of your sample to a test tube.
2. Add 2cm³ of biuret solution to the sample and mix the contents of the tube by gently shaking it.
3. If the food sample contains protein, the solution will change from blue to purple. If no protein is present, the solution will stay blue.
45
What would you use to test for lipids?
Sudan III stain solution.
46
How would you use sudan III stain solution to test for lipids?
1. Prepare a sample of the food you're testing (no need to filter). Transfer about 5cm³ to a test tube.
2. Use a pipette to add 3 drops of Sudan III stain solution to the test tube and gently shake the tube.
3. Sudan III stains lipids. If the sample contains lipids, the mixture will seperate out into two layers. The top layer will be bright red. If no lipid is present, no seperate red layer will form.
47
Where are the lungs located?
The thorax.
48
Name the structure which carries air from the nose/mouth.
Trachea.
49
Name the two structures which branch off from the trachea.
Bronchi (singular: bronchus).
50
Name the structure which branch off from the bronchi.
Bronchiole(s).
51
What are the small gas exchange structures in the lungs called?
Alveoli (singular: alveolus).
52
Explain how gas exchange works.
1. Blood passing next to the alveoli has just returned to the lungs from the rest of the body, so it contains lots of carbon dioxide and very little oxygen.
2. Oxygen diffuses out of the alveolus (high concentration) into the blood (low concentration). Carbon dioxide diffuses out of the blood (high concentration) into the alveolus (low concentration) to be breathed out.
3. When the blood reaches body cells oxygen is released from the red blood cells and diffuses into the body cells. At the same time, carbon dioxide diffuses out of the body cells into the blood where it is then carried back to the lungs.
53
How do you calculate breathing rate?
Breaths per minute = number of breaths/number of minutes.
54
What is the circulatory system made up of?
Heart, blood vessles and blood.
55
What is a double circulatory system?
Two circuits joined together.
1. Right ventricle pumps deoxygenated blood to the lungs to take in oxygen. The blood then returns to the heart.
2. Left ventricle pumps oxygenated blood around the organs in the body. The blood gives up its oxygen at the body cells and the deoxygenated blood returns to the heart to be pumped out by the lungs again.
56
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.
57
What are the walls of the heart made of?
Muscle tissue.
58
What is the purpose of valves?
Preventing the backflow of blood.
59
What are the four chambers of the heart?
Right atrium, right ventricle, left atrium, left ventricle.
60
Describe the direction that blood flows through the heart.
1. Blood flows into the two atria from the vena cava and pulmonary vein.
2. The atria contract, pushing the blood into the ventricles.
3. The ventricles contract, forcing the blood into the pumonary artery and the aorta, and out of the heart.
4. The blood then flows to the organs thorugh arteries, and returns through veins.
5. The atria fill again and the cycle starts over.
61
What arteries make sure the heart gets it's oxygenated blood?
Coronary ateries (branch off the aorta surrounding the heart).
62
What is a natural pacemaker?
Group of cells in the right atrium wall that control your resting heart rate. They produce a small electric impulse which spreads to the surrounding muscle cells, causing them to contract.
63
What is an artificial pacemaker?
Used to control heartbeat if the natural pacemaker cells don't work properly, eg. if the patient has an irregular heartbeat). It is a device implanted under the skin and has a wire going to the heart producing an electric current to keep the heart beating reguarly.
64
What are the three types of blood vessels?
Arteries, capillaries and veins.
65
What are arteries?
Vessels that carry blood away from the heart.
66
What are features of the arteries?
1. Heart pumps blood at high pressure so the artery walls are strong and elastic.
2. Walls are thick compared to the lumen.
3. Contain thick layers of muscle to make them strong.
4. Have elastic fibres to allow them to stretch and spring back.
67
What are capillaries?
Vessles which are involved in exchanging materials at the tissues.
68
What are the features of the capillaries?
1. Really tiny
2. Carry blood really close to every cell in the body to exchange substances with them.
3. Have permeable walls, so substances can diffuse in and out.
4. They supply food and oxygen, and take away waste like CO2.
5. Their walls are usually only one cell thick which increases the rate of diffusion by decreasing the distance over which it occurs.
69
What are the veins?
Vessles which carry blood to the heart.
70
What are features of the veins?
1. Blood is at a lower pressure so have thinner walls.
2. Have a bigger lumen to help the blood flow.
3. Have valves to keep the blood flowing in the right direction.
71
To where does blood flow after leaving the right hand side of the heart?
The lungs.
72
To where does blood flow after leaving the left hand side of the heart?
The rest of the body.
73
Through which blood vessel does blood flow away from the heart?
Arteries.
74
Through which blood vessel does blood flow back into the heart?
Veins.
75
Name the blood vessel by which blood leaves to the rest of the body.
Aorta.
76
Name the blood vessel by which blood arrives back from the rest of the body.
Vena cava.
77
Name the blood vessel by which blood leaves the heart to the lungs.
Pulmonary artery.
78
Name the blood vessel by which blood leaves the lungs to go back to the heart.
Pulmonary vein.
79
Which blood vessels have thick walls containing muscle tissue and elastic fibres?
Arteries.
80
Which blood vessels have thinner walls and contain valves?
Veins.
81
How do you calculate rate of blood flow?
Volume of blood/number of minutes.
82
What is the job of red blood cells?
Carry oxygen from the lungs to the cells around the body
83
What are adaptations of the red blood cells?
Biconcave disc shape which gives a large surface area for absorbing oxygen. Don't have a nucleus allowing more room to carry oxygen. Contain a red pigment called haemoglobin.
84
What happenes to haemoglobin in the body?
Binds to oxygen in the lungs to become oxyhaemoglobin. In body tissue, the reverse happens, oxyhaemoglobin splits up into haemoglobin and oxygen to release oxygen to the cells.
85
What is the job of white blood cells?
Defend against infection.
86
How do white blood cells defend against infection?
Phagocytosis, producing antibodies and antitoxins.
87
What is the job of platelets?
Helping blood clot.
88
Describe platelets.
Small fragments of cells which have no nucleus. They help blood clot at a wound to stop your blood pouring out and microorgsnisms getting in. The lack of platelets can cause excessive bleeding and bruising.
89
What is plasma?
Pale coloured liquid which carries everything.
90
What does plasma carry?
1. Red and white blood cells, platelets.
2. Nutrients like glucose and amino acids.
3. Carbon dioxide.
4. Urea
5. Hormones.
6. Proteins.
7. Antibodies and antitoxins.
91
What is coronary heart disease and how can it cause a heart attack?
When the coronary arteries that supply blood to the muscle of the heart get blocked by layers of fatty material building up. This causes the arteries to become narrow, so blood flow is restricted and there is a lack of oxygen to the heart muscle resulting in a heart attack.
92
What are stents?
Tubes that are inserted inside the arteries. They keep them open making sure blood can pass through to the heart muscle.
93
What is an advantage and disadvantage of stents?
+ Lower the risk of heart attacks, are effective for a long time, recovery time from the surgery is relatively quick.
- Risk of complications during the operation and risk of infection from surgery. Also risk of thrombosis (devoloping a blood clot near the stent).
94
What is cholesterol and how can it lead to coronary heart disease?
Lipid your body produces to function properly. Too much LDL (bad) cholesterol can cause health problems. Can cause fatty deposits to form inside arteries, which can lead to coronary heart disease.
95
What are statins?
Drug that reduce the amount of bad cholesterol present in the bloodstream by slowing down the rate of fatty deposits forming.
96
What are adavantages and disadvantages of statins?
+ Reduce the risk of strokes, CHD and heart attacks.
+ Increase the amound of HDL (good) cholesterol.
+ May also help prevent other diseases.
- Long-term drug that must be taken reguarly.
- Sometimes have negative side effects eg. headaches, kidney faliure, liver damage and memory loss.
- Effect isn't instant, takes some time to kick in.
97
Why may doctors use an artificial heart?
If a patient has heart faliure and donor organs aren't available right away.
98
What are artificial hearts?
Mechanical devices which pump blood for a person whose heart has failed. Usually only temporary, eg. to keep someone alive whilst waiting for a donor heart or to allow a person to recover.
99
What are some disadvantages of artificial hearts?
Surgery to fit an artificial heart can lead to bleeding and infection. They also don't work as well as healthy natural ones, part of the heart could wear out or the electrical motor could fail. As blood doesn't flow through the heart as smoothly, it could result in blood clots leading to strokes. The patient also has to take drugs to thin their blood which can cause problems with bleeding if hurt in an accident.
100
How can heart valves be damaged or weakened?
By heart attacks, infection or old age.
101
What does a damaged valve cause?
This could cause the valve tissue to stiffen so it won't open properly. Or the valve may beome leaky allowing the blood to flow in both directions. This means that the blood doesn't circulate as effectively as normal.
102
What are the two types of replacement valves?
Biological (cows or pigs) or mechanical (man-made).
103
What problems could occur when fitting valves?
Blood clots.
104
What is artificial blood?
Blood substitute, eg. salt solution ('saline'), which is used to replace the lost volumel of blood. This may give the patient enough time to produce new blood cells. If not the patient will need a blood transfusion.
105
What is health?
The state of physical and mental wellbeing. Diseases are often responsible for causing ill health.
106
What are communicable diseases?
Those that can spread from person to person or between animal to people. Can be caused by bacteria, viruses, parasites and fungi. They are contagious/infectious.
107
What are non-communicable diseases?
Those that can not be spread between animals or people. Generally last for a long time and get worse slowly.
108
Describe how different diseases can interact.
1. People who have immune system problems have a greater chance of getting a communicable disease becuase their body is less likely to be able to defend itself against the pathogen.
2. Some types of cancer can be triggered by infection by certain viruses. HPV can cause cervical cancer.
3. Immune system reactions cause by infection by a pathogen can trigger allergic reactions, eg. skin rashes can worsen asthma.
4. Mental heath issues such as depression can be triggered when someone is suffering from severe physical health problems.
109
What factors can effect your health?
1. Diet.
2. Stress.
3. Life situation.
110
What is a risk factor?
Things linked to the increased likelihood that a person will develop a certain disease in their lifetime. Often aspects of a persons lifestyle, environment, or sustances.
111
Give examples of risk factors which cause a disease directly.
1. Smoking - direct cause to cardiovascular disease, lung disease and lung cancer. Damages the walls of the arteries and the cells in the lining of the lungs.
2. Obesity - Type 2 Diabetes - makes the body less sensitive or resistant to insulin, so it struggles to control the concentration of glucose in the blood.
3. Drinking too much alcohol - Liver disease, brain function - damages the nerve cells in the brain causing the brain to lose volume.
4. Smoking and drinking alcohol when pregnant causes health problems for new born babies.
5. Exposure to substances or radiation - cancer. Carcinogens, eg. ionising radiation.
112
What is cancer?
Uncontrolled growth and division, result of changes that occur to the cells resulting in the formation of a tumour.
113
What is a benign tumour?
Tumour stays in one place rather than invading other tissues. Isn't cancerous.
114
What is a malignant tumour?
Where the tumour grows and spreads to neighbouring healthy tissue. Cells break off and spread to other parts of the body by travelling in the bloodstream. The malignant cells then invade healthy tissues everywhere in the body and form secondary tumours. They are dangerous and cancerous.
115
What are lifestyle risk factors for various types of cancers?
1. Smoking - lung cancer and other types of cancer.
2. Obesity - bowel, liver and kidney cancer.
3. UV exposure - skin cancer.
4. Viral infection - liver cancer.
116
What is another risk factor related to developing cancer?
Inheriting faulty genes/mutations.
117
Give examples of plant organs.
Stems, roots and leaves.
118
What are examples of plant tissue?
1. Epidermal tissue - covers the whole plant.
2. Palisade mesophll tissue - part of the leaf where most photosynthesis happens.
3. Spongy mesophyll tissue - big air spaces to allow gases to diffuse in and out.
4. Xylem and phloem tissue - transport substances.
5. Meristem tissue - found at the growing tips of shoots and roots and is able to differentiate into different types of plant cells allowing the plant to grow.
119
What does mesophyll mean?
Middle of a leaf.
120
What is the purpose of the waxy cuticle?
Helps to reduce water loss by evaporation.
121
What is the adaptation of the upper epidermis?
Transparent so light can pass through it to the palisade layer.
122
How is the palisade layer adapted for photosynthesis?
Has lots of chloroplasts near the top of the leaf where they can get the most light.
123
What do the xylem and phloem form?
A network of vascular bundles which deliver water and other nutrients to the entire leaf and take away the glucose produced by photosynthesis. Also help to to support the structure.
124
How are the tissues of the leaf adapted for gas exchange?
Lower epidermis is full of stomata which let co2 diffuse directly into the leaf. The opening and closing of the leaf is controlled by guard cells in response to environmental conditions. The air spaces in the spongy mesophyll tissue increase the rate of diffusion of gases.
125
What is the structure of phloem tubes?
Made of columns of elongated living cells with small pores in the end walls to allow cell sap to flow through.
126
What is the function of the phloem tubes?
Translocation - Transporting food substances (mainly dissolved sugars) made in the leaves to the rest of the plant for immediate use or for storage. Transport goes in both directions.
127
What is the structure of xylem tubes?
Made of dead cells joined end to end with no end walls between them and a hole down the middle. Strengthened by lignin.
128
What is the function of xylem tubes?
Transpiration - carrying water and mineral ions from the roots to the stems and leaves.
129
What is the transpiration stream?
Transpiration stream is the movement of water from the roots, through the xylem and out of the leaves.
130
How is transpiration caused and where does it happen most?
Caused by the evaporation and diffusion of water from a plant's surface. Mostly happens in the leafs.
131
What are the main factors effecting the rate of transpiration?
1. Light intensity - the brighter the light, the greater the rate of transpiration.
2. Temperature - the warmer, the faster (particles have more energy).
3. Air flow - the better (stronger wind), the greater.
4. Humidity - the drier, the faster.
132
Explain how air flow effects transpiration.
If low, higher conc of water particles outside the leaf so diffusion doesn't happen quickly. If good air flow, water vapour is swept away, maintaining a low concentration of water particles outside the leaf so diffusion can happen quickly.
133
Explain how humidity effects transpiration.
If the air is humid there is a lot of water in it already so there isn't a big difference between the inside and outside of the leaf so diffusion happens slowly.
134
How can you estimate the rate of transpiration?
Measuring the uptake of water by a plant. Assume the water uptake is directly related to water loss. Use a potometer, record the starting position of the air bubble. Then record the distance the bubble moves per unit of time. Keep the conditions constant eg. temp, humidity.
135
How do the guard cells adapt to open and close the stomata?
1. Kidney shape which opens and closes the stomata.
2. When the plant has lots of water, the guard cells fill with it and go turgid.
3. When the plant is short of water, the guard cells lose water and become flaccid making the stomata close helping stop too much water escaping.
4. Thin outer walls and thickened inner walls make the opening and closing work.
5. Sensitive to light so close at night to save water.
6. Found on the underside of the leaf as less water is lost because it is cooler.
