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Organisation Flashcards

1
Q

what is a tissue?

A

-a group of cells with a similar structure or function

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2
Q

what is an organ?

A

-a group of tissues working together for a specific function
-organs are grouped into organ systems which work together to form organisms

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3
Q

what is digestion?

A

-when large food molecules are broken down into small molecules by enzymes
-these small molecules can then be absorbed into the bloodstream

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4
Q

what is an example of an organ?

A

-the stomach which contains muscular tissue and glandular tissue (releases enzymes)

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5
Q

what are the three main nutrients food contains?

A

-carbohydrates e.g starch
-protein
-lipids ( fats )

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6
Q

describe the process of digestion + main functions of the different organs.

A

-first, food is chewed in the mouth. Enzymes in the saliva begin to digest the starch into smaller sugar molecules
-the food then passes down the oesophagus into the stomach . In the stomach, enzymes begin the digestion of proteins
-the stomach also contains hydrochloric acid which helps the enzymes to digest proteins
-churning action of the stomach muscles turns food into fluid increasing the surface area for enzymes to digest.
-fluid passes into the small intestine
-chemicals are released into small intestine from the liver and pancreas
-pancreas releases enzymes which continue the digestion of starch and protein. They also start the digestion of lipids
-the liver releases bile which helps speed up the digestion of lipids.Bile also neutralises acid released from the stomach
-the walls of the small intestine release enzymes to continue the digestion of protein and lipids
-in the small intestine, the food molecules produced by digestion are absorbed into the bloodstream either by diffusion or active transport.
-fluid makes its way through the large intestine, where water is absorbed into the blood stream
-faeces is released from the body

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7
Q

what happens to products of digestion?

A

-products of digestion are used by the body to build new carbohydrates, lipids and proteins.
-some of the glucose produced is used in respiration

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8
Q

what are enzymes and what do they do?

A

-enzymes catalyse chemical reactions.
-they are large protein molecules that have a groove on their surface called the active site
-the active site is where the substrate attaches to
-enzymes are specific. The substrate must fit perfectly into the active site ( lock and key theory)

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9
Q

what are proteins broken down by?

A

-enzymes called proteases found in the pancreatic fluid and the stomach

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10
Q

what are proteins?

A

-the long chains of chemicals called amino acids

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11
Q

describe what happens when we digest proteins.

A

-the protease enzymes convert the protein back to the individual amino acids which are then absorbed into the bloodstream
-when the amino acids are absorbed by the body cells, they are joined together in a different order to make human proteins

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12
Q

what is starch?

A
  • a chain of glucose molecules
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13
Q

what are carbohydrates broken down by ? +
what do they produce when digested?

A

-enzymes called carbohydrases
-in the case of starch this is called amylase
-amylase is found in the saliva and pancreatic fluid
-when carbohydrates like starch are digested we produce simple sugars

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14
Q

what is a lipid molecule?

A

-a molecule of glycerol attached to three molecules of fatty acids

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15
Q

what are lipid molecules digested by?

A

-the enzyme lipase which produces glycerol and fatty acids
-lipase is found in the pancreatic fluid and in the small intestine

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16
Q

where is bile made and how does it affect lipids?

A

-in the liver and stored in the gall bladder
-bile converts large lipid droplets into smaller droplets
-bile emulsifies the lipid which increases the surface area of the lipid droplets
-this increases the rate of lipid breakdown by lipase

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17
Q

what is bile?

A

-alkaline which allows it to neutralise stomach acid, creating alkaline conditions in the small intestine
-this increases the rate of lipid digestion by lipase

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18
Q

what is the definition of enzymes?

A

-biological catalysts which speed up the rate of chemical reactions without being used up.

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19
Q

how does the shape of an enzyme affect its function?

A

-enzymes have a specific active site which is complementary to their substrate

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20
Q

describe how temperature affects the activity of enzyme

A

-as we increase the temperature, the activity of the enzyme increases
-this is due to the enzyme and substrate moving faster so there are more collisions per second between the substrate and the active site
-at a certain temperature, the enzyme is working at the fastest possible rate - the optimum temperature
-there is maximum frequency of successful collisions between the substrate and active site
-as we increase temperature past the optimum, enzyme activity rapidly decreases to zero
-this is due to the shape of the active site changing
-substrate no longer fits perfectly into the active site. Active site is denatured.
-the enzyme can no longer catalyse the reaction

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21
Q

describe the affect of pH on the activity of enzyme

A

-the enzyme has an optimum pH - activity is maximum
-if we make pH more acidic or alkaline then activity drops to zero
-active site denatures if conditions are too acidic or too alkaline
-if enzyme works best at an acidic pH it could be a protease enzyme in stomach
-if enzyme works best at alkaline pH it could be an enzyme released from pancreas into small intestine

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22
Q

how is the small intestine adapted for absorbing the products of digestion? + 5 ways

A

-the small intestine is long providing a very large surface area for the absorption of the products of digestion
-the interior of the small intestine is covered with millions of villi which increase the surface area for the absorption of molecules
-microvilli on the surface increase surface area further
-villi have very good blood supply and this increases the concentration gradient
-villi have a thin membrane which ensures a short diffusion path

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23
Q

describe the circulatory system in fish

A

-single circulatory system
-deoxygenated blood is pumped from the heart to the gills where it becomes oxygenated
-the oxygenated blood passes from the gills to the organs where the oxygen diffuses out of the blood and into body cells
-the blood then returns to the heart

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24
Q

what is the problem with the single circulatory system in fish?

A

-the blood loses pressure as it passes through the gills before reaching the organs
-the blood travels to the organs slowly, delivering less oxygen

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25
what is the double circulatory system?
-deoxygenated blood is pumped from the heart to the lungs where it receives oxygen -the oxygenated blood then returns to the heart -the heart now pumps the oxygenated blood to the organs where the blood transfers its oxygen to the body cells -the blood then pumps back to the heart
26
what is the advantage of a double circulatory system?
-as blood passes through the heart twice it can travel rapidly through the body cells, delivering the oxygen that the cells need
27
what does the heart consist mainly of?
-muscle tissues
28
why does the left side of the heart have a thicker muscular wall ?
-the left ventricle pumps blood to the entire body so it needs to provide a greater pressure
29
what is the purpose of the coronary arteries?
-to provide oxygen to the muscle cells of the heart -the oxygen is used in respiration to provide the energy for contraction
30
what is the heart rate controlled by?
-a group of cells found in the right atrium called the pacemaker
31
what is an artificial pacemaker?
-a small electrical device that corrects irregularities in the heart rate
32
describe the structure of arteries?
-they have very thick muscular walls allowing them to withstand high pressure of the blood -elastic fibres stretch when the surge of blood passes through and then recoils in between surges, keeping the blood moving
33
what happens when blood passes through capillaries?
-substances such as glucose and oxygen diffuse from the blood to the cells -carbon dioxide diffuses from the cells back to the blood -capillaries have thin walls for a short diffusion path, allowing substances to diffuse rapidly between the blood and body cells
34
describe the structure of veins
-veins have a thin wall. The blood pressure is low so the wall does not need to be thick -veins contain valves -valves have a large lumen
35
what is the function of valves?
-to stop blood flowing backwards
36
what are the four main components of blood?
-plasma -red blood cells -white blood cells -platelets
37
what does blood plasma transport?
-the liquid part of the blood -soluble digestion products from the small intestine to the other organs -carbon dioxide from the organs to the lungs to be breathed out -the waste product urea from the liver to the kidneys to be excreted in urine
38
what do red blood cells transport?
-oxygen from the lungs to the body cell
39
how are red blood cells adapted?
-they contain the oxygen-carrying molecule haemoglobin -red blood cells have no nucleus which means they have more room for haemoglobin -they have a shape called a biconcave disc which gives the red blood cells a greater surface area so that oxygen diffuses in and out rapidly
40
describe the features of white blood cells?
-they contain a nucleus which contains DNA which encodes the instructions that the white blood cells need to do their job
41
what is the function of platelets?
-they are tiny fragments of cells and their job is to help the blood clot
42
what are three uses for donated blood in medicine?
-to replace blood lost during injury -some people are given platelets extracted from blood to help in clotting -proteins extracted from blood can also be useful for example antibodies
43
what are disadvantages of donated blood?
-the patient's immune system could reject the blood if the donated blood is not the same blood type as the patient's so they could die -lots of different diseases can be transmitted via blood
44
describe how to investigate the effect of pH on the enzyme amylase
-place one drop of iodine solution into each well of a spotting tile -we use 3 test tubes -in the first test tube we add 2 cm^3 of starch solution -in the second test tube we add 2 cm^3 of amylase solution -in the third test tube we add 2 cm^3 pH 5 buffer solution -place all three test tubes in a water bath at 30 °C. -leave them for 10 minutes to allow the solutions to reach the correct temperature -now combine the three solutions into one test tube and mix with a stirring rod. Return to the water bath and start a stopwatch -after thirty seconds, use the stirring rod to transfer one drop of solution to a well in the spotting tile which contains iodine -the iodine should turn blue-black showing starch is present -we now take a sample every thirty seconds and we continue until the iodine remains orange -when iodine remains orange this tells us that starch is no longer present -we now repeat the whole experiment several times using different pH buffers for example pH 6, 7 and 8
45
what are the two problems with the effect of pH on amylase required problem? + solutions
-we are only taking samples every thirty seconds so we only have an approximate time for the reaction to complete -we could address this by taking samples every ten seconds -we are looking for the time when the iodine does not go blue-black. This is not always obvious as the colour change tends to be gradual so it can be difficult to see when the reaction has finished -we can address this problem by asking several people to look at the spotting tile and decide when the reaction has completed
46
describe how we make the solution used to carry out food tests?
-take the food sample and grind this with distilled water using a mortar and pestle to make a paste -transfer the paste to a breaker and add more distilled water. Stir so the chemicals in the food dissolve in the water -filter the solution to remove suspended food particles
47
how do we test for starch?
-we place 2cm^3 of food solution into a test tube -add a few drops of iodine solution which is an orange colour -if starch is present then the iodine solution will turn blue-black -if there is no starch present then the iodine solution will stay orange
48
describe how to test for sugars for example glucose
-place 2cm^3 of food solution into a test tube -we add 10 drops of Benedict's solution which is a blue colour -we place the test tube containing our solution into a beaker and half-fill the beaker with hot water from a kettle -we now leave this for around five minutes -if sugars are present, the Benedict's solution will change colour -a green colour tells us there is a small amount of sugar -a yellow colour tells us that there is more sugar present -a brick-red colour tells us that there is a lot of sugar present
49
what sugars does Benedict's test work for?
-only certain sugars such as glucose -these sugars are called reducing sugars -it does not work for sugars that are non-reducing such as sucrose
50
describe how to test for protein
-we take 2cm^3 of food solution and we add 2cm^3 of biuret solution which is a blue color -if protein is present then the biuret solution will change from blue to a purple or lilac colour
51
describe how to test for lipids/ fats
-we transfer 2cm^3 of our food solution to a test tube -we then add a few drops of distilled water and a few drops of ethanol -we then gently shake the solution -if lipids are present, then a white cloudy emulsion forms
52
why do we not filter the solution when testing for lipids?
-lipid molecules can stick to filter paper
53
why is it important that no naked flames are present during the lipids test?
-ethanol is highly flammable
54
what are cardiovascular diseases?
-diseases of the heart and blood vessels -they are non-communicable
55
what is coronary heart disease?
-when layers of fatty material build up inside the coronary arteries causing it to become narrow -this reduces the flow of blood through coronary arteries
56
what does coronary heart disease result in?
-a lack of oxygen for the heart muscle which can result in a heart attack
57
what are statins?
-drugs which reduce the level of cholesterol in the blood -this slows down the rate that fatty materials build up in the arteries
58
what is a disadvantage of statins?
-they have unwanted side effects e.g liver problems
59
what are two treatments for coronary heart disease?
-stents -statins
60
what is a stent?
-a tube which can be inserted into the coronary artery to keep it open
61
what is a disadvantage of stents?
-it will not prevent other regions of the coronary arteries from narrowing -it does not treat the underlying causes of the disease
62
what leaky valves cause?
-the patient to feel weak and tired
63
compare a mechanical valve and a valve from an animal
-mechanical valves can last a lifetime but they increase the risk of blood clots -patients have to take anti-clotting drugs -valves from animals do last as long and may need to be replaced.However, patients do not need to take drugs
64
what are two disadvantages of donated hearts?
-there are not enough donated hearts available to treat every patients -patient must take drugs to stop the donated heart from being rejected by the body's immune system
65
what are two disadvantages of artificial hearts?
-they increase the risk of blood clotting -they are not a long-term solution to heart failure
66
describe the features of the trachea
-rings of cartilage prevent trachea from collapsing during inhalation
67
what are alveoli?
-the site of gas exchange
68
describe the 3 adaptations of alveoli
-millions of alveoli mean that the lungs have a huge surface area -alveoli have very thin walls so the diffusion path is short -alveoli have a good blood supply
69
how does breathing affect rate of diffusion?
-breathing brings fresh oxygen into the alveoli and takes away the carbon dioxide -this makes the concentration gradient high for these gases and that increases the rate of diffusion
70
what are benign tumours?
-growths of abnormal cells which are found in one area -they are usually contained within a membrane -they do not invade other parts of the body and stay in one place
71
what are malignant tumours?
-they invade neighbouring tissues and move into the bloodstream -they are classed as cancer -once in the bloodstream, the malignant cells spread to different parts of the body and form secondary tumours
72
what are risk factors for cancers?
-genetics -lifestyle -radon, a radioactive gas which increases your risk of developing lung cancer
73
what are communicable diseases?
-diseases can be spread from person to person. e.g measles -they are spread by pathogens such as bacteria or viruses
74
what is non-communicable disease?
-diseases that cannot be passed from person to person
75
what is the definition of health?
-the state of physical and mental well-being
76
what can bad health be caused by?
-poor diet -high levels of stress
77
what is a disadvantage of a defective immune system?
-people are much more likely to suffer from infectious disease
78
what can disease be triggered by?
-the immune system
79
what is a key fact of correlation?
-correlation does not prove cause
80
describe the risk factors for cardiovascular disease
-a diet high in fat and low in vegetables increases the levels of cholesterol in the blood -this increases the rate that fatty materials build up in arteries -a diet high in salt can increase blood pressure -it is increased in people who smoke but is decreased in people who exercise regularly
81
describe the risk factors for lung disease and lung cancer
-smoking
82
what are the effects of smoking on unborn baby?
-increases the risk of miscarriage and premature birth -lead to baby being born with a low body-mass
83
what are the effects of drinking on unborn baby?
-drinking alcohol when pregnant can cause fetal alcohol syndrome and can have learning difficulties
84
what are the effects of drinking alcohol on adults?
-increases their risk of liver cancer and liver cirrhosis -it can lead to addiction and memory loss
85
what is the role of the epidermis?
-protects the surface of the leaf -transport, allowing light to pass through the photosynthetic cells below
86
what is the role of the waxy cuticle?
-reduces the evaporation of water from the surface of the leaf -helping to prevent the leaf from drying out
87
what is the role of the stomata?
-allows carbon dioxide to enter the leaf and oxygen to leave -helps to control the amount of water vapour that can pass out of the leaf
88
what is the role of the palisade mesophyll?
-it consists of palisade cells which have chloroplasts which contain chlorophyll that absorb light energy needed for photosynthesis
89
describe the key feature of the spongy mesophyll
-it is full of air spaces which allow carbon dioxide to diffuse from the stomata through spongy mesophyll to the palisade cells -oxygen also diffuses from the palisade cells through the spongy mesophyll to the stomata.
90
what is the role of xylem tissue?
-transports water and dissolved mineral ions from the roots to the stem and leaves -some of the water is then used in photosynthesis
91
what is the role of phloem tissue ?
-transports dissolved sugars produced by photosynthesis from the leaves to the rest of the plant
92
what are two ways sugars can be used?
-glucose is used in respiration -sugars can also be stored for example as starch
93
what is translocation?
-the movement of sugars and other molecules through phloem tissue
94
where can meristem tissue be found ?
-growing tips e.g shoots and roots
95
what is transpiration?
-the process by which water is constantly evaporating from the surface of the leaves
96
describe the transpiration stream
-transpiration starts with the evaporation of water from the cells inside the leaf -water vapour then diffuses through the air spaces in the spongy mesophyll and out of the leaf through the stomata -water passes from the xylem into the leaf to replace the water that has been lost -water is drawn into the root hair cells and up the xylem vessels to the leaf
97
what are three reasons that transpiration is important?
-brings water to the leaf which is required for photosynthesis -transports dissolved minerals such as magnesium -evaporation of water from the leaf cools the leaf down especially in warm weather
98
what are the factors that increase the rate of transpiration?
-higher temperature -dry conditions -windy conditions -increased light intensity
99
how does high light intensity affect the stomata?
-the guard cells swell and change their shape causing the stomata to open -carbon dioxide diffuses into the leaf and can be used in photosynthesis
100
how does hot conditions affect the stomata?
-the plant closes its stomata to reduce water loss by transpiration -the plant can not photosynthesise

Biology (9 decks)

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