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organisation Flashcards

this is a massive topic, i'm so sorry

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AP® Biology flashcards Biology 101 flashcards
1
Q

what are cells?

A

the basic building blocks of all living organisms.

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2
Q

what is a tissue?

A

a group of similar cells that work together to carry out a particular function.
- e.g. muscle cells form muscle tissue. they contract and relax to move different parts of the body.

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3
Q

what is an organ?

A

a group of different tissues that work together to carry out a particular function.
- e.g. epithelial, muscle, and glandular tissue all work together to form the stomach, which has the function of killing microorganisms and breaking down proteins.

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4
Q

what is the next step of organisation above organs?

A

organs are organised into organ systems, which work together to form organisms.

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5
Q

what are the three main nutrients in food, and how are they absorbed into the bloodstream?

A
  • carbohydrates (e.g. starch), protein, and lipids (fats)
  • all of these are large molecules and are too large to be absorbed into the bloodstream, and so have to be digested.
  • enzymes break down these molecules into smaller molecules, which can then be absorbed into the bloodstream.
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6
Q

what is the pathway of food through the digestive system?

(this is a really massive flashcard with a lot of content on it, so if you don’t get it straight away, don’t worry, you will eventually)

A
  1. food is chewed in the mouth. amylase enzymes in the saliva begin to digest the starch into smaller sugar molecules.
  2. the food then passes down the oesophagus and into the stomach. in the stomach, protease enzymes begin the digestion of proteins. the food spends several hours in the stomach.
    > the stomach also contains hydrochloric
    acid, helping the digestion of large
    molecules and killing bacteria.
    > the churning action of the stomach
    muscles turns the food into fluid,
    increasing the surface area and making
    it quicker for enzymes to digest.
  3. the fluid now passes into the small intestine. the pancreas releases chemicals into the small intestine which continue the digestion of starch and protein. it also begins the digestion of lipids.
    > the liver releases bile, which helps to
    speed up the digestion of lipids. bile also
    neutralises the acid released from the
    stomach.
  4. the fluid continues down the small intestine, and its walls release more enzymes to continue the digestion of protein and lipids.
    > here, the small food molecules
    produced by digestion are absorbed
    into the bloodstream, either by diffusion
    or active transport.
  5. the fluid then makes its way into the large intestine, where water is absorbed into the bloodstream.
  6. the faeces is released from the body.
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7
Q

what are the different large molecules broken down into, and what are the names of the enzymes that break them down?

A
  • carbohydrates (including starch) - simple sugars
    CARBOHYDRASE (E.G. AMYLASE BREAKS
    DOWN STARCH)
  • proteins - amino acids
    PROTEASE
    > proteins are long chains of amino
    acids. in digestion, they’re broken down
    into individual amino acids, and once
    absorbed into the bloodstream, they’re
    joined together in a different order to
    make human proteins.
  • lipids (fats) - 1 molecule of glycerol attached to 3 molecules of fatty acids.
    LIPASE
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8
Q

describe enzymes and how they work:

A
  • enzymes catalyse chemical reactions.
  • they are large protein molecules, with a groove on their surface called the active site.
  • the active site is where the substrate attaches to - the substrate is the molecule that the enzyme breaks down.
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9
Q

describe the ‘lock and key’ theory:

A

enzymes are specific. the substrate must fit perfectly into the active site of the enzyme.

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10
Q

where are the different enzymes secreted?

A

amylase - salivary glands, stomach
protease - stomach, pancreas, small intestine
lipase - pancreas, small intestine

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11
Q

describe bile:

A
  • made in the liver, stored in the gallbladder.
  • speeds up the digestion of lipids BUT is not an enzyme.
  • bile emulsifies lipids, increasing the surface area of lipid droplets and increasing the rate of digestion by lipase.
  • bile is alkaline. neutralises the acidic conditions (from hydrochloric acid) in the small intestine and the stomach. the alkaline conditions and large surface area increase the rate of lipid digestion by lipase.
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12
Q

what is the effect of temperature on enzymes?

A
  • initially, the activity of the enzyme increases as the temperature increases - the enzyme and the substrate are moving faster, so there are more collisions per second between the enzyme and the active site.
  • however, the enzyme will reach the optimum temperature (37 degrees celsius for more human enzymes). after this temperature has been surpassed, the activity of the enzyme rapidly decreased to 0.
  • these high temperatures have denatured the enzyme, and the changed the shape of its active site. now the substrate doesn’t fit perfectly anymore, and enzyme can no longer catalyse the reaction.
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13
Q

what is the effect of pH on enzymes?

A
  • the enzyme has an optimum pH, where the activity is maximum.
  • if we make the pH more acidic or more alkaline, then the activity drops to 0, as the enzyme has denatured.
  • each enzyme has a specific optimum pH. protease enzymes, for example, work best at an acidic pH.
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14
Q

how is the small intestine adapted to absorb the products of digestion into the bloodstream?

A
  • very long. provides a large surface area for absorption of the products of digestion.
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15
Q

how are villi adapted to absorb the products of digestion into the bloodstream?

A
  • the interior of the small intestine is covered with millions of villi, which increase the surface area for the absorption of molecules.
    > the villi are covered with micro-villi,
    increasing the surface area even more.
    > villi have a good blood supply, so the
    bloodstream rapidly removes the
    products of digestion. this maintains a
    high concentration gradient, and
    increases the rate of diffusion/active
    transport.
    > very thin membrane, ensuring a short
    diffusion path.
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16
Q

what is the structure and function of the heart?

A

function: an organ that pumps blood around the body in a double circulatory system.

structure:
- four chambers (left and right atrium, left and right ventricle). the atria are separated from the ventricles by valves.
- four main blood vessels.
> vena cava. brings deoxygenated
blood from the body.
> pulmonary artery. deoxygenated
blood passes from the heart to the
lungs.
> pulmonary vein. oxygenated blood
passes from the lungs to the heart.
> aorta. oxygenated blood pumped
from the heart to the body.

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17
Q

what is the path of blood through the heart?

A
  1. blood enters through the vena cava into the right atrium.
  2. the atrium contracts, forcing blood through a valve into the right ventricle.
    - the blood is taken from the right ventricle, through the pulmonary artery, to the lungs, where it becomes oxygenated.
    - the now oxygenated blood enters into the left atrium through the pulmonary vein.
    - the atrium contracts again, forcing it through the valve into the right atrium.
    - the blood is carried out of the right atrium and pumped into the body by the aorta.
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18
Q

what is the purpose of a valve in the heart?

A

prevents the blood from flowing back into the atria during contraction.

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19
Q

why does the left side of the heart have a thicker, muscular wall than the right side?

A

the left ventricle pumps blood around the entire body, so it needs to provide a greater force. the right ventricle only needs to pump blood to the lungs.

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20
Q

what are coronary arteries?

A
  • branch out of the aorta and spread across the heart muscle.
  • provides oxygen to the muscle cells of the heart (this oxygen is used in respiration to provide energy for contraction).
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21
Q

how is the natural, resting heartrate controlled?

A

controlled by a group of cells in the top of the right ventricle, called the ‘pacemaker’.
- if the natural pace maker stops working, doctors can plant an artificial pacemaker, which corrects irregularities in the heart rate.

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22
Q

describe the lungs:

A
  • provide an exchange surface adapted for:
    - absorbing oxygen (for respiration) into the blood from the air.
    - transferring carbon dioxide (produced by respiration) from the blood, into the lungs, then the air.
  • this transfer of gases is called gas exchange.
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23
Q

describe the structure of the respiratory system:

A
  • adapted to allow air to pass in and out of the body, and to allow efficient gas exchange to occur.
  • lungs enclosed in the thorax, protected by 12 pairs of ribs.
  • ribs are moved by two sets of intercostal muscles.
  • there is a muscular diaphragm beneath the lungs.
  • the trachea branches into two bronchi. rings of cartilage in the walls of the lungs help to keep it open as air draws in.
  • the bronchi split into smaller branches and then into smaller tubes called bronchioles - these all end in a cluster of microscopic air sacs called alveoli.
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24
Q

describe the process of gaseous exchange in the alveoli:

A
  • occurs between the alveoli and the blood in the capillaries that supply the lungs. capillaries cover 70% of the outside of the alveoli, providing a large surface area for gases to diffuse across.
  • each of the alveoli is a small sphere about 300 micrometres in diameter, giving it a large surface area : volume ratio. there are around 700 million alveoli. the total surface area of the alveoli is 70 square metres.
  • blood flows from the heart across the alveoli, carbon dioxide diffuses out of the blood and into the alveoli, and oxygen diffuses out of the alveoli and into the blood - the blood then returns to the heart.
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25
Q

how has gaseous exchange been made efficient in the alveoli?

A
  • large surface area (see different flashcard)
  • short diffusion path (walls of alveoli and capillaries are one cell thick).
  • alveoli lined with thin film of moisture. gases dissolve in this water, making the diffusion path even smaller.
  • the ventilation of the lungs and the blood flow through the surrounding capillaries means gases are being removed continually, and steep concentration gradients are set up for gases to diffuse.
26
Q

describe the structure and function of arteries:

A
  • carries high pressure blood from the heart to the rest of the body.
  • very thick muscular walls, to withstand high pressures.
  • surges of blood pass through the arteries when the heart beats. elastic fibres stretch when the surge of blood passes through, and then recoil in between surges, keeping the blood moving.
27
Q

describe the structure and function of capillaries:

A
  • when blood passes through capillaries, substances (e.g. glucose, oxygen) diffuse from the blood to the cells.
  • carbon dioxide then diffuses from the cells back to the blood.
  • very thin walls, allowing rapid diffusion due to a short diffusion pathway.
28
Q

describe the structure and function of veins:

A
  • carry blood from the body to the heart.
  • thin walls. the blood pressure is low, so thick walls aren’t required.
  • contains valves. stops blood from flowing backwards.
    > when blood is flowing in the correct
    direction, the valves open to allow blood
    through. when the blood starts to flow
    backwards, the valves shut.
29
Q

what are red blood cells (structure and function)?

A
  • carries oxygen from the lungs to our body’s tissues, for cellular respiration.
  • contain haemoglobia, which combines with oxygen to become oxyhaemoglobin. once the blood reaches tissues, the oxygen and haemoglobia can split apart, to allow oxygen to diffuse into cells.
  • don’t have a nucleus - more space for haemoglobin and oxygen.
  • shaped like a bi-concave disk. large surface area for absorbing oxygen.
30
Q

what are white blood cells (structure and function)?

A
  • defends and protects us against infection.
    > phagocytosis. the cell engulfs a
    pathogen.
    > producing antibodies. bind onto
    pathogens and destroy them.
    > producing antitoxins. neutralise toxins
    that pathogens may produce.
  • do have a nucleus.
31
Q

what are platelets (structure and function)?

A
  • not cells, just small fragments of cells, so don’t have a nucleus.
  • float around in our blood until we get a cut, when they rush to the wound and act like a glue, patching up the hole. ‘CLOTTING’.
  • stops blood from escaping us, and prevents microorganisms from getting in, as they could cause an infection.
32
Q

what is plasma (structure and function)?

A
  • pale, straw-coloured liquid, makes the blood watery so that it can flow
  • carries everything (including red and white blood cells, platelets) and nutrients, such as glucose, amino acids and waste products.
33
Q

describe artificial blood:

A
  • artificial blood (basically salt water). adds volume to our circulatory system, keeping our vessels full, and allowing our heart to keep pumping. doesn’t contain any red blood cells though, meaning it can’t transport any oxygen.
34
Q

describe a blood transfusion:

A
  • a person is given real blood that’s been donated by blood donors.
  • includes red blood cells, which is the key to surviving blood loss.
  • the blood must be compatible with the patient’s blood type, though.
35
Q

what are cardiovascular diseases?

A
  • diseases of the heart and blood vessels.
  • non-communicable (not infectious).
36
Q

describe coronary heart disease:

A
  • layers of fatty material build up inside the coronary arteries, causing them to narrow.
  • this results in a lack of oxygen to the coronary arteries (and the heart), which could result in a heart attack.
37
Q

what are statins, how can they treat coronary heart disease, and what are their pros and cons?

A
  • drugs which reduce the levels of cholesterol in the blood.
  • slows down the rate that fatty material builds up in the arteries.
  • PROS: effective treatment.
  • CONS: can cause liver problems, you have to take statins for the rest of your life.
38
Q

what are stents, how can they treat coronary heart disease, and what are their pros and cons?

A
  • a stent is a tube which is inserted into a coronary artery to keep it open.
  • PROS: blood can flow normally through the artery.
  • CONS: doesn’t prevent other regions of the coronary artery from being blocked. doesn’t treat the underlying cause of the disease (too much cholesterol in the blood)
39
Q

what are other examples of diseases of the heart, and how can we treat them?

A
  • the heart valves sometimes don’t fully open, so the heart has to pump extra hard to get the blood through, enlarging the heart.
  • the valves can sometimes be leaky, causing the patient to be weak or tired.
  • can replace the valves with a mechanical valve. these last a lifetime but can cause blood clots, so patients have to take anti-clotting drugs.
  • can also treat with animal (biological) valves (e.g. pigs), however, these may need to be replaced. on the other hand, patients don’t need to take drugs.
40
Q

what is heart failure?

A

where the heart can’t pump enough blood around the body. these patients are sometimes given a donated heart, or heart and lungs.

41
Q

what are the disadvantages to the treatment of heart failure?

A
  • there aren’t enough donated hearts to treat every patient.
  • the patient must take immunosuppressant drugs to stop the heart from being rejected from the body’s immune system.
42
Q

describe artificial hearts, and their pros and cons:

A
  • a temporary solution while waiting for a heart transplant, or to allow their damaged heart to rest.
  • artificial hearts increase the risk of blood clotting, and can only be used for a relatively short time.
43
Q

define health:

A

the state of physical and mental well-being.

44
Q

how do you maintain good health, and how can you become unhealthy?

A

good health:
- good, balanced diet
- sufficient exercise/sleep
- access to medical care (e.g. vaccines)

bad health: (can result in illness)
- none of the above
- too much stress
- disease, both communicable and non-communicable

45
Q

what is the difference between a communicable and non-communicable disease?

A
  • communicable: can spread from person to person, or between animals and people. INFECTIOUS. can be caused by viruses, bacteria, parasites and fungi.
    > common cold, malaria, meningitis
  • non-communicable: can’t be spread between people. not caused by pathogens. these start more slowly and last a long time (some never go away)
    > asthma, coronary heart disease,
    diabetes, cancer.
46
Q

what are 4 examples of different types of diseases that interact?

A
  • defects in the immune system mean that an individual is more likely to suffer from communicable diseases.
  • viruses living in cells can be the trigger for cancers.
  • immune reactions initially caused by pathogens can trigger allergies such as skin rashes and asthma.
  • severe physical health can lead to depression and other mental illnesses.
47
Q

what are the lifestyle factors that can increase the risk of non-communicable diseases?

this is a big card, good luck!

A
  • a diet high in fat and low in vegetables can increase the levels of types of cholesterol in the blood, leading to a build up of fatty material in the arteries.
  • a diet high in salt can increase blood pressure, increasing the risk of cardiovascular diseases.
  • smoking increases the risk of cardiovascular disease, lung cancer and emphysema.
    > cigarette smoke contains carcinogens,
    which can trigger cancer.
  • excessive alcohol consumption can increase the risk of liver cirrhosis and liver cancer. it can also lead to addiction and memory loss.
  • excessive exposure to radiation can increase the risk of developing lung cancer.
48
Q

how can smoking and alcohol consumption during pregnancy harm the baby?

A
  • smoking increases the risk of miscarriage and premature birth, or of the baby being born with a low body mass.
  • alcohol consumption can cause foetal alcohol syndrome. children born with this can have learning difficulties or other mental an physical problems.
49
Q

describe type 2 diabetes and its implications:

A
  • when the body struggles to control its blood glucose levels.
  • can lead to blindness, or require the amputation of a limb.
  • obese people have a much bigger risk of developing type 2 diabetes.
50
Q

what is a tumour, and what is the difference between a benign and malignant tumour?

A
  • an abnormal mass of cells, where they’ve undergone uncontrolled growth and division.
  • benign tumour: group of cells are controlled in one area, usually a membrane. so they’re not normally dangerous, and aren’t called cancer.
  • malignant tumour: don’t stay in one place. invade other tissues, and spread to different parts of the body, where they can form secondary tumours. these are very dangerous, and potentially fatal. they’re classified as cancer.
51
Q

what are the risk factors associated with cancer?

A
  • smoking is mainly linked to lung cancer. it’s also linked to mouth, stomach and cervical cancer.
  • obesity is linked to bowel, liver, and kidney cancer.
  • ultraviolet light exposure (from sun and sunbeds) is linked to skin cancer, as the UV rays damage our skin cells.
  • drinking alcohol is linked to an increased risk in liver cancer.
  • sometimes not all of the cancer risk factors are due to our lifestyle. some can be genetic.
    > the BRCA genes are linked to breast
    and ovarian cancer in women.
52
Q

what are the top and bottom layers of a leaf called?

A

the upper and lower epidermis.
- very thin cells (epidermal cells forming epidermal tissue).
- protects the surface of the leaf.

  • the upper epidermis is transparent, allowing light to pass through to the photosynthetic cells below.
  • the upper epidermis is also covered with the waxy cuticle (oily material), which reduces the evaporation of water from the surface of the leaf.
  • lower epidermis is covered with tiny pores - stomata. they allow carbon dioxide to enter the leaf, and oxygen to leave. controls the amount of water vapour passing out of the leaf.
53
Q

what is the role of the palisade mesophyll?

A
  • consists of palisade cells
  • packed full of chloroplasts, meaning that photosynthesis can occur.
54
Q

what is the role of the spongy mesophyll?

A
  • full of air spaces.
  • the air spaces allow carbon dioxide to diffuse from the stomata through the spongy mesophyll to the palisade cells.
  • oxygen also diffuses from the palisade cells, through the spongy mesophyll, to the stomata.
55
Q

what is the role of xylem tissue in the leaf?

A

transports water from the roots to the stem and the leaves. some of the water is then used in photosynthesis. transports dissolved mineral ions (e.g. magnesium), which is used to make chlorophyll.

56
Q

what is the role of phloem tissue in the leaf?

A

transports dissolved sugars produced by photosynthesis from the leaves to the rest of the plant.
- these sugars can be used immediately (e.g. glucose can be used in respiration)
- these sugars can be stored (e.g. as starch)

  • THIS IS CALLED TRANSLOCATION
57
Q

how do guard cells work to control stomata?

A
  • when the plant has lots of water, so it doesn’t have to worry about conserving it, the guard cells will be well-hydrated (turgid).
  • this make the gap between them larger, allowing more carbon dioxide to diffuse through.
  • when the plants don’t have a lot of water, the guard cells will lose water, due to osmosis. they’ll become flaccid, and close the gap.
  • the plant no longer takes in carbon dioxide, and will conserve its water vapour.
58
Q

how do guard cells respond to light?

A

guard cells are sensitive to light, and close at night-time, when photosynthesis isn’t taking place, and so the leaf doesn’t require carbon dioxide.

59
Q

why are guard cells on the underside of the leaf?

A

the underside is more shaded, making it cooler. this means that less water will evaporate, conserving water.

60
Q

what is transpiration?

A

the process of water movement through plants, and its evaporation from certain parts (e.g. leaves)
> this evaporation cools the leaf down,
especially in warm weather.

61
Q

how is a constant water supply maintained in the leaf?

A
  • water vapour diffuses through the gaps in the spongy mesophyll and out through the stomata.
  • water passes from the xylem into the leaf, to replace the water that’s been lost.
  • finally, water is drawn into the root hair cells and up the xylem vessels to the leaf.

THE TRANSPIRATION STREAM

62
Q

what are the factors that affect the rate of transpiration?

A
  • higher temperatures increase the rate of transpiration (evaporation is faster at higher temperatures).
  • dry conditions (e.g. not humid) also increase the rate of transpiration. evaporation takes place quicker under dry conditions.
  • windy conditions increase the rate of transpiration. wind removes surrounding water vapour, allowing more evaporation to occur.
  • increased light intensity increases the rate of transpiration as this increases the rate of photosynthesis. this means the stomata have opened to allow carbon dioxide in. once they’ve opened, water vapour can pass out of the leaf.

biology (8 decks)

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