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AQA Biology > Organisation > Flashcards

Organisation Flashcards

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1
Q

what is the cell hierarchy?

A

cell - basic building block of all living organisms
tissue - a group of similar cells working together to perform a specific function
organ - a group of similar tissues working together to perform a specific function
organ system - a group of similar organs working together to perform a specific function
organism - a group of similar organ systems working together to perform a specific function

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2
Q

what are the roles of the organ of the digestive system?

A
  • salivary glands - produce saliva
  • oesophagus - carries food from mouth to stomach
  • stomach - has HCl to kill bacteria+right pH for pepsin (protease) to work, produces pepsin, churns food
  • liver - produces bile (neutralises stomach acid+emulsifies fats)
  • gall bladder - stores bile
  • pancreas - produces protease, amylase, lipase + release the into small intestine
  • small intestine - produces lipase, protease, amylase + digested food absorbed
  • large intestine - absorbs water from waste
  • rectum - where faeces are stored
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3
Q

what is digestion?

A

breakdown of large insoluble molecules into small soluble molecules so they can be absorbed into the blood

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4
Q

what are enzymes?

A

globular proteins which are also biological catalysts

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5
Q

what conditions are needed for enzymes to work?

A

temp - 37 C
pH - depends on the enzyme eg. pepsin works at pH 2 and amylase works best in alkaline conditions

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6
Q

when do enzymes denature (active site changes shape)?

A

when temp is above 37 C
when the pH isn’t right

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7
Q

what is the lock and key theory?

A

enzyme=lock
substrate=key
only one substrate can fit in the active site of an enzyme

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8
Q

what enzymes break down the different nutrients?

A

carbohydrases break carbs into simple sugars eg. amylase=starch into glucose

lipases
lipids=glycerol+fatty acids

proteases
protein=amino acids

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9
Q

where are the enzymes produced?

A
  • amylase=pancreas, small intestine, salivary glands
  • lipase=pancreas, small intestine
  • protease=stomach (pepsin), pancreas, small intestine
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10
Q

what are the products of digestion used for?

A
  • some glucose used for respiration
  • build new carbs, proteins, lipids
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11
Q

how does bile aid digestion?

A
  • alkaline to neutralise HCl
  • emulsifies fat to form small droplets which increases the surface area
  • alkaline conditions and large surface area increase the rate of fat breakdown by lipase
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12
Q

how does the heart pump blood?

A
  • pumps blood around the body in a double circulatory system
  • right ventricle pumps blood to the lungs where gas exchange takes place
  • left ventricle pumps blood around the rest of the body
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13
Q

what path does blood take?

A

vena cava -> right atrium -> atrium contracts -> valve -> pulmonary artery -> lungs -> pulmonary vein -> valve -> left atrium -> left atrium contracts -> left ventricle -> left ventricle contracts -> aorta -> body

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14
Q

where are pacemaker cells found?

A

right atrium
control heart rate

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15
Q

what are artificial pacemakers?

A

devices that correct irregularities in heart rate

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16
Q

how are arteries adapted?

A
  • thick layer of muscle+elastic fibres (stretch when blood comes at high pressure)
  • thick walls
  • small lumen
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17
Q

how are veins adapted?

A
  • thin walls
  • large lumen
  • valves (prevent back flow of blood)
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18
Q

how are capillaries adapted?

A
  • thin wall (one cell thick)
  • narrow lumen
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19
Q

what is blood made of?

A
  • plasma
  • r.b.c
  • w.b.c
  • platelets
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20
Q

how are the components of blood adapted?

A

r.b.c
- biconcave= large surface area to absorb O2
- x nucleus=more space for O2
- contain haemoglobin which binds to O2

w.b.c
- phagocytosis (engulfing pathogens)
- produce antibodies/antitoxins for bacteria

platelets
- small fragments of cells
- x nucleus
- help clot wounds

plasma
- carries waste eg. CO2+urea
- hormones
- proteins
- antibodies/antitoxins
- glucose+amino acids

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21
Q

what are the parts of a lung?

A
  • trachea
  • bronchi which narrow into bronchioles which end in alveoli
22
Q

how are alveoli adapted for gas exchange?

A
  • surrounded by a capillary network
  • blood from body (high in CO2)=oxygen diffuses out of alveoli+CO2 diffuses into alveoli=breathed out
  • blood reaches body cells=oxygen release from rbc & diffuses into body cells+CO2 diffuses into body cells=carried back to lungs
  • cauliflower shaped=large surface area
23
Q

what is coronary heart disease (CHD)?

A

layers of fatty deposits build up in the coronary arteries, narrowing them=reduces the flow of blood through the coronary arteries=lack of oxygen for the heart muscle

24
Q

how to treat CHD?

A

statins - drugs that reduce blood cholesterol
stents - wire mesh tube that widens arteries

25
Q

pros and cons of statins

A

pros
- reduce ‘bad’ cholesterol (LDL) in blood=reduces risk of stroke, heart attacks, coronary heart disease
- increase amount of ‘good’ cholesterol (HDL)=can remove LDL from blood
- may prevent other diseases

cons
- long-term drug+taken regularly=someone may forget t take them
- negative side effects eg. headaches, kidney failure, liver damage, memory loss
- take time to cause an effect

26
Q

pros and cons of stents

A

pros
- lower risk of heart attacks in people with CHD
- effective for long
- quick recovery time

cons
- risk of complications in surgery
- risk of infections
- risk of blood clot developing near stent (thrombosis)

27
Q

why are faulty valves dangerous?

A
  • valve won’t open properly
  • valve may leak=blood can go both ways=blood x circulating effectively
28
Q

how to treat faulty valves?

A
  • valve replacement - either biological or mechanical
  • less drastic than heart transplant but carries risks of blood clots+danger
29
Q

why are artificial hearts used?

A
  • to keep patients alive
    whilst waiting for a heart transplant
  • to allow the heart to rest as an
    aid to recovery
30
Q

what are communicable diseases?

A
  • disease that can be spread from person to person or animals to people
  • caused by pathogens
31
Q

what are non-communicable diseases?

A
  • disease that cannot be spread from person to person or animals to people
  • last for a long time+get worse overtime eg. asthma, cancer, allergies
32
Q

what is health?

A

state of physical and mental well-being

33
Q

what affects your health?

A
  • diseases
  • diet
  • stress
  • life situation eg. access to medicines
34
Q

how can diseases interact?

A
  • Defects in the immune system mean that an individual is more likely to suffer from infectious diseases eg. influenza
  • Viruses living in cells can be the trigger for cancers eh. HPV can cause cervical cancer in women
  • 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
35
Q

what are the human+financial costs of non-communicable diseases globally/nationally, locally and individually?

A

human cost
- around 10 million people die from non-communicable diseases each year=may have lower quality of life+short life expectancy
- doesn’t only affect sufferers but their loved ones

financial cost
- expensive for NHS to research+treat the diseases (same around the world)
- families have to adapt or move house to help person with disease=costly
- person with disease stops work/dies=low income for family+affect country’s econmy

36
Q

how does lifestyle affect the incidence of disease?

A
  • in HICs=people have higher income=can buy high-fat food (global)
  • people in deprived areas=more likely to smoke+poor diet+ x exercise=higher chance of diseases (national)
  • individual choices affect local incidence of diseases
37
Q

what are risk factors?

A

factors that are linked to an increased rate of a disease

38
Q

examples of risk factors

A
  • 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.
  • The effect of smoking on lung disease and lung cancer.
  • The effects of smoking and alcohol on unborn babies.
  • Carcinogens, including ionising radiation, as risk factors in cancer
39
Q

what is cancer?

A

changes in cells which cause a rapid or uncontrolled growth

40
Q

what are benign tumours?

A
  • growths of abnormal cells which are contained in
    one area, usually within a membrane
  • do not invade other parts of
    the body
41
Q

what are malignant tumours?

A
  • cancers
  • they invade neighbouring tissues and spread to different parts of the body in the blood where they form secondary tumours
42
Q

what are lifestyle risk factors that affect cancers?

A
  • smoking - lung/mouth/bowel/stomach/cervical cancer
  • most preventable
  • obesity - bowel/liver/kidney cancer
  • second most preventable
  • UV exposure - skin cancer
  • viral infections - hepatitis B+C=liver cancer
43
Q

how do genetics affect cancer?

A

you can inherit faulty genes=more likely to get cancer eg. BRCA gene=breast+ovarian cancer

44
Q

what are the plant tissues?

A
  • epidermal tissues
  • palisade mesophyll
  • spongy mesophyll
  • xylem and phloem
  • meristem tissue
45
Q

how is a leaf adapted?

A
  • waxy cuticle=reduces water loss+transparent=lets light through to palisade mesophyll
  • palisade mesophyll=lots of chloroplasts+near top+upright+tightly packed=get more light for efficient photosynthesis
  • spongy mesophyll=round+spread out=allow gases eg. CO2 to diffuse+reach palisade cells
  • guard cells=flacid or turgid to open or close stomata=prevent transpiration
46
Q

how are root hair cells adapted?

A

large surface area to absorb as much water as possible

47
Q

how is the xylem adapted?

A
  • transports water and mineral ions from the roots to the stems and leaves
  • made of hollow tubes strengthened by lignin adapted for the
    transport of water in the transpiration stream
48
Q

how is the phloem adapted?

A
  • transports dissolved sugars from the
    leaves to the rest of the plant for immediate use or storage
  • made of tubes of elongated cells
  • Cell sap can move from one phloem cell to the next through pores in the end walls
49
Q

what is translocation?

A

movement of food molecules (sugars) through phloem tissue

50
Q

what factors affect the rate of transpiration?

A
  • low light intensity=stomata close=x photosynthesis in dark=minimises water loss
  • high temp=particles have more energy=evaporate+diffuse out of stomata
  • high wind intensity=water molecules swept away=low concentration of water outside=faster diffusion
  • high humidity=water concentration is similar on outsisde+inside=slow diffuseion

AQA Biology (7 decks)

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