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Biology 9-1 iGCSE Oxford AQA > Organisation > Flashcards

Organisation Flashcards

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1
Q

What are large multicellular organisms made up?

A

Are made up of organ systems

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2
Q

What are cells essentially?

A

Basic building blocks that make up all living organisms

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3
Q

What do specialised cells do?

A

They carry out a particular function

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4
Q

What do specialised cells form?

A

Tissues

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5
Q

What is differentiation?

A

Processes which cells become specialised

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6
Q

When does differentiation occur?

A

During development of a multicellular organism

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7
Q

What is a tissue?

A

A group of similar cells - work together to carry out particular function

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8
Q

What are tissues organised into?

A

Organs

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9
Q

What is an organ?

A

A group of different tissues - work together to perform certain function

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10
Q

What are organs organised into?

A

Organ systems

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11
Q

What is an organ system?

A

Organ system is a group of organs working together to perform particular job

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12
Q

What the purpose of the digestive system?

A

Breaks down and absorbs food

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13
Q

What are enzymes made out of?

A

Proteins (chains of amino acids are folded into unique shapes = enzymes can do their jobs)

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14
Q

What do enzymes act as?

A

Biological catalysts

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15
Q

How do enzymes work?

A

Every enzyme has active site (with unique shape) that fits onto substance involved in reaction (catalyse one specific reaction)

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16
Q

What actually happens to enzyme’s active site?

A

Active site changes shape a little as substrate bonds to get tighter fit (‘induced fit’ model)

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17
Q

Describe how enzymes work?

A
  1. Substrate attaches to active site forming ‘Enzyme Substrate Complex’
  2. Enzyme breaks substrate down (breaks bonds)
  3. Broken down substrate is released - products are produced
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18
Q

As you increase the temperature, what happens to rate of the reaction and why?

A

Increases the rate at first, enzymes have enough kinetic energy for collisions between enzymes and substrates

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19
Q

What happens to enzymes if you increase the temperature too high?

A

Some bonds holding enzyme together break = changes shape of enzyme’s active site so substrate won’t fit ∴ enzyme is denatured

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20
Q

What happens to enzymes if the temperature is too low?

A

They’re inactive - not enough kinetic energy for collisions

between enzymes and substrates

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21
Q

What affects enzymes (name two things)?

A

Temperature & pH

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22
Q

What happens to enzymes if the pH is too high/low?

A

Interferes with bonds holding enzyme together = changes shape of active site and denatures enzyme

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23
Q

What is often the optimum pH for enzymes?

A

Neutral - pH 7

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24
Q

Why does starch, proteins and fats are big molecules have to be broken down?

A

Too big to pass through walls of digestive system (insoluble) (& absorbed into bloodstream)

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25
Q

What does amylase catalyse?

A

Breakdown of starch

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26
Q

What does starch break down into?

A

Sugars

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27
Q

Where is amylase found?

A

Salivary glands, pancreas, small intestine

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28
Q

What does protease do?

A

Converts proteins into amino acids

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29
Q

Where is protease found?

A

Stomach (called pepsin), pancreas, small intestine

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30
Q

What does lipase do?

A

Converts lipids into fatty acids and glycerol

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31
Q

What does bile do?

A

Neutralises stomach acid and emulsifies fats

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32
Q

Where is bile produced?

A

In the liver

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33
Q

Where is bile stored?

A

Gall bladder

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34
Q

Where is bile released into?

A

Small intestine

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35
Q

Why does bile neutralise stomach acid?

A
  1. Hydrochloric acid in stomach makes pH too acidic for enzymes in small intestine to work
  2. Bile is alkaline → it neutralises acid and makes conditions alkaline
  3. Enzymes in small intestine work best in alkaline conditions
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36
Q

What is meant by bile emulsifying fat and why does it do this?

A

Breaks fat into tiny droplets = gives bigger surface are of fat for enzyme lipase to work on ∴ makes its digestion faster

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37
Q

What does the stomach do?

A

Churns food with its muscular walls (via peristalsis)

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38
Q

What does the stomach produce?

A

Protease = pepsin and hydrochloric acid

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39
Q

Why is hydrochloric acid used in the stomach?

A
  1. To kill bacteria

2. Give optimum pH for protease to work in (acidic - pH 2)

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40
Q

What do the salivary glands produce?

A

Amylase enzyme in the saliva

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41
Q

How does the oesophagus do?

A

Moves food along (via Peristalsis - muscle contractions)

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42
Q

What does the pancreas do?

A

Produces enzymes and releases them into small intestine

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43
Q

What does the small intestine produce?

A

Protease, amylase, lipase to complete digestion

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44
Q

What happens in the small intestine?

A

Digested food is absorbed out of the digestive system and into the blood

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45
Q

What does the gall bladder do?

A

Stores bile before it’s released into small intestine

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46
Q

What does the large intestine do?

A

It’s where excess water is absorbed from food

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47
Q

What does the rectum do?

A

Where faeces are stored before they pass out through the anus

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48
Q

Where do we get enzymes from (e.g. to use industrially)?

A

Some micro-organisms produce enzymes which pass out of cells

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49
Q

Give an example of enzymes used in the home

A

They’re used in biological detergents

50
Q

What are biological detergents used for?

A

Used to remove stains from clothes

51
Q

What do biological detergents contain and why?

A

Contain proteases and lipase which break down proteins and fats in stains = cleaner wash

52
Q

What is an advantage of using biological detergents opposed to normal ones?

A

Work best at lower temperatures than non-biological detergents → less electricity used

53
Q

Give two examples of enzymes used in the industry

A
  1. Proteases - used to make baby foods

2. Carbohydrase - used to convert starch into glucose syrup

54
Q

Why are proteases used to make baby foods?

A

Pre-digest some of protein in food = easier for babys to digestive (e.g. easier for them to get amino acids needed from food)

55
Q

Why do manufactures use carbohydrase to convert starch into glucose syrup?

A

Starch made by plants (e.g. corn) = cheap → using enzymes to convert plant starch into sweet sugar = cheap source of sweetness of food manufactures

56
Q

Manufacturer’s use ___ quantities of sugar syrup in food production

A

high

57
Q

What else is carbohydrase used for in the industry?

A

Used for making fuel (ethanol) from plants = simple sugars used by yeast for anaerobic respiration

58
Q

What is the advantage of using enzymes in industrial processes?

A

Enzymes catalyse reactions at lower temperatures & normal pressures = cheaper to run

59
Q

What are the disadvantages of using enzymes in industrial processes? Name 2

A
  1. Require specific temperatures and pHs = costs money to control these conditions
  2. Enzymes expensive to produce
60
Q

Why are enzymes expensive to produce if microorganisms are relatively cheap?

A

Supplying microorganisms with food + oxygen & removing waste is expensive

61
Q

What does the respiratory system do?

A

Takes air into and out of body so oxygen from air can diffuses into bloodstream and carbon dioxide can diffuse out of bloodstream and into air

62
Q

Where are the lungs in the body?

A

Thorax (top part of your body)

63
Q

How are the lungs separated from the lower part of body?

A

By the diaphragm

64
Q

What are lungs protected by?

A

Ribcage

65
Q

Explains what happens when you breathe in air?

A

Air goes though trachea → bronchi → bronchioles → alveoli

66
Q

What happens in the alveoli?

A

Gas exchange

67
Q

When you inhale, what happens to the intercostal muscles and what effect does this have?

A

Contract, pulling up ribcage

68
Q

When you inhale, what happens to the diaphragm and what effect does this have?

A

Diaphragm muscles contacts, causing diaphragm flatten

69
Q

When you inhale, what happens to the lung volume?

A

It increases

70
Q

When you inhale, what happens to the pressure in the thorax and what effect does this have?

A

Decreases (compare to air surrounding body) = air rushes into lungs

71
Q

When you exhale, what happens to the intercostal muscles and what effect does this have?

A

Relax, ribcage moves downwards

72
Q

When you exhale, what happens to the diaphragm and what effect does this have?

A

Diaphragm muscles relax and diaphragm resumes its domed shape

73
Q

When you exhale, what happens to the lung volume?

A

Decreases

74
Q

When you exhale, what happens to the pressure in the thorax and what effect does this have?

A

Increases (compare to air surrounding body) = air forced out

75
Q

What are alveoli (millions of little air sacs) surrounded by?

A

Network of blood capillaries

76
Q

What does the blood passing next to alveoli contain and why?

A

Contains lots of carbon dioxide and very little oxygen bc it has just returned to lungs from rest of body

77
Q

What happens to the blood passing next to an alveolus?

A
  1. Oxygen diffuses out of alveolus (high concentration) into blood (low concentration)
  2. Carbon dioxide diffuses out of blood (high concentration) into alveolus (low concentration) to be breathed out
78
Q

When the blood reaches the body cells, what happens?

A
  1. Oxygen is released from red blood cells (high concentration) and diffuses into body cells (low concentration)
  2. Carbon dioxide diffuses out of body cells (high concentration) into blood (low concentration) and then it’s carried back into the lungs
79
Q

When spontaneous breathing is stopped (due to disease or injury), what can the patient use?

A

A mechanical ventilator

80
Q

What are the two types of mechanical ventilators?

A
  1. Negative pressure ventilators

2. Postive pressure ventilators

81
Q

What do negative pressure ventilators do?

A

Cause air to be ‘drawn’ into lungs

82
Q

What do positive pressure ventilators do?

A

Force air into lungs

83
Q

What are used instead of negative pressure ventilators and why?

A

Positive pressure ventilators = don’t have to be placed inside an iron lung machine

84
Q

What do positive pressure ventilators come as?

A
  1. Simple face mask

2. Tube going into trachea

85
Q

What are the advantages of using positive pressure ventilators? Name 3

A
  1. Equipment can be used at home & patient can move around
  2. Patients have control over system
  3. Modern systems can link ventilator to computer system = helps patients manage their own breathing more easily
86
Q

What can full-scale positive pressure ventilating machines be used for?

A
  1. Can keep patients alive during major surgery

2. Help people who are paralysed survive for several years

87
Q

What is transpiration?

A

Water loss from upper parts of plant

88
Q

What is transpiration caused by?

A

Caused by evaporation and diffusion of water from a plant’s surface

89
Q

Where does most transpiration occur in a plant?

A

Happens in the leaves

90
Q

Explain how the transpiration stream works?

A
  1. Water evaporates = slight shortage of water in leaf
  2. = more water drawn up from rest of plant through xylem vessels
  3. Means more water is drawn up from roots and so there’s a constant transpiration stream of water though plant
  4. AND because there’s more water inside plant than in air outside = water escapes from leaves through stomata by diffusion
91
Q

What 3 things affect the rate of transpiration

A
  1. Temperature
  2. Air Flow
  3. Humidity
92
Q

Why is it that when it’s warmer, the rate of transpiration increases?

A

Water particles have more energy to evaporate and diffuse out of stomata

93
Q

Why is it that when there’s a low air flow around a leaf (weaker wind), that the transportation rate is less?

A

Water vapour just surrounds leaf and doesn’t move away = there’s high concentration of water particles outside the leaf as well as inside it so diffusion doesn’t happen quickly

94
Q

Why is it that when it’s dry, the rate of transpiration is faster?

A

High concentration of water particles inside leave and low concentration of water molecules outside leave = concentration gradient = water will diffuse out

95
Q

Why does stomata begin to close as it gets darker?

A

Photosynthesis can’t happen in dark so they don’t need to be open to let CO2 in

96
Q

When there’s a lot water in the plant, what do guard cells do and what effect does this have?

A

Guard cells fill with it & go plump and turgid = makes stomata open so gases can be exchanged for photosynthesis

97
Q

Why do guard cells have a kidney shape?

A

To open and close the stomata in leaf

98
Q

When a plant is short of water, what do the guard cells do?

A

Guard cells lose water & become flaccid, making stomata close (prevents wilting)

99
Q

Why do guard cells have thin outer walls and thickened inner walls?

A

To make opening and closing work

100
Q

Why are guard cells sensitive to light?

A

So they can close at night to save water without losing out

on photosynthesis

101
Q

Why do you usually find more stomata on undersides of leaves than on top?

A

Lower surface is shaded and cooler = less water is lost through stomata than if they were on upper surface

102
Q

What are guard cells adapted for?

A

For gas exchange and controlling water loss within a leaf

103
Q

What does the xylem do?

A

Carry water and mineral ions from roots to stem and leaves

104
Q

What is the xylem made out of and how is it joined?

A

Dead cells joined end to end with no end walls between

them and a hole down the middle

105
Q

What is the transpiration stream?

A

Movement of water from roots through xylem and out of leaves

106
Q

What is the structure of the phloem like?

A

Made of columns of elongated living cells with small pores in the end walls (to allow cell sap to flow through)

107
Q

What does the phloem do? What is translocation?

A

Transport food substances (mainly dissolved sugars) made in leaves to rest of plant for immediate use (e.g. growing regions) or for storage

108
Q

What is the purpose of mucus in the stomach?

A

Prevents stomach lining from being damaged by hydrochloric acid

109
Q

What does lipids consist of?

A

3 molecules of fatty acids bonded to molecule of glycerol

110
Q

What do simple sugars that are carbohydrates consist of?

A

Only one or two sugar units

111
Q

What do complex carbohydrates (e.g. starch) consist of?

A

Long chains of simple sugar units bonded together

112
Q

What are protein molecules made out of?

A

Long chains of amino acids

113
Q

Long chains of amino acids are ______ to form _____ ______ related to their different functions

A

folded to form specific shapes

114
Q

What is cancer caused by?

A

Uncontrolled Cell Growth and Division

115
Q

Name 2 types of tumours

A
  1. Benign

2. Malignant

116
Q

Name 3 features of benign tumours

A
  1. Tumour grows until there’s no more room
  2. Tumour stays in once place (usually within membrane)
  3. Isn’t normally dangerous - tumour isn’t cancerous
117
Q

What can malignant tumours do?

A

Tumour grows and spread to neighbouring healthy tissues

118
Q

How can malignant tumours spread to neighbouring healthy tissues?

A
  1. Cells can break off and spread to other parts of body by
    travelling in bloodstream
  2. Invade healthy tissues and form secondary tumours
119
Q

Malignant tumours are…

A

dangerous & be fatal - there are cancerous

120
Q

Name 5 risk factors that can increase chance of some cancers

A
  1. Genetics
  2. Smoking
  3. Viral infection
  4. Obesity
  5. UV exposure
121
Q

Explain how genetics can increase chance of some cancers

A

Inherit faulty genes that make you more susceptible to cancer

Biology 9-1 iGCSE Oxford AQA (11 decks)

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