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A Biology IGCSE course > Enzymes, digestion and biological molecules(Y9) > Flashcards

Enzymes, digestion and biological molecules(Y9) Flashcards

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1
Q

What are carbohydrates and examples?

A

Carbohydrates are substrates used in respiration to release energy.
Examples are pasta, fruit and bread

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2
Q

What are fats and examples

A

Long term energy stores
Provides thermal insulation
A component of cell
membranes
Some hormones
examples are butter and oil

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3
Q

What are proteins and examples?

A

Growth and repair of cell
Meat, fish, eggs and some dairy

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4
Q

What is vitamin A and where is it found?

A

Vitamin A forms a pigment needed for vision, which helps us to see when there is not much light. Vitamin A also protects the surface of the eye.
It is found in Liver, fish oil and eggs

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5
Q

What is vitamin C and where is it found?

A

Vitamin C is needed for healthy skin and healing
It is found in fruits and some green vegetables.

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6
Q

What is vitamin D and where is it found

A

Vitamin D is needed to increase the absorption of calcium which is needed for strong teeth and bones.
It is found in sunlight.

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7
Q

What are the minerals that are needed for strong bones and teeth and to make red blood cells and where are they found

A

Calcium which is found in milk and Iron which is found in red meat and green vegetables

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8
Q

What is calcium

A

Calcium is a mineral needed for strong teeth and bones

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9
Q

What is Iron?

A

Iron is a mineral that is needed to make haemoglobin which is a pigment in red blood cells

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10
Q

What is Fiber?

A

Fiber is needed to provide roughage and keep food moving through the gut by peristalsis
Fiber prevents constipation

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11
Q

Why is water needed

A

To hydrate cells

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12
Q

What happens when there is a lack of Vitamin C?

A

The illness of scurvy

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13
Q

What happens when there is a lack of vitamin D?

A

Rickets

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14
Q

What happens when there is a lack of Vitamin A?

A

Night blindness

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15
Q

What happens when a person does not have enough Iron?

A

Anaemia - Due to not enough red blood cells, people become tired

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16
Q

Lack of calcium

A

Rickets

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17
Q

What is the result of a lack of protein

A
  • Kwashiorkor
  • wasting muscles
  • loss of teeth
  • thinning hair
  • swelling of abdomen
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18
Q

What is metabolism

A

The reactions in your body

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19
Q

What happens if a person has a high energy intake and low energy demand

A

Excess energy is stored as glycogen and then fat.
Leads to an increase in body mass and obesity
Obesity leads to coronary heat disease, high blood pressure and arthitis

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20
Q

What type of people need more fat?

A

Small people to grow and they usually have less fat
Young people to grow
Pregnant women as the baby in them needs to grow
People who do more sports or exercise as they are more active which requires more energy which is provided via respiration which needs glucose which can be extracted from fats

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21
Q

How is the energy content of foods measured

A

In the calirometer practical
Energy released from food per gram in joules is
mass of water (g) x temperature rise(celcius) x 4.2/mass of food sample(g)

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22
Q

Different types of calorimetry

A

Bomb calirometer, copper calirometer and calirometer

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23
Q

How does bomb calirometer work?

A

Ignition wires sets a food on fire in an oxygen atmosphere which passes to the water and a stirrer stirs the water.

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24
Q

What do lipids do?

A

Makes cell membranes and hormones

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25
Q

What are the elements found in carbohydrates

A

Carbon, hydrogen and oxygen

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26
Q

What are the shape of carbohydrates

A
  • Hexagons - they are called monosaccharide(1) e.g. glucose
  • disaccharide(2) e.g. sucrose or
  • polysaccharide (many) e.g. starch or glycogen
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27
Q

What are the properties of carbohydrate polymers

A

They are large, insoluble storage molecules. A polymer of glucose in stored as glycogen in animals.

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28
Q

What are proteins made of?

A

Carbon, hydrogen, oxygen and nitrogen

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29
Q

What is the structure of proteins

A
  • 1 protein is called an amino acid
  • 2 are called Dipeptide
  • many are called polypeptide which can make enzymes or hormones
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30
Q

What are the properties of protein polymers?

A

Properties and shape changes between functions

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31
Q

What are lipids made out of

A

Carbon, hydrogen and oxygen

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32
Q

What is the structure of lipids

A

glycerol backbone and three fatty acid connected to the glycerol in tubes

33
Q

What is the property of lipids

A

Can be either liquid or solid at room temperature

34
Q

What different types of fats are there?

A

saturated, poly saturated and mono - unsaturated

35
Q

What is saturated fat?

A

When there are no double bonds between carbon which leads to the molecules being straight which leads to saturated fat packing tightly which leads to saturated fats being a solid at room temperature, like butter

36
Q

What is unsaturated fat?

A

When there is a double bond which causes the atoms in the unsaturated fat to bend and not pack tightly so it is liquid at room temperature

37
Q

What is the cause of cholesterol?

A

Too much saturated fat which then enters blood vessels making arteries narrower which leads to less blood flow and less oxygen

38
Q

What are the different tests for food molecules

A

Benedict’s solution to test for reduced sugars (e.g. glucose, iodine solution to test for starch, Biuret solution to test for protein and ethanol Emulsion test to test for lipids

39
Q

How does Benedict’s solution work?

A

2cm^3 of solution
2cm^3 Benedict’s reagent
Leave in boiling water bath 3mins
no reduced sugar - blue
Low conc of reduced sugar→ Green
Medium conc of reduced sugar→ Yellow
High conc of reduced sugar→ Brick red/orange

40
Q

How does iodine solution work?

A

2cm^3 starch
10 drops of iodine
no starch: orange brown
starch: blue black

41
Q

How does Biuret solution work?

A

2cm^3 solution
2cm^3 biuret solution
mix
protein = purple/lilac
no protein = blue

42
Q

How does ethanol emulsion work?

A
  • 1cm^3 food
  • 2cm^3 ethanol
  • shake
  • 3cm^3 water
  • if cloudy white there are lipids
  • if not cloudy no lipids
43
Q

What are enzymes?

A

Enzymes are large protein molecules containing carbon, hydrogen, oxygen, nitrogen. They are also made up of amino acids which join to make long chains which can make shapes so that other molecules with a complimentary shape can fit in it. Enzymes act as a catalyst

44
Q

What do enzymes do?

A

Enzymes are a catalyst that lower the activation energy.

45
Q

What is the region that the substrate binds to?

A

The active site which is complementary in shape to only one type of substrate molecule

46
Q

What is made when a substrate and enzyme bind?

A

An enzyme substrate complex forms

47
Q

What is the name of the result of a chemical reaction?

A

A product

48
Q

What are the factors affecting rate of enzyme reactions?

A

Temperature, pH, substrate concentration, enzyme concentration

49
Q

What is the effect of temperature on an enzyme?

A

the higher the temperature, the higher the kinetic energy and the faster the reaction. However, after 40 degrees celcius the enzymes start to denature and the reaction slows down.

50
Q

What is the effect of pH on an enzyme?

A

The optimum pH is best for an enzyme because if the pH is not optimum the enzyme starts to denature.

51
Q

What is the effect of substrate concentration on the rate of reaction?

A

More substrates will mean that the enzymes will be able to break up more which speeds up the rate of reaction

52
Q

What is the effect of enzyme concentration on rate of reaction?

A

The more enzymes there are, substrates can be broken down faster

53
Q

What is digestion?

A

Digestion is the chemical and mechanical breakdown of food. It converts large insoluble molecules into small soluble molecules which can be absorbed into the blood.

54
Q

What is mechanical digestion?

A

Mechanical digestion is the physical breakdown of food e.g. using teeth and the churning of food in the stomach. Mechanical digestion creates a larger surface area for enzymes to work on

55
Q

Chemical digestion

A

Chemical digestion is the breaking down of large insoluble molecules into small soluble molecules by using enzymes.

56
Q

How are food molecules absorbed?

A

By diffusion and active transport into the villi

57
Q

Why do the molecules need to be small and soluble?

A

So that they can fit in the partially permeable membrane of the villi and microvilli so that the nutrients can be absorbed into the blood stream

58
Q

label digestive system https://www.sporcle.com/games/shapiror/digestive_system

A
59
Q

What is peristalsis?

A

When circular and longitudinal muscles in the gut contract to push a bolus of food forward through the gut. This starts in the oesophagus

60
Q

What is the role of the mouth?

A

Mechanically breaks down food to increase the SA:V ratio. Forms food into a bolus which is easier to swallow.

61
Q

What is the role of the salivary glands?

A

Produces saliva which is a mixture of amylase, mucus and water. Amylase converts starch to maltose

62
Q

What is the role of Oesophagus?

A

moves food into the stomach by peristalsis. When it contracts, it pushes food through the gut

63
Q

What is the role of the stomach

A

glandular tissue which produces protease pepsin, hydrochloric acid and mucus.
Pepsin breaks down large proteins into small polypeptide chains/amino acids
Hydrochloric acid provides pH of 2 which is the optimum pH for pepsin
Hydrochloric acid kills bacteria
Muscular wall contracts which churns food
which is mechanical digestion

64
Q

What is the role of the liver?

A

Produces bile
Bile neutralises acidic chyme
Bile emulsifies lipids to increase their SA:V
Removes lactic acid from the bloodstream and then breaks it down into glucose that can be used in the future

65
Q

What is the role of the gall bladder?

A

Where bile is stored and passed to the food

66
Q

What is the role of the Duodenum

A

produces enzymes Trypsin (proteins and polypeptides to amino acid)
Amylase
Lipase(lipids to fatty acids and glycerol)
Has an optimum pH of 9

67
Q

What is the role of the ileum

A
  • food is absorbed via villi by diffusion and active transport
  • Villi make mucus and proteases:
  • lipase
  • amylase
  • maltase (maltose to glucose)
  • sucrose(sucrose to glucose and fructose)
  • lactase (lactose to glucose and galactose)
68
Q

What is the role of the colon (large intestine)

A

reabsorbs water by osmosis

69
Q

What is the role of the rectum?

A

Stores faeces before expulsion

70
Q

What is the role of the anus

A

A muscle which regulates the release of faeces (egestion)

71
Q

optimum pH small intestine

A

9

72
Q

optimum pH mouth

A

7

73
Q

optimum pH stomach

A

2

74
Q

What does pancreas do?

A

Makes pancreatic juice filled with enzymes

75
Q

How are nutrients absorbed?

A

villi absorbs nutrients in the ileum.

76
Q

Adaptations of villi

A

many microvilli for high SA:V ratio
Lots of blood capillaries and a dense capillary network to transport diffused food away quickly to maintain a steep concentration gradient
1 cell thick diffusion pathway to make diffusion faster and easier
Lacteal takes away fatty acid and glycerol molecules to maintain a steep concentration gradient

77
Q

What is assimilation

A

Using food for synthesis of new molecules for growth

78
Q

Where is the removal of undigested food

A

Anus

A Biology IGCSE course (16 decks)

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