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National 5 Biology > UNIT 1: (1.4) Proteins > Flashcards

UNIT 1: (1.4) Proteins Flashcards

1
Q

what subunits are proteins made up of?

A

subunits called amino acids

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2
Q

How many different amino acids are there?

A

20

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3
Q

How are amino acids held together?

A

amino acids are held together by peptide bonds to form long polypeptide chains

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4
Q

what do polypeptide chains go onto form?

A

chains form the protein molecule

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5
Q

what does the structure of a protein depend on?

A

specific sequence of amino acids

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6
Q

what does the sequence of amino acids determine?

A

The sequence of amino acids determines the shape and function of the protein

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7
Q

what would happen if the order of bases is incorrect?

A

The protein shape will be altered and it may not be able to do its job

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8
Q

what is the function, shape and example of a structural protein?

A
  • collagen makes up the body cartilage
    keratin makes up hairs and nails
  • composed of fibres
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9
Q

what is an example, function and shape of an enzyme?

A
  • examples: amylase, pepsin, lipase, phosphorylase
  • involved in metabolism, break down or build-up
  • globular proteins with a shape that fits snugly with the chemicals they work on
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10
Q

Describe an example, function, shape of a hormone.

A
  • e.g insulin
  • act as chemical messengers in the body
  • insulin controls blood glucose levels
  • small globular proteins
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11
Q

Describe the function and shape of a antibodies

A
  • combine with foreign proteins ( antigens) and mark them to be destroyed by the body’s immune system
  • globular proteins, shaped to recognise and bind with the foreign protein
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12
Q

Describe the function and shape of receptors

A
  • found on the surface of particular cells which allow hormones to target these cells
  • the shape of a receptor protein on a cell allows the cell to respond to a specific hormone
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13
Q

what are enzymes known as?

A

biological catalysts which are present in all living cells. They speed up chemical reactions but remain unchanged by these reactions

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14
Q

what effect do enzymes have on activation energy?

A

lower the activation energy needed for metabolic reactions to proceed in cells

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15
Q

name which are the catalyst, reactant and products

manganese dioxide
water + oxygen
hydrogen peroxide

A

manganese dioxide= catalyst
water + oxygen= products
hydrogen peroxide= reactant

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16
Q

what is the function of the enzyme catalase?

A

breakdown hydrogen peroxide which is produced in living cells into harmless oxygen and water

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17
Q

why does dead tissue show no reaction when boiled?

A

as boiling denatured the enzyme

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18
Q

what does denatured mean?

A

The change in the shape of a protein such as an enzyme that results in them no longer fitting their substrate

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19
Q

what are different variables?

A
  • volume
  • mass/substrate
  • concentration
  • temprature
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20
Q

what is a degradation reaction?

A

A breakdown reaction - when a chemical compound splits into smaller parts.

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21
Q

what is a synthesis reaction?

A

A build-up reaction - when two or more substances join together to form one product.

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22
Q

how are enzymes different from other catalysts?

A
  • enzymes are made inside living cells

- all enzymes are proteins but all catalysts are not

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23
Q

why are enzymes vital to living organisms?

A

speed up chemical reactions inside cells to sustain life

24
Q

what temperature do enzymes work best in the human body?

A

37°C

25
Q

why do you use different syringes for different liquids?

A

to prevent cross-contamination of the solutions

26
Q

what is the function of phosphorylase?

A

builds up glucose-1-phosphate into starch

27
Q

what is meant by a control?

A

control acts as a comparison to show that it is the factor being investigated that is having an effect

28
Q

what is meant by optimum?

A

the conditions under which an enzyme is most active (eg temperature and pH)

29
Q

what happens during digestion?

A

large insoluble molecules are degraded with the help of enzyme action into smaller soluble ones

30
Q

what are the 3 main groups of digestive enzymes?

A
  • carbohydrases
  • proteases
  • lipases
31
Q

what is the function of carbohydrates?

A

break down carbohydrates into sugars such as maltose and glucose

32
Q

what is the function of proteases?

A

break down proteins into polypeptides then into amino acids

33
Q

what is the function of lipases?

A

break down fats into fatty acids and glycerol

34
Q

what happens during an enzyme controlled reaction?

A

where the substrate joins temporarily at the active site on the surface of the enzyme

35
Q

why is the shape of the active site of an enzyme important?

A

the shape of the active site of an enzyme molecule is complementary to its specific substrate

36
Q

what is the function of a substrate molecule?

A

substrate molecules fit into the active site creating the enzyme-substrate complex

37
Q

what can the structure and shape of all proteins be affected by?

A
  • temperature

- pH

38
Q

what are enzymes made of?

A

proteins

39
Q

in general what pH are most enzymes most active?

A

neutral pH ( pH 7 )

40
Q

draw a conclusion about the working range of different enzymes

A

Each enzyme has a different working range

41
Q

what will happen when pepsin on egg albumen cylinders is investigated?

A
  • pepsin will digest the insoluble egg protein
  • decrease in length of cylinders ( indicates the amount of digestion)
  • the greater the decrease in length of the cylinders, the more active the enzyme pepsin
42
Q

how do you work out percentage change?

A

difference ÷ original number x 100

43
Q

how does the change of pH in solutions relate to the activity of the enzyme used?

A
  • As the pH of the solution decreases enzyme activity increases.
  • can be observed as a greater percentage change in length
44
Q

what are the names of the substrate, enzyme and product(s) in the egg albumen investigation

A

substrate - egg albumen
enzyme - pepsin
product(s) - solid white albumen

45
Q

what happens to enzymes at higher pHs ( 6.7)?

A

the enzymes active site changes shape and is no longer complementary to its substrate so is not active

46
Q

what happens to enzymes at high temperatures?

A

enzymes can be denatured resulting in a change to their shape

47
Q

in the investigation of the effect of temperature on the activity of invertase, why was the sucrose and invertase adjusted to the correct temperature before being mixed?

A

so they would not start to react with each other before reaching the required temperature

48
Q

what can be done to make results more reliable?

A

class results can be compared and averages calculated to make it more reliable

49
Q

if the temperature denatured the enzyme but was brought back to a normal temperature.
what would happen to enzyme activity?

A

the rate would stay at 0% as the enzyme has denatured and the shape change is permanent

50
Q

what are the 2 types of enzyme reactions?

A
  • degradation reaction

- synthesis reaction

51
Q

what are examples of a degradation reaction?

A

hydrogen peroxide + catalyase = oxygen + water
surcrose + invertase = glucose + frucose
starch + amylase = maltose

52
Q

what is an example of a synthesis reaction?

A

glucose-1-phosphate + phosphorylase = starch

53
Q

what is a test for starch?

A 
benedicts reagent 
orange= sugar present 
brick red ( once heated) = maltose
54
Q

where does sugar come from?

A

broken down starch

55
Q

what are examples of proteins?

A
  • hormones
  • enzymes
  • antibodies
  • receptors
  • structural proteins ( HEARS )
56
Q

what is the active site?

A

location on the surface of the enzyme which matches the shape of the substance that it works on ( its substrate)

57
Q

around what temperature will it denature the enzyme?

A

45 or above

National 5 Biology (20 decks)

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