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Year 10 Biology > Biological Molecules > Flashcards

Biological Molecules Flashcards

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1
Q

What elements do carbohydrates, proteins and lipids all have?

A

Carbon, hydrogen and oxygen (protein also has nitrogen)

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2
Q

What are carbohydrates made of?

A

starch (mainly in plants) / glycogen (mainly in plants), which are made up of long chains of simple sugars

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3
Q

What are simple sugars?

A
  • e.g glucose
  • the chemical name for a simple sugar is a monosaccharide
  • when 2 simple sugars join together they form a disaccharide
  • when lots of simple sugars join together they form a polysaccharide
  • examples of polysaccharides are starch and cellulose and glycogen
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4
Q

What is the most common type of lipid found in the body?

A

Triacylglycerol
-made up of two different sub units called glycerin and fatty acids

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5
Q

Draw a diagram of a triaglycerol

A

Include: -glycerol, fatty acids

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6
Q

What are proteins?

A
  • made up of long chains of amino acids
  • there are 20 different types of amino acid and they can be joined together in different orders to make many different types of protein.
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7
Q

What is used to test for starch?

A

Iodine solution

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8
Q

What is a positive/negative result of starch by iodine solution

A

Positive result: blue/black colour
Negative result: orange/ yellow colour-doesn’t change

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9
Q

What is used to test for glucose?

A

Benedictus solution-must be heated to above 80°C

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10
Q

What is a positive/negative result of glucose by Benedicts solution?

A

Negative: pale blue
Small amount of glucose: green/yellow
Large amount of glucose: orange/red

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11
Q

Name things containing starch in the experiment

A

Bread, starch

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12
Q

Name the things (objects)used to test for glucose

A

Glucose (p), biscuits(p), egg white (n),rice(n)

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13
Q

Name the things (objects)used to test for fat

A

Crisps (p), lipid (p)

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14
Q

Name the things (objects)used to test for protein

A

Rice (n), tuna (p), albumen (p)

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15
Q

What is used to test for lipids

A

Ethanol

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16
Q

Briefly explain the practical for the test of starch

A
  • place food on dropping tile
  • drop iodine solution onto food
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17
Q

Briefly explain the practical for the test of glucose

A
  • add the food to a test tube
  • add the benedicts solution
  • put in a water bath at 85°C and leave for 5-10 mins
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18
Q

Briefly explain the practical for the test of protein

A
  • add the food to a test tube
  • add a few drops of the biuret’s solution
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19
Q

Briefly explain the practical for the test of lipids

A
  • add food to a test tube
  • add a few drops of ethanol, put a bung on top and shake
  • pour solution into a test tube containing water
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20
Q

What is a positive/ negative result for the test of protein with biurets solution

A

Negative: blue
Positive: purple/blue

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21
Q

What is a positive/negative result for the test of fats by ethanol

A

Positive: white emulsion forms
Negative: no white emulsion forms

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22
Q

What are enzymes?

A
  • enzymes are biological catalysts
  • they speed up chemical reactions in cells
  • without enzymes, the reactions in cells would be too slow to support life
  • some enzymes catalyse synthetic reactions (where large molecules are built-up from small molecules) e.g making glycogen from glucose (glucose synthase)
  • other enzymes catalyse the breakdown reactions (splitting large molecules into smaller ones). E.g making glucose from glycogen (glycogen phosphorylase)
  • enzymes are proteins: they are made up of long chains of amino acids which are folded into a specific shape
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23
Q

What is the lock and key hypothesis?

A
  • it suggests that the substrate fits into an enzyme molecule like a key fits into a lock
  • the active site of the enzyme fits onto ( complimentary shape) to the substrate
  • the enzyme weakens the bonds in the substrate, causing it to split and form the products
  • the products of the reaction are released at the end, leaving the enzyme free to be used again
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24
Q

What is a metabolic reaction?

A

The breaking down of a compound

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25
Q

What are the properties of enzymes?

A
  • they work very rapidly
  • only needed in small amounts
  • they are specific: will only catalyse one reaction
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26
Q

What is an optimum temperature (enzymes)?

A

-the temperature at which the rate of reaction of an enzyme-controlled reaction is fastest at

27
Q

Why is the rate of reaction of an enzyme slow at low temperatures?

A
  • the enzyme and substrate move slowly due to low kinetic energy
  • this means there are less collisions per second, so they hook onto each other less often, so less enzyme-substrate complexes form
28
Q

Why does the rate of reaction of enzymes increase as temperature increases?

A

The rate increases as the temperature gets closer to the optimum temperature of the enzyme

29
Q

What happens to rate of reaction of enzymes at high temperatures and why?

A
  • at temperatures above the optimum temperature, enzymes become denatured as their active site denatures and no longer fits onto the substrate
  • this means less enzyme-substrate complexes can form.
  • denatured means the enzyme is irreversibly damaged
30
Q

What is optimum pH?

A
  • the certain pH needed by enzymes for them to work efficiently
  • some enzymes work best in acidic conditions, other in alkaline conditions
  • pH conditions which are too different from the optimum pH of the enzyme can change the enzyme’s active site shape
31
Q

What are the different enzymes?

A

Amylase (pancreatic and salivary), Maltase, protease, lipase

32
Q

What is the site of production and action of salivary Amylase?

A

Produced in salivary glands, works in mouth

33
Q

What is the site of production and action of pancreatic amylase?

A

Produced by pancreas, works in small intestine

34
Q

What is the optimum pH of salivary amylase?

A

8

35
Q

What is the optimum pH of pancreatic amylase?

A

7

36
Q

What is the substrate of amylase?

A

Starch

37
Q

What is the product of amylase?

A

Sugars (maltose)

38
Q

What is the site of production and action of maltase?

A

Made in small intestine, works in small intestine

39
Q

What is the substrate of maltase?

A

Maltose

40
Q

What is the product of maltase?

A

Glucose

41
Q

Where are sites of production and action of protease?

A

Made by cells in stomach wall-works in stomach
Made by pancreas-works in small intestine
Made in small intestine wall-works in small intestine

42
Q

What is the optimum pH of protease made in cells in stomach wall?

A

2 (hydrochloric acid produced by the stomach acidifies food)

43
Q

What is the optimum pH of protease made in the pancreas and small intestine wall?

A

8 (bile from liver neutralises the acid food leaving the stomach)

44
Q

What is the substrate of protease?

A

Protein

45
Q

What is the product of protease?

A

Amino acids

46
Q

What is the site of production and action of lipase?

A

Made in pancreas and cells in the small intestine wall, works in small intestine

47
Q

What is the optimum pH of lipase?

A

8

48
Q

What is the substrate of lipase?

A

Lipids

49
Q

What are the products of lipase?

A

Fatty acids and glycerol

50
Q

Where is bike stored?

A

Gall bladder (made by liver)

51
Q

What is the function of bile?

A

Neutralises acidic food after being in the stomach and emulsified fats for faster rate of reaction with enzymes

52
Q

Explain the practical investigating affect of temperature on rate of reaction of enzymes

A
  • developed black-and-white negative film consist of a celluloid backing covered with a layer of gelatin
  • where the film has been exposed the gelatin layer consists of tiny particles of silver which make that area black
  • gelatine is a protein and is easily digested by proteases (tripsin is used)
  • strips of exposed film are soaked in protease solution at different temperatures
  • where the gelatin has been digested, the silver grains fall away from the celluloid backing, leaving transparent film
53
Q

Why does pH have an effect of enzyme activity?

A
  • Changing the pH will change the shape of the active site of an enzyme.
  • Many amino acids in an enzyme molecule carry a charge.
  • Within the enzyme molecule, positively and negatively charged amino acids will attract.
  • This contributes to the folding of the enzyme molecule, its shape, and the shape of the active site.
  • Changing the pH will affect the charges on the amino acid molecules. Amino acids that attracted each other may no longer. Again, the shape of the enzyme, along with its active site, will change.
  • Extremes of pH also denature enzymes.
54
Q

Describe the practical used to see the effect of pH on the enzyme pepsin

A
  • pepsin is found in the stomach, it is a type of protease
  • egg whites contains protein and when pepsin breaks it down into amino acid it turns from cloudy into a clear solution
  • therefore we can tell that pepsin is working and breaking down if we see a colourless solution produced
  • in this experiment acidic, neutral or alkaline conditions are set up to find out the best, optimum conditions for the enzyme pepsin
55
Q

At what pH does pepsin work best at?

A

3-acidic

56
Q

What is three errors that may occur in the experiment showijg effect of pH on enzyme activity

A
  • uneven amounts of egg whites added to tubes
  • not taking the sample at exactly 10mins
  • adding too much/little of the acid/alkali
57
Q

At what temperature do the strips of exposed film clear fastest?

A

30 degrees

58
Q

Why does a cloudy layer form in ethanol when lipids are present?

A
  • lipids dissolve in ethanol, not water
  • when the lipid is dissolved in the ethanol, then added to water, a cloudy layer forms on top of the water because the lipid solution floats
59
Q

What two chemicals are found in biuret’s reagent?

A

Copper sulphate and sodium hydroxide

60
Q

What do proteins contain in addition to carbon, hydrogen and oxygen?

A

nitrogen, and sometimes sulfur.

61
Q

What is a nutrient?

A

A nutrient is a substance which is needed for growth, repair and metabolism. The main three are carbohydrates, proteins and lipids

62
Q

What is metabolism?

A

All the chemical reactions in the cells of an organism, including respiration.

63
Q

What are starch and glycogen made up of?

A

Simple sugars

Year 10 Biology (6 decks)

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