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Biology > Biological molecules > Flashcards

Biological molecules Flashcards

1
Q

What are the main elements found in carbohydrates?

A

Carbon

Hydrogen

Oxygen

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2
Q

What is a monomer?

A

Individual molecules that make up a chain

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3
Q

What is a polymer?

A

A long molecule made up of repeating smaller molecules, monomers, joined up together

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4
Q

What is the name for a sugar monomer?

A

Saccharide or monosaccharide

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5
Q

What is the name for 2 monosaccharides joined together?

A

Disaccharide

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6
Q

What is the name for many saccharides joined together?

A

Polysaccharide

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7
Q

What is the difference between alpha and beta glucose?

A

Alpha - hydroxyl group above

Beta- hydroxyl group below

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8
Q

What is the test for reducing sugars?

A

Blue Benedict’s solution turns brick red on heating

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9
Q

What is a condensation reaction?

A

When monomers are joined together

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10
Q

What is always made during a condensation reaction?

A

Water

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11
Q

what type of reaction breaks down polymers into their monomers?

A

Hydrolysis

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12
Q

Name 2 polysaccharides that make up starch

A

Amylose

Amylopectin

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13
Q

What type of glucose makes starch?

A

Alpha

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14
Q

Describe the shape of amylose molecules

A

Unbranched alpha glucose chain

Coiled

Compact

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15
Q

Describe the shape of amylopectin molecules

A

Long branched alpha glucose

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16
Q

Explain which molecule, amylose or amylopectin, can be broken down quickly to release glucose

A

Amylopectin, because its side branches let enzymes get to the glycosidic bonds quickly

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17
Q

Why is it useful for starch to be insoluble in water?

A

Does not cause water to enter cells by osmosis - so can be used for storage without cells swelling up with water. It doesn’t affect the water potential.

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18
Q

What type of glucose makes glycogen?

A

Alpha

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19
Q

Describe the shape of glycogen molecules

A

Long

Very branched alpha glucose

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20
Q

What makes glycogen a good storage molecule?

A

Lots of branches so glucose can be released off it quickly

Very compact

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21
Q

What type of glucose makes up cellulose?

A

Beta

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22
Q

Describe the structure of cellulose

A

Long unbranched chains

Linked together by hydrogen bonds

To make strong microfibrils

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23
Q

What is the test for starch?

A

Brown iodine solution turns blue/black

Iodine solution is dissolved in potassium iodide solution

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24
Q

What are the 3 elements in lipids?

A

Carbon

Hydrogen

Oxygen

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25
Q

Are lipids soluble in water?

A

No

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26
Q

What do lipids dissolve in?

A

Alcohol/ acetone

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27
Q

What is the difference between an oil and a fat?

A

Fats are solid at room temperature

Oils are liquid at room temperature

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28
Q

What is a triglyceride?

A

3 fatty acids linked to 1 glycerol

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29
Q

What type of reaction joins the fatty acid to glycerol?

A

Condensation

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30
Q

What type of reaction would separate the fatty acid from glycerol?

A

Hydrolysis

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31
Q

What enzyme hydrolyses lipids?

A

Lipase

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32
Q

What is a saturated fatty acid?

A

Single C-C bonds only

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33
Q

What is an unsaturated fatty acid?

A

Double C=C bonds

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34
Q

How do unsaturated bonds affect the structure of lipids?

A

Make the molecules bend

So cannot pack closely together

So are solids at room temperature

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35
Q

What are the products when glycerol reacts with 3 fatty acids?

A

Triglyceride + 3 water molecules

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36
Q

What type of bond is formed when a fatty acid if joined with glycerol?

37
Q

Draw an ester bond

38
Q

Draw a triglyceride

A 
G
L - fatty acid
Y
C - fatty acid
E
R - fatty acid
O
L
39
Q

What are the 2 main properties of lipids?

A

Energy store

Insoluble in water

40
Q

Why are lipids a good energy store?

A

Long fatty acid chains contain lots of stored chemical energy

41
Q

What are the 5 main uses of lipids?

A

Plasma membranes

Waterproofing

Insulation

Energy source

Protection

42
Q

Give an example where lipids are used as waterproofing

A

Waxy cuticle of plants and insects

43
Q

What is a phospholipid?

A

Triglyceride where 1 fatty acid is replaced by 1 phosphate group

44
Q

What are the 2 main parts of a phospholipid?

A

Hydrophilic phosphate head

Hydrophobic fatty acid tail

45
Q

How do phospholipids position themselves in water?

A

Hydrophilic head close to water

Hydrophobic tail far away from water

46
Q

Where are phospholipids found in cells?

A

Cell membranes - phospholipid bilayer

47
Q

What is the test for lipids?

A
  1. Shake sample with ethanol for about a minute
  2. Then add water and shake
  3. Cloudy precipitate = lipid present
48
Q

What are the 4 groups attached around the central carbon of an amino acid?

A

NH2 (amino group)

COOH (carboxylic acid group)

H (hydrogen)

R (variable group)

49
Q

What monomer makes up a protein?

A

Amino acid

50
Q

What is the name of the polymer made of lots of amino acids joined together?

A

Polypeptide

51
Q

What is the name of the chemical bond joining amino acids together?

A

Peptide bond

52
Q

What reaction joins amino acids together?

A

Condensation

53
Q

What are the products when 2 amino acids join together?

A

Dipeptide and water

54
Q

What is the name of the enzyme that breaks down polypeptides?

55
Q

What reaction breaks down polypeptides?

A

Hydrolysis

56
Q

What is a polymerisation reaction?

A

When lots of monomers are joined together

57
Q

What is the primary structure of a protein?

A

Order and sequence of the different amino acids

58
Q

Why is the primary structure important?

A

Determines the shape of the protein and will affect its function

59
Q

What bonds are found in the primary protein structure?

60
Q

What is the secondary structure of proteins?

A

Alpha helix

Beta pleating

61
Q

What bonds cause the secondary structure of a protein?

A

Hydrogen bonds between C=O and N-H

62
Q

What is the tertiary structure of a protein?

A

Twisted and folded 3D shape of protein

63
Q

What bonds cause the tertiary structure of a protein?

A

Disulphide bonds - strong bonds

Ionic bonds - weaker

Hydrogen bonds - easily broken

64
Q

What is the quaternary structure of proteins?

A

Number of polypeptide chains that make up the protein

65
Q

What is the chemical test for proteins?

A

Biuret test

Alkaline solution of very dilute copper sulphate solution

Pale blue solution turns purple

66
Q

What is the function of fibrous proteins?

67
Q

Give examples of fibrous proteins

A

Collagen

Keratin

68
Q

What is a globular protein?

A

Carry out metabolic functions

69
Q

Give examples of globular proteins

A

Enzymes

Hormones

Haemoglobin

70
Q

What is a catalyst?

A

Speeds up rate of chemical reaction without being used up

71
Q

What is an enzyme?

A

Biological catalyst

72
Q

What are enzymes made from?

73
Q

How do enzymes change the rate of reaction?

A

Lower activation energy needed

74
Q

What 3 things have to happen for a chemical reaction to take place?

A

Particles collide

with enough energy

correct orientation

75
Q

How do enzymes change the rate of reaction?

A

Lower activation energy

76
Q

What is the substrate?

A

Substance/ reactant that fits into the active site

77
Q

What is formed when the substrate fits into the active site?

A

Enzyme-substrate complex

78
Q

How does the enzyme substrate complex lower the activation energy?

A

When joining 2 molecules - holds them close together to reduce repulsion

When splitting molecules - strains the bonds to break up more easily

79
Q

In the lock and key model, what is the lock?

A

Enzyme (active site)

80
Q

In the lock and key model, what is the key?

81
Q

What is the induced fit model?

A

Substrate makes the active site change shape slightly;y to fit in to it

82
Q

Does the substrate have the same shape as the active site?

A

No - complementary shape

83
Q

What determines the shape of the active site?

A

Tertiary structure of protein

84
Q

How can the tertiary structure of an enzyme be changed?

A

Change in temperature

Change in pH

Primary structure of protein changes

85
Q

What are the 2 ways to measure the rate of reaction?

A

How fast product is made

How substrate is broken down/used up

86
Q

Why does the rate of an enzyme reaction slow down and stop above a certain temperature?

A

Enzyme molecules vibrate more

Vibration breaks some of the bonds holding the enzyme together

Enzyme loses shape

Active site changes shape

Substrate no longer fits into active site

Enzyme DENATURES

87
Q

Why does increasing the substrate concentration increase the rate of reaction?

A

More substrate molecules so more chance of collisions

88
Q

Why does the rate of reaction stay the same at saturation point?

A

All the active sites of all the enzymes are full with substrate

Biology (19 decks)

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