Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

A-level Biology > Chapter 1 Biological Molecules > Flashcards

Chapter 1 Biological Molecules Flashcards

1
Q

Define a monomer

A

Smaller units which can create larger molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define a polymer

A

Made from lots of monomers bonded together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Examples of monomers

A

Glucose
Amino acid
Nucleotide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Examples of polymers

A

Starch
Cellulose
Glycogen
Protein
DNA
RNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What do carbohydrates contain

A

C
H
O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the 3 types of carbohydrates

A

Monosaccharides (monomers)

Disaccharides (diners)

Polysaccharides (polymers)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are 3 examples of monosaccharides

A

Glucose
Fructose
Galactose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are 3 examples of disaccharides

A

Sucrose
Maltose
Lactose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are 3 examples of polysaccharides

A

Starch
Cellulose
Glycogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Define isomer

A

Same molecular formula but different structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What’s the molecular formula of glucose

A

C6H12O6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are disaccharides made of

A

2 monosaccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the Bond in disaccharides

A

Glycosidic bond joining 2 monosaccharides together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Disaccharides are formed via which reaction

A

Condensation recation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the 3 disaccharides word equations

A

Glucose + glucose —> maltose + water

Glucose + galactose —> lactose + water

Glucose + fructose —> sucrose + water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Define a condensation reaction

A

Joining 2 molecules together by removing water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Define a hydrolysis reaction

A

Splitting apart molecules through addition of water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How are polysaccharides formed

A

Created by condensation reactions between many glucose monomers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Where is starch found

A

Plant cells (e.g. in chloroplast)

(Can be found in starch grains inside plant cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Where is cellulose found

A

Plants - cell wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Where is glycogen found

A

In animals - mainly in muscle and liver cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the function of starch

A

insoluble store of glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the function of cellulose

A

Provide Structural strength for cell wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the function of glycogen

A

Insoluble Store of glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are the monomers in starch

A

Alpha glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are the monomers in cellulose

A

Beta glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are the Monomers in glycogen

A

Alpha glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the bond between monomers in starch

A

1-4 glycosidic bonds in amylose

1-4 & 1-6 in amylopectin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the bond between monomers in cellulose

A

1-4 glycosidic bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the bond between monomers in glycogen

A

1-4 & 1-6 glycosidic bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is the structure of starch

A

Made of 2 polymers

Amylose - unbranched helix

Amylopectin - branched molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is the structure of cellulose

A

Polymer forms long, straight chains.

Chains held parallel by many hydrogen bonds to form fibrils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is the structure of glycogen

A

Highly branched molecule

1-6 glycosidic bond creates branch, even more 1-6 glycosidic bonds branch of this branch to create highly branched polymer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Explain how structure leads to function in starch

A

Helix shape of amylose compact to fit lots of glucose in small space.

Amylopectin branched structure - multiple exposed ends of molecule, increases SA - rapid hydrolysis back to glucose.

insoluble - wont affect water potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Explain how structure leads to function in cellulose

A

Many hydrogen bonds - collective strength (HBs weak individually but collectively strong)

Insoluble - wont affect water potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Explain how structure leads to function In glycogen

A

Branched - increases SA for rapid hydrolysis back to glucose

Insoluble - wont affect water potential

compact easily, store lots of glucose in small space - advantage = animals need to move, movement requires energy, glucose needed in respiration to release that energy, so animals have more branched store of glucose compared to plants.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is a triglyceride made up of

A

1 glycerol
3 fatty acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is a phospholipid made up of

A

1 glycerol
2 fatty acids
1 phosphate group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

How are triglycerides formed

A

3 condensation reaction between 1 glycerol and 3 fatty acids

Produces 3H2O as bi products

Forms 3 ester bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What is an R group in a triglyceride

A

Fatty acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Define a saturated fatty acid

A

The hydrocarbon chain has only single bonds between carbons

42
Q

Define an unsaturated fatty acid

A

The hydrocarbon chain consists of at least 1 double bond between carbons

43
Q

What are the properties of triglycerides

A

1) energy storage; large ratio of energy-storing C-HBs:number of Carbons, a lot of energy stored in molecule

2)high ratio of H:O atoms, act as metabolic H2O source. Can release H2O if oxidised. essential for desert animals , e.g. camels

3) don’t affect water potential + osmosis; they’re large + hydrophobic - insoluble to H2O.

4) relatively low mass, therefore a lot can be stored without increasing mass + preventing movement.

44
Q

Emulsion test for lipids

A

Dissolve sample in ethanol
Add distilled water
White emulsion appears

45
Q

How are phospholipids formed

A

2 fatty acids bond to glycerol via 2 condensation reactions

Form 2 ester bonds

46
Q

What are the properties of a phospholipid

A

Hydrophilic head - attract water its charged - phosphate group charged, repels other fats.

Hydrophobic tail - Fatty acid chains not charged, repel water, mix with fats.

47
Q

Properties of phospholipids (bilayer)

A

2 charged regions, they’re polar.

In H2O, positioned so heads exposed to water and tails aren’t.

Forms phospholipid bilayer membrane, which makes up plasma membrane around cells.

48
Q

How many different types of amino acids are there

A

20 different amino acids

49
Q

What are proteins made up of

A

Amino acids

50
Q

Describe how the amino acids are joined together to form a dipeptide

A

Via condensation reaction

H2O removed

Peptide bond forms between OH of carboxyl and H of amine group

51
Q

What is the name of bond in proteins

A

Peptide bond

52
Q

What are proteins

A

Polymers made up of monomer amino acids

53
Q

How are the 4 structures of a protein

A

Primary

Secondary

Tertiary

Quaternary

54
Q

Describe primary structure of a protein

A

The order (sequence) of amino acids in polypeptide chain - this is a polymer

55
Q

What are the 2 types of secondary protein structure

A

Alpha-helix

B-pleated sheet

56
Q

Describe the secondary protein structure

A

sequence of amino acids causes parts of protein molecule to bend into a-helix shapes or fold into B-pleated sheets

HBs hold secondary structure

57
Q

Where are the HBs located in the secondary structure of a protein

A

HBs form between the C=O groups of carboxyl group of 1 amino acids and H in amine group of another amino acid

58
Q

Describe tertiary structure of protein

A

Further folding of secondary structure

form unique 3d shape

Held in place by ionic, hydrogen and disulphide bonds

59
Q

Describe location of bonds in tertiary structure of protein

A

Ionic & disulphide bonds form between R groups of diff AAs.

Disulphide bonds only sometimes occur, as there must be sulfur in R groups for this bond to occur.
(S- - -S)

60
Q

Describe quaternary structure of protein

A

protein made up of more than one polypeptide chain

E.g. haemoglobin is made of 4 polypeptide chains

61
Q

What happens to the protein structure when a protein is denatured

A

Protein denatured

bonds holding tertiary & secondary structure in shape break (ionic and hydrogen bonds break)

Unique 3d shape lost
(e.g. enzymes lose their unique active site shape)

62
Q

Conditions that denature protein

A

Too high temp (too much kinetic energy)

Too high/low pH (too many H+ or -OH)

63
Q

Describe the importance of primary structure

A

AA in sequence is diff then it cause ionic/hydrogen/disulfide bonds to form in diff location

results in diff 3d shape

64
Q

impact of change in protein structure on enzymes

A

have a diff shaped active site (will be non-functioning)

Carrier proteins will have diff shaped binding site (molecules no longer complementary and cannot be transported across membranes)

65
Q

What might cause a change in AA sequence

A

Mutations

If there’s a change in DNA sequence, it might then code for diff AA & therefore primary structure changes

66
Q

Test for starch

A

Add iodine

orange —> blue/black

67
Q

Test for reducing sugar

A

Add Benedict’s reagent + heat

blue —> green, yellow, orange or brick red

(more red, higher conc of reducing sugar)

68
Q

Why does the colour change occur at the top of the solution first in the reducing sugar test?

A

Convection currents

Hotter particles in solution rising

hottest point in solution at top

molecules have most kinetic energy, more successful collisions + faster reaction rate

So colour change 1st occurs at the top

69
Q

Test for non-reducing sugars

A

Following neg Benedict’s test (reagent remains blue)

Add acid + boil (acid hydrolysis)

Cool solution + then add alkali to neutralise

Add Benedict’s reagent + heat

blue —> green, yellow, orange or brick red

70
Q

What are 3 types of carbohydrates

A

Starch

Reducing sugars

Non-reducing sugars

71
Q

Examples of reducing sugars

A

Glucose

Fructose

Galactose

Lactose

Maltose

72
Q

Example of non-reducing sugar

A

Sucrose

73
Q

What are reducing sugars

A

Sugars that can reduce copper sulphate (blue) in Benedict’s reagent to copper oxide (brick red)

74
Q

What are non-reducing sugars

A

Reducing group involved in glycosidic bond in sucrose, and therefore sucrose cannot reduce copper sulphate to copper oxide

75
Q

What happens to sucrose when its hydrolysed

A

When sucrose hydrolysed (boiling with acid)

Glycosidic bond is broken so reducing group becomes exposed

Pos results achieved with Benedict’s reagent following hydrolysis

76
Q

Test for proteins

A

Add Biuret

blue —> purple

77
Q

What are enzymes

A

Tertiary structure proteins

Catalyse reactions

78
Q

What part of enzyme attaches to substrate

A

Enzymes are large molecules

Only small part of enzyme attaches to substrate to catalyse reaction

known as ‘active site’

79
Q

Why can enzymes only attach to substrates that are complementary in shape

A

Active site is specific & unique in shape due to specific folding and bonding in tertiary structure of protein.

80
Q

What are the 2 models of enzyme action

A

Lock & key model

Induced fit model

81
Q

Define activation energy

A

All reactions require certain amount of energy before they occur

82
Q

How do enzymes speed up a reaction

A

Enzymes attach to substrate

Can lower activation energy needed for reaction to occur

so speed up reaction

83
Q

Describe the lock and key model

A

Enzyme = lock and substrate = key that fits into it due to being complementary in shape

Model suggests : active site is fixed shape + due to random collisions substrate can collide & attach to enzyme - forms an enzyme-substrate complex (E-SC)

When E-SC formed, charged groups in active site are thought to distort the substrate & so lower Ea

Products then released & active site is empty and ready to be reused

84
Q

Describe induced fit model (accepted model for how enzymes function)

A

Enzyme = glove and substrate = hand

Empty glove isn’t exactly complementary in shape to a hand, but when hand enters it enables glove to mould around hand and become completely complementary.

Induced fit is where active site’s induced/slightly changes shape to mould around substrate.

When E-SC occurs, due to enzyme moulding around substrate - puts strain on bonds + so lowers Ea. Products are then removed, active sire returns to original shape.

85
Q

Factors that affect rate of enzyme controlled reactions

A

Temp

pH

Substrate conc

Enzyme conc

Inhibitors

86
Q

Temp affect on enzymes

A

Temp too low, not enough Ek for successful collisions between enzymes and substrate

Temp too high, enzymes denature, active site changes shape, E-SC cannot form

87
Q

pH effect on enzymes

A

Too high/too low pH, it’ll interfere with charges in AAs in active site.

This can break bonds holding tertiary structure in place & so active site changes shape.

So enzyme denatures & fewer E-SC form

Diff enzymes have a diff optimal pH

88
Q

Substrate & enzyme conc effect on enzymes

A

Insufficient substrate, reaction will be slower as there’ll be fewer collisions between enzymes & substrate.

Insufficient enzymes, active site will become saturated with substrate & unable to work any faster.

89
Q

Competitive inhibitor

A

Same shape as substrate & bind to active site,

prevents substrate binding & reaction occurring.

add more substrate it will out-compete inhibitor, knocking them out of active site.

90
Q

Non-competitive inhibitors

A

Bind to enzyme away from active site, allosteric site

causes active site change shape, substrate no longer bind, regardless of how much substrate added.

91
Q

Describe structure and function of globular proteins

A

Spherical & compact

Hydrophilic R groups face outwards & hydrophobic
R groups face inwards = usually water-soluble

Involved in metabolic processes e.g. enzymes & haemoglobin.

92
Q

Describe the structure and function of fibrous proteins.

A

Can form long chains or fibres

insoluble in water

Useful for structure and support e.g. collagen in skin.

93
Q

Outline how chromatography could be used to identify the amino acids in a mixture.

A

Use capillary tube to spot mixture onto pencil origin line & place chromatography paper in solvent.

Allow solvent to run until it almost touches other end of paper. Amino acids move different distances based on relative attraction to paper & solubility in solvent.

Use revealing agent or UV light to see spots.

Calculate R, values & match to database.

94
Q

Contrast competitive and non-competitive inhibitors.

A

Competitive inhibitors
- similar shape to substrate = bind to active site
- don’t stop reaction; E-SC forms when inhibitor is released
- increasing substrate conc decreases their effect

Non-competitive inhibitor
- bind at allosteric binding site
- may permanently stop reaction; triggers active site to change shape
- increasing substrate conc has no impact on their effect

95
Q

Outline how to calculate rate of reaction from a graph.

A

gradient of line or tangent to a point.

initial rate: draw tangent at t = 0.

96
Q

Outline how to calculate reaction rate from raw data

A

Change in conc of product or reactant/time

97
Q

Why is it advantageous to calculate initial rate?

A

Represents maximum rate of reaction before concentration of reactants decreases & ‘end product inhibition’.

98
Q

Similarities of phospholipids and triglycerides.

A

Both have:

glycerol backbone

may be attached to mixture of saturated, monounsaturated & polyunsaturated fatty acids

contain elements C, Н, О

formed by condensation reactions

99
Q

Contrast phospholipids and triglycerides.

A

Phospholipids
- 2 fatty acids & 1 phosphate group attached
- Hydrophilic head & hydrophobic tail
- Used primarily in membrane formation

triglycerides:
- 3 fatty acids attached
- Entire molecule is hydrophobic
- Used primarily as a storage molecule (oxidation releases energy)

100
Q

Are phospholipids and triglycerides polymers?

A

No; they are not made from a small repeating unit. They are macromolecules.

A-level Biology (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions