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A-Level Biology > Biological Molecules > Flashcards

Biological Molecules Flashcards

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1
Q

What are monosaccharides?

A

Simple sugars

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2
Q

What is an example of a monosaccharide?

A

Glucose

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3
Q

What is the general formula for monosaccharides?

A

Cn(H20)n

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4
Q

What is a disaccharide?

A

A sugar formed from two monosaccharides

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5
Q

How are disaccharides joined?

A

By a 1-4 glycosidic bond

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6
Q

What is lactose made from?

A

Glucose + galactose

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7
Q

What is sucrose made from?

A

Glucose + fructose

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8
Q

What is maltose made from?

A

Glucose + glucose

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9
Q

What is removed in a condensation reaction?

A

H2O

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10
Q

How do you test for non- reducing sugars?

A 
Reducing sugar test
If no colour change get fresh sample
Add 2cm3 of HCl
Place in water bath for 3mins
Add 1/2 spatula of sodium hydrogen carbonate to neutralise
Add Benedict's to hydrolysed sample
If now positive is a reducing sugar
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11
Q

Why is sucrose not a reducing sugar?

A

Cannot become linear so no free aldehyde group to react with

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12
Q

Why are most disaccharides reducing sugars?

A

Able to reduce oxidising agents

Ring opens to reveal aldehyde group

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13
Q

What are the reducing sugars?

A

Glucose
Fructose
Galactose

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14
Q

Which monomer is starch made from?

A

Alpha glucose

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15
Q

What is starch’s structure?

A

Chains branched + unbranched

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16
Q

What is the branched structure called in starch?

A

Amylopectin

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17
Q

What is the unbranched structure called in starch?

A

Amylase

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18
Q

Where is starch found?

A

Form of a small grain

Never in animals

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19
Q

What is starch’s function?

A

Energy store

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20
Q

What is starch’s structure related to its function?

A

Large so can’t diffuse out
Insoluble so doesn’t effect water potential
Compact so can be stored in small place]

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21
Q

What is good about starch having a branched structure?

A

Enzymes simultaneously act on it to produce glucose monomers rapidly

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22
Q

Which monomer is glycogen made from?

A

Alpha glucose

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23
Q

What is glycogen’s structure?

A

Similar to starch but shorter chains + highly branched

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24
Q

Where is glycogen found?

A

Animals + bacterial cells

Stored as small granules in muscles + liver

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25
What is glycogen's function?
Main carbohydrate storage product of animals
26
What is glycogen's structure related to its function?
Insoluble so won't effect water potential | Large so won't diffuse out
27
What is good about glycogen having a highly branched structure?
Enzymes act on it simultaneously so it is rapidly broken down into glucose
28
Which monomer is cellulose made from?
Beta glucose
29
What is cellulose's structure?
Straightened, unbranched chains | That run parallel to allow H bods to form cross links
30
Where is cellulose found?
Plant cell walls
31
What is cellulose's function?
Provides rigidity to the cell | Exerts inward pressure to stop cell from bursting
32
What is cellulose's structure related to its function?
Every 2nd beta glucose is rotated 180 degrees to create linear chain Cross linked by H to provide strength
33
How is the H bonds in cellulose grouped to provide strength?
Grouped to form microfibilis, which are grouped to form fibres
34
What are the lipids?
Triglycerides Phospholipids Cholesterol Steroids
35
What are the functions of lipids?
``` Waterproofing Substrate for respiration Store of energy Insulation Protection of organs Cell membranes Buoyancy + streamlining Hormones ```
36
What does hydrophobic mean?
Molecules that are not polar so do not dissolve/mix with water
37
What does hydrophilic mean?
Molecules that are polar so dissolve/mix with water
38
What does saturated mean?
A hydrocarbon chain that doesn't contain a double carbon bond
39
What does unsaturated mean?
A hydrocarbon chain that does contain a double carbon bond
40
What do double bonds do to a lipids structure and what does this mean?
It bends the structure so it cannot pack tightly together so is a liquid at room temperature
41
Are lipids soluble?
They aren't in water but are in organic solutions
42
What solutions are lipids soluble in?
Alcohol and acetone
43
What is the difference between fats and oils?
``` Fats= solids at room temperature Oils= liquids at room temperature ```
44
How do lipids arrange themselves in water?
Hydrophilic heads are at the surface of the water and hydrophobic tails are above the water
45
Why is a triglyceride a good energy store?
High ratio of energy storing C-H bonds to C atoms | Can store a large amount in small place
46
Why does the storage of a triglyceride not effect osmosis?
Because it is insoluble
47
Why does a triglyceride release water when oxidised?
High hydrogen to oxygen atoms ratio
48
How does a phospholipid structure allow them to form glycolipids?
By combining carbohydrates with cell surface membrane
49
What are glycolipids important for?
Cell recognition
50
What happens when a phospholipids are in aqueous environment?
Form a bi layer with cell-surface membranes so a hydrophobic barrier is formed between the inside + outside of cell
51
What do amino acids form?
Polymers that form polypeptide chains that form proteins
52
How many amino acids occur naturally?
20
53
What does that fact that the sane 20 amino acids occur i each organism prove?
Evolution
54
What is the structure of an amino acid?
``` 1 central carbon atom Amino acid group (NH2) Carboxyl group (COOH) Hydrogen atom R(side) group ```
55
What varies with each amino acid?
R group
56
How many different side chain is there?
20
57
What do side chains contain?
H, C and O atoms
58
What do some R groups contain?
Sulphur/nitrogen atoms
59
How are dipeptides formed?
Condensation reaction
60
What is removed during the formation of dipeptides?
H2O
61
What is the bond between the nitrogen and carbon in a dipeptide?
Peptide bond
62
What are the functions of proteins?
``` Enzymes eg amylase Structure eg. keratin Membrane transport Antibodies Hormones eg. insulin Receptors Cell recognition Mass transport eg. haemoglobin ```
63
What is the structure of a triglyceride?
Glycerol with 3 fatty acid chains joined with an ester bond
64
What is the structure of a phospholipid?
``` Hydrophobic tail Hydrophilic head One glycerol molecule 2 fatty acids Third fatty acid is a polar phosphate group Ester bond ```
65
What is a tertiary structure?
Secondary structure is folded more giving the protein a 3D shape, maintained by bonds
66
What is a quaternary structure?
Complex molecules containing many polypeptide chains and contain non-protein molecules
67
What is the function of haemoglobin?
Transport oxygen | Associate with oxygen at gas exchange and disociate at tissues
68
What is the structure of haemoglobin?
Quaternary- all 4 polypeptide chains linked to form a spherical group Each associated with a haem group
69
What is haemoglobin's structure related to its function?
Changes affinity for oxygne under different conditions Shape changes in presence of CO2 New shape binds more loosely to O2
70
Is haemoglobin globular or fibrous?
Globular
71
What is the function of collagen
Found in tendons which join to muscles | Muscles contract and bone is pulled in direction of contraction
72
What is the structure of collagen?
Quaternary- made up of 3 poltpeptide chains wound together in the same way
73
What is collagen's structure related to its function?
Individual polypeptide chains held together by crosslinks | Between amino acids of other chains
74
Is collagen globular or fibrous?
Fibrous

A-Level Biology (21 decks)

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