Brainscape's Knowledge GenomeTM

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


See full index

Biology Alevel > Biological Molecules( Biological Molecules ) > Flashcards

Biological Molecules( Biological Molecules ) Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What are the four elements amino acids are made up from

A

Carbon , hydrogen ,oxygen and nitrogen

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

What do amino acids often contain (2 elements )

A

Sulphur and phosphorus

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

What test detects proteins

A

Buiret test detects the prescience of peptide bonds .

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

What is a dipeptide

A

Two amino acids

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

How are dipeptides created

A

Condensation of two amino acids forms a dipeptide bond held by a peptide bond

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

What happens when a dipeptide is created

A

The peptide bond is formed between the CH (carboxyl) group on first amino acid and amino group on second amino acid which also releases water

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

What is the name for the reaction breaking the disaccharide

A

Hydrolysis reaction splits apart the disaccharide leaving 2 monosaccharides

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

What is polymerisation (amino acids)

A

Dipeptides can become polypeptides in repeated condensation reactions

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

Example peptide bond question : if you have 383 amino acids , how many peptide bonds do you have?

A
  1. (-1 as 3 amino acids only has 2 peptide bonds )
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does the primary structure of a protein determine

A

It’s shape and function

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

What is the primary structure protein

A

It’s a chain of amino acids joined in condensation reactions by peptide bonds , creating a specific sequence of amino acids . Which therefore dictates its bonds and therefore structure and function

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

What is the secondary structure protein

A

Either alpha helix or beta pelted sheet , hydrogen bonds form which causes the long polypeptide chain to be twisted into a 3D shape.

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

What is the tertiary structure of proteins

A

Can be twisted and folded into more complex 3D shapes which is maintained by a number of different bonds

Hydrogen bonds -between amino and carboxyl to maintain shape
But easily broken
Ionic bonds -are easily broken by changes in ph . Polar interactions of the R groups maintain shape
Disulphide bridges -fairly strong not easily broken .

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

Why is the 3D shape of a protein so important

A

It makes each protein distinctive and allows it to recognise and be recognised by other molecules , it can then interact with them in a very specific way.

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

What is the quaternary structure

A

Quaternary protein structures are made of 2 or more tertiary proteins joined together by all the same bonding as tertiary

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

How is haemoglobin a quaternary structure

A

Haemoglobin consists of 4 tertiary structures bonded together with iron in the middle

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

what is the structural formula for glucose

A

CH2OH (C6H12O6)
c o
c h oh h c h oh
h c c c
ho h oh

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

describe how hydrolysis works with a disaccharide?

A

when water is added to a disaccharide under suitable conditions it breaks the glycocidic bond releasing the monosaccharides.

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

what is a monosaccharide

A

a simple sugar molecule( one unit of carbohydrate)

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

what elements do all carbohydrates contain?

A

all carbohydrates contain only carbon , hydrogen and oxygen

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

give 3 examples of monosaccharides

A

glucose , galactose , fructose

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

are monocaccharides soluble or insoluble

A

soluble

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

what is the general formula of a monosaccharide

A

(Ch20)n

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

what do monosaccharides end in

A

‘ose’

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

what is hexose

A

hexose is a sugar which contains 6 carbon atoms glucose is an example of a hexose

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

in alpha glucose the OH on carbon 1 is on the bottom how is it in beta glucose?

A

it is flipped so the OH (carboxyl) group is above

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

how do disaccharides form?

A

through condensation reactions which water is removed and a glycocidic bond is formed between c1 and c4

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

examples of disaccharides

glucose + glucose =

A

maltose (malt sugar) 2 glucose molecules joined by an alpha 1-4 glycocidic bond

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

glucose + fructose =

A

sucrose . joined by an alpha 1-4 glycocidic bond

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

galactose + glucose =

A

lactose (milk sugar) . joined by a 1-4 glycocidic bond

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

what are the 2 main functions of monosaccharides

A

they are used as a primary energy source for fuelling metabolism and joining together to form ccarbohydrate macromolecules

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

what are isomers

A

isomers are compounds with the same chemical formula but different arrangements of atoms so have different properties. for example glucose - alpha and glucose -b are both c6h12o6 but the oh and h are flipped round

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

give 3 examples of polysaccharides and state if they are in plant or animals

A

starch (plant) , glycogen (animal) and cellulose(plant)

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

why are polysaccarides insoluble

A

because they are very large molecules

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

what are the two types of starch

A

amylose and amylopectin

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

describe amylose

A

amylose is unbranched and monomers are connected by an alpha 1-4 glycocidic bond and is wound into a tight coil which makes it compact

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

describe amylopectin

A

amylopectin is branched with 1-4 and 1-6 bonds

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

describe glycogen

A

glycogen is branched 1-4 bonds and 1-6 bonds it is insoluble , compact .

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What are the two types of proteins and what they have and an example

A

Fibrous have structural functions eg collagen and globular have metabolic functions eg enzymes and haemoglobin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Describe fibrous proteins

A

Fibrous proteins form long chains which run parallel to one another . These chains are linked by cross bridges and so form very stable molecules.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Why are fibrous proteins generally insoluble in water

A

Fibrous proteins have a large proportion of amino acids with hydrophobic r groups , this means unlike globular proteins , fibrous proteins are insoluble in water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What is the shape of fibrous proteins

A

Long and narrow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What is the shape of globular proteins

A

Round / spherical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What is the acid sequence of fibrous proteins

A

Repetitive amino acid sequence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What is the acid sequence of globular proteins

A

Irregular amino acid sequence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

How durable are fibrous proteins

A

They are less sensitive to changes in PH, TEMP etc than globular

49
Q

How durable are globular proteins

A

More sensitive to changes in PH , temp etc than fibrous

50
Q

Give 6 examples of fibrous proteins

A

Collagen , myosin , fibrin , actin , keratin , elastin

51
Q

Give 4 examples of globular proteins

A

Enzymes , haemoglobin , insulin , immunoglobulin

52
Q

Are globular proteins soluble or insoluble in water

A

Generally soluble in water

53
Q

What are enzymes structure

A

A chain of amino acids in a globular tertiary structure

54
Q

How do enzymes speed up a reaction

A

Reduces the activation energy

55
Q

What is the word for bond breakage

A

Catabolic

56
Q

What is the word for bond formation

A

Anabolic

57
Q

What is the word for inside cell reactions

A

Intracellular

58
Q

What is the word for outside cell reactions ( eg tissue fluid , blood )

A

Extracellular

59
Q

What is the induced fit theory

A

Active site does not fit substrate so The active site can be partially flexible enzyme active site changes shape slightly so they are complementary , and therefore enzyme-substrate complex forms and so a substrate can bind even when it’s not a perfect fit .
Therefore bending bonds in substrate leading to a reaction

60
Q

What is the lock and key theory

A

Random movement causes the enzyme and substrate to collide , and the substrate enters the active site . Enzyme - substrate complex forms . Charged groups attract distorting the substrate and aiding catabolic or anabolic . Then products are released from the active site leaving the enzyme unchanged and ready to accept another substrate molecule

61
Q

What does it mean when an enzyme is denatured

A

The active site of an enzyme changes shape and can no longer fit the substrate

62
Q

How are enzyme reactions affected

A

Temperature , ph , enzyme concentration , substrate concentration and the presence of inhibitors

63
Q

Define a catalyst

A

A substance that alters the rate of a chemical reaction without undergoing permanent change

64
Q

what is an inhibitor

A

they are subtances that directly or indirectly interfere with the functioning of the active site of an enzyme and so reduce its activity

65
Q

define a competitive inhibitor

A

a substance which binds to the active site of an enzyme

66
Q

define a non competitive inhibitor

A

a substance which binds to an enzyme at a postition other than the active site

67
Q
A
68
Q

What is a reducing sugar

A

One which can donate an electron to another molecule

69
Q

What’s the test for a reducing sugar

A

Add 2cm^3 sample to a test tube , if not already liquid grind add water and filter , add 2cm^3 Benedict’s reagent 3. Ensure the solutions are mixed by gently tilting , heat the mixture in a water bath for 5 min

70
Q

Test for non reducing sugars

A

Add 2 cm^3 sample to a test tube then add 2cm^3 of dilute hydrochloric acid and heat for 5 min in a water bath to hydrolyse the glycosidic bonds then add sodium hydrogen carbonate solution drop by drop to neutralise the acid (it will fizz) , test with universal indicator paper to ensure it has neutralised if not keep adding solution . Then add 2cm^3 Benedict’s reagent and heat in a water bath

71
Q

what are the two types of lipids

A

triglycerides and phospholipids

72
Q

how are triglycerides made

A

made up of 2 different molecules , glycerol and 3 fatty acids . 3 condensation reactions (releasing h20) forming ester bonds

73
Q

where are the ester bonds in a triglyceride

A

between the carbons and oxygen from fatty acids and glycerol

74
Q

what are the functions of lipids

A

buoyancy in marine mammals , cell membranes , energy storage , insulation , metabolic water and protection of organs

75
Q

how can lipids be a source of energy

A

when oxidised lipids provide more than twice the energy as the same mass of carbohydrate and release valuble water

76
Q

how do triglycerides provide metabollic water for eg camels

A

as they have a high ratio of hydrogen to oxygen atoms triglycerides release water when oxidised and therefore provide an important source of water

77
Q

how are lipids good at waterproofing

A

lipids are insoluble in water and therefore useful as a waterproofing

78
Q

what is ther r group on the fatty acids

A

the straight chain of carbon atoms

79
Q

what does it mean if the lipid is saturated

A

The fatty acid hydrocarbon chain has only single bonds between carbons . they tend to be solid at normal temps because they can be tightly packed

80
Q

what does it mean if the lipid is unsaturated

A

The fatty acid hydrocarbon chain consists of at least one double bond between carbons . doesnt have enough hydrogens . normally liquid

81
Q

what is a phospholipid made of

A

phosphate , glycerol and fatty acids

82
Q

why is phospholipids polar

A

They have two charged regions .they have a hydrophillic head and a hydrophobic tail therefore they can position themselves so that the hydrophillic heads are as close to the water as possible and hydrophobic as far away as possible

83
Q

what is the bond between fatty acids and glycerol called

A

ester bond

84
Q

what is the test for lipids

A

emulsion test .

  1. take a completely dry and grease free test tube
  2. if sample is sold break up into very small peices . if liquid just add 2 cm 3 of sample . then add 5cm3 ethanol
  3. shake the tube thoroughly to dissolve any lipid in the sample
    4.add 5cm3 of water and shake gently add distilled water
  4. a milky white emulsion indicates the prescence of a lipid if its clear none prescent
    6.as a control repeat proceedures using water instead of the sample and this should stay clear
85
Q

why is there a cloudy colour

A

the cloudy colour is due to any lipid in the sample being finely dispersed in the water. to form a emulsion light passing through the emulsion is refracted as it passes from oil to water droplets making it appear cloudy

86
Q

What kind are animal lipids and what do they occur as

A

Animal lipids are saturated and occur as fats eg butter

87
Q

What kind are plant lipids and what do they occur as

A

Plant lipids are unsaturated and occur as oils eg olive oil

88
Q

What is the initial rate of a reaction

A

The instantaneous rate at the start of the reaction

89
Q

Why is rate initially high

A

Lots of substance , rate slows down over time as amount of substance decreases

90
Q

what is collagen an example of

A

a fibrous protein

91
Q

what is the primary structure of collagen

A

an unbranched polypeptide chain

92
Q

what is the secondary structure of collagen

A

very tightly wound polypeptidechain

93
Q

how does collagen pack closely

A

it has lots of the amino acid glycine

94
Q

what is the tertiary structure of collagen

A

the chain is twisted into a second helix

95
Q

what is the quaternary structure of collagen

A

three polypeptide chains would together to form a triple helix. these make microfibrils and fibrils and these are staggerd so there are no weak spots and furtheer strengthened by cross links between triple helical molecules

96
Q

state two properties of collagen which make it suitable for ligaments (bones to bones)

A

strong and insoluble (also flexible but does not stretch)

97
Q

what is it called when a graph levels off

A

reaches plateau

98
Q

What’s the location of starch

A

Plants as starch grains

99
Q

What’s the location of starch

A

Plants as starch grains

100
Q

How does the structure of starch relate to its function

A

Helix shape can compact to fit a lot of glucose into a small space. Branched structure increases surface area for rapid hydrolysis from starch to glucose . Additionally it’s insoluble so won’t affect water potential so water is not drawn into cells by osmosis and it itself cannot diffuse out of cells

101
Q

What is the structure of cellulose

A

Long straight chains , which run parallel with hydrogen bonds in between to form fibrils. monomers of beta glucose . cellulose molecules alternate .

102
Q

How does cellulose structure relate to its function

A

Many hydrogen bonds collectively provides strength to cell wall as many hydrogen bonds is difficult to break. cellulose can resist turgor pressure

103
Q

How does glycogen structure relate to its function

A

It’s very highly branched and therefore a lot of free ends and faster hydrolysis back to glucose , this is important because animals have a high metabolic rate and therefore need glucose for respiration and this can be rapidly converted to glucose as it’s highly branched additionally insoluble so won’t affect water protein tusk

104
Q

Where is glycogen found

A

Muscle and liver cells

105
Q

Describe two differences between the structure of a cellulose molecule and a glycogen molecule.

A

1.Cellulose is made up of β-glucose (monomers) and glycogen is made up of α-glucose (monomers);
2. Cellulose molecule has straight chain and glycogen is branched;

106
Q

Describe and explain two features of starch that make it a good storage molecule.

A

Insoluble (in water), so doesn’t affect water potential;
2. Branched / coiled / (α-)helix, so makes molecule compact;
OR
Branched / coiled / (α-)helix so can fit many (molecules) in
small area;
3. Polymer of (α-)glucose so provides glucose for respiration;
4. Branched / more ends for fast breakdown / enzyme action;
5. Large (molecule), so can’t cross the cell membrane

107
Q

What’s the tips for polysaccharide questions

A

Say about glucose being used for respiration and say they are polysaccharides

108
Q

What are the reducing sugars

A

Glucose , fructose , galactose , lactose and maltose

109
Q

What are the non reducing sugars

A

Sucrose

110
Q

Why would an animal use lipids instead of carbohydrates as an energy store

A

Lipids provide more than twice as much energy than carbohydrates when oxidised as they have a low mass to energy ratio making them good storage molecules as more energy can be stored in a smaller volume

111
Q

In the secondary structure protein how do the hydrogen bonds form

A

They form between the NH group and C=O group ( as water has been removed )

112
Q

Two proteins have the same number and type of amino acid but different tertiary structures, explain why

A

Different sequence of amino acids , so different primary structure and therefore hydrogen bonds , ionic and disulphide Bridges form in different places

113
Q

What is one difference between competitive and non competitive inhibitors

A

Non competitive , increase in substrate concentration does not change enzyme activity / high substrate conc does not overcome inhibition / maximum rate not retained

114
Q

Why does an unsaturated fatty acid increase the fluidity of the membrane

A

Increase in fluidity caused by increased unsaturated fatty acids as contain double bonds which cause kinks in fatty acid tail therefore phospholipids further apart

115
Q

Why does an unsaturated fatty acid increase the fluidity of the membrane

A

Increase in fluidity caused by increased unsaturated fatty acids as contain double bonds which cause kinks in fatty acid tail therefore phospholipids further apart

116
Q

What must you remember with the induced fit model

A

Active site changes shape not the substrate

117
Q

State how enzymes help reactions to proceed quickly at lower temps

A

Lower the activation energy

118
Q

why does maltose lower water potential

A

because it is soluble in water

Biology Alevel (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions