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A Level Biology > Biological Molecuoles 1 > Flashcards

Biological Molecuoles 1 Flashcards

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1
Q

What are monomers?

A

smaller units from which larger molecules are made

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2
Q

What are polymers?

A

molecules made from a large number of monomers joined together

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3
Q

What is a condensation reaction?

A

a reaction that joins two molecules together to form a chemical bond whilst eliminating of a molecule of water

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4
Q

What is a hydrolysis reaction?

A

A reaction that breaks a chemical bond between two molecules and involves the use of a water molecule

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5
Q

What is a monosaccharide

A

Monomers from which larger carbohydrates are made

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6
Q

How is a glycosidic bond formed?

A

A condensation reaction between two monosaccharides

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7
Q

Name the three main examples of polysaccharides.

A

glycogen, starch, cellulose

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8
Q

Describe Benedict’s test for reducing sugars

A

gently heat a solution of a food sample with an equal volume of Benedict’s solution for five minutes, the solution turns orange/brown if reducing sugar is present

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9
Q

Name the two main groups of lipids

A

Phospholipids and triglycerides (fats and oils)

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10
Q

Give four roles of lipids

A

source of energy, waterproofing, insulation, protection

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11
Q

What is an ester bond?

A

A bond formed by a condensation reaction between glycerol and a fatty acid

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12
Q

Describe the emulsion test for lipids

A

mix the sample with ethanol in a clean test tube, shake the sample, add water, shake the sample again, a cloudy white colour indicates that lipid is present

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13
Q

What are the monomers that make up proteins?

A

Amino Acids

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14
Q

Draw the structure of an amino acid

A 
R
                      |
         H2N — C — COOH
                       |
                       H
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15
Q

How is a peptide bond formed?

A

a condensation reaction between two amino acids

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16
Q

What is a polypeptide?

A

many amino acids joined together

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17
Q

Describe the biuret test for proteins

A

mix the sample with sodium hydroxide solution at room temperature, add very dilute copper(II) sulfate solution, mix gently, a purple colour indicates that peptide bonds are present

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18
Q

How does an enzyme affect a reaction?

A

It lowers the activation energy

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19
Q

Give five factors which can affect enzyme action.

A

temperature, pH, enzyme concentration, substrate concentration, inhibitor concentration

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20
Q

What is a competitive inhibitor?

A

A molecule with a similar shape to the substrate, allowing it to occupy the active site of the enzyme

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21
Q

What is a non - competitive inhibitor?

A

A molecule that changes the shape of the enzyme by binding somewhere other than the active site.

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22
Q

Water is a polar covalently bonded molecule. Explain.

A

Because the electrons are not shared equally there is an uneven distribution of charge in which the opposite to the bonded parts of hydrogen are slightly positive and the top of oxygen is slightly negative.

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23
Q

Cohesion in water molecules

A

Weak Inter-molecular forces between the slightly positive H and the slightly negative oxygen due to its polarity are called hydrogen bonds. Together many mean there is some strength in the hydrogen bonds.

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24
Q

Cohesion of water shows in various forms

A

What causes h20 to travel up the xylem
Cohesion results in droplets curving inwards (tear drop shape)
Results in súrcate tensión

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25
Q

Adhesion in water molecule

A

The attraction between H2O molecule and the wall of container or even xylem wall
Causes a Meniscus shape in container

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26
Q

Explain what like dissolves like means

A

Water is a solvent - a polar solution dissolves other polar or ionic solids like salt

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27
Q

What is a metabolite and give an example

A

Involved in metabolic reactions
Can be a substrate or a product hence is used as a transport medium
For example condensation and hydrolysis

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28
Q

In animals and humans how is water used as a transport medium.

A

Human and Animals plasma

Plants is water and xylem

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29
Q

What is specific heat capacity?

A

The energy needed to raise the temperature of 1kg by 1°C

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30
Q

Why is water a buffer

A

A large amount of energy is needed to raise the temperature hence the water resists changes.

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31
Q

What is thermostable environment

A

An environment that doesn’t change much in terms of heat - for example water; the sea doesn’t change much in terms of temp so animals can live there

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32
Q

What is high latent heat of vaporisation and how does it relate to human body

A

A lot of energy is needed to break all the Hydrogen bonds and molecules with enough energy evaporate carrying heat away, hence when we sweat we cool down because a lot of energy evapourated

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33
Q

Why does ice float on water

A

As water freezes it expands and the molecules are held further apart so when frozen is less dense than liquid water so floats. Hence the ice insulates the water below so it does at freeze.

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34
Q

Biological Macromolecules

A

Contain carbon
Can be organic (C-H bonds)
Can be inorganic (CO2)

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35
Q

Saturated macromolecules have

A

No double carbon covalent bonds

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36
Q

Unsaturated macromolecules have

A

double carbon bonds

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37
Q

Polymers go through hydrolysis to…

A

Monomers

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38
Q

Monomers go through condensation reaction to form

A

Polymers

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39
Q

An example of a monomer is amino acids give the name of the polymer it forms and the cellular structure it is found in

A

Polypeptide chain

Intermediate Filament

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40
Q

An example of a monomer is nucleotide give the name of the polymer it forms and the cellular structure it is found in

A

DNA Strand

Chromosome

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41
Q

An example of a monomer is monosaccharide give the name of the polymer it forms and example and the cellular structure it is found in

A

Polysaccharide
Starch
Starch grains in chloroplast

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42
Q

An example of a monomer is fatty acids give the name of the polymer it forms and the cellular structure it is found in

A

Fat molecule

Adipose cells with fat droplets

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43
Q

What are carbohydrates made of and give which types are simple and which are complex

A

Carbon, hydrogen and oxygen
Monosaccharides and Disacchardies are simple
Polysaccharides are complex

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44
Q

General formula of monosaccharides

A

(CH2O)n

Where n is the number of carbon atoms

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45
Q

Two shape forms of glucose diagrams are called

A

Linear (acyclic form)
Cyclic Form
Must know

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46
Q

Glucose formula is

A

C6H12O12

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47
Q

Two isomers of glucose are and name difference at one point

A

Alpha glucose and beta glucose
There are two ring forms and one linear
Beta is the same as alpha however at carbon one the OH is on top and the H is in the bottoms
Must know these diagrams

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48
Q

Disaccharides are
What type of bind
What type of reaction

A

Two monosaccharide units join forming a glycosidic bond
They can be made by two of the same of two different monosaccharides
It is a condensation reaction so a molecule of water is expelled

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49
Q

Maltose is made from which monomers and give word equation and what type of saacharide

A

Glucose + glucose-> maltose + water

Disaccharide

50
Q

Sucrose is made from which monomers and give word equation and what type of saacharide

A

Glucose + fructose -> sucrose + water

Disaacharide

51
Q

Lactose is formed from which monomers and give word equation and what type of saacharide

A

Glucose + glacatose -> lactose + water

Disaacharide

52
Q

OILRIG

A

oxidation is loss reduction is gain

53
Q

Ionic equation for copper sulfato Benedicta reagent

A

Cu2+ + e- -> Cu+

54
Q

Non reducing sugars test

A

Once they show a negative result against Benedicta solution
Boil unknown solution with dilute HCl,which causes any disaccharide molecules that might be present to hydrolyse (split) into monosaccharides which are all reducing sugars
Then repeat Benedicts test

55
Q

All monosaccharides are

A

Reducing sugars

56
Q

Hydrolysis is the

A

Addition of H2O that causes break down

57
Q

Starch test

A

Changes colour of iodine from yellow to blue-black
2cm3 if sample into test tube or spotting tile
Blue-black indicates the presence of starch

58
Q

Polysaccharides are

A

Polymers firmed by the joining of many monosaccharides by glycosidic bonds (formed through many condensation reactions)
When they are hydrolysed they are broken into monosaccharides or disaccharides.

59
Q

Polysaccharides generally perform two functions which are….

A

Storage of energy and structural help

60
Q

Polysaccharides storage of energy in plants

A

Starch is only made in plants which is a major energy source for humans
Starch is made up of two polysaccharides; Amylose (20%) and Amylopectin (80%)
Both are chains of alpha glucose

61
Q

Amylase acts on starch

A

It is found in salivary glands and breaks down into maltose

62
Q

Amylose (20%)

A

Formed by an alpha glucose chain
Alpha 1,4 glycosidic bonds between monomers ((the one after O)C1 and C4 join in a condensation reaction)
Chain forms into a slightly coiled shape

63
Q

Amylopectin (80%)

A

Formed by an alpha glucose chain
Alpha 1,4 and alpha 1,6 glycosidic bonds (carbone one to carbon four and carbon one and carbon six)
Branched shape due to extra alpha in 1,6 bonding
Forms branches slightly coiled chain

64
Q

Polysaccharides storage of energy in animals

A

Glycogen is found as a means of storage in animal, fungi and bacterial cells
A more branched version of amylopectin
Formed from chains of the monosaccharide alpha glucose but there is less alpha 1,4 and more alpha 1,6 hence more branching and more area for enzymes to work on hence quicker mobilisation of energy
Stored in small granules and found mainly in the muscles and liver

65
Q

Why is it useful that glycogen has more alpha 1,6 bonds then alpha 1,4

A

There is more branching hence more end and surface area for the enzymes to walk on hence more energy is mobilised in less time

66
Q

Why do plants store energy in the form of starch as opposed to glycogen

A

There is no need for quick mobilisation of energy

67
Q

Why are glycogen and starch good for storage

A

Compact - a lot can be stored in very little space
Easy access to glucose- energy source released by the hydrolysis of glucose molecules from multiple branched ends
Large and insoluble - doesn’t diffuse out of cells or affect water potential

68
Q

Polysaccharide Structural support

A

Cellulose
Major component of plant cell walls
Formed by chains of beta glucose
Small change of OH pointing up at C1 causes huge differences in the structure and function
Every other glucose molecule is rotated by 180° or flipped to allow the glysocisdic bonfd to form between beta glucose molecules
Straight unbranched chains are formed and because of the flipping the C2H2OH is in the bottom weak hydrogen bonds are built between chains and it stabilises the structure
Cellulose strands are arranged to make tough microfibrils providing strength and support

69
Q

Structural roles of cellulose

A

Provides rigidity
Prevent plant cells bursting when water enters via osmosis
Maintains turgidity in plant cells and therefore in the whole plant (stems and leaves) maximising the surface area for photosynthesis

70
Q

Lipids -> difference in oil and fat

A

A liquid form is oil

A solid form is fat

71
Q

Characteristics of lipids are

A

They are all made of carbon and hydrogen and a small amount of oxygen
They are non-polar due to a large percentage of carbon and hydrogens hence add insoluble in water (hydrophobic)
Soluble in other solvents that are organic for example ethanol and acetone

72
Q

Explain how a change in the primary structure of a protein mag result in a different three dimensional structure

A

A change in the sequence of amino acids means the tertiary structure may fold differently forming bonds in different places

73
Q

Hydroxylating means

A

Adding OH group

74
Q

Two proteins have the same number and type of amino acids but a different tertiary structure
Explain why

A

A different sequence of amino acids forms ionic,disuadidos and hydrogen bonds in different places hence folds differently

75
Q

Explain how cellulose molecules are adapted for their function in plant cells

A

Linear chains become linked by H+ bonds to form fibrils that provide strength to cell for example don’t burst when water enters via osmosis

76
Q

Explain one way in which starch molecules are adapted for their function in plant cells

A

Compact - more energy less space

Insoluble hence don’t affect water potential

77
Q

Triglycerides store energy in what type of cells

A

Adipose

78
Q

Phospholipids are the main components in

A

Cell membranes

79
Q

Glycerol formula and monomer for which polymer/s

A

C3H8O3
(3 OHs)
Triglycerides and phospholipids

80
Q

Properties of saturated fatty acids

A 
Contain only single covalent bonds between carbon atoms 
Form linear chains 
Fatty acids pack closely together 
Strong attraction between chains 
Solid at room temperature
81
Q

Properties of unsaturated fats

A

Contain one or more double covalent bonds between carbon atoms, which causes the chains to bend
The non linear chains do not allow fatty acid molecules to pack closely together
Fewer interactions between fatty acid chains hence weaker attraction
Liquids at room temperature
The more double Covalent bonds between carbon atoms the lower the melting point

82
Q

Ester bonds are

A

C double bond O and one bond H

83
Q

Triglycerides are located where and for what reason/s

A

Around delicate organs like heart or kidney for protection

And under skin to insulate the body

84
Q

Triglycerides structure description

A

Each fatty acid forms an Ester bond with glycerol in a condensation reaction which involves the removal of 3 water molecules (one for each Ester bond)

85
Q

Hydrolysis of a triglyceride results in

A

Splitting the triglyceride back into glycerol and 3 fatty acids.

86
Q

Hydrolysis of a triglyceride requires an addition of

A

3 water molecules

87
Q

Lipid Emulsion Test

A

Mix sample of fat with (5cm3 of alcohol) and shake tube
Add five cm 3 of cold water and shake until a milky white colour indicated the presence of a lipid

For control repeat procedure with a sample of water and now white should be seen

88
Q

Describe diagram of phospholipids

A

The head of the molecule is a negatively charged phosphate which is hydrophilic (attracts water) and has two tails which are long chains of fatty acids that are hydrophobic hydrocarbons. They can be either saturated or unsaturated not necessarily the same tail.this means the head is polar

89
Q

Hydrophilic meaning

A

Attracted to water

90
Q

Why do we say phospholipids are ampipathic

A

Has both hydrophobic and hydrophilic parts

91
Q

Describe the diagram of a membrane

A

Two rows of polar heads with tails facing each other. The hydrophilic phosphate head interacts with aqueous solution on either side that could be for example cytoplasm or muscle tissue whilst the negative hydrophobic hydrocarbon tails face each other.

92
Q

Vesicles have hydrophobic or hydrophilic heads

A

Hydrophilic

93
Q

Roles of Lipids

A

Waterproof - skin,waxy cuticle of leaf
Thermal Insulation - slow conductors of heat
Protection - of organs
Buoyancy - slightly pensé dense than H2O
Electrical Insulation - around nerves to increase electrical impulse speed
Hormones - steroid hormones are derived from cholesterol like cortisol,oestrogen and progesterone

94
Q

H+ ions in body contribute to

A

pH of bodily fluids

95
Q

Nitrogen is needed for the body because

A

It is a source of amino acids and helps to further synthesise human proteins. RNA needs nitrogen as does the digestive process.

96
Q

Carbon makes up 18% of the body - what’s its function?

A

Sugars in body hold C atoms. Macromolecules including proteins, RNA & DNA, lipids and other carbohydrates. A subset of any organic molecule

97
Q

Oxygen needed for body?

A

Oxidation changes food and liquid into energy - ultimately provides fuel for our body.

98
Q

Phosphorus is needed in the body to

A

Build and repair bones and teeth, help nerves function, muscles contract. 85% is in bones the rest is stored in tissues in the body

99
Q

Silicon is needed in the body to

A

Make proteins, regulate gene expression and for the building and repairing of DNA and to metabolise food.

100
Q

Sodium is needed in the body to

A

Maintain a balance of water in and around cells - important for proper muscle function and never even function and to maintain a stable blood pressure

101
Q

Magnesium is needed in the body because

A

It is used in over 300 biochemical reactions and for the active transport of Ca and K ions across cell membranes

102
Q

Iron is needed in the body to

A

Carry oxygen in haemoglivin if RBC so energy can be produced
Low iron means low ATP which is what energy turns into hence fatigue

103
Q

Calcium is needed in the body to

A

Build string bones and teeth
Clotting blood
Receiving and sending nerve signals
Relaxing muscles

104
Q

Structure of triglycerides related to their properties

A

High ratio of energy storing of carbon hydrogen bonds to carbon atoms so make an excellent source of energy
Low mass to energy ratio which means a lot of energy in a small volume. This means it easier for animals to move around so reduces mass
Large non polar insoluble in water hence there is no water potentials
High ratio of hydrogen to oxygen so release water when oxidised so important source for organism living in dry deserts

105
Q

Monomer for proteins are

A

Amino acids

106
Q

Structure of amino acid

A

Amino group - NH2
Carboxyl Group - COOH
hydrogen atom connected to the carbon in middle
R group under main carbon which makes each amino acid different

107
Q

Peptide bonds are formed between what atoms, are what type of reaction and what element within those atoms

A

Amino acids
Condensation so expel water molecule
Nitrogen combines with the carbon
Lose one H from nitrogen and carboxyl group lose OH

108
Q

Primary structure of polypeptide

A

Linear sequence of amino acids that form one polypeptide chain
Peptide bonds

109
Q

Secondary Structure of proteins

A

Secondary structure Creates three dimensional geometry with regular folding patterns forming a tightly coiled alpha helix structure or beta sheet which is like a zig zag n shape
Hydrogen bonds in seciondary structure

110
Q

Tertiary structure polypeptide

A

The overall shape of protein so either globular or fibrous
Disulphides bridges between between two sulfur atoms but only in a structure with sulfur with hydrogen at end so not in methanine
Contains secondary structure forms
Hydrogen bonds stabilise
Ionic bond between amino group and carboxyl group

111
Q

Three types of bonds that stabilise tertiary structure in order of highest strength to lowest

A

Disulphides bridge
Ionic are easily broken by changes in pH
Hydrogen bonds numerous so strong but easily broken

112
Q

Quaternary structure polypeptide

A

Describes appearance when a protein is composed of two or more polypeptide chains which may hyyderogen bonds with each other in unique patterns to create the desired protein the desired protein configuration

113
Q

Biuret test

A

Place a sample of in test tube
Add sodium hydroxide and copper sulfur (birrete Reagan’s) and mix
Must be equal parts
Blue to purple indicates presence of proteins

114
Q

The quaternary structure of collagen makes it a suitable molecule for tendon

A

Individual polypeptide chains are held together in fibres are held together by bonds between amino acids in adjacent chains

115
Q

Structure description of fibrous proteins

A

Primary is unbranched polypeptide chain
Secondary is tightly wound
Loads of the amino acids glycine helps close packing
Tertiary chain is twisted into a second helix
Quaternary made up of three such polypeptide chains wound together like a rope

116
Q

Difference in function between globular and fibrous proteins

A

Metabolic functions

Structural function

117
Q

Explain that all living things have a similar biochemical basis

A

Variety of organisms based on versatile carbon atom. Only few atoms that can bind to carbon in living organisms ergo life is based on a few elements.

118
Q

Triglycerides and phospholipids structural difference is

A

One fatty acid is substituted by a phosphate molecule

119
Q

Phospholipid structure related to their properties

A

Polar and have hydrophilic phosphate head and hydrophobic tail so form a hydrophobic belayer that acts as a barrier between inside and outside of cell
Hydrophilic allows holding of cell surface membrane
Structure allows doming of glycolipids which are important in cell recognition

120
Q

Proteins variety of functions

A

Channel and carrier proteins for transport
Enzymes for synthesis of atp and other proteins
Ribosomes

121
Q

Importance of water

A

Metabolism - hydrolysis and condensation eg: amino acids and proteins.
Solvent - readily dissolved gases like O2 and CO2 so acts as a transport medium. Provides aqueous medium for enzyme reactions to take place.
High latent heat if vapoursiation means that sweating cooks down mammals as a lot of heat energy in the sweat.
Cohesion and adhesion allows for transpiration
High specific heat capacity - thermos table buffer for aquatic organisms
Hard to compress - hydrostatic skeletons

122
Q

Inorganic ions hydrogen, iron and phosphate

A

Phosphate ions make compounds more reactive by lowering Ea : glycolysis
Hydrogen ions determine pH so affect enzyme reactions
Fe in haemoglobin allows max four oxygen to bind for transport

A Level Biology (18 decks)

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