Biology🧬 > Biochemistry🧪 > Flashcards

Biochemistry🧪 Flashcards

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1
Q

Magnesium function

A
  • Used to form chlorophyll

* Present bone and teeth

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2
Q

Iron function

A

Component of haemoglobin

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3
Q

Calcium function

A
  • Used to strengthen bones and teeth
  • Used to strength cell walls in plants - major part of middle lamellae
  • Important role in blood clotting and muscle contraction
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4
Q

Phosphate function

A
  • Used to form phospholipids
  • In many biological compounds such as ATP and nucleic acid
  • Needed for root growth
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5
Q

Why is water polar?💧

A

The hydrogen atoms are slightly positive and the oxygen atom is slightly negative

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6
Q

What does the polar nature of water allow to form?💧

A

Hydrogen bonds form between a hydrogen atom of one water molecule and the oxygen atom of another - this creates cohesion

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7
Q

What is water cohesion?💧

A
  • Hydrogen bonds between water molecules creates cohesion

* Molecules stick together in a strong lattice structure - long water columns don’t break, e.g. transpiration stream

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8
Q

What is surface tension of water?💧

A
  • At the air/water interface, cohesion produces surface tension
  • Some insects can exploit this property - body is supported by surface tension
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9
Q

Why is water’s solvent properties important?💧

A
  • Known as a universal solvent
  • Chemical reactions can occur in a solution - chemicals are free to move about
  • Makes transport easier - solutes are able to dissolve, e.g. in the blood, and then be carried around the organism
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10
Q

Why is water a metabolite?💧

A

Used up in many reactions

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11
Q

Why is water a good transport medium?💧

A
  • Good solvent
  • Viscous
  • Lubricant
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12
Q

Why is water’s high specific heat capacity important?💧

A
  • Takes large amount of energy to raise the temperature of a body of water
  • Important to cells - large amount of energy to raise a cell’s temperature, so cell can maintain stable internal temperature which is important for actions of enzymes
  • Important In bodies of water - provides a relatively stable environment for aquatic animals
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13
Q

Water’s high latent heat of evaporation💧

A
  • Relatively large amount of energy required to turn water from a liquid to a gas
  • Important for organisms as evaporation of water takes energy away from skin, causing a cooling effect
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14
Q

Density changes in water💧

A
  • Solid water has a lower density than liquid water - ice floats
  • Important as ice provides an insulating layer on top of a body of water - liquid below ice has higher temperature than air above it - organisms survive
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15
Q

Water’s transparency💧

A

Light can travel through water, meaning organisms such as plants and algae are able to photosynthesise underwater

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16
Q

Water as a buoyancy aid💧

A

Water provides support and buoyancy for aquatic organisms

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17
Q

What is a polymer?

A

Large molecules made up of repeating units of monomers

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18
Q

What is a condensation reaction?

A

A chemical reaction involving the joining together of two molecules and the removal of a molecule of water

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19
Q

What is a hydrolysis reaction?

A

The splitting of a large molecule into smaller molecules by the addition of water

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20
Q

What are carbohydrates?🍞

A
  • Source of energy in all living organisms

* All contain carbon - forms 4 bonds, hydrogen - forms 1 bond and oxygen - forms 2 bonds

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21
Q

What is a monosaccharide?🍞

A
  • CnH2nOn
  • Classified by number of carbon atoms: triose (3), pentose (5), hexose (6)
  • Provides building blocks for larger carbohydrate molecules
  • Act as a respiratory substrate
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22
Q

Glucose🍞 (monosaccharide)

A
  • Used in respiration to produce ATP
  • Monomer for many different polysaccharides
  • Has two isomers: alpha and beta - differ in arrangement of H and OH on carbon 1
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23
Q

What is an isomer?

A

Molecules with the same chemical formula but different structure

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24
Q

What is a disaccharide?🍞

A
  • Two monosaccharides joined by a glycosidic bond - condensation reaction (produces a molecule of water)
  • Can be broken back into monosaccharides (hydrolysis)
  • Small and water soluble - suitable for transport
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25
What are reducing sugars?🍞 (disaccharide)
* Monosaccharides and some disaccharides * Have carbonyl groups which can be oxidised to carboxylic acids * Reduce other compounds, forming a precipitate
26
What is a polysaccharide?🍞
* Three or more monosaccharides joined by condensation reactions * Either have a structural or storage function * Large size - insoluble * Osmotically inactive - stored without being affected by osmosis
27
What is starch? (Storage polysaccharide)🍞
* Store of glucose - made up of many alpha glucose molecules * Two components - amylose and amylopectin
28
What is amylose?🍞(Starch)
Chain of glucose monomers joined by 1,4 glycosidic bonds and formed into a helix - unbranched
29
What is amylopectin?🍞(starch)
Has 1,4 and 1,6 glycosidic bonds, giving it a branched structure
30
What makes starch a good good store?🍞(Storage polysaccharide)
* Compact - pack lots of energy into a smaller space than glucose * Insoluble - has little effect on osmotic pressure, doesn’t get transported from storage areas by water * Readily converted to sugars -easily converted into transportable molecules
31
What is glycogen?🍞(storage polysaccharide)
* Polymer made up of many alpha glucose monomers * Similar to amylopectin - 1,4 and 1,6 glycosidic bonds - branched structure * Store glucose in animals
32
Why does glucose’s structure indicate animals’ higher metabolic requirements?🍞
More branched structure - broken down more rapidly
33
What is cellulose?(structural polysaccharide)🍞
* Polysaccharide made up of beta glucose monomers joined by 1,4 glycosidic bonds - forms long straight (unbranched) chains - strength * Each beta glucose molecule is rotated 180’ from the previous molecule - enables hydrogen bonds to form between OH groups in adjacent chains * Many cellulose chains form a microfibril, many microfibrils form a cellulose fibre, cellulose fibres make up cell walls of plants
34
What gives cellulose its strength?🍞(structural polysaccharide)
Many hydrogen bonds and unbranched structure
35
What is chitin?(structural polysaccharide)🍞
* Made up of chains of beta glucose monomers, rotated 180’ from previous monomer, with hydrogen bonds between chains forming microfibrils * Amino acids added to form a mucopolysaccharide * Contains nitrogen * Strong and lightweight * Forms exoskeletons of insects and cell walls of fungi
36
What is used to test starch?🍞
* Several drops of iodine added to sample | * If present, sample turns blue/black
37
What is used to test for reducing sugar?🍞
* Benedict’s reagent is added to sample * Solution is boiled * If present, change from blue to brick red precipitate
38
What is used to test for non-reducing sugar?🍞
* If reducing sugar test shows a negative result, this test can be carried out * Hydrolysing glycosidic bond by heating with hydrochloric acid - forms two monosaccharides * Neutralised by adding sodium hydrogen carbonate * Boiled with Benedict’s reagent * If present, brick red precipitate
39
What are lipids?🍔
* Made up of carbon, hydrogen and oxygen * Made up of glycerol and fatty acids * Non-polar, insoluble
40
What are fatty acids?🍔
* Consist of a methyl group, a variable length hydrocarbon chain and a carboxyl group * Hydrocarbon chains contain an even number of carbon atoms - between 14 and 22 * Either saturated or unsaturated * Vary - length of hydrocarbon tail or how saturated the molecule is * Fatty acids affect the lipids’ properties
41
Difference between saturated and unsaturated fatty acids🍔
* Saturated - no carbon-carbon double bonds in the hydrocarbon chain * Unsaturated - carbon-carbon double bonds in the hydrocarbon chain
42
Difference between monounsaturated fatty acids and polyunsaturated fatty acids🍔
* Monounsaturated - one carbon-carbon double bond | * Polyunsaturated - two or more carbon-carbon double bonds
43
What are triglycerides?🍔
* 1 glycerol and 3 fatty acids * 3 condensation reactions which form 3 ester bonds * When oxidised, releases more energy than carbohydrates and produces metabolic water
44
What are phospholipids?🍔
•2 fatty acids and a phosphate group combine with a glycerol molecule
45
Functions of lipids in living organisms🍔
* Energy storage - 2x more than same mass of carbohydrate * Protection of delicate organs * Thermal insulation * Buoyancy * Source of metabolic water for organisms such as camels * Waterproofing
46
Why is a high intake of saturated fats a contributory factor in heart disease?🍔
Raises LDL cholesterol level, increasing the risk of atheroma in coronary and other arteries
47
What are waxes?🍔
* Long chained fatty acids linked to a long chained alcohol | * Insoluble and form a waterproof layer
48
What are steroids?🍔
* Four-ring structure with various side chains * Insoluble in water but soluble in organic solvents * Important as hormones * Synthesised from cholesterol
49
What is cholesterol?🍔
* Important constituent of body cells, especially cell membrane * Too much cholesterol and saturated fat can produce atheroma deposits - reduce blood flow in arteries
50
What are proteins?🥩
Polypeptides made up of carbon, hydrogen, oxygen, nitrogen and sometimes sulphur
51
What is a polypeptide?🥩
* A polymer consisting of a chain of amino acid molecules * Joined by peptide bonds formed by condensation * One or more polypeptides form a protein
52
What is used to test for lipids?🍔
* Emulsion test * Ethanol added to sample and shaken thoroughly * Distilled water is added * If present, a layer of cloudy white suspension will form
53
Roles of proteins🥩
* Enzymes * Carrier proteins * Antibodies * Structural proteins * Hormones * Transport - haemoglobin * Contractile proteins
54
What are amino acids?🥩
* Made up of a amino group (NH2) and a carboxyl group (COOH) and a variable residual (R) group * Amino end - base - positive amino acid ion * Carboxyl end - acid - negative amino acid ion * They are amphoteric - act as base and acid, so can act as a pH buffer
55
How many R groups are there?🥩
20 different R groups, so 20 different amino acids
56
How is a dipeptide Formed?🥩
* Two amino acids combine in a condensation reaction to form a dipeptide - a molecule of water is also formed * Peptide bond forms between carboxyl group of one amino acid and the amino group of the other amino acid
57
What is a protein’s primary structure?🥩
The type, number and sequence of amino acids in a protein | Peptide bonds
58
What is a protein’s secondary structure?🥩
* Polypeptide can twist to form either an alpha helix or a beta pleated sheet * Shape is held together by hydrogen bonds between the peptide bonds
59
What is a protein’s tertiary structure?🥩
* Polypeptide helix twists and folds into specific complex 3D shapes * Specific structure is maintained by hydrogen bonds, ionic bonds and disulphide bonds between the R groups of the amino acids
60
What is a protein’s quaternary structure?🥩
* Only some proteins have a quaternary structure | * Two or more polypeptides with a tertiary structure can combine to form a quaternary structure
61
What is the hydrophobic effect?🥩
* Helps some proteins maintain their structure * When globular proteins are in solution, the hydrophobic groups point inwards, away from the water * Allows molecule to be soluble in water
62
Stability of proteins🥩
* Increases in temperature/changes in pH or presence of heavy metal ions or organic solvents cause the atoms to vibrate * Bonds break - 3D structure changes * Affects tertiary and quaternary structure - denatures
63
Globular proteins🥩
* Tertiary and quaternary structure * Compact molecules * Highly twisted polypeptide chains roll up into a ball - specific in shape * Hydrophobic R groups point out - water soluble * Tend to be less stable and are involved in metabolic reactions * Includes enzymes, antibodies and hormones
64
What is haemoglobin?🥩(globular)
* Globular protein * Consists of 4 polypeptide chains - disulphide bridges hold them together * At the centre of each polypeptide is a haem group
65
Fibrous proteins🥩
* Secondary structure * Insoluble, strong, stable and flexible * Polypeptides Laos sown in parallel chains, linked together to form long fibres or sheets * E.g. keratin or collagen
66
What is collagen?🥩(fibrous)
* Fibrous protein * Provides the tough properties needed in tendons and bones * Consists of 3 alpha helix chains formed into long strands - wind around each other held together by hydrogen bonds
67
What is used to test for proteins?🥩
* Biuret test * Biruet reagent is added to sample * If present, change from blue to lilac/purple
68
Number of bonds formed by Carbon, oxygen and hydrogen🍞🍔
* Carbon - 4 * Oxygen - 2 * Hydrogen - 1
69
Monosaccharides and the disaccharides they form🍞
* Glucose + glucose = maltose * Glucose + fructose = sucrose * Glucose + galactose = lactose
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