Biological molecules Flashcards

1
Q

how many elements do carbs have?

A

3 carbon, hydrogen and oxygen

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2
Q

general formula for carbohydrate?

A

Cx(H2O)y

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3
Q

what ae carbohydrates?

A

they are macromolecules

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4
Q

some carbs are polymers what are these?

A

they are made of monomers joined in polymerisation

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5
Q

what are the different types of polymers?

A

Monosaccharide - monomers of carbs
disaccharide - two monosaccharides
polysaccharide - many monosaccharides

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6
Q

what is the formula for monosaccharides?

A

(CH2O)n n= 3—7

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7
Q

characteristics of monosaccharides?

A

they are sweet and soluble in water

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8
Q

when n = 3 what occurs?

A

C3H6O3 — Triose

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9
Q

when n=6 what happens?

A

C6H12O6 — hexose

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10
Q

what do all monosaccharides end in?

A

ose

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11
Q

formula for alpha and beta glucose ring structure?

A

OH! ABBA

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12
Q

what does glucose form?

A

2 isomers alpha and beta same chemical formula different structures

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13
Q

what are 2 roles of these isomers?

A

source of energy for respiration - C-H bonds release energy when broken and they are important for building large molecules, glucose makes starch and deoxyribose

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14
Q

how are disaccharides formed?

A

when 2 monosaccharide join in condensation reaction H2O is released bond between monomers is glycosidic bond.

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15
Q

disaccharide maltose from 2 alpha glucose.

A

OH groups involved in condensation reaction, hydrolysis addition of H2O, C bonds join to O with 1-4 glycosidc bond H2O is released

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16
Q

what are the rules for these reactions?

A

circle groups involved
show water is released
circle + label bond formed

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17
Q

where are glycoproteins found?

A

in external layers of bilayer

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18
Q

what are glycoproteins for?

A

receptor sites on hormones + transmitters also for intercellular lubrication

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19
Q

what are polysaccharides?

A

polymers made of many monosaccharides joined in condensation reaction linked by glycosidic bond

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20
Q

where is the polysaccharide starch found and what monomer is used?

A

plants and alpha glucose

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21
Q

where is polysaccharide glycogen used and what monomer is used?

A

animal and fungi alpha glucose is used

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22
Q

where is polysaccharide cellulose found and what monomer is used?

A

plants and beta glucose

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23
Q

what do many plants use polysaccharides as?

A

as an energy store as its insoluble and doesn’t affect water potential unlike glucose

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24
Q

what is the main role of starch in plants?

A

used as an energy store , stored as granules in chloroplasts starch is 20% amylose and 80% amylopectin

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25
what is the primary structure?
the order and sequence of amino acids in polypeptide chain, this is responsible for the final 3D shape, changing one amino acid may alter shape and therefore function
26
what is secondary structure?
this is how polypeptide chain begins to fold, can fold to form alpha helix or beta pleated, both held by H bonds. these can be broken by high heat and pH changes
27
what happens in alpha helix?
H bonds between amino acids 4 residules apart, it forms between carboxylic acid and amine group 4 molecules away.
28
what happens in beta pleated?
polypeptide chain folded into a structure with parallel amino acids held by H bonds
29
what is the tertiary structure?
how the secondary structure presen in the polypepide chain fold to produce 3D shape, shape is held by 4 bonds.
30
what are the 4 types of bond?
Hydrogen bonds Ionic bonds disulphide bonds hydrophobic interactions
31
where do hydrogen bonds occur?
between R groups of amino acids or carboxylic of one and amine of then other broken by high temps or pH changes
32
where do ionic bonds occur?
between oppositely charged R groups these can be broken by pH changes
33
where do disulphide bonds occur?
between R groups of different cysteine amino acids these can be broken by reducing agents
34
where do hydrophobic interactions occur?
between hydrophobic R groups of different amino acids they come close together away from water
35
what is quaternary structure?
two or more polypeptide chains held by H bonds, ionic, disulphide and hydrophobic interactions
36
what is haemoglobin?
globular protein with 4 polypeptide chains two alpha chains and two beta chains held by H bonds.
37
what does each chain contain?
a haem group containing iron ion
38
what is the haem group known as?
the prosthetic group as it is not made by amino acids
39
what can bond with the iron?
one oxygen molecule can reversibly bond
40
what can each haemoglobin carry?
4 oxygen molecule
41
how does the chain fold?
amino acids with hydrophilic r groups arrange themselves on the outside and hydrophobic amino acids arrange on inside to maintain the shape
42
what is collagen?
it is a fibrous protein with quaternary structure it has 3 helical polypeptide chains arranged in triple helix held by H bonds. they are closely packed due to every 3rd amino acid being glycine, the smallest Amino acid R group just H atom
43
how do collagens bond to each other?
using covalent bonds
44
how do collagen fibrils form?
covalent bonds are staggered increasing tensile strength, lots of collagen fibrils together form fibres
45
what are lipids?
diverse group of chemicals
46
what is the most common lipid?
triglycerides found in Fats and Oils.
47
what is triglyceride made of?
iglycerol and 3 fatty acids joined in condensation reactions linked by ester bonds
48
3 roles of triglycerides?
source of energy- respired to release ATP energy storage - can be stored in indipose cells all biological membranes are made of lipids
49
characteristics of amylose?
200-5000 alpha glucose per molecule unbranched helical chain 1-4 glycosidic bonds when coloured with iodine it is deep blue
50
characteristics of amylopectin?
``` 5000 - 100000 glucose per molecule branched chain 1-4 glycosidic bonds on chain 1-6 glycosidic bonds between branches red/purple when coloured with iodine ```
51
what is role of glycogen?
main role in animals is store- stored as granules in muscle and liver.
52
characterisitcs of glycogen?
1-4 glycosidic bonds between monomers | 1-6 between branches similar to amylopectin however shorter branches
53
role of cellulose?
to provide structural support it is made of beta glucose joined by 1-4 glycosidic bonds
54
why must beta glucose be rotated 180 degrees?
because OH group is above the ring on C1.
55
what does beta glucose form?
straight unbranched parallel chains
56
how are these parallel chains linked?
cross linked by H bonds making the structure strong 60 - 70 linked known as microfibrils
57
what are bundles of microfibrils known as ?
cellulose fibrils they are linked by H bonds
58
where is cellulose found??
in the plant cell wall providing strength makes up 20 - 40 %
59
features of cellulose?
it is fully permeable and high tensile strength this prevents the cell bursting during osmosis
60
what are proteins?
they are macromolecules made of amino acids (monomers) make more than 50% of the dry cell mass
61
what are elements found in proteins?
``` carbon sulphur hydrogen oxygen nitrogen ```
62
what are functions of proteins?
component of plasma membrane enzymes control cellular reaction haemoglobin proteins found in blood cell transports O2
63
how many types of amino acids are there?
20 types 8 are essential. they all have the same general structure vary by chemical elements found in the R group.
64
what do amino acids have?
structure shown as amine group on left two C and N in central branch, R group above central C carbocylic acid on the second C, OH below.
65
what are dipeptides?
two amino acids joined in condensation reaction using peptide bond
66
how do two amino acids join?
carboxylic acid of one and amine of the other join in condensation reaction (hydrolysis) forming molecule plus water. joined using peptide bond.
67
how can amino acids be linked?
by peptide bonds to form polypeptides.
68
how many polypeptide chains are in collagen and haemoglobin?
collagen has 3 | haemoglobin has 4
69
why must polypeptide chains be folded?
to create specific 3D shape to allow them to carry out a specific funsction
70
what is a phospholipid?
special type of lipid found in cell membrane, fatty acid tail is replaced by phosphate group.
71
features of phospholipid?
head is hydrophilic | tail is hydrophobic
72
roles of phospholipids?
major component of plasma membrane form a bi layer in water, they are responsible for partially permeable allow lipid soluble substances to enter and leave the cell.
73
what does P.A.W.S stand for?
polar are water soluble
74
how many regions does cholesterol have?
Hydrocarbon tail at bottom then ring structures in middle and hydroxyl group at the top
75
what is polar?
hydroxyl group is polar - hydrophilic
76
what is non polar?
ring structure and hydrocarbon tail - hydrophobic - lipid soluble
77
why is cholesterol described as amphipathic molecule?
has water soluble and fat soluble regions
78
what ios role of cholesterol?
as part of cell membrane regulates fluidity (less fluid at high temp) reduces side to side phospholipid movement they increase cell mechanical stability also prevent water and dissolved ion leakage
79
what is the reducing sugar test?
you add benedicts reagent and then heat the solution a positive result will give brick red result
80
what is starch test?
you add iodine which contains iodine dissolved I potassium iodide, a positive result is a blue black result
81
what is the lipid test?
you add ethanol to the sample and shake, then poor liquid into water, result is emulsion result
82
what is protein test?
add biurets to a sample which contains potassium hydroxide copper -2- sulphate and heat. a positive result is purple colour
83
what is non reducing sugars test?
same as reducing if a negative result use benedicts test add HCL heat it and then neutralise with sodium hydrocarbonate. add benedicts and heat. positive is a brick red result