Module 2.2 Biological Molecules Flashcards

1
Q

Water

Properties of water

A

High specific heat capacity: water acts as a buffer for temperature, so it’s acts of a habit for fish

Ice: the hydrogen bonds are frozen in place ice insulated water, acts as a habitat,

Latent heat of vaporisation: heat energy evaporated from skin for cooling mechanism like sweating

Solvent: good solvent, can be used to transport substances (blood plasma, xylem vessels)

Cohesive properties: water molecules stick together, causes surface tension acts of surface of water to act as habiats (pond skaters)

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2
Q

Carbohydrates

What elements are carbohydrates made up of?
give the properties of monosaccharides?
Give examples of monosaccharides

A

All carbohydrates contain carbon hydrogen and oxygen
Glucose is a hexose sugar
Soluble because of hydroxyl groups, small
Examples: Galactose, glucose, fructose

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3
Q

What is a disaccaride

A

Two monosaccharides joined together by a 1,4 glycosidic bond

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4
Q

What type of reaction produces disaccharides

A

Condensation reaction

Produces water

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5
Q

Carbohydrates

Give examples of disaccharides

A

Sucrose: glucose and fructose
Maltose: glucose and glucose
Lactose: glucose and galactose

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6
Q

Carbohydrates

What is the structure of amylose

A

Structure of amoylose

  • polymer of alpha glucose
  • joined by (1,4 glycosidic bonds)
  • twists into a compact helix
  • unbranched
  • forms hydrogen molecules with glucose molecules along the chain
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7
Q

Carbohydrates

What is the structure of amylopectin

A

Structure

  • polymer of alpha glucose
  • has a branch every 25/30 glucose molecules
  • forms a 1,6 glycosidic bonds
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8
Q

Carbohydrates

How does the structure of starch relate to its function

A
  • compact- store a large amount of gocuose molecules for its size
  • insoluble: so does not change water potential of cells
  • amylopectin has many ends so it’s easier for enzymes to break starch down

70% amylose and 30% amylopectin

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9
Q

What is the structure of glycogen

A

Structure

  • polymer of alpha glucose
  • many branches
  • has 1,4 glycosidic bonds and 1,6 bonds
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10
Q

How does the structure of glycogen relate to its function

A

Properties

  • large: so it can’t diffuse into cells
  • insoluble: so it can’t change water potential of cell
  • many branches: enzymes can break down glycogen quicker as animals have a higher metabolic
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11
Q

Carbohydrates

What is the structure of cellulose

A

Structure

  • polymer of beta glucose
  • every other carbon ring is rotated 180
  • forms 1,4 glycosidic bonds
  • unbranched
  • forms a straight chain, which allows hydrogen bonds to form between chains
  • huge numbers means cellulose strong
  • forms microfibrils which forms macro-fibrils
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12
Q

How does the function of cellulose relate to its function?

A
  • strong due to high tensile strength provided through hydrogen bonds
  • prevents cell from bursting
  • impermeable to water, still doesn’t burst when contents of cell is pushing against it
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13
Q

What is the general structure of amino acids

A

Amino acids contains carbon, hydrogen, oxygen, nitrogen and sometimes sulphur
-contains an amine group and a carboxyl group
Amino acids can have different r groups

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14
Q

What is the difference between a polypeptide and protein

A

Polypeptide: a large number of amino acids joined together

-protein: polypeptide folded into a shape that can carry out a function

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15
Q

What are the levels of protein structure

A

Primary structure- a sequence of amino acids joined by a peptide bond. Helps determine final 3D shape. This is determined by DNA sequence

Secondary structure: hydrogen bonds form causing an alpha helix and beta pleated sheet

Tertiary structure: overall 3D shape of chain, folding depends on the Interactions of r groups (Hydrogne bonding, ionic bonding, hydrophilic and phobic interactions, disulphides bridges)

Quaternary structure: polypeptides interact with other polypeptide chains

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16
Q

What are the features of globular proteins

A

-spherical
-soluble in water: due to r groups that are attracted to water on their surface
Hydrophobic amino acids in centre of protein

17
Q

Proteins

Haemoglobin

A
  • made up of 4 polypeptide subunits
  • two alpha and two subunits
  • contains prosthetic group haem
  • so it’s a conjugated protein
  • when oxygen attaches to haemoglobin changes quaternary structure making it easier for other oxygen molecules to bind onto haemoglobin
18
Q

Proteins

Insulin

A
  • two polypeptide chains
  • linked by disulphides bonds
  • globular protein
  • hormone
  • shape of insulin molecule means that it complimentary to target cells
19
Q

Proteins

Enzymes

A
  • only react with specific substrates

- the active site is complimentary to the substrate

20
Q

Proteins

What is the general structure of fibrous proteins

A
  • play a structural role
  • form linear chains
  • insoluble in water due to hydrophobic r groups
21
Q

Proteins

Collagen

A
  • found in tendons
  • strong molecule due to structure
  • forms a triple helix
  • joined together by cross links, these form microfibrils
  • the molecule is staggered so there are no weak spots
  • third amino acid is glycine which alleos collagen to wrap tightly making it strong
22
Q

Keratin

A

Found in hair nails
Strong
Long stranded
Contains cysteine which forms disulphides brides increases strength of kertain molecules

23
Q

Elastin

A
  • Found in artery walls and skin
  • long strands which are cross linked
  • hydrophobic strands associate
  • when stretched they remain attached to crosslinks
  • making molecule stretchy
24
Q

Lipids

What is the functions of lipids

A
  • source of energy
  • store energy
  • cushioning around organs
  • waterproofing
  • electrical insulation around neurone
  • thermal insulation
  • can make vitamins and steroid hormones
  • buoyancy
25
Triglycerides
Formed from 1 molecule of glycerol and 3 fatty acids The fatty acids can be unsaturated (has a double bond) Or saturated (no double bond) -form an ester bond -called estérification -form through condensation reaction -non polar -large number of carbon carbon bonds means lost of energy can be released
26
What is the structure of a phospholipid
Structure Glycerol molecule bonded to a phosphate and two fatty acids Part hydrophilic and part hydrophobic Can form a phospholipid bilayer
27
Cholesterol
- hydroxyl group is hydrophilic - rest is hydrophobic - insert it’s self in membranes - controls fluidity - starting point for steroid hormones like oestrogen, can pass through cell membranes - vitamin D - used in liver for bile
28
Tests for biological molecules Starch
Process - grind up food - add water - filter out water Test for starch - add 1 cm3 of iodine and potassium iodide - positive result should turn blue black
29
Tests for biological molecules Proteins
Process - grind up food - add water - filter out water Using filtrate Add 3cm3 of NAOH and mix Then add 10 drops of copper two sulfate Detects for peptide bonds
30
Tests for biological molecules Lipids
Food should not be filtered as lipids could stick to filter paper Add 3cm3 of food soutien Add 3cm3 of ethanol and water If lipids of present a white cloudy emulation will form Should not do this near a naked flame
31
Tests for biological molecules Reducing and non reducing sugars
A reducing sugar can donate electrons to another molecule Reducing sugars - grind up food - add water - filter out water - add 3cm3 of filtrate and Bénédicts to a test tube - positive test from blue to yellow, orange, red Benedicts test is semi quantitive, gives is an idea of amount of sugar, people can perceive colours differently Non reducing sugars -we need to break glycosidic bond of sucrose -get unknown solution and add 3cm3 of HCL, then place in boiling tube for 5 minutes (hydrolyses glycosidic bonds) -then add 3cm3 add NAOH -check if solution is alkaline Then do the Benedicts tests
32
What are the other ways of testing for biological molecules that aren’t food tests
- Colorimeter | - bio sensor