Biological Molecules (complete) Flashcards

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1
Q

Monomers of: Maltose, Sucrose and Lactose.

A

Maltose: Glucose-Glucose
Sucrose: Glucose-Fructose
Lactose: Glucose-Galactose

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2
Q

Test for Non-reducing Sugars.

A

Add HCl. Heat for few mins. Add sodiumhydrogencarbonate. Add Benedict’s solution. Heat for few mins.
Blue-Green-Orange-Brick red.

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3
Q

Test for Reducing sugars.

A

Add Benedict’s solution. Heat for a few minutes.
Blue-Green-Orange-Brick red.

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4
Q

Test for Starch.

A

Add Iodine.
Amber-Blue/Black

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5
Q

Test for Proteins.

A

Add Biuret A+B.
Blue-Purple/Lilac.

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6
Q

Test for Lipids.

A

Add Ethanol.
Colourless-Milky white

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7
Q

Alpha vs Beta glucose - Similarities

A

Same Molecular Formula.
Both formed into polymers through condensation reactions, which contain glycosidic bonds.

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8
Q

Define:

  • polar molecule
  • hydrogen bond
  • glycosidic bond
  • metabolism
A
  • molecules with an uneven distribution of charge.
  • a bond formed between polar molecules.
  • a covalent bond forming between sugar molecules.
  • the combination of chemical reactions taking place within a cell.
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9
Q

Reducing sugar vs Non-reducing sugar.

A

Reducing - ‘donate’ electrons to other molecules in chemical reactions.

Non-reducing - don’t ‘donate’ electrons during chemical reactions.

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10
Q

What are the properties of starch?

A

Branched chain - allows the molecule to be easily hydrolysed by many enzymes simultaneously.
Coiled shape - allows the molecule to be easily compacted, so large amounts of it can be stored in small spaces.
Insoluble - won’t affect the cells water potential, and it can’t diffuse out of the cell.
Large - the molecule can’t diffuse out of the cell.

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11
Q

What are the properties of cellulose?

A

Straight, unbranched chain - allows for hydrogen bonds to form, increasing strength of molecule.
Grouped molecules - form microfibrils, which when grouped form fibres, providing more strength to the molecule.

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12
Q

What are the properties of glycogen?

A

Insoluble - it won’t affect the cells water potential, and can’t diffuse out of the cell.
Branched chain - allows the molecule to be easily hydrolysed by many enzymes simultaneously.
Coiled shape - allows the molecule to be compacted easily to store large amounts in small areas.
Large - the molecule can’t diffuse out of the cell.

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13
Q

Properties and uses of Triglycerides

A

Properties:
- contains ester bonds.
- contains carbon, hydrogen and oxygen.
- the fatty acids can be saturated or un-saturated.
- they only contain a hydrophobic region.
- they are formed by condensation reactions.
- they contain three fatty acids and glycerol.
- non-polar molecule, so won’t affect water potential of cell.
Uses:
- large form of energy storage due to high number of C-H bonds.
- used for insulation and protection of organs.
- important source of water due to release of water when oxidised as high H:O ratio.

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14
Q

Properties and uses of Phospholipids

A

Properties:
- contains ester bonds.
- contains carbon, hydrogen, oxygen and phospholipids.
- their fatty acids can be saturated or un-saturated.
- they contain both a hydrophobic and hydrophilic region.
- they are formed by condensation reactions.
- they are polar molecules, which form a bilayer with an aqueous environment.
- they contain glycerol, two fatty acids and a phospholipid group.
Uses:
- help maintain stability and strength of cells.
- act as semi-permeable barrier, helping maintain proper balance of substances within cell.
- aids protection against ‘environmental insults’.
- forms the phospholipid bilayer.

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15
Q

Uses of Lipids

A
  • Energy source
  • Insulation.
  • Protection.
  • Waterproofing.
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16
Q

Proteins:

  • What they are made of;
  • Definition of ; primary, secondary, tertiary and quaternary structures
A
  • made of a carboxyl group, an amine group, a hydrogen and carbon, and an R group.
  • contain peptide bonds
  • primary; specific sequence of chain of amino acids
  • secondary; hydrogen bonding of peptide backbone causes amino acids to fold into repeating patterns (alpha helix/beta pleats)
  • tertiary; 3-D folding pattern of secondary structure (polypeptide chains) due to side chain interactions (di-sulphide bridges, ionic bonds, hydrogen bonds, hydrophobic interactions)
  • quaternary; multiple polypeptide chains held together
17
Q

Fibrous proteins; structure and function

A
  • form long (polypeptide) chains which run parallel to one another. the chains are linked by cross-links/bridges, forming very stable molecules.
  • provide structural functions.
18
Q

Globular proteins; structure and function

Conjugated proteins; structure

A
  • form ‘round’ structures due to the hydrophobic areas (R groups in amino acids) folding inwards while the hydrophilic areas arrange around the external surface.
  • provide metabolic functions.
  • proteins that occur in combination with a non-protein (prosthetic) substance that is permanently bound to the protein, and are specific non-polypeptides required for the biological function of some proteins.
19
Q

The induced fit hypothesis

A

When the substrate binds to the enzymes active site, it ‘induces’ a change of shape onto the active site. This puts strain onto the substrate, which distorts it, lowering the activation energy.

20
Q

Factors affecting enzyme activity and how

A

Temperature; increasing temp mean increased kinetic energy, resulting in the enzymes and substrate moving more rapidly and successfully colliding more often in a given time.

pH; a change in pH alters the charges on the amino acids that make up the active site of enzymes, resulting in changes of shape of the active site, therefore no longer complementary to substrate, so enzyme-substrate complex cannot be formed.

Enzyme Concentration;
- Low - too few enzyme molecules to allow for all substrate molecules to find an active site at one time.
- Intermediate - all substrate molecules can occupy an active site at one time.
- High - excess enzyme molecules has no effect due to there being enough active sites already.

21
Q

What are the two types of enzyme inhibitor?

A

Competitive inhibitor
Non-competitive inhibitor

22
Q

Competitive inhibitors function

A

have similar molecule shape to substrate molecules. occupy the active site of an enzyme, ‘competing with it’. not permanent however greatly slows rate of reaction.

23
Q

Non-competitive inhibitors function.

A

attach to enzyme at ‘non-active site’ binding site, and alters the shape of the active site by changing the enzyme shape. stops active site and substrate being complementary so can’t bind. only permanent if inhibitor remains bound to enzyme.