1 Biological molecules Flashcards

1
Q

What is the difference between alpha glucose and beta glucose?

A

Alpha glucose- both Hs up
Beta glucose- one H, one OH up

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2
Q

Describe the reducing sugars test

A
  1. Grind up the food sample in water.
  2. Add an equal volume of Benedict’s reagent
  3. heat mixture gently in boiling water for 5 minutes.
  4. observe the colour change from blue to orange-brown (brick red)
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3
Q

Describe the non-reducing sugars test

A
  1. First carry out the reducing sugars test, do the if it is negative.
  2. grind up sample in water, add equal amounts of hydrochloric acid (this hydrolyses the disaccharides). Place in water bath for 5 mins.
  3. Add an alkali solution to neutralise it. Test with PH paper.
  4. Re-test- add benedicts solution and heat. observe colour change.
    colour change- blue to orange-brown.
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4
Q

Describe the test for starch

A
  1. Add some drops of iodine to a food sample.
  2. Observe colour change from orange to blue-black.
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5
Q

Describe the properties of triglycerides related to their function.

A
  • High ratio of energy storing carbon-hydrogen bonds to carbon atoms (excellent source of energy)
  • Low mass to energy ratio- Good storage molecules as energy can be stored at a small volume.
    -Large and non-polar- they are insoluble in water so do not change water potential.
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6
Q

Describe the properties of phospholipids related to their function.

A

Polar- hydrophilic head and hydrophobic tails mean that they form a bilayer in water
Hydrophilic heads- hold together the surface of the cell membrane.
Structure allows them to form glycolipids on the surface of the membrane (recognition sites)

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7
Q

Draw an amino acid- what are its components.

A

amino group (NH2), carboxyl group (COOH), hydrogen atom (H), R group (variant of any of 20 amino acids)

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8
Q

What bonds help to form the different structures of proteins?

A

Primary- just the sequence of amino acids
Secondary- hydrogen bonds
Tertiary- disulphide, ionic and hydrogen
Quaternary- same as tertiary.

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9
Q

Describe the test for proteins

A
  1. Grind up food sample in water and add biurets reagent.
  2. Observe colour change from blue-lilac
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10
Q

Factors affecting enzyme action:enzyme concentration

A

increases rate of reaction as it increases because the substrates are being broken down quicker and more effectively.

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11
Q

Factors affecting enzyme action: substrate concentration

A

Increases rate of reaction originally, until all enzymes active sites are occupied and there are substrates that are not actively being broken-down, causing the rate of reaction to slow.

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12
Q

Factors affecting enzyme action: competitive/non-competitive inhibitors

A

if the concentration increases, then rate of reaction will slow due to active sites being occupied/active sites being changed shape so they no longer fit their substrate.

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13
Q

Factors affecting enzyme action: PH and temperature

A

Temperature-increases rate of reaction due to more kinetic energy and collision theory until it exceeds the optimum and enzymes denature.
PH: Alters the tertiary structure of the enzyme causing it to denature and no longer fit the substrate.

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14
Q
A
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15
Q

What are the basic elements of carbohydrates?

A

carbon, hydrogen and oxygen

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16
Q

name two simple sugars

A

glucose and fructose

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17
Q

what are the primary functions of carbohydrates?

A

energy source and structural support

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18
Q

define the term monosaccharide

A

simple sugar unit

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19
Q

give an example of a disaccharide

A

maltose, lactose and sucrose

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20
Q

how do plants store carbohydrates?

A

as starch

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21
Q

what is the difference between starch and cellulose?

A

starch: energy storage
cellulose: structure

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22
Q

what is the function of glycogen?

A

animal energy storage carbohydrate

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23
Q

what is the chemical formula of glucose

A

C6H12O6

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24
Q

what are the main components of lipids?

A

glycerol and fatty acids

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25
Q

name one function of lipids

A

energy storage, insulation and hormones

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26
Q

define the term triglyceride

A

three fatty acids and a glycerol backbone

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27
Q

how do lipids differ from carbohydrates?

A

more energy per gram

28
Q

explain the term phospholipid

A

phosphate head and fatty acid tail

29
Q

what role do lipids play in the cell membrane?

A

structural integrity
selective permeability

30
Q

what is cholesterol?

A

steroid lipid in membranes

31
Q

what are two types of cholesterol carriers?

32
Q

how do lipids contribute to energy storage?

A

long term energy storage molecule

33
Q

what elements make up proteins?

A

carbon
hydrogen
oxygen
nitrogen

34
Q

name 4 functions of proteins

A

enzymes
structure
transport
defense

35
Q

define the term amino acid

A

building blocks of proteins

36
Q

give an example of a structural protein

A

collagen
keratin

37
Q

how do enzymes function?

A

catalysts- lower activation energy

38
Q

explain the term polypeptide

A

chain of amino acids

39
Q

what is the primary structure of a protein?

A

base sequence of amino acids

40
Q

what is the secondary structure of a protein?

A

folding of polypeptide into an alpha helix or beta pleated sheet shape

41
Q

what is the tertiary structure of a protein?

A

take me a specific 3D shape and it becomes functional at this stage

42
Q

what is the quaternary structure of a protein?

A

polypeptide associates with other polypeptides in order to carry out a function

43
Q

what is denaturation?

A

protein structure distribution via heat or PH

44
Q

how do proteins contribute to immunity?

A

antibody production and immune response

45
Q

name one function of enzymes

A

catalysts for biochemical reactions

46
Q

define the term enzyme inhibition, how does this happen?

A

blocking enzyme activity temporarily
competitive: occupy the active site
non-competitive: bind to the enzyme somewhere else to change active site shape

47
Q

how does enzyme concentration affect rate of reaction?

A

increased rate until saturation

48
Q

what is the role of cofactors?

A

not proteins but they assist enzyme activity

49
Q

how do enzymes lower activation energy?

A

provide an alternative reaction pathway

50
Q

describe the induced fit model

A

substrate induces enzyme shape change so that it is completely complimentary

51
Q

describe the induced fit model

A

substrate induces enzyme shape change so that it is completely complimentary

52
Q

describe waters polarity

A

unequal sharing of electrons

53
Q

how does water form hydrogen bonds

A

hydrogen attracts to oxygen

54
Q

what’s waters role in cells

A

solvent, medium for reactions to occur

55
Q

define cohesion in water

A

water molecules stick together

56
Q

what is waters heat capacity

A

high, moderates temperature changes

57
Q

explain waters solvent properties

A

dissolves polar and ionic substances

58
Q

describe waters surface tension

A

resistance to breaking surface

59
Q

what is waters importance in metabolism

A

medium for biochemical reactions

60
Q

how does water regulate temperature

A

absorbs and releases heat

61
Q

What does ATP stand for, what is its structure and function?

A

Adenosine triphosphate
adenine base, ribose sugar and three phosphates
energy transfer molecule

62
Q

how is ATP syntheised

A

through cellular respiration

63
Q

what enzyme catalyses ATP synthesis

A

ATP synthase
regenerates by combining ADP and Pi

64
Q

what are inorganic ions

A

charged particles in a solution

65
Q

name a common cation

A

sodium (Na+)

66
Q

name an anion

A

chloride (Cl-)