1.2- biological molecules 1 Flashcards

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1
Q

what are organic compounds?

A

-compounds which contain carbon atoms
-they also contain; hydrogen, oxygen and sometimes nitrogen suplfur and phosphorus

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2
Q

how many bonds can each carbon make

A

4

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3
Q

why are carbohydrates important?

A

-important in cells as a usable energy store
-storing energy, and in plants, fungi and bacteria and form an important part of the cell wall
-

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4
Q

basic structure of carbs

A

-made up of carbon, hydrogen and oxygen
-3 main groups; monosaccharides, disaccharides, polysaccharides

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5
Q

what are monosaccharides?

A

-simple sugars in which there is one oxygen atom and two hydrogen atoms for each carbon atom present in the molecule
-general formula can be written as (CH2O)n+

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6
Q

triose sugars

A

-n=3
-have 3 carbon atoms and the molecular formula C3H6O3
-they are important in mitochondria, where glucose is broken down into triose sugars during respiration

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7
Q

pentose sugars

A

-n=5
-have 5 carbon atoms and the molecular formula C5H1O5
e.g. ribose and deoxyribose

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8
Q

hexose sugar

A

-n=6
-have six carbon atoms and the molecular formula C6H12O6
-often taste sweet including glucose, galactose and fructose

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9
Q

examples of monosaccharides

A

glucose
fructose
ribose

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10
Q

examples of disaccharides

A

sucrose
maltose
lactose

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11
Q

exmaples of polysaccharides

A

starch
cellulose
glycogen

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12
Q

how do monosaccharides form disaccharides

A

condenstaion reaction occurs to join the 2 monosaccharides, monosacs joined by a glycosidic bond (covelant)
-a molecule of water is removed

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13
Q

which disaccharide is not a reducing sugar

A

sucrose

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14
Q

test for reducing sugars

A

-add benedicts solution
-heat in hot water bath 90degrees
-reducing sugar reacts with benedicts and reduces copper (ii) ions to copper (i) ions
-colour changes from blue to orange/red

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15
Q

test for non reducing sugars

A

-heat non reducing sugar with few drops of hydrochloric acid
-neutralise with sodium hydrogen carbonate
-this produces sugars which are monosacs to give a pos benedicts test

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16
Q

why are monosaccharides soluble in water

A

have lots of hydroxyl (OH) groups which can readily engage in H bonding with water

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17
Q

what are polysaccharides

A

-polymers containing monosaccharides linked by glycosidic bonds
-formed by condensation reactions
-mainly used as energy store and structural components
e.g. starch and cellulose

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18
Q

oligosaccharides vs polysaccharides

A

-3-10 is a oligosaccharide
-more than 11 sugar units is a polysaccharide

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19
Q

why are polysaccharides so good for storage

A

-the glygosidic bond is easily broken meaning monosaccharides can be released quickly for respiration
-can be very compact, so many stored in cells
-not soluble, no no effect on water potential

20
Q

starch- amylose

A

-long chain of a glucose
-unbranched with 1,4 glycosidic bonds
-coiled to make it compact and good for storage

21
Q

starch-amylopectin

A

-long chains of a glucose
-branched
-1,4 and 1,6 glycosidic bonds
-branches allow enzymes to break down easily so glucose can be released quickly

22
Q

cellulose

A

-polymer of b glucose
-each monomer inverted
-forms chains which run parallel with H bonds between the chains to form microfibrils
-these are very strong
-structurally important in plant cell walls as it is fibrous

23
Q

glycogen

A

-animals store carbs as glycogen
-made of a glucose
-1,6 glycosidic bonds
-branched structure
-glycogen stored as small granules
-broken down more rapidly than starch, less dense and more soluble
-to meet higher metabolic demand in animals

24
Q

what are the 2 types of lipids

A

1.triglycerides
2.phospholipids

25
Q

2 examples of triglycerides

A

1.fats
2.oils

26
Q

what 2 molecules make up triglycerides

A

glycerol
3 fatty acids

27
Q

what bond joins glycerol and fatty acids

A

ester

28
Q

triglyceride formation

A

-triglyceride formed when each hydroxyl group on the glycerol combines with carboxyl group on fatty acid
-this is a condensation reaction
-esterfication
-water removed in reaction

29
Q

how to tell if it is saturated or unsaturated

A

-unsaturated have double bonds
-they have a low melting point and tend to be liquid at normal temps

30
Q

saturated fatty acids

A

-carbons joined by single covelant bond
-carbon atoms bonded to max number of atoms
-chain is relatively straight
-tend to be solids (fats) at room temp

31
Q

unsaturated fatty acids

A

-one or more double covelant bond present in carbon chain
-not bonded to max number of other atoms
-2 or more have double bonds
-usually liquid at room temp (oils)

32
Q

phospholipid structure

A

-2 fatty acid chains attached to glycerol
-polar phosphate group

33
Q

what do phospholipids make up

A

plasma membranes
-hydrophillic (polar) head and hydrophobic tail

34
Q

summary of phospholipids

A

-Glycerol phosphate (polar) head is hydrophilic.
-non polar, oily, hydrophobic tail
-said to be amphipathic
-gived cell membranes fluid properties and allow lipid soluble substances through

35
Q

bonds in proteins

A

-peptide between amino acids
-hydrogen
-disulphide’
-ionic

36
Q

hydrogen bonds

A

singally weak
-collectively strong
-easily broken

37
Q

disulphide bond

A

Formed in an oxidation reaction between 2 sulfur containing groups.
Results in a strong covalent bond.

38
Q

ionic bonds

A

-Not as common
-Form between strongly positive and negative amino side chains.
-Can be known as salt bridges.

39
Q

primary protein structure

A

-sequence of amino acids in polypeptide chain
-peptide bonds

40
Q

secondary protein structure

A

-a helices
-b pleated sheets
-form as a result of hydrogen bonding between different amino acids in the chain

41
Q

tertiary protein structure

A

-secondary structure folds up to form a very precise 3D structure
forces responsible;
1.hydrogen bonds
2.ionic bonds
3.disulphide bonds
4.van der waals forces

42
Q

how can all 4 forces be split

A

hydrogen- high temp and altered pH
ionic- changing pH
disulphide- reducing agent
van der waal- rise in temp

43
Q

what is van der waals forces

A

-weak forces of attraction between non polar groups

44
Q

quaternary structure

A
  • Some proteins consist of more than one polypeptide chain held together in a precise three-dimensional structure
    -2 main types are globular and fibrous
    -can also involve the addition of non-amino acid derived groups known as prosthetic groups
45
Q

globular proteins

A

-form a spherical mass
-They fold up so that hydrophillic groups are on the outside and hydrophobic groups are inside the molecule
-e.g.haemoglobin

46
Q

fibrous proteins

A

-form long chains or fibres
-fibrous nature makes them insoluble in water
-form triple helix of polypeptide chains
-held by hydrogen bonds
-e.g. collagen