Topic 1 - Biological molecules Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

what type of molecules are carbohydrates ?

Carbohydrates

A

polymers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are polymers ?

Monomers and Polymers

A

large complex molecules composed of long chains of monomers joined together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are monomers ?

Monomers and Polymers

A

small, basics molecular units that join together to form polymers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

name 3 monomers

Monomers and Polymers

A

monosaccharides, amino acids and nucleotides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what elements to all carbohydrates contain ?

Carbohydrates

A

C, H and O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what monomers are carbohydrates made from ?

Carbohdrates

A

monosaccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

name 3 monosaccharides

Carbohdrates

A

glucose, galactose and fructose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are monosaccharides

Carbohdrates

A

sugar molecules that create polymers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what type of molecule is glucose and what does this mean

Carbohdrates

A

hexose sugar - a monosaccharide with 6 carbon atoms in each molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are the two types of glucose ?

Carbohdrates

A

alpha glucose and beta glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Draw the structure of alpha glucose

Carbohdrates

A

.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Draw the structure of beta glucose

Carbohdrates

A

.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what’s an isomer

Carbohdrates

A

molecules with the same formula as each other but the atoms are connected differently

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what’s a condensation reaction ?

Monomers and Polymers

A

two molecules join together with the formation of a new chemical bond and the release of a water molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is a disaccharide ?

Carbohdrates

A

two monosaccharides joined together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what bond is formed during a condensation reaction for carbohydrates

Carbohdrates

A

1,4 glycosidic bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

glucose + glucose =

Carbohdrates

A

maltose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

glucose + galactose =

Carbohdrates

A

lactose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

glucose + fructose =

Carbohdrates

A

sucrose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what happens during a hydrolysis reaction

Monomers and Polymers

A

polymers are broken down into monomers by breaking the chemical bond using a water molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what disaccharides are reducing sugars ?

Carbohdrates

A

maltose and lactose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

list the method for testing for reducing sugars

Carbohdrates

A
  1. Add blue benedict’s reagent to the sample and heat it in a water bath that’s been brought to the boil.
  2. if the test is positive a coloured precipitate will form
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is the colour scale for positive reducing sugar test ?

Carbohdrates

A

blue, green, yellow, orange, brick red

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Give an accurate way to compare the amount of reducing sugars in a solution

Carbohdrates

A

filter the solution and weigh the precipitate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what disaccharide is a non reducing sugar

Carbohdrates

A

sucrose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

list the method for testing for non reducing sugars

Carbohdrates

A
  1. Add dilute hydrochloric acid to the food sample and heat it in a water bath that’s been brought to the boil.
  2. Add sodium hydrogencarbonate to neutralise it.
  3. Add blue benedict’s reagent and heat in a water bath that’s been brought to the boil.
    4.if the test is positive a coloured precipitate will form depending on the concentration of the non reducing sugar.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is a polysaccharide and how is it formed

Carbohdrates

A

A polymer formed when more than 2 monosaccharides are joined together by condensation reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are the three polysaccharides

Carbohdrates

A

starch, glycogen and cellulose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

in plants, what’s alpha glucose stored as

Carbohdrates

A

starch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What’s starch a mixture of

Carbohdrates

A

two polysaccharides of alpha glucose: Amylose and amylopectin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Describe the structure and function of amylose

Carbohdrates

A

long, unbranched chains of alpha glucose. The angles of the 1,4 glycosidic bonds give it a coiled shape making it compact and good for storage as you can fit more into a smaller space.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

describe the structure and function of amylopectin

Carbohdrates

A

long, branched chains of alpha glucose. it’s side branches allowed the enzymes that break down the molecule to get to the glycosidic bonds easier so glucose can be released quickly. made from 1,4 and 1,6 glycosidic bonds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Give a positive of starch

Carbohdrates

A

it’s insoluble in water so doesn’t affect water potential meaning it won’t draw water into cells by osmosis which prevents them from swelling, making it good for storage.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

give the method for testing for starch

Carbohdrates

A
  1. Add iodine dissolved in potassium iodide solution to the food sample
  2. if the test is positive the colour will change from orangey brown to blue back
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

what’s glycogen’s role

Carbohdrates

A

to store glucose in animals so it is the main energy source for animals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what type of molecule is glycogen

Carbohdrates

A

polysaccharide of alpha glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

describe the structure and function of glycogen

Carbohdrates

A

it is made from long branched chains meaning that enzymes can reach the binds easily so stored glucose can be released quickly which is important for energy release in animals. It’s also a very compact molecule so is good for storage as more can fit into a smaller space. 1,4 and 1,6 glycosidic bonds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

what type of molecule is cellulose

Carbohdrates

A

polysaccharide of beta glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

describe cellulose’s structure and function

Carbohdrates

A

it’s long and unbranched. When beta glucose molecules bond (1,4 glycosidic bonds) they form cellulose chains these cellulose chains bond together by hydrogen bonds to form strong fibres called microfibrils. these fibres give cellulose strength allowed it to provide support and structure for plant cell walls

40
Q

name a type of lipid

Lipids

A

triglyceride phospholipid

41
Q

Draw the structure of a triglyceride

A

.

42
Q

what’s a triglyceride made of

Lipids

A

one glycerol molecule and 3 fatty acids

43
Q

draw the basic structure of a fatty acid

Lipids

A

O
||
HO—C—-R

44
Q

Draw a saturated and unsaturated fatty acid

Lipids

A

.

45
Q

Describe the fatty acids structure and function

Lipids

A

fatty acid molecules have long tails made of hydrocarbons. the tails are hydrophobic so repel water molecules. these tails make lipids insoluble in water.

46
Q

What bond holds lipids together

Lipids

A

ester bonds

47
Q

how is a triglyceride formed

Lipids

A

a glycerol molecule joins 3 fatty acids, when the ester bonds are formed, 3 molecules of water are released

48
Q

what are saturated fatty acids

Lipids

A

fatty acids that don’t have any carbon carbon double bonds, the fatty acid is saturated with hydrogen

49
Q

what are unsaturated fatty acids

Lipids

A

unsaturated fatty acids have at-least one carbon carbon double bond causing the chain to have a kink.

50
Q

what are phospholipids

Lipids

A

lipids found in cell membranes

51
Q

describe the structure of phospholipids

Lipids

A

one glycerol molecule with 2 fatty acids and one phosphorus group bonded to it.

52
Q

Draw the structure of a phospholipid

Lipids

A

.

53
Q

explain the relation with water both the phosphorus group and the fatty acid tails have.

Lipids

A

the phosphorus ‘head’ is hydrophilic so attracts water, the fatty acid (hydrocarbon) tails are hydrophobic so repel water.

54
Q

what’s the main use of triglycerides

Lipids

A

energy storage

55
Q

describe the structure and function of triglycerides

Lipids

A

the long hydrocarbon tails of the fatty acids contain lots of chemical energy so lots of energy is released when they’re broken down. because of these fails the lipids contain about twice as much energy per gram than carbohydrates. They’re insoluble in water so don’t affect water potential so no water is drawn into cells by osmosis which would cause the cell to swell. the triglycerides clump together as insoluble droplets in cells because the fatty acid tails are hydrophobic so the tails face inwards protecting them from water by the glycerol heads

56
Q

what are phospholipids structure and function

Lipids

A

phospholipids make up the holster of cell membranes. their heads are hydrophilic and their tails are hydrophobic so they from a double layer with their heads facing out towards the water either side. the centre of the bilayer is hydrophobic so water molecules can’t easily pass through them- the membranes act as a barrier to those substances.

57
Q

describe the test for lipids

Lipids

A
  1. add ethanol to the food sample
  2. add decanted water
  3. any lipid will show as a white/ milky emulation. the more lipid there is, the more noticeable the milky colour will be.
58
Q

what’s the monomers of protein

Proteins and Enzymes

A

amino acids

59
Q

what’s a dipeptide

Proteins and Enzymes

A

two amino acids joined together

60
Q

what’s a polypeptide

Proteins and Enzymes

A

more than two amino acids joined together

61
Q

what’s a protein

Proteins and Enzymes

A

a polymer made of one or more polypeptides ( long chains of amino acids)

62
Q

give the general structure of an amino acid and draw it

Proteins and Enzymes

A

an amine group (H2N), a carbnonatom, a carboxyl group (COOH), a hydrien atom, and a variable group (R).

63
Q

how are polypeptides formed

Proteins and Enzymes

A

condensation reactions reactions between amino acids. a molecule of water is released once the peptide bond is formed between the amino acids.

64
Q

what bonds are formed between amino acids

Proteins and Enzymes

A

peptide bonds

65
Q

For proteins, what is the primary structure ?

Proteins and Enzymes

A

The sequence of amino acids in a polypeptide chain.

66
Q

For proteins, what is the secondary structure ?

Proteins and Enzymes

A

Hydrogen bonds form between the amino acids in the chain causing the chain to coil into an alpha helix or fold into a beta pleated sheet.

67
Q

For proteins, what is the tertiary structure ?

Proteins and Enzymes

A

The coiled or folded chain of amino acids is coiled or folded further. More bonds from between amino acids R groups, hydrogen bonds, ionic bonds and disulphide bridges form when 2 of the amino acid cysteine come close together. For proteins made from a single polypeptide chain, this is there final 3D structure.

68
Q

For proteins, what is a quaternary structure ?

Proteins and Enzymes

A

Some proteins are made from several polypeptide chains held together by bonds. The quaternary structure is the way these chains are assembled together. This is their final 3D structure for proteins made of more than one polypeptide chain.

69
Q

What are the 4 functions of proteins ?

Proteins and Enzymes

A

Enzymes, antibodies,transport proteins and structural proteins.

70
Q

What is the role of proteins in enzymes ?

Proteins and Enzymes

A

They’re usually a rough spherical shape due to the right folding of polypeptide chains. They’re soluble and often have roles in metabolism. Some synthesise larger molecules.

71
Q

What’s the role of proteins in antibodies ?

Proteins and Enzymes

A

They’re involved in the immune system. Made of two light polypeptide chains and two heavy polypeptide chains bonded together. Antibodies have variable regions, the amino acid sequence in these regions vary greatly.

72
Q

What’s the role of transport proteins ?

Proteins and Enzymes

A

E.g. channel proteins present in cell membranes contain hydrophobic and hydrophilic amino acids. Which causes the protein to fold up into a channel. These proteins transport ions and molecules across membranes.

73
Q

What’s the role of proteins in structural proteins ?

Proteins and Enzymes

A

They’re psychically strong and consist of long polypeptide chains lying parallel to each other with cross links between them. It include keratin (hair and nails) and collagen (connective tissue).

74
Q

How would u test for proteins ?

Proteins and Enzymes

A

Biuret test
1. Add a few drops of sodium hydroxide solution in order to make the solution alkaline.
2. Add some copper (II) sulfate solution.
3.if proteins are present the solution will turn purple, if not it will remain blue.

75
Q

What are enzymes ?

Proteins and Enzymes

A

Biological catalysts

76
Q

What do enzymes do ?

Proteins and Enzymes

A

catalyse metabolic reactions at a cellular level (respiration) and for the organism as a whole (digestion). Enzyme action can be intracellular (within the cell) or extracellular( outside of the cell). They speed up the rate of reactions by lowering the activation energy without being used up or changed.

77
Q

What’s the active site of an enzyme ?

Proteins and Enzymes

A

The area on the enzyme that the substrate binds to which forms an enzyme substrate complex.

78
Q

How do enzymes lower the activation energy in a breakdown reaction ?

Proteins and Enzymes

A

When the substrate fits to the active site if the enzyme an enzyme substrate is formed - its this that lowers the activation energy as the active site changes shape to get a tighter fit around the substrate (induced fit), this puts a strain on the bonds, making them weaker so that less energy (heat) is needed to break them.

79
Q

How does an enzyme catalyse the joining molecules ?

Proteins and Enzymes

A

Being attached to the enzymes active site holds them closer together, reducing any repulsion between the molecules so they can bond easily.

80
Q

What’s the lock and key model ? and what did new evidence suggest ?

Proteins and Enzymes

A

The idea that the substrate fits into the enzyme’s active site the way a key fits into a lock. However, new evidence suggest that the enzyme substrate complex changes shape slightly to complete the fit this locks the substrate into the active site and is called the induced fit model.

81
Q

What’s the induced fit model ?

Proteins and Enzymes

A

the enzyme substrate complex changes shape slightly to complete the fit this locks the substrate into the active site forming an enzyme substrate complex.

82
Q

What are enzymes active site shape determined from ?

Proteins and Enzymes

A

The enzymes active sit shape is determined by it’s tertiary structure (which is determined by its primary structure). Each enzyme has a different tertiary structure so has a different shaped active site. Making only one substrate complimentary to it.

83
Q

What will happen if the tertiary structure of an enzyme is altered ?

Proteins and Enzymes

A

The tertiary structure of the enzyme determines thee shape of the active site, therefore if the tertiary structure is altered the active site shape will change. This means that the substrate will not fit to the active site so an enzyme substrate complex will not form and the enzyme cannot carry out its function. The enzyme will become denatured

84
Q

What things can change the enzymes tertiary structure ?

Proteins and Enzymes

A

pH and temperature. Also, the primary structure is determined by a gene, if mutations occur in the genes it could change the tertiary structure produced.

85
Q

Explain the relationship between rate of reactional and temperature in enzymes.

Proteins and Enzymes

A

The rate of reaction increases as temperature increases as more hear means more kinetic energy, so molecules move faster meaning enzymes are more likely to collide with the substrate and from enzyme substrate complexes. However, if temperature gets too high the reaction stops. This is because as temperature increases particles vibrate more, if the temp is above the enzymes optimum temp the vibrations break some of the bonds which hold the enzyme in shape. The active site then changed shape and the enzyme substrate complex can no longer form - the enzyme is denatures and can no longer function as a catalyst.

86
Q

Explain the relationship between rate of reaction and pH in enzymes.

Proteins and Enzymes

A

All enzymes have an optimum pH value. Above and below the optimum pH values the OH- and H+ ions can mess up the hydrogen bonds that hold the tertiary structure together - changing the shape of the active site and the enzyme becomes denatured.

87
Q

Explain the relationship between rate of reaction and enzyme concentration

Proteins and Enzymes

A

The more enzyme molecules there are in a solution, the more likely a substrate molecules is to collide with one and form an enzyme substrate complex. So, increasing enzyme concentration increases the rate of reaction. But, if the amount of substrate is limited, there will be a point where there’s excess enzyme molecules to deal with the substrate, so adding more enzymes wouldn’t affect the rate of reaction.

88
Q

Explain the relationship between the rate of reaction and substrate concentration

Proteins and Enzymes

A

The higher the substrate concentration, the faster the rate of reaction - more substrate molecules means that more collisions will occur to form enzyme substrate complexes- more active sites are used. However, this is only true until the saturation point. After that there are extra substrate molecules as all active sites are occupied.

89
Q

What’s a competitive inhibitor ?

Proteins and Enzymes

A

Competitive inhibitor molecules have a similar shape of the substrate molecules. they compete with the substrate molecules to bind to the enzyme’s active site, but no reaction takes place, instead they block the active site so that no substrate can fit to it.

90
Q

Explain the relationship between rate of reaction substrate concentration and competitive inhibitors

Proteins and Enzymes

A

If there’s a high concentration of the substrate then the substrates chances if colliding with the enzyme before the inhibitor does increases. so increasing the substrate concentration increases the rate of reaction. however if there’s a high concentration of inhibitors they have more chance of colliding with the enzyme and binding the the active site - hardly any substrate will collide wuth the enzyme decreasing the rate of reaction.

91
Q

What’s a non competitive inhibitor ?

Proteins and Enzymes

A

A non competitive inhibitory binds to the alosteric site of the enzyme this causes the active sites shape to change so substrates can no longer bind to it. they don’t compete with the substrate to bind to the active site because they’re a different shape to the substrate.

92
Q

Explain the relationship between the rate of reaction with non competitive inhibitors and substrate concentration

Proteins and Enzymes

A

increasing the concentration of the substrate won’t make any difference to the rate of reaction as the enzyme activity is inhibited as the inhibitor changing the shape of the active site so enzyme substrate complexes can no longer form so less reactions are catalysed.

93
Q

what are cofactors ?

Proteins and Enzymes

A

an additional non protein molecule that is needed by some enzymes to help the reaction

94
Q

what are prosthetic groups ?

Proteins and Enzymes

A

they’re tightly bound co-factors

95
Q

what are coenzymes ?

Proteins and Enzymes

A

cofactors that bound and release