Biological Molecules (Not finished) Flashcards

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1
Q

What are ions in solution called

A

Electrolytes

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2
Q

What elements are carbohydrates made up of

A

C, H, O

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3
Q

What elements are lipids made up of

A

C, H, O

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4
Q

What elements are proteins made up of

A

C, H, O, N, S

Only 3 amino acids contain S

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5
Q

How many amino acids contain S

A

3

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6
Q

What elements are nucleic acids made up of

A

C, H, O, N, P

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7
Q

What are monomers

A

Atoms or molecules that bond together to form long-chains

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8
Q

What are the monomers for carbohydrates

A

Saccharides

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9
Q

What are the monomers for proteins

A

Amino acids

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10
Q

What are polar molecules

A

Molecules that have regions of positivity and negativity

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11
Q

Water is a liquid at room temperature. Explain why it has a high boiling point

A

Water molecules continually move around, and as they do, they form hydrogen bonds. These bonds mean that a lot of energy is required to increase the temperature of water and cause it to become gaseous.

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12
Q

Explain why water’s density is important

A

The density of water provides an ideal habitat for living things. if water was less dense, aquatic organisms would find it very difficult to float. As water cools, it becomes more dense up until 4 degrees, after which it becomes less dense because the water molecules align themselves in a structure less dense than liquid water. This means that:

Aquatic organisms have a stable environment in which to live in

It can be beneficial for the movement of animals, such as polar bears

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13
Q

What does water being cohesive mean

A

It moves as one mass as the molecules are attracted to each other. This means that:

Plants are able to draw up water through their roots

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14
Q

What does water being adhesive mean

A

Where water molecules are attracted to other materials. For example, when you wash your hands, your hands become wet, the water doesn’t run off.

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15
Q

Why is water a good solvent

A

The polar nature of water means that the positive and negative parts of the water molecules cluster around the charged parts of the solute molecules and will help to separate them and keep them apart. This means that:

Molecules and ions can move around and react together in water

Molecules and ions can be transported around living things whilst dissolved in water

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16
Q

Water has a high specific heat capacity. Explain what this means

A

Water molecules are held together quite tightly by hydrogen bonds. Therefore, you have to put in a lot of heat energy to increase their kinetic energy and temperature. This means that

Living things can survive because they need a stable temperature for enzyme-controlled reactions to happen properly

Aquatic organisms need a stable organisms need a stable environment in which to live

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17
Q

Water has a high latent heat of vaporisation. Explain what this means

A

When water evaporates, heat energy, known as the latent heat of vaporisation, helps the molecules to break away from each other to become a gas. because the molecules are held together by hydrogen bonds, a relatively large amount of energy is required for water to change state. therefore water can help to cool living things and keep their temperature stable. This means that

Mammals are cooled when sweat evaporates

Plants are cooled when water evaporates from mesophyll cells

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18
Q

What is the name of a carbohydrate polymer

A

Polysaccharide

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19
Q

How are alpha and beta glucose different

A

The H on carbon 1 is up on alpha glucose and down on down glucose

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20
Q

What kind of reaction joins glucose molecules together

A

Condensation reaction

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21
Q

What kind of bond is formed between 2 glucose molecules in a condensation reaction

A

Glycosidic

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22
Q

What are 5 functions of carbohydrates

A

Substrate for respiration

Hereditary information

Energy stores

Structure

Recognition of molecules outside of the cell

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23
Q

What are isomers

A

Molecules that have a different structure to each other but the same chemical formula

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24
Q

What is the difference between ribose and deoxyribose

A

Deoxyribose doesn’t have an oxygen on carbon 2, whereas ribose does

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25
Q

Where is the ribose sugar present

A

RNA nucleotides

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26
Q

Where is deoxyribose the sugar present

A

DNA nucleotides

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27
Q

What do 2 alpha glucose molecules make

A

Maltose

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28
Q

What does alpha glucose and fructose make

A

Sucrose

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29
Q

What does alpha glucose and beta galactose make

A

Lactose

30
Q

What do 2 beta glucose molecules make

A

Cellobiose

30
Q

What is starch made up of

A

Amylose and amylopectin

31
Q

What is the monomer of starch

A

Alpha glucose

32
Q

What are amylose and amylopectin joined together by in starch

A

Hydrogen bonds

33
Q

Why does starch have branches

A

More glucose can be hydrolised due to a larger SA and more endings

34
Q

What reaction releases glucose for respiration

A

Hydrolysis

34
Q

What is the monomer for cellulose

A

Beta glucose

35
Q

What is unique about cellulose in the terms of monomers

A

Every other beta glucose is flipped 180 degrees so the OH groups can bond together

36
Q

What kind of bond do the beta glucose molecules form in cellulose

A

1,4 beta glycosidic bonds

37
Q

What is glycogen used as in the liver and muscles for animals

A

A storage molecule

38
Q

What bonds are formed in the chain of glycogen

A

1,4 alpha glycosidic bonds

39
Q

What bonds are formed in the branches of glycogen

A

1,6 alpha glycosidic bonds

40
Q

Why do animals use glycogen instead of starch as a storage molecule

A

The molecule is more compact and more branched (compared to amylopectin). This allows for faster breakdown of the molecule during respiration as there can be more hydrolysis of free ends

41
Q

Is the chain of cellulose straight or coiled

A

Straight

42
Q

Does cellulose have stacked chains

A

Yes

42
Q

How are fibres that are used to make cell walls made

A

Cellulose molecules join together to make microfibrils. The microfibrils then join together to form macrofibrils, which combine to give these fibres

43
Q

What can reducing sugars do

A

Donate electrons or reduce another molecules

44
Q

Which type of molecule are reducing sugars

A

All monosaccharides and some disaccharides

45
Q

What test is used for reducing sugars

A

Benedicts solution

46
Q

What are the steps to the Benedict’s test for reducing sugars

A

Place the sample in a boiling tube. If it’s not in liquid form, grind it up

Add an equal volume of Benedict’s reagent

Heat the mixture gently for 5 minutes (at least 60 degrees)

47
Q

What colour change indicates a positive result for reducing sugars

A

Blue to green to amber to red

48
Q

Explain the results behind a positive reducing sugars test

A

The blue Cu2+ will have electrons added to them, making them brick-red Cu+ ions

49
Q

What is the test for starch

A

Iodine solution

50
Q

What are the steps to the test for starch

A

Add iodine solution which is dissolved in potassium iodide

51
Q

What colour change indicates a positive result for starch

A

Yellow-brown to blue-black

52
Q

Explain why a colour change is seen in a positive starch test

A

Iodine (I2) formed a triiodide ion (I3-), which slips into the middle of the amylose helix, causing the colour change and forming an iodine-starch complex

53
Q

What are the advantages of using reagent strips to test for reducing sugars

A

With the use of a colour-coded chart, the concentration of glucose can be determined

54
Q

How to use Benedict’s solution to test for non-reducing sugars

A

Have to check that it is not a reducing sugar first using Benedict’s solution

Then boil with HCl to separate sample into monosaccharides

Then test again. If a positive result is given then the sample was a non-reducing sugar

55
Q

Why are lipids not soluble in water

A

They are non-polar, so the electrons within the bonds more are evenly shared than in polar molecules

56
Q

How is a triglyceride made

A

By combining one glycerol molecule with three fatty acids

57
Q

What kind of bond is formed between glycerol and fatty acids

A

Ester bonds by esterification

58
Q

What is a phospholipid made of

A

A phosphate group, glycerol molecule and 2 fatty acids

59
Q

Which part of the phospholipid is hydrophilic

A

The charged heads

60
Q

Which part of the phospholipid is hydrophobic

A

The non-polar tails

61
Q

Why is cholesterol important in a cell membrane

A

It has an important role in the formation of cell membranes and regulates their fluidity

62
Q

What are some roles of lipids

A

Membrane formation

Hormone production

Electrical insulation in nerve transmission

Waterproofing

Buoyancy in animals

63
Q

What is the test for lipids

A

Emulsion test

64
Q

What are the steps in the emulsion test

A

Mix sample with ethanol

Filter and add solution to water in a test tube

Shake. If a cloudy white emulsion forms then this indicates the presence of a lipid

65
Q

What is the monomer for proteins

A

Amino acids

66
Q

What happens in the levels of protein production

A

1 - sequencing of amino acids

2 - initial folding into an alpha helix or beta pleated sheet held together by H bonds

3 - folding into a 3D shape, held together by the 4 different kind of bond (hydrogen, ionic, disulphide and hydrophilic and hydrophobic interactions)

4 - multiple tertiary structures joined together

67
Q

What are the physical qualities of globular proteins

A

Compact, water soluble and roughly spherical

68
Q

Why are globular proteins water-soluble

A

The way that they fold into their tertiary structures means that their hydrophobic R group is kept away from the aqueous environment

69
Q
A