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a level biology > Biological Molecules 1.1-1.3 > Flashcards

Biological Molecules 1.1-1.3 Flashcards

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AP® Biology flashcards
1
Q

What’re biological molecules?

A

molecules made and used by living organisms e.g. Carbohydrates, Proteins, Lipids, DNA, ATP, Water, Inorganic Ions

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2
Q

What are the building blocks for carbohydrates called?

A

Monosaccharides

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3
Q

Monomers

A

The smaller units from which larger molecules are made

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4
Q

Polymers

A

Molecules made up from a large number of monomers joined together

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5
Q

Examples of monomers

A

Monosaccharides
Amino acids
Nucleotides

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6
Q

Condensation reaction

A

Joins two molecules together with the formation of a chemical bond and involves the elimination of a molecule of water

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7
Q

Hydrolysis reaction

A

Breaks a chemical bond between two molecules and involves the use of a water molecule in

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8
Q

Monosaccharide

A

The monomers from which larger carbohydrates are made

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9
Q

Name some monosaccharides

A

Glucose
Galactose
Fructose

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10
Q

A condensation reaction between two monosaccharides forms

A

A glycosidic bond

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11
Q

Glycosidic bond

A

Forms from a condensation reaction between two monosaccharides

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12
Q

Name some disaccharides

A

Maltose
Sucrose
Lactose

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13
Q

How’s maltose formed

A

The condensation of two glucose molecules

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14
Q

How’s sucrose formed

A

The condensation of a glucose molecule and fructose molecule

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15
Q

How’s lactose formed

A

The condensation of a glucose molecule and a galactose molecule

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16
Q

Two glucose isomers

A

Alpha

Beta

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17
Q

Alpha glucose

A

H

OH

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18
Q

Beta glucose

A

OH

H

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19
Q

Polysaccharide

A

Formed by the condensation of many glucose units

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20
Q

What are polysaccharides

A

carbohydrates
− made of a long chain of monosaccharides joined by condensation reaction/glycosidic ​bonds
− 3 examples: Starch, Glycogen, Cellulose

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21
Q

Name polysaccharides

A

Glycogen
Starch
Cellulose

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22
Q

How’s glycogen formed

A

The condensation of alpha glucose

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23
Q

How’s starch formed

A

The condensation of alpha glucose

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24
Q

How’s cellulose formed

A

The condensation of beta glucose

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25
Q

Alpha glucose polysaccharides

A

Starch and glycogen

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26
Q

A beta glucose polysaccharide

A

Cellulose

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27
Q

Carbohydrates

A

Most are polymers
Made form monomers called monosaccharides
All contain elements C H O

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28
Q

Two groups of carbohydrates

A

Sugars

Polysaccharides

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29
Q

Two sugar groups

A

Monosaccharide

Disaccharide

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30
Q

Two polysaccharide groups

A

Storage

Structure

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31
Q

Polysaccharides used for storage

A

Glycogen

Starch

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32
Q

Polysaccharides used for structure

A

Cellulose

Chitin

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33
Q

Test for reducing sugars

A

Benedict’s
Add 2 cm³ of the sample to a test tube
Add 2 cm³ of Benedict’s solution to this test tube. Benedict regrant is an alkaline solution of copper sulphate
Heat in a water bath at a minimum of 70°C
After three minutes record the colour of the solutions. The colour will change from blue to brick red copper oxide.

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34
Q

Test for non reducing sugars

A

Add 2 cm³ of the sample to a test tube
Add dilute hydrochloric acid, and heat in gently boiling water for five minutes. The acid will hydrolyse any disaccharide present (breaks the glycosidic bonds)
Add sodium hydrogen carbonate to then neutralise the acid
Retest the solution using Benedicts reagent. If the test is negative for any sugar at all, blue colour will remain. If the red precipitate is formed, then a non-reducing sugar would have been present in the original sample

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35
Q

Test for starch

A

Iodine solution
Add 2cm3 of the sample to a spotting tile/ test tube
Add 2 drops of iodine solution
A colour change from orange/brown to blue/black shows that starch is present

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36
Q

Reducing sugar

A

A sugar that can donate electrons to another chemical called Benedict’s reagent, ‘reducing’ it, causing it to change colour

37
Q

Name reducing sugars

A

All monosaccharides (glucose, galactose, fructose)
Maltose
Lactose

38
Q

What’s Starch

A

Polysaccharide

Made up of Chains of a-glucose monosaccharides linked by glycosidic bonds formed by condensation reactions

39
Q

Starch main role

A

Storage

40
Q

Starch’s structure for function

A

Insoluble so can’t draw water into cell by osmosis
Large and insoluble so cannot diffuse out of cell
Compact so lots of it can be stored in a small area
When hydrolysed it forms alpha glucose which can be easily transported and used in respiration
The branched form has many ends, each can be acted on by enzymes simultaneously meaning that glucose monomers are released very rapidly

41
Q

Where is starch found

A

Plants

Seeds and storage organs

42
Q

What is glycogen

A

Polysaccharides found in animals
Small chains with many branches
Stored as small granules in muscles and liver
Alpha glucose chains linked by glycosidic bonds

43
Q

Main role of glycogen

A

Storage

44
Q

Glycogen structure for function

A

Insoluble so doesn’t draw water into cells by osmosis
Being insoluble it doesn’t diffuse out of cells
Compact, so a lot of it can be stored in a small space
More branched than starch, so has more ends that can be acted on simultaneously by enzymes. It is therefore more rapidly broken down to form glucose monomers for respiration

45
Q

What is Celulose

A

Made of beta glucose monomers
Has straight unbranched chains
These chains run parallel to each other, allowing the hydrogen bonds to form cross linkages between adjacent chains
The overall number of the hydrogen bonds makes a considerable contribution to strengthening Celulose
The cellulose molecules molecules are grouped together to form microfibrils which are arranged in parallel groups called fibres

46
Q

Cellulose structure

A

B glucose molecules in long chains parallel
Hydrogen binds forming cross bridges
Unbranched chains
Cellulose chain has adjacent glucose molecules rotated by 180 degrees
Allows hydrogen bonds to be formed between (-OH) groups on adjacent parallel chains that help to give cellulose its structural stability

47
Q

Celulose main role

A

Structure

48
Q

cellulose structure for function

A

Prevents the cell from bursting as water enters it by osmosis
Does this by exerting an inward pressure that stops any further influx of water
Long unbranched chains run parallel to each other and are cross-linked by hydrogen bonds which adds collective strength
these molecules are grouped to form microfibrils which in turn group to form fibres all of which provides yet more strength

49
Q

How to remember lipids roles

A

WIMPE

50
Q

Lipids waterproofing

A

Insoluble in water

51
Q

Lipids insolation

A

Helps retain body heat

52
Q

Lipids membranes

A

Contributes to flexibility of cell membranes

53
Q

Lipids protection

A

Around delicate organs

54
Q

Lipids energy

A

When oxidised, releases two times quantity of energy as carbohydrates

55
Q

Two lipids groups

A

Triglycerides

Phospholipids

56
Q

Triglycerides two groups

A

Fats

Oils

57
Q

Difference between fats and oils

A

Both triglycerides
Fats are solid at room temp
oils are liquid at room temp

58
Q

Forming triglycerides

A

1 glycerol + 3 fatty acids

Makes 1 triglyceride and 3H2O

58
Q

Two types of triglycerides

A

Saturated and unsaturated fat

59
Q

Glycerol formula

A

C3H8O3
-OH Group

     H     
      |
H-C-OH
      |
H-C-OH
      |
H-C-OH
      |
     H
60
Q

Fatty acid formula

A

RCOOH-

     O 
     || HO-C-R
61
Q

Triglyceride formula

A 
H        O
      |         ||
H-C-O-C-R
      |         O
      |         ||
H-C-O-C-R
      |        O
      |        ||
H-C-O-C-R
      |
     H
62
Q

Triglyceride structure related to function

A

High ratio of energy storing C-H bond to carbon atoms, therefore is an excellent source of energy
Low mass to energy ratio, makes them good energy storage molecules. Beneficial as reduces the mass animals have to carry as they move
Large, non polar molecule, meaning they’re insoluble in water. Don’t effect water potential/osmosis in cells
High ratio of hydrogen to oxygen atoms- release lots of water therefore when oxidised
Double bonds in polyunsaturated fatty acids makes the molecule bond. They cannot pack together so closely. Liquid at room temp

63
Q

Phospholipid

A

Phospholipids are a class of lipids that are a major component of all cell membranes. They can form lipid bilayers because of their amphiphilic characteristic. The structure of the phospholipid molecule generally consists of two hydrophobic fatty acid “tails” and a hydrophilic “head” consisting of a phosphate group.

64
Q

Phospholipid structure

A

Glycerol, 2 fatty acids and phosphate

Hydrophilic phosphate Head and hydrophobic fatty acid tails

65
Q

Phospholipid structure related to function

A

Polar molecules, meaning that in an aqueous environment, phospholipid molecules form a bilayer within cell-surface membranes. So hydrophobic barrier is formed between the inside and outside of a cell
Hydrophobic phosphate head helps to hold the cell membrane together
Structure allows them to form glycolipids by combining with carbohydrates within the cell surface membrane. These glycolipids are important in cell recognition

66
Q

What binds join fatty acids to glycerol

A

Ester bonds

67
Q

Saturated fatty acid structure

A

No double C bond
No kink
Solid at room temp

68
Q

Monounsaturated fatty acid structure

A

One double C bond
Kink
Liquid at room temp

70
Q

Polyunsaturated fatty acid

A

Two double C bonds

71
Q

Test for lipids

A 
Emulsion Test
Grease free tube
2cm3 of sample and 5cm3 ethanol
Shake to dissolve any lipid present
Add 5cm3 water and gently shake
Cloudy white colour indicates presence of lipid
72
Q

What causes emulsion

A

Light passing through the emulsion is refracted as it passes from oil droplets to water droplets- makes it look cloudy

73
Q

Where are Ester bonds formed

A

Between fatty acid and glycerol in a condensation reaction

Triglyceride and phopolipid

74
Q

Lipids WIMPE

A 
Water proofing 
Insulation
Membrane
Protections
Energy
75
Q

Monosaccharide formula

A

C6H12O6

76
Q

Disaccharide formula

A

C12H22O11

77
Q

Butter

A

Solid at room temp

saturated fat

78
Q

Oil

A

Liquid at room temp

Unsaturated fat

79
Q

Why is butter solid at room temp whilst vegetable oil is liquid

A

Butter- saturated fat (molecules can pack closely together because they have no kink, so it’s easier to solidify)

Liquid- unsaturated (has kink so molecules are less likely to pack tog)

80
Q

Hydrophilic head phospholipids

A

Water loving
Interacts with water, not fat
Is the phosphate molecule

81
Q

Hydrophobic tail phospholipids

A

Hates water
Interacts with fat not water
Are the fatty acids

82
Q

Isomer

A

When two molecules has the same amount of each atom but they have a different arrangement
E.g. a and B glucose

83
Q

Guidelines advise people to reduce their intake of saturated fats to reduce the risk of

A

Cardiovascular disease

84
Q

What’s starch and glycogen used for in plants and animals

A

Energy

Converts into glucose (hydrolysis)

85
Q

Starch is made up of what two polymers (composed of glucose units)

A

Amylose (linear)

Amylopectin (branched)

86
Q

What’s glycogenolysis

A

process by which glycogen, the primary carbohydrate stored in the liver and muscle cells of animals, is broken down into glucose to provide immediate energy and to maintain blood glucose levels during fasting.

87
Q

Why is glucose stored as polysaccharides

A

Glucose is soluble in water
Would effect water potential of any fluid it’s dissolved in
Can’t be stored
However polysaccharides are insoluble in water

88
Q

Which has more branches

Starch or glycogen

A

Glycogen

Animals have higher need for energy than plants

a level biology (20 decks)

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