T1: Biological Molecules Flashcards

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1
Q

What are monomers?

A

Small molecular units that join to make polymers

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2
Q

Define polymer

A

A molecule made from long chains of monomers

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3
Q

What is a condensation reaction?

A

The joining of two monomers together with the release/elimination of a
molecule of water (forming a chemical bond)

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4
Q

What is a hydrolysis reaction?

A

The breaking of a chemical bond between two molecules involving the use of a water molecule

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5
Q

Two monosaccharides = ?

A

A disaccharide (joined by a condensation reaction forming a glycosidic bond)

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6
Q

More than two monosaccharides = ?

A

Polysaccharide (joined together by condensation reactions forming glyosidic bonds)

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7
Q

Name 3 monosaccharides

A

glucose
galactose
fructose

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8
Q

Name one non reducing sugar?

A

sucrose

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9
Q

glucose + glucose = ?

A

maltose

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10
Q

glucose + galactose = ?

A

lactose

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11
Q

glucose + fructose = ?

A

sucrose

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12
Q

Name the 2 types of glucose

A

Name the 2 types of glucose

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13
Q

In alpha glucose the OH is…

A

below

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14
Q

In beta glucose the OH is…

A

above

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15
Q

How are glycogen and starch formed?

A

by the condensation of alpha glucose

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16
Q

How is cellulose formed?

A

by the condensation of beta glucose

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17
Q

Where is starch located in organisms?

A

Many parts of plants in the form of small grains + large amounts found in seeds & storage organs

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18
Q

What is the purpose of starch?

A

Plants store excess glucose as starch

19
Q

How is starch produced?

A

Condensation of many α-glucose sub units, which then form hydrogen bonds with molecules in the same chain

20
Q

Starch is a mixture of…

A

2 polysaccharides of alpha-glucose
amylose + amylopectin

21
Q

Describe the structure of amylose

A

Long, UNbranched chain of α-glucose

22
Q

Describe how the structure of amylose relates to its function

A

Angles of the glycosidic bonds = coiled structure → makes it compact = can fit more into a small space (= good for storage)

23
Q

Describe the structure of amylopectin

A

Long, BRANCHED chain of α-glucose

24
Q

Describe how the structure of amylopectin relates to its function

A

Its side branches allow the enzymes that break down starch to get at the glycosidic bonds easily = glucose can be released quickly

25
Q

α-glucose molecules are formed by what type of glycosidic bonds?

A

1,4 & 1,6 glycosidic bonds

26
Q

How is cellulose formed?

A

by the condensation of beta glucose

27
Q

Where is glycogen located in organisms?

A

Stored as small granules mainly in liver and some in muscles

28
Q

What is the purpose of glycogen?

A

In animals: excess glucose is stored as glycogen

29
Q

Glycogen is a p______…

A

Polysaccharide of α-glucose

30
Q

Describe glycogen’s structure

A

Chain of α-glucose with many side branches coming off it + short chains

31
Q

Describe how glycogen’s structure relates to its function

A
  1. Loads of branches & shorter chains = stored glucose can be released even quicker than in starch → important for energy releases in animals
  2. Very compact molecule, making it good for storage
32
Q

Why is starch suited for its role? 3x

A
  1. Insoluble in water = doesn’t affect water potential (doesn’t cause water to enter cells by osmosis)
  2. Compact = lots of it can be stored in small space
  3. When hydrolysed, alpha glucose can be easily transported & used in respiration
33
Q

Describe the structure of cellulose

A
  1. Long, unbranched chains of beta-glucose
  2. Straight cellulose chains run parallel to each other in cell walls = allows hydrogen bonds to form cross-linkages between chains

Result: formation of bundles called micro fibrils which then join together to make macro fibrils

34
Q

What is the purpose of cellulose?

A

To provide rigidity to plant cells

35
Q

Describe the test for reducing sugars

A

Add Benedict’s reagent (blue) to sample & heat it in a boiling water bath (5 mins)
Positive result = orange/red precipitate
Higher the concentration of reducing sugar = further the colour change goes
blue - green - yellow - orange - brick red

36
Q

Describe the test for non-reducing sugars

A

Heat a new sample with dilute HCl in a boiling water bath
Neutralise with alkali
Repeat Benedicts test for reducing sugars

37
Q

Describe the structure of a triglyceride

A

3 fatty acids attached to a single glycerol

38
Q

What do fatty acids have?

A

Have long ‘tails’ made from hydrocarbons

39
Q

Describe the structure of a phospholipid

A

2 fatty acids attached to a glycerol + a phosphate group

40
Q

Name two kinds of fatty acids

A

saturated
unsaturated

41
Q

Describe how a triglyceride forms

A

1) A fatty acid joins to a glycerol molecule
2) When ester bonds are formed a molecule of water is released (condensation)
3) This process repeats twice to form a triglyceride

42
Q

Why are triglycerides good energy storage molecules?

A

Long hydrocarbon tails of fatty acids contains lots of chemical energy SO lots of energy is released when they are broken down

43
Q

Describe how the structure of triglyceride makes them insoluble?

A

Triglycerides clump together as insoluble droplets in cells due to the fatty acids which are hydrophobic

Tails face inwards shielding themselves from water with their glycerol heads