Chap3 Biological Molecules

Question 1

What is a monomer?

Answer 1

Small unit from which larger molecules are made

Question 2

What molecules are made from monomers;

amino acids
nucleotide
glucose

Answer 2

proteins

DNA

carbohydrates

Question 3

Give three examples of monosaccharides

Answer 3

glucose

fructose

galactose

Question 4

What is the name of monosaccharide containing 5 carbon atoms? Give example

Answer 4

Pentose monosaccharide

Ribose

Question 5

Name a property of monosaccharides

Why is this?

Answer 5

Soluble in water

Large number of hydroxyl groups form hydrogen bonds.
Hydrophillic molecules.

Question 6

Give chemical formula of glucose

Answer 6

C6 H12 O6

Question 7

Describe test for sugar

Answer 7

1. Benedicts reagent
2. Hot water bath
3. Positive result = brick red colour

Question 8

Why does benedicts reagent turn brick red?

Answer 8

Electrons gained in solution.
Precipitate produced

Question 9

Sucrose:

Lactose:

Maltose:

Answer 9

glucose + fructose

glucose + galactose

glucose + glucose

Question 10

Name bonds that are present in maltose

Answer 10

Glycosidic bonds (1, 4)

Question 11

What is the reaction for maltose called?

Answer 11

Condensation reaction

Question 12

What is the reverse of condensation reaction?

Answer 12

Hydrolysis reaction
(water added back in)

Question 13

What are all monosaccharides?

Answer 13

reducing sugars

Question 14

What does acid do to disaccharide?

Answer 14

Neutralises it

Question 15

In test for non-reducing sugars, how would we check if not added too much sodium hydrogen carbonate?

Answer 15

Litmus paper

Question 16

Describe test for non-reducing sugars

Answer 16

1. Complete test for reducing sugars
2. If solution does not change colour dispose of liquid
3. Add 1cm uknown solution and 1cm HCl into boiling tube
4. Add sodium hydrogen carbonate
5. Retest with benedicts solution
6. If now positive result, this means you started off with non-reducing sugar (orange/brown)

Question 17

What monomer is starch?

What bonds does it consist of?

Answer 17

Alpha glucose

(1, 4) glycosidic bonds for amylose
(1, 6) glycosidic bond for amylopectin due to branching

Question 18

What monomer is glycogen?

What bonds does it consist of?

Answer 18

Alpha glucose

(1, 4) and (1, 6) glycosidic bonds

Question 19

What monomer is cellulose?

What bonds does it consist of?

Answer 19

Beta glucose

Hydrogen bonds

Question 20

What is the main role of starch in the plant?

Answer 20

Energy storage

Question 21

How is starch suited for its role?

Answer 21

(amylose) Insoluble. Does not effect osmotic balance.
Compact molecule due to helical shape

Question 22

What is the main role of glycogen in animals?

Answer 22

Provides quick energy when needed

Question 23

How is glycogen suited for its role?

Answer 23

Many branches allow rapid hydrolysis to provide high glucose level
(meaning more respiration to maintain metabolic needs)

Question 24

What is the main role of cellulose in the plant cell wall?

Answer 24

Structural support

Question 25

How is cellulose suited for its role?

Answer 25

Strong support structure and arranged parallel to each other

Question 26

Why are hydroxyl groups polar?

Answer 26

Small negative charge on oxygen atom and small positive charge on hydrogen atom

Question 27

What are the two polymers starch consists of?

Answer 27

Amylose and amylopectin (amylose is a polysaccharide containing hundreds of alpha glucose molecules)

Question 28

What molecule is water?

Answer 28

Covalent molecule

Question 29

Surface tension

Answer 29

Allowed movement on water surface

Question 30

Strong cohesion

Answer 30

Holds water molecules together

Question 31

Adhesion

Answer 31

Allows water molecules to stick to Eg) xylem vessel walls

Question 32

What is capillary action?

Answer 32

Water moving up the vessel

Question 33

What makes water a good solvent?

Answer 33

Polar molecules allow for water molecules to bind to solute molecules

Question 34

Why is high specific heat capacity important?

Answer 34

Allows organisms to live in environment with small changes in temperature

Question 35

Why does water have large latent heat of vaporisation?

Answer 35

Efficient as coolant

Question 36

How is water a useful metabolite?

Answer 36

Hydrolysis and condensation reactions

Question 37

Aquatic habitat

Answer 37

Light penetrates through transparency of water

Question 38

Ice habitats

Answer 38

Breeding areas for animals because ice floats Ice insulates water below

Question 39

What does R group do in amino acids?

Answer 39

Determines chemical property

Question 40

What joins amino acids together?

Answer 40

Peptide bonds

Question 41

What is a chain of amino acids called

Answer 41

Polypeptide

Question 42

Primary structure of protein

Answer 42

DNA determines sequence Peptide bonds Carboxyl and amine amino acids

Question 43

Secondary structure

Answer 43

Coils and folds. Alpha helix and beta pleated sheet. Hydrogen bonds Carboxyl and amine amino acids

Question 44

Tertiary structure

Answer 44

3D shape (further coiling of secondary structure) R group interactions Hydrogen bonds Ionic bonds Disulphide bonds Hydrophobic /phillic interactions

Question 45

Quaternary structure

Answer 45

Two or more polypeptide chains in protein. Insulin, haemoglobin.

Question 46

Fibrous protein Eg) collagen

Answer 46

Staggered cross links between molecules Form tendons and ligaments

Question 47

Globular protein Eg) Elastin and keratin

Answer 47

Insoluble and strong Chains form H bonds

Question 48

Globular proteins Eg) haemoglobin

Answer 48

Cool up due to hydrophobic/phillic groups Soluble Specific shape

Question 49

How do you identify amino acids?

Answer 49

Chromatography

Question 50

How to test for proteins

Answer 50

Equal volume sodium hydroxide to solution Add few drops of dilute sulphate solution and mix gently Protein present if purple shows (peptide bonds)

Question 51

Saturated fatty acid

Answer 51

One single C-C bond

Question 52

Unsaturated fatty acid

Answer 52

At least one double C-C bond

Question 53

Characteristics of lipids

Answer 53

Hydrophobic Non-polar molecules Fatty acid and glycerol -> triglyceride Do not form polymers

Question 54

Functions of triglyceride

Answer 54

Energy source and Heat insulation

Question 55

What bond is found in triglyceride?

Answer 55

Ester bond

Question 56

What is the function of sterol cholesterol

Answer 56

Regulates fluidity of membrane

Question 57

Testing for lipids

Answer 57

Mix sample with ethanol Mix with water and shake White emulsion = lipids present

Question 58

Which biological molecule contain only C H and O?

Answer 58

Carbohydrates and lipids

Question 59

What biological molecule contains nitrogen and sulphur?

Answer 59

Proteins Eg) insulin

Question 60

Which processes involve formation of ester bonds?

Answer 60

Synthesis of polynucleotides Synthesis of triglycerides