Biological Molecules

Question 1

What are anabolic and catabolic reactions

Answer 1

Anabolic - Larger molecules are built from smaller molecules
Catabolic - Larger molecules are broken down into smaller molecules

Question 2

What is a condensation reaction

Answer 2

When a water molecule is released due to the bonding between two molecules

Question 3

What is a hydrolysis reaction

Answer 3

When a water molecule is used to break the covalent bond between a molecule to form two smaller molecules

Question 4

What is metabolism

Answer 4

The sum total of all the chemical reactions that take place in an
organism.

Question 5

How does hydrogen bonding occur

Answer 5

The slight negative charge on the oxygen atom makes it attract
the slightly positive hydrogen atom of another water molecule.

Question 6

What are the properties of water

Answer 6

High latent heat of vaporisation
High specific heat category
Ice is less dense than water
Effective solvent
Cohesion/adhesion
Surface tension
Transparent

Question 7

Why does water having a high latent heat of vaporisation help life

Answer 7

Means that evaporation is an effective cooling mechanism as large amount of energy is required

Question 8

Why does water having a high specific heat capacity help life

Answer 8

Lots of energy needed to heat water means it can provide a thermally stable environment

Question 9

Why does ice being less dense than water help life

Answer 9

Water beneath ice is insulated, aquatic organisms can swim, habitat is provided

Question 10

Explain the benefits of ice being less dense than water

Answer 10

insulates water underneath, aquatic organisms dont freeze, habitat is provided

Question 11

Explain the benefits of water being transparrant

Answer 11

photosynthesis can occur underwater

Question 12

Explain the benefits of water being an effective solvent

Answer 12

Medium for enzyme controlled reactions
Ions can be taken up via roots

Question 13

Explain the benefits of water having surface tension

Answer 13

it provides a habitat for invertabrae

Question 14

Explain the benefits of water having high latent heat of vaporisation

Answer 14

Lots of energy is needed for water to change state so it is an effective cooling mechanism

Question 15

Explain the benefits of water having high specific heat capacity

Answer 15

Lots of energy needed to heat water up, means it provides a thermally stable environment

Question 16

Explain the benefits of water having cohesion/adhesion

Answer 16

cohesive - helps transpiration stream
adhesion - adhesion of water to lignin in the xylem

Question 17

Functions of Carbs

Answer 17

Energy source
Energy store
Structure
Form part of a larger molecule

Question 18

What are monosaccharides

Answer 18

have between 3 and 6 carbons
sweet tasting
soluble in water

Question 19

Draw a ribose

Answer 19

C5 H10 O5
pentose sugar,
O COHH CHOH CHOH CCH2OHH
pentagon with a branch

Question 20

Draw a glucose

Answer 20

C6 H12 O6
hexose sugar
O CHOH CHOH COHH CHOH CCH2OH
Hexagon with a branch

Question 21

What is maltose

Answer 21

glucose + glucose

Question 22

What is sucrose

Answer 22

glucose + fructose

Question 23

What is lactose

Answer 23

glucose + galactose

Question 24

What are the bonds between polysaccharides called

Answer 24

C-O-C glycosidic bonds

Question 25

What are the major polysaccharides

Answer 25

Starch (energy storage in plants Cellulose (structural role in plants) Glycogen (energy storage in animals)

Question 26

What is Amylose

Answer 26

Alpha glucose 1-4 glycosidic bonds coiled

Question 27

What is the difference between alpha and beta glucose

Answer 27

the H is on top of the 1st carbon in alpha glucose the OH is on top of the 1st carbon in beta glucose

Question 28

What is Amylopectin

Answer 28

Alpha glucose 1-4, 1-6 glycosidic bonds coiled side branches

Question 29

Glycogen structure

Answer 29

alpha glucose 1-4, 1-6 glycosidic bonds coiled side branches

Question 30

Starch and glycogen shared features

Answer 30

insoluble energy storage molecules glucose can be broken off ends via hydrolysis

Question 31

Cellulose structure

Answer 31

Beta glucose 1-4 glycosidic bonds Every alternative glucose is rotated by 180 straight chain hydrogen bonds between chains

Question 32

What is a fat

Answer 32

solid lipid

Question 33

what is an oil

Answer 33

liquid lipid

Question 34

Functions of lipid

Answer 34

Energy store Energy production Biological membranes Insulation Buoyancy Protection Waterproofing Vitamin D, Bile and steroid hormone production

Question 35

What are triglycerides

Answer 35

Glycerol + 3 fatty acids

Question 36

What is Glycerol's formula

Answer 36

H-(CHOH)3-H

Question 37

What do fatty acids look like

Answer 37

All have a carboxyl acid group at one end (COOH) and the rest of the molecule is a hydrocarbon Can be saturated or unsaturated

Question 38

What is a phospholipid structure

Answer 38

Phosphate group + Glycerol (hydrophilic) + 2 Fatty acids (hydrophobic) CHOP

Question 39

Difference between triglycerides and phospholipids

Answer 39

Triglycerides = glycerol + 3 fatty acids, only ester bonds, all hydrophobic Phospholipids = glycerol + 2 fatty acids + phosphate, phosphoester + ester bonds

Question 40

Why do organisms in cold climates have more unsaturated fatty acids

Answer 40

Because it makes the membrane more fluid as the unsaturated fats are bent and cant bunch up as closely

Question 41

Features of cholesterol

Answer 41

Not formed from glycerol/fatty acids 4 carbon rings small and narrow hydrophobic regulates fluidity + strength

Question 42

Features of steroid hormone

Answer 42

Made from cholesterol Lipophilic Testosterone Oestrogen Progesterone

Question 43

What is the test for reducing sugar

Answer 43

Add Benedict's reagent and boil mixture If reducing sugar is present, it'll go from Blue to Brick Red

Question 44

What is the test for non reducing sugars

Answer 44

Add HCL then neutralise with an alkali Add Benedict's reagent and boil If non reducing sugars are present it'll go from blue to brick red

Question 45

What is the test for lipids

Answer 45

Add ethanol and shake Pour in water If present, there should be a milky white emulsion

Question 46

What is the test for proteins

Answer 46

Add Biurets Should go from blue to purple

Question 47

What is the test for starch

Answer 47

Add iodine solution Should go from orange to blue black