iB

Question 1

Define macromolecules

Answer 1

molecules composed of a large number of atoms

Question 2

Main classes of macromolecules in living organisms (3)

Answer 2

polysaccharides

polypeptides

nucleic acids

Question 3

Define a disaccharide

Answer 3

2 monosaccharides linked together

Question 4

Features of carbon bonds (3)

Answer 4

covalent

carbon can bond to 4 atoms

single carbon bonds allow atoms to rotate

Question 5

Shape which chains of carbon atoms can form (2)

Answer 5

rings

zig zag shape

Question 6

Condensation Polymerisation (3)

Answer 6

two molecules join together

one molecule loses a hydroxyl group (-OH), another loses a hydrogen atom (-H)

causes formation of water

Question 7

Describe a glycosidic bond

Answer 7

oxygen atom shared between 2 glucose molecules

Question 8

Define hydrolysis (2)

Answer 8

chemical reaction where water is used to break covalent bond between monomers

-OH will attach to one monosaccharide, -H will attach to other

Question 9

Number of carbon atoms for pentose (2)

Answer 9

5

e.g ribose

Question 10

Number of carbon atoms for hexose (2)

Answer 10

6

e.g glucose, fructose

Question 11

Isomers of glucose (2)

Answer 11

alpha-glucose

beta-glucose

Question 12

Orientation of alpha-glucose (2)

Answer 12

hydroxyl group (OH) is orientated downward

e.g glycogen + starch

Question 13

Orientation of beta-glucose (2)

Answer 13

hydroxyl group (OH) is orientated upward

e.g cellulose

Question 14

Properties of glucose (3)

Answer 14

glucose is soluble + small –> easily transported

glucose is chemically stable

yields energy when oxidised

Question 15

Why glucose is soluble (4)

Answer 15

soluble because it is polar

contains (-OH) molecules which are polar

oxygen atoms are partially negative

so carbon-hydrogen (C-H) atoms are partially positive

Question 16

Applications of glucose being soluble (2)

Answer 16

polar so able to dissolve in water

dissolves in plasma - can be transported in blood, OH groups bond with water in plasma

Question 17

Why is glucose chemically stable (2)

Answer 17

ring structure - atoms are bonded to minimise strain + allows for strong covalent bonds

hydroxyl groups - forms bonds with water molecules (stable in aqueous solution) + prevents glucose from undergoing reactions

Question 18

Application of property of glucose being chemically stable (2)

Answer 18

improves structural role of cellulose in plants

helpful in starch and glycogen for storage

Question 19

Oxidisation as a property of glucose (3)

Answer 19

addition of oxygen to a molecule

loss of hydrogen atom

loss of electrons to another atom/ion

Question 20

Application of glucose property of being easily oxidised (2)

Answer 20

oxygen important reactant for cellular respiration

broken down by losing electrons to oxygen to form CO2 and H2O

Question 21

Name 2 types of starch (2)

Answer 21

amylose

amylopectin

Question 22

Describe amylose (2)

Answer 22

polysaccharide made of glucose monomers linked through alpha-1,4 -glycosidic bonds

helical shaped chain

Question 23

Describe amylopectin (2)

Answer 23

polysaccharide made up of glucose monomers linked through alpha-1,4-glycosidic bonds with ocassional 1,6-glycosidic bonds

branched shaped chain

Question 24

Amylopectin property (3)

Answer 24

branch shape allows amylopectin to be more packed together - allows for more efficient storage of glucose

adding + removing glucose is quicker since branch shape has more ends

major component of starch

Question 25

Starch properties (2)

Answer 25

compact in structure due to branching and coiling - efficient storage for small space

insoluble due to large size - can store lots of glucose, ensures that water is not drawn in