Edexcel Salters Nuffield Biology A Level: Topic 1 Question and Answer
Define monosaccharide and give the structural isomers for glucose - Answer-Carbohydrate monomer
which cannot be broken down further
- fructose
-galactose
Alpha Glucose structure - Answer---
Monosaccharide general properties - Answer-small - can diffuse through cell membranes
soluble - in water so can dissolve in blood for transport
sweet
How are disaccharides and polysaccharides formed? Bonding? - Answer-Condensation reactions
(reversible, passive)
Glycosidic 1-4 bonds
Water produced
Where are Maltose, sucrose and lactose found, and what monosaccharides and bonding do they each
have? - Answer-maltose: 2 glucose, found in barley seeds, alpha 1-4 glycosidic bonds
sucrose: plants, glucose and fructose, alpha 1-2 glycosidic bonds
lactose: milk sugar, galactose and B glucose, beta 1-4 glycosidic bonds
Describe the structure of starch - Answer-- mixture of amylose and amylopectin
- amylose is linear, non-branched, 1-4 bonds only
- amylopectin is branched, with 1-6 bonds for branches - it is less compact than amylose and is broken
down more quickly
Function of starch - Answer-- short term storage of energy in plants, which does not disrupt osmotic
gradient
- found in plasmids, stored as starch grains, insoluble
, Glycogen structure - Answer-Branches have alpha(1,6) bonds; Linkages have alpha(1,4) bonds
Highly branched - more than amylopectin - animals have highperbasal metabolic rate so needs energy
faster and more
- less dense than starch
- broken down by glycogen phosphoyrlase
fatty acid structure - Answer-COOH carboxyl group head, hydrocarbon tail (R group that varies in length)
saturated or unsaturated
Difference between saturated and unsaturated fatty acids? - Answer-Saturated = full
- they have no double bonds and no kinks - one straight chain - this means they can pack more tightly
and require more energy to split apart - solid at RTP
Unsaturated = not full
- they have at least one double bond (mono or polyunsat) creating kinks
- they don't pack as tightly and require less energy to break apart so liquid at RTP
What elements are lipids made of? - Answer-carbon, hydrogen, oxygen
What elements are carbohydrates made of? - Answer-carbon, hydrogen, oxygen
What elements are proteins made of? - Answer-carbon, hydrogen, oxygen, nitrogen
What is the structure of a triglyceride? - Answer-one glycerol and three fatty acids
ester bonds
condensation reaction
CH2O-OC.R x3
Properties of triglycerides - Answer--insoluble - storage of energy
Define monosaccharide and give the structural isomers for glucose - Answer-Carbohydrate monomer
which cannot be broken down further
- fructose
-galactose
Alpha Glucose structure - Answer---
Monosaccharide general properties - Answer-small - can diffuse through cell membranes
soluble - in water so can dissolve in blood for transport
sweet
How are disaccharides and polysaccharides formed? Bonding? - Answer-Condensation reactions
(reversible, passive)
Glycosidic 1-4 bonds
Water produced
Where are Maltose, sucrose and lactose found, and what monosaccharides and bonding do they each
have? - Answer-maltose: 2 glucose, found in barley seeds, alpha 1-4 glycosidic bonds
sucrose: plants, glucose and fructose, alpha 1-2 glycosidic bonds
lactose: milk sugar, galactose and B glucose, beta 1-4 glycosidic bonds
Describe the structure of starch - Answer-- mixture of amylose and amylopectin
- amylose is linear, non-branched, 1-4 bonds only
- amylopectin is branched, with 1-6 bonds for branches - it is less compact than amylose and is broken
down more quickly
Function of starch - Answer-- short term storage of energy in plants, which does not disrupt osmotic
gradient
- found in plasmids, stored as starch grains, insoluble
, Glycogen structure - Answer-Branches have alpha(1,6) bonds; Linkages have alpha(1,4) bonds
Highly branched - more than amylopectin - animals have highperbasal metabolic rate so needs energy
faster and more
- less dense than starch
- broken down by glycogen phosphoyrlase
fatty acid structure - Answer-COOH carboxyl group head, hydrocarbon tail (R group that varies in length)
saturated or unsaturated
Difference between saturated and unsaturated fatty acids? - Answer-Saturated = full
- they have no double bonds and no kinks - one straight chain - this means they can pack more tightly
and require more energy to split apart - solid at RTP
Unsaturated = not full
- they have at least one double bond (mono or polyunsat) creating kinks
- they don't pack as tightly and require less energy to break apart so liquid at RTP
What elements are lipids made of? - Answer-carbon, hydrogen, oxygen
What elements are carbohydrates made of? - Answer-carbon, hydrogen, oxygen
What elements are proteins made of? - Answer-carbon, hydrogen, oxygen, nitrogen
What is the structure of a triglyceride? - Answer-one glycerol and three fatty acids
ester bonds
condensation reaction
CH2O-OC.R x3
Properties of triglycerides - Answer--insoluble - storage of energy
