biomolecules

Question 1

what are the functions of carbohydrates

Answer 1

energy storage
fuel molecules
structural support
molecular recognition

Question 2

what features are carbohydrates classified by?

Answer 2

1. number or carbon atoms

2. nature of carbonyl group (ketoses vs aldoses)

Question 3

which diagram best shows the stereochemistry of carbohydrates

Answer 3

Fischer projections

Question 4

what is the most important isomer of glyceraldehyde

Answer 4

D isomer

Question 5

where is the OH group located on Beta isomers of glucose

Answer 5

above the ring

Question 6

where is the OH group located on Alpha isomers of glucose

Answer 6

below the ring

Question 7

where is the anomeric carbon in a ring?

Answer 7

to the right of the -o- (ester)

Question 8

which glucose anomer is favoured

Answer 8

beta, less steric hindrance

Question 9

isomers

Answer 9

have the same molecular formula but different arrangement of atoms and thus different physical and chemical properties

Question 10

what is a chiral carbon atom

Answer 10

asymmetric carbon atom that has 4 different substituents

Question 11

how many isomers are possible if there are n chiral atoms

Answer 11

2 to the power of n

Question 12

stereoisomers

Answer 12

same chemical formula but different structure

• enantiomers: mirror images
• diastereomers: not mirror images

Question 13

epimers

Answer 13

differ in configuration at a single asymmetric carbon

Question 14

anomers

Answer 14

configuration of OH group at anomeric carbon

Question 15

how many monosaccharides make up an oligosaccharide

Answer 15

less than 20 monosaccharides covalently linked together

Question 16

what are oligosaccharides important for

Answer 16

molecular recognition as parts of cell surface receptor

Question 17

what is the storage polysaccharides for plants

Answer 17

starch forms:

• amylose
• amylopectin

Question 18

what is the storage polysaccharide for animals

Answer 18

glycogen

- more frequent branching than amylopectin

Question 19

what is the structural polysaccharide for plants

Answer 19

cellulose

• principal component of cell walls
• linear unbranched

Question 20

what is the structural polysaccharide for invertebrates

Answer 20

chitin

• makes up exoskelatons
• also found in cell walls of fungi and algae

Question 21

general formula for carbohydrates

Answer 21

(CH20)n

Question 22

general lipid description

Answer 22

hydrophobic, water insoluble organic molecules

Question 23

lipid examples

Answer 23

• fatty acids
• mono/di/triglycerides
• phospholipids, glycolipids
• steroids, sterols
• waxes

Question 24

function of lipids

Answer 24

energy storage
fuel molecules
membrane formation
communication
protection of organs
thermal insulation

Question 25

composition of fatty acids

Answer 25

hydrophilic carboxyl group & unbranched hydrophobic hydrocarbon chain (amphipathic)

Question 26

saturated fatty acids

Answer 26

no double bonds

Question 27

unsaturated fatty acids

Answer 27

contains double bonds

Question 28

features that contribute to variation in fatty acids

Answer 28

number of carbon atoms
if saturated/unsaturated
cis vs trans
presence of other groups

Question 29

what are the head groups of phospholipids

Answer 29

serine, ethanol amine, choline, inositol

Question 30

2 types of phospholipids

Answer 30

phosphoglycerides

phosphosphingolipids

Question 31

which part of phospholipids are hydrophobic/hydrophilic

Answer 31

hydrophilic polar head

hydrophobic non-polar tails

Question 32

general characteristics of steroids

Answer 32

rigid, planar, amphipathic

derived from cholesterol

Question 33

main component of cell membranes

Answer 33

phospholipids, glycolipids and sterols