Sugars and Lipids

Question 1

What are the 3 major types of carbohydrates

Answer 1

• Monosaccharides
• Disaccharides
• Polysaccharides

Question 2

Formula for glucose

Answer 2

C6H12O6

Question 3

Ketose vs Aldose

Answer 3

• An Aldose has a carbonyl group at the end of its carbon chain
• A Ketose has a carbonyl in middle of carbon chain

Question 4

What is an Isomer?

Answer 4

Isomers have same chemical formula but different formation

Question 5

What is a stereoisomer?

When do they occur?

Answer 5

Its an optical isomer- groups is attached in way that the molecules are mirror images of each other
-They occur whenever a carbon has four different atoms or group has four different atoms or groups attached to it

Question 6

Give a common example of stereoisomers

Answer 6

Glucose (OH up) and Galactose (OH down)

Question 7

Describe difference between alphaglucose and betaglucose

Answer 7

Both result from a glucose ring formed from linear chain.

• Alpha glucose has both OH groups on same side of molecule
• Betaglucose has OH groups on opposite sides

Question 8

What is B1->4 vs Alpha1->4?

Which is more stable?

Answer 8

-Beta 1 4 has the oxygen bond crossing over CELLULOSE. More stable due to its symmetry
-A1 4 has oxygen bond straight between
MALTOSE

Question 9

What is the monosaccharide of starch?

Answer 9

Maltose

Question 10

What are differences and similarities between starch and glycogen?

Answer 10

• Both are used for energy storage
• Glycogen is in muscles while starch is in plants
• Both are from alpha glucose bonds
• Glycogen is exclusively highly branched helices

Question 11

Describe the solubility of lipids in water

Answer 11

Lipids are insoluble in water

Question 12

List the 7 main roles for

lipids in organisms

Answer 12

THEWCC

• Thermal Insulation
• Hormones and vitamins (steroids, modified fatty acids…)
• Energy Storage
• Water repellency
• Cell membranes (phospholipids)
• Capture of light energy

Question 13

What is B-carotene?

Answer 13

An isoprene made of two vitamin A molecules

Question 14

List 4 common steroids. What group do most steroids fall in?

Answer 14

-Cholesterol
-Vitamin D2
-Cortisol
-Testosterone
Steroids are Lipids!

Question 15

What group is key to a fatty acid?

Answer 15

A fatty acid is a hydrocarbon chain with a carboxyl group at the end

Question 16

How do fats form?

Answer 16

Fats form via dehydration reactions

Fatty acid linking to glycerol (losing water)

Question 17

Structure of a fat

Answer 17

Glycerol linked by ester linkage to 3 fatty acids

Question 18

What is a phospholipid?

Answer 18

A phospholipid is two hydrophobic fatty acid tails and one hydrophobic head attached to glycerol

Question 19

Why do lipid bilayers form?

How do phospholipids behave in the bilayer?

Answer 19

• It is energetically favourable for the bilayers to seal.

- Phospholipids are in constant lateral motion across the bilayer- but rarely flip

Question 20

How do double bonds affect phospholipid tails?

Answer 20

Double bonds cause kinks in phospholipid tails (double bonds also makes it unsaturated)

Question 21

Saturated lipid vs Unsaturated Lipids

Answer 21

• Saturated lipids are all single bonds

- Unsaturated lipids have double bonds with kinks

Question 22

How does a lipid bilayer containing unsaturated fatty acids affect it’s permeability?

Answer 22

• A lipid bilayer with no unsaturated fatty acids will have lower permeability, therefore less fluid able to travel through it
• A lipid bilayer with unsaturated fatty acids will have higher permeability, therefore more fluid will be able to travel through it