Macromlecules :carbohydrates, lipids

Question 1

What are carbohydrates made of?

Answer 1

Small sugar molecules -monosaccharides. A monosaccharide chain is called a polysaccharide.

Question 2

What are the functional groups in a carbohydrate?

Answer 2

Hydroxyls and carbonyl. (meaning it is hydrophilic and therefore, carbohydrates are easily metabolised in our body)

Question 3

What is the main role of carbohydrates in our body?

Answer 3

It is a short term source of energy.

Question 4

In aqueous solutions, most pentoses and hexoses form rings, true or false?

Answer 4

True.

Question 5

glucose + glucose = ?
glucose + fructose =?

Answer 5

glucose + glucose = maltose

glucose + fructose = sucrose

Question 6

What is sucrose?

Answer 6

Sucrose is formed when one glucose and one fructose join together. Sucorse is the most abundant disaccharide and it provides an energy source for plants.

Question 7

State 3 glucose polymers and contrast between them.

Answer 7

Starch, glycogen and cellulose.

1. The oxygens in starch and glycogen are in an orientation of downward formation.
2. Starch and glycogen are very similar and they are also easily metabolised. Cellulose however, acts as a fibre and is harder to metabolise.
3. The oxygens in cellulose are in an up-down alternating formation. This allows cellulose to interact with other polysaccharide chains using hydrogen bonds.
4. The structural difference b/w starch and glycogen is that glycogen starts forming branches.

Question 8

The orientation of polysaccharides does not affect its chemical property. True or false?

Answer 8

False.

Question 9

How do plants and animals respectively store glucose in them?

Answer 9

Plants store glucose as starch and animals store glucose as glycogen. Animals have enzymes to break down starch as glucose.

Question 10

Where is glycogen stored in humans?

Answer 10

Liver and muscles.

Question 11

What is the most abudant organic compund?

Answer 11

Cellulose.

Question 12

How does cellulose give structural integrity to plant cell walls?

Answer 12

Parallel orientation of strands help form hydrogen bonds for structural integrity.

Question 13

Why are pandas stupid?

Answer 13

A panda’s diet is ~90% composed of bamboo shoots, in which the major component (~50-70%) in cellulose
Pandas have not (yet) evolved the ability to digest cellulose and still retain a carnivore digestive tract.

Question 14

Why can herbivores digest cellulose?

Answer 14

Certain herbivore animals (including cows and termites) and decomposing fungi have the enzymes (cellulase) to hydrolyze cellulose.

Question 15

Where can chitin be found?

Answer 15

Insect exoskeletons and fungi cell walls.

Question 16

Name one practical use of cellulose for humans?

Answer 16

Cellulose helps towels be absorbent

Question 17

Why are lipids diversely hydrophobic and what are fats composed of?

Answer 17

Lipids are hydrophobic because of the large amounts of carbons and hydrogens (methyls). Fats are formed through a dehydration reaction between glycerol and 3 fatty acid chains.

Question 18

Differentiate between saturated and unsaturated fats?

Answer 18

Saturated fats :-
- fats with only single bonds
-fats that exist as a solid in room temp
ex : animal fats,butter

Unsaturated fats :-
-fats with one more double bonds
-Due to the kinks in unsaturated fats , they exist mostly as liquid in room temp.
ex: fish fat, oil

Question 19

What are the types of unsaturated fats?

Answer 19

Cis fats : the hydrogens are on adjacent or on the same side

Trans fats : The hydrogens are on opposite sides.

Question 20

What is partial and complete hydrogenation?

Answer 20

Partial hydrogenation is when a hydrogen is introduced to the double bond of a cis isomer or an unsaturated fat, and the hydrogen moves to one side of the double bond creating a trans fat.

Complete hydrogenation involved introducing a hydrogen to the double bond of a cis isomer, and a hydrogen would be added on both sides forming a saturated isomer.

Question 21

Partial hydrogenation was done to increase the shelf life of oils, but what was the downside?

Answer 21

Partial hydrogenation of oils would sometimes result in complete hydrogenation or the formation of a trans fat, which would lead to cardiovascular diseases.

Question 22

What are phospholipids?

Answer 22

• Phospholipds are composed of a hydrophobic diglyceride and a negatively charged polar phosphate group. (amphipathic)

-Phospholipids are the major component of cell membranes

-The amphipathic property allows for cell membranes to retain their shape

Question 23

Define amphipathic?

Answer 23

Compounds in which segments have distinct polarities are amphipathic (one side is water soluble and other is insoluble).

Question 24

How does the amphipathic nature of soap help to wash away dirt and viruses?

Answer 24

Soap has a hydrophilic head and hydrophobic tail. The hydrophobic tail attracts fat lipid membranes and the hydrophilic head attracts water, together they break apart the the virus membrane.

Question 25

What are steroids?

Answer 25

Steroids are lipids with a hydrocarbon chain and 4 fused rings.

Question 26

What is the most common component in animal cell walls?

Answer 26

Cholesterol is the most common components of animal cell membranes
Also acts as a precursor for making other steroids, including sex hormones.

Question 27

Why is cholesterol bad for us?

Answer 27

The polar head groups of steroids and phospholipids interact with another and can integrate into the cell membrane.
Inclusion of cholesterol into cell membrane’s decreases their fluidity, affecting what molecules can pass through

Question 28

What happens if there is an increase of cholesterol in RBC?

Answer 28

RBCs are responsible for transporting oxygen from the lungs to different parts of the body for energy production. Increase of cholesterol can cause the motility of RBC to decease, thereby decreasing oxygen transport.