2.3 Carbohydrates and Lipids Flashcards Preview

IB Biology HL > 2.3 Carbohydrates and Lipids > Flashcards

Flashcards in 2.3 Carbohydrates and Lipids Deck (15)
1

What are some examples of monosaccharides?

Glucose, fructose, and ribose.

2

Distinguish between mono-, di-, and poly- saccharides.

Mono-: single sugar unit
Di-: two monosaccharides linked together
Poly-: many monosaccharides linked together

3

Define condensation of monosaccharides.

Combination of monosaccharides (anabolic process) by the loss of an -OH from one monomer and an H from an -OH from another, which together form H2O. The two molecules then bind through the remaining O from the second -OH which is known as a glycosidic bond.

4

Differentiate between alpha and beta glucoses.

Beta-glucose: -OH group pointing downward on C1.
Alpha-glucose: -OH group pointing up on C1.

5

Where is starch found? What is its structure?

-Found in plants.
-Linking of alpha-glucose molecules. Formed by condensation reaction between -OH groups on C1 and C4. Both point down so molecules can be oriented in the same way-> curved structure.
-two types: amylose which forms an unbranched helix and amylopectin which forms a branched globular shape.

6

How does starch's structure relate to its function?

-Can't be dissolved in H20 due to its size-> useful in cells where large amounts of glucose need to be stored but where a concentrated glucose concentration solution would cause too much water to enter by osmosis -> good store of glucose and thus energy

7

Where is cellulose found? What is its structure?

-Found in plants.
-Linking beta-glucose molecules. -OH groups attached to C1 and C4 point in opposite directions, so each beta-glucose must be added in a straight line relative to the previous molecule, meaning the glucose subunits in the chain alternate in their orientations.

8

How does cellulose's structure relate to its function?

-Cellulose is a straight chain rather than curved, allowing it to form bundles with H bonds linking the cellulose molecules -> high tensile strength, making it ideal for use in cell walls.

9

Where is glycogen found? What is its structure? How does its structure relate to its function?

-Found in animals and fungi.
-Similar to starch but with more branching, making it more compact.
-As it is more compact, it makes for a great storage of energy in the liver and muscles where a concentrated glucose solution would yield too much osmosis.

10

How are triglycerides formed?

By condensation from three fatty acids and one glycerol, forming ester bonds between the two.

11

Differentiate between fats and oils.

Fats are liquid at body temperature but solid at room temperature while oils are liquid at both. Oils are formed from cis-unsatured fatty acids while fats are made from trans-unsaturated fatty acids.

12

Why are lipids better for long term energy storage than carbohydrates?

-The amount of energy released in cellular respiration per gram of lipids is greater. They don't require water to be held in cells.
-Lipids have secondary roles like being heat insulators or shock absorbers, which carbohydrates could not do.

13

What carbohydrate is stored in the liver and muscles? Why?

-Glycogen.
-Glycogen broken down to glucose rapidly and then easily transported by the blood while fats can't be mobilized quickly. Plus, glucose can be used in both aerobic and anaerobic respiration.

14

What is the difference between saturated and unsaturated fats?

Saturated fats have carbons filled with oxygens while unsaturated fats have double bonds between at least one pair of carbons.

15

What is the difference between cis and trans isomers?

Cis: H bonds on the same side of acid. Symmetrical.
Trans: H bonds on different side of acid.