Topic 2.3: Carbohydrates and Lipids Flashcards Preview

HL Biology > Topic 2.3: Carbohydrates and Lipids > Flashcards

Flashcards in Topic 2.3: Carbohydrates and Lipids Deck (16):
1

What are the monomers of carbohydrates called?

monosaccharides

2

What is the linkage between two monomers called?

glycosidic linkage

3

What is the role of monosaccharides?

(one sugar unit) are typically sweet-tasting and function as an immediate energy source for cells

4

What is the role of disaccharides?

(two sugar units) are small enough to be soluble in water and commonly function as a transport form

5

What is the role of polysaccharides?

(many sugar units) may be used for energy storage or cell structure, and also play a role in cell recognition

6

What subunit of carbohydrates (one sugar unit) are typically sweet-tasting and function as an immediate energy source for cells?

monosaccharide

7

What subunit of carbohydrates (two sugar units) are small enough to be soluble in water and commonly function as a transport form?

disaccharides

8

What subunit of carbohydrates (many sugar units) may be used for energy storage or cell structure, and also play a role in cell recognition?

polysaccharides

9

What is the structure and function of cellulose?

Cellulose is a structural polysaccharide that is found in the cell wall of plants

It is a linear molecule composed of β-glucose subunits (bound in a 1-4 arrangement)

Because it is composed of β-glucose, it is indigestible for most animals (lack the enzyme required to break it down)

Ruminants (e.g. cows) may digest cellulose due to the presence of helpful bacteria in a specialised stomach
Caecotrophs (e.g. rabbits) will re-ingest specialised faeces that contain digested cellulose (broken down in the caecum)

10

What is the structure and function of starch?

Starch is an energy storage polysaccharide found in plants

It is composed of α-glucose subunits (bound in a 1-4 arrangement) and exists in one of two forms – amylose or amylopectin

Amylose is a linear (helical) molecule while amylopectin is branched (contains additional 1-6 linkages)
Amylose is harder to digest and less soluble, however, as it takes up less space, is the preferred storage form in plants

11

What is the structure and function of glycogen?

Glycogen is an energy storage polysaccharide formed in the liver in animals

It is composed of α-glucose subunits linked together by both 1-4 linkages and 1-6 linkages (branching)

It is akin to amylopectin in plants, but is more highly branched (1-6 linkages occur every ~10 subunits as opposed to ~20)

12

What is the structure of a saturated fatty acid?

no double bonds

13

What is the structure of a monounsaturated fatty acid?

1 double bond

14

What is the structure of a polyunsaturated fatty acid?

greater then 1 double bond

15

What is the linkage between multiple fatty acids called?

ester linkage

16

How are triglycerides formed?

Triglycerides are formed when condensation reactions occur between one glycerol and three fatty acids

The hydroxyl groups of glycerol combine with the carboxyl groups of the fatty acids to form an ester linkage
This condensation reaction results in the formation of three molecules of water

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