Lecture 2

Question 1

What are the 4 main elements of biological importance?

Answer 1

Carbohydrates, lipids, nucleic acids, and proteins

Question 2

Why are the biological elements important?

Answer 2

Makes up the structure of cells/tissues,

transmits info, regulates and participates metabolic reactions, and provides energy for life

Question 3

What do carbohydrates include?

Answer 3

Sugars, starches and glycogen, cellulose, and chitin

Question 4

What is the main function of a starch?

Answer 4

Energy source found in plants

Question 5

What is the main function of sugars (glycogen)?

Answer 5

Energy source for animals

Question 6

What are amyloplasts and what is stored in them?

Answer 6

Where plants store their starch (a-amylose and amylopectin)

Question 7

What is the structure of a-amylose?

Answer 7

It is a single long unbranched chain of glucose, linked by a(1-4) bonds

Question 8

What are micelles?

Answer 8

Balls of water, formed by a-amylose

Question 9

How does the starch, a-amylose, get broken down in animals?

Answer 9

It first gets broken down (hydrolysed) by the a-amylase enzyme. The products from this are glucose and single maltose units. The enzyme, B-amylase, then breaks down the single maltose units to glucose.

Question 10

How does the starch, amylopectin, get broken down in animals?

Answer 10

It first gets broken down (hydrolysed) by the a-amylase enzyme. The products from this are glucose, single maltose units, and dextrin. The enzyme, B-amylase, then breaks down the single maltose units to glucose, and the enzyme glucosidase breaks down dextrin into limit dextrin

Question 11

What is the structure of amylopectin?

Answer 11

Highly-branched polymer

Question 12

Monosaccharide?

Answer 12

Single sugar unit (glucose)

Question 13

Two sugar units?

Answer 13

Disaccharide (sucrose)

Question 14

Polysaccharide?

Answer 14

Many sugar units (glycogen and starch) joined by glycosidic linkages

Question 15

What is the most abundant monosaccharide?

Answer 15

Glucose

Question 16

Glycosidic bonding?

Answer 16

Joins/links sugars together through hydrolysis

Question 17

What two monosaccharides make up sucrose?

Answer 17

glucose-a(1-2)-fructose

Question 18

What two monosaccharides make up lactose?

Answer 18

galactose-B(1-4)-glucose

Question 19

What two monosaccharides make up maltose?

Answer 19

glucose-a(1-4)-glucose

• A homodimer of glucose units
• Occurs as a byproduct of starch hydrolysis

Question 20

What does the alpha and beta mean?

Answer 20

If the OH group is pointing down (alpha), and if the OH group is pointing up (beta)

Question 21

What enzymes hydrolysis sucrose, maltose, and lactose?

Answer 21

Sucrose=invertase
Maltose=maltase
Lactose=lactase
All breakdown through hydrolysis (breaking bonds using water)

Question 22

Where is amylase, which is used to break down starch, found in humans?

Answer 22

In our saliva and pancreatic juices

Question 23

What is the function of cellulose and chitin?

Answer 23

Cellulose (plant) and chitin (animal) are both structural components

Question 24

Homopolysaccharides?

Answer 24

One type of monosaccharide linked together

Question 25

Heteropolysaccharides?

Answer 25

Different types of monosaccharide linked together

Question 26

How do polysaccharides get broken down into monosaccharides? What one is more effective?

Answer 26

Either through enzymatic or acid hydrolysis. Enzymatic is more effective

Question 27

What are glycoproteins? What is the process of making a glycoprotein called?

Answer 27

When a sugar (oligosaccharide) links to a protein through glycosidic linkage. This process is called glycosylation

Question 28

What is the purpose of glycoproteins?

Answer 28

To provide protection or adhere to produce mucus (waste removal)

Question 29

Phosphorylation?

Answer 29

This makes sugars anionic and allows some of them to participate in glycosidic bonding as reactive intermediates

Question 30

What are glycolipids?

Answer 30

Carbohydrate combined with lipids to form glycolipids - compounds on the surfaces of animal cells that allow cells to recognise and interact with one another

Question 31

How are cellulose and starch different?

Answer 31

Cellulose contains beta glucose monomers joined by beta 1-4 linkages where as glucose subunits are joined by alpha 1-4 glycosidic linkages

Question 32

What is glucose?

Answer 32

- Most abundant monosaccharide - A hexose sugar (C6H12O6) - Energy source in most organisms - Used as a component in the synthesis of other compounds like fatty acids and amino acids

Question 33

What are two storage polysaccharides and where can you find them?

Answer 33

Plants - starch Animals - glycogen Deposited as granules in the cytoplasm

Question 34

What is a starch?

Answer 34

- homopolymer of alpha-glucose units joined by glycosidic bonds - storage polysaccharide - in plants - a-amylose and amylopectin

Question 35

Can animals break down cellulose?

Answer 35

No, bc we don't have the enzymes needed to break the bonds. Cellulose only provides roughage in the diet

Question 36

Where is chitin found?

Answer 36

The cell wall of fungi, the external skeleton of insects (arthropods) and as various structural components in animals

Question 37

Where is glycogen stored?

Answer 37

Liver and muscle cells

Question 38

What digests glycogen?

Answer 38

alpha-glucosidase enzyme