Exam 2

Question 1

What are macromolecules?

Answer 1

Large molecules composed of thousands of covalently bonded atoms

Question 2

What are the four classes of macromolecules?

Answer 2

• carbohydrates
• lipids
• proteins
• nucleic acid

Question 3

What is a polymer?

Answer 3

Long molecule consisting of many similair building blocks.

Question 4

What is a monomer?

Answer 4

The building blocks of polymers.

Question 5

Which 3 of the 4 types of macromolecules are polymers?

Answer 5

• carbohydrates
• proteins
• nucleic acids

Question 6

What is a dehydration reaction?

Answer 6

Two monomers bonded together through the loss of a water molecule.

Question 7

What is hydrolysis?

Answer 7

A reaction were a polymer is broken down by adding water molecules.

Question 8

What are carbohydrates?

Answer 8

• serve as fuel and building material
• includes sugars and polymers of sugars
• simplest carbohydrates are monosaccharides, or single sugars
• polysaccharides are polymers composed of many sugar building blocks

Question 9

What is the typical molecular formula of monosaccharides?

Answer 9

Multiples of CH20

• C2H402
• C6H12O6

Question 10

What is the most common monosaccharide?

Answer 10

Glucose (C6H12O6)

Question 11

How are monosaccharides classified?

Answer 11

• By the location of carbonyl group (C=O) as aldose (if carbonyl group is at the end of the skeleton) or ketose (if carbonyl group is within the carbon skeleton).
• By the number of carbons in the carbon skeleton

Question 12

How are monosaccharides often presented, and how does this differ from their actual typical form?

Answer 12

• Often depicted as linear skeleton

- Typically form rings in aqueous solutions

Question 13

What is a disaccharide?

Answer 13

Two monosaccharides joined by a dehydration reaction?

Question 14

What is the covalent bond between the two monosaccharides in a disaccharide called?

Answer 14

Glycosidic linkage

Question 15

What are the roles of polysaccharides?

Answer 15

storage and structural

Question 16

What determines the structure and function of a polysaccharide?

Answer 16

Its sugar monomers and the positions of it’s glycosidic linkages.

Question 17

What is starch?

Answer 17

• A storage polysaccharide of plants consisting entirely of glucose monomers
• plants store surplus starch as granules within chloroplasts and other plastids
• simplest form of starch is amylose

Question 18

What is glycogen?

Answer 18

• storage polysaccharide in animals

- vertebrates store glycogen mainly in liver and muscle cells

Question 19

What is cellulose?

Answer 19

• A polysaccharide that is a major component of cell walls
• like starch it is a polymer of glucose, but the glycosidic linkages differ
• difference is based on two ring forms for glucose : alpha (α) and beta (β)

Question 20

What is the shape of polymer with α glucose?

Answer 20

Helical

Question 21

What is the shape pf polymers with β glucose?

Answer 21

Straight. H atoms on one strand can bond with OH groups on other strands.

Question 22

What are microfibrils?

Answer 22

• Parallel cellulose molecules held together by straight polymers of β glucose monomers bonding H atoms to OH groups.
• Form strong building materials for plants

Question 23

Can humans digest cellulose?

Answer 23

No. The enzymes hat digest starch by hydrolysing α linkages cannot hydrolyse the β linkages in cellulose, and it passes through the digestive tract as insoluble fibre.

Question 24

How do some animals digest starch?

Answer 24

Many herbivores have symbiotic relations with microbes the produce enzymes that can break down cellulose.

Question 25

What is chitin?

Answer 25

A structural polysaccharide found in the exoskeleton of arthropods and cell walls of fungi.

Question 26

What are lipids?

Answer 26

- hydrophobic - consist mostly of hydrocarbons which form non polar covalent bonds - the one class of macromolecules that do not form polymers

Question 27

What are fats?

Answer 27

Constructed from glycerol and fatty acids

Question 28

Wha is clycerol?

Answer 28

a three carbon alcohol with a hydroxyl (-OH) group attached to each carbon

Question 29

What is a fatty acid?

Answer 29

a carboxyl group - C = O attached to a long carbon skeleton \ OH

Question 30

What is a triacylglycerol?

Answer 30

- Three fatty acids joined by an ester linkage | - also called triglyceride

Question 31

How do fatty acids vary?

Answer 31

- length (number of carbons) | - number and location of double bonds

Question 32

What is a saturated fatty acid?

Answer 32

- A fatty acid that has the maximum number of hydrogen bonds possible and no double bonds - saturated fatty acids make saturated fats - solid at room temperature - most animal fats are saturated

Question 33

What is an unsaturated fatty acid?

Answer 33

- A fatty acid that has one or more double bonds - unsaturated fatty acids called unsaturated fat or oils - liquid at room temperature - plant and fish fats are usually unsaturated

Question 34

What is the danger of saturated fats?

Answer 34

They may contribute to heart disease through plaque deposits

Question 35

What is hydrogenation?

Answer 35

Process of converting unsaturated fats to saturated fats by adding hydrogen.

Question 36

What are trans fats?

Answer 36

Fats with trans double bonds created by hydrogenating vegetable oils. They may contribute more to heart disease than saturated fat.

Question 37

What is an example of a fatty acid that is not synthesised in the human body?

Answer 37

- Omega-3 fatty acids - required for normal growth and thought to protest against cardiovascular disease - must be supplied through diet

Question 38

What us the major function of fats?

Answer 38

Energy storage, in mammals stored in adipose cells. Also used to cushion vital organs an insulate body.

Question 39

What is a phospholipid?

Answer 39

-two fatty acids and a phosphate group O are attached to a glycerol (-OH) I O = P - O(δ-) I O I - two fatty acid tails are hydrophobic, but phosphate group and its attachments form a hydrophilic head

Question 40

What are phospholipids a major component of?

Answer 40

The phospholipid bilayer is found in all cell membranes.

Question 41

What are steroids?

Answer 41

Lipids characterised by a carbon skeleton consisting of four fused rings

Question 42

What is cholesterol?

Answer 42

A steroid that is a component in animal cell membranes

Question 43

Why can cholesterol be dangerous?

Answer 43

Although it is essential, high levels of cholesterol in blood can contribute to cardiovascular disease

Question 44

What are proteins?

Answer 44

Large molecules composed of long chains of amino acids intricately folded into a specific 3-D shape, with a wide diversity and range of functions

Question 45

What are 8 types of proteins?

Answer 45

- Enzymatic proteins: Selective acceleration of chemical reactions e.g. digestive enzymes catalyse the hydrolysis of bonds in food molecules - Defensive proteins: Protect against disease e.g. antibodies destroy viruses and bacteria - Storage proteins: storage of amino acids e.g. casein in milk, stores amino acids for baby mammals in milk - Transport proteins: transport of substances e.g. haemoglobin transports oxygen - Hormonal proteins: Coordination of an organisms function e.g. insulin regulating blood sugar levels - Receptor proteins: Response of cell to chemical stimuli e.g. receptors in walls of nerve cells detecting signal molecules from other nerve cells - Contractile and motor proteins: Movement e.g. responsible from movement of cilia and flagella, and actin and myosin responsible for con traction of muscles - Structural proteins: Support e.g. keratin in hair, horns, feathers; collagen and elastin framework off animal connective tissues.