Chapter 4 - Sugar, Carbs, Fats

Question 1

What sugar is the most common and most important sugar in living things?

Answer 1

Glucose

Question 2

Glucose

Answer 2

In water, glucose can be linear and can have two different ring forms- alpha and beta.

Can have left handed and right handed isomers.

Another term for D-glucose (right handed isomer) is dextrose.

Question 3

Typical general formula of sugar?

Answer 3

n(CH2O)

Question 4

Sugar

Answer 4

Aldoses or Ketoses.
Polar
Hydrophilic
Highly soluble.

Question 5

What are carbohydrates

Answer 5

Includes single sugar molecules and also polymers of sugar molecules.

Made up of C,H,O with 2 H for every O.

Question 6

What are monosaccharides?

Answer 6

One sugar molecule.

Glucose

Question 7

Disaccharides

Answer 7

Two sugar molecules or two monosaccharides linked together as one molecule.

Sucrose (dextrose (glucose), fructose)
Lactose (dextrose (glucose), galactose)

Two sugars linked by dehydration reaction.

Question 8

Oligosaccharides

Answer 8

Short polymers, 3-12 sugars. Different sugars. Often branching. Often attached to other molecules.

Can yield energy but often informational molecules.

Raffinose
Stachyose

Have many complex structures and often attached to other molecules.

Lipids with attached oligosaccharides are called: glycolipids.
Proteins with attached oligosaccharides are called: glycoproteins.

Question 9

Polysaccharides

Answer 9

Very long polymers. Repeating the same sugar unit over and over. Often branching.

Another term: Glycan.

Question 10

What are the use of storage polysaccharides?

Answer 10

Storage polysaccharides are broken down to get glucose for energy.

Question 11

What is glycogen?

Answer 11

Storage polysaccharide. - Helical

(In animals). Energy storage in muscles and liver. Quickly broken down into glucose. Polymer that branches out.

Question 12

What is Starch?

Answer 12

Storage polysaccharide. - Helical

(In plants). Energy storage in plant cells. Also a glucose polymer - much like glycogen.

Natural starch can be amylose (unbranched) or amylopectin (branched) or both.

Question 13

What is cellulose?

Answer 13

Straight structural polysaccharide.

Long polymer of beta glucose in plant cell walls.

E.g. Cotton.

Question 14

What is Chitin?

Answer 14

Nitrogenous polysaccharide. In shells or exoskeletons of insects.

Indigestible to most organisms. They pass through digestion as fiber.

Question 15

What is a polymer?

Answer 15

Molecular chain of repeating subunits.

Question 16

What is a polypeptide?

Answer 16

Protein. Polymers of amino acids.

Question 17

What is a nucleic acid?

Answer 17

Polynucleotide. Polymers of nucleotides

Question 18

What is Dehydration?

Answer 18

Water molecule is created by left over H & OH.

Subunits are attached by dehydration.

Question 19

What is Hydrolysis?

Answer 19

Water molecule is broken into H & OH.

Subunits are detached by dehydration.

Question 20

Can short fatty acids dissolve in water?

Answer 20

Yes because one end is polar.

Question 21

What is a fatty acid?

Answer 21

A fatty acid is a linear hydrocarbon with a carboxyl at one end and a methyl at the other end. They never branch.

Question 22

Draw a fatty acid.

Answer 22

DRAW

Question 23

What are saturated fatty acids?

Answer 23

Have no double bonds in the hydrocarbon. Straight chains. ‘Saturated’ with hydrogens.

Question 24

What are unsaturated fatty acids?

Answer 24

One or more double bonds causing kinks in the hydrocarbon chain.

Question 25

General formula for most saturated fats?

Answer 25

CH3 - n[CH2]-CO2H

Question 26

What is glycerol? + DRAW

Answer 26

Part of a fat molecule. Polar. Highly soluble.

Question 27

What is a fat molecule made out of?

Answer 27

Three fatty acids attached to a glycerol by dehydration. Any combination of fatty acids. Also called triglycerides.

Question 28

What is the main function of fat?

Answer 28

Long term energy storage.

Question 29

Melting Fats/Fatty Acids

Answer 29

Melting point of fat goes up with the length of the fatty acids. Melting point goes down with the number of double bonds in the fatty acids. Saturated fats are more solid - higher melting points. Unsaturated fats are usually liquid - have lower melting points.

Question 30

Examples of saturated fats

Answer 30

Coconut Oil, Butter, Beef Fat, Lard

Question 31

Examples of unsaturated fats

Answer 31

Olive Oil, Soybean Oil, Avocados, Peanut Butter

Question 32

What is a phospholipid?

Answer 32

A glycerol with 2 fatty acids and a phosphate group. One polar end and one nonpolar end.

Question 33

What are cis fats.

Answer 33

Natural unsaturated fatty acids. Kinks at the double bond.

Question 34

What are trans fats

Answer 34

Naturally unsaturated fatty acids that are artificial modified to become trans. This makes them straighter and more solid. Clog arteries because we can't digest them. 'Partially hydrogenated'

Question 35

What are waxes?

Answer 35

Simple linear molecules that consist of very long hydrocarbon chains.

Question 36

Difference between alpha glucose and beta glucose?

Answer 36

When alpha-glucose molecules are joined chemically to form: apolymer starch is formed. When beta-glucose molecules are joined to form: a polymer cellulose is formed.