Carbohydrates and Lipids - Class notes 1

Question 1

what are biomolecules?

Answer 1

these are molecules made by and used by organisms.

Question 2

what are the main groups for this class?

Answer 2

carbohydrates
lipids
proteins - enzymes
nucleic acids

Question 3

what are the two broad groups that molecules can be divided into?

Answer 3

organic

inorganic

Question 4

describe organic molecules and give examples

Answer 4

organic molecules are based upon 'skeletons' made up of hydrogen and carbon. typically these molecules tend to be quite large (when compared to inorganic molecules). 
glucose
starch
protein
fats (lipids)
DNA
RNA

Question 5

describe inorganic molecules and give examples

Answer 5

inorganic molecules/substances are not based upon hydrogen and carbon (though these two elements may be present).
salts 
water
hydrogen gas
oxygen

Question 6

what is the empirical formula for carbohydrates?

Answer 6

Cx(H2O)x

Question 7

what are the main groups in carbohydrates? give examples

Answer 7

monosaccharides (single sugar) - glucose, fructose, galactose
disaccharides (two sugars) - sucrose, maltose and lactose
polysaccharides (many sugars) - starch, glycogen and cellulose.

Question 8

what are the sub-groups in monosaccharides? give examples

Answer 8

hexose (6 carbon atoms) - glucose, fructose and galactose
pentose (5 carbon atoms) glycolysis- ribose and deoxyribose
triose (3 carbon atoms) - TP and GP seen in glycolysis

Question 9

what is the molecular formula for glucose?

Answer 9

C6 H12 O6

Question 10

Know the structure of Alpha glucose and beta glucose

Answer 10

See diagram. remember the difference.

Question 11

Know condensation and hydrolysis reactions

Answer 11

see diagram

Question 12

describe starch

Answer 12

plants convert excess glucose into starch (in animals, glycogen is produced). starch, therefore, is an energy store.
Starch (as well as glycogen) is a polysaccharides. Starch (as well as glycogen) is formed from alpha glucose.

Question 13

describe cellulose.

Answer 13

Plants also produce cellulose. Cellulose is used for structure and support.
cellulose is formed from beta glucose.

Question 14

What are the two different types of structures of starch and what are their names?

Answer 14

helix structure = amylose

Branched chain = amylopectin

Question 15

why are the helix and branched chain structures suitable as energy store polysaccharides?

Answer 15

they are both open structures, hence readily accessed by digestive enzymes - e.g., amylase.

Question 16

what is glycogen similar to?

Answer 16

glycogen is similar in structure as amylopectin but more highly branched. Glycogen is stored glucose in animals.

Question 17

Know how to form cellulose.

Answer 17

see diagram.

Question 18

what type of reaction forms cellulose?

Answer 18

condensation

Question 19

what type of hydrogen bonding occurs in cellulose?

Answer 19

it forms complex hydrogen bonds within the same chain, and between different chains.

Question 20

what is the name for bundles cellulose chains bonded together via hydrogen bonding?

Answer 20

microfibril

Question 21

what type of pattern do cellulose microfibrils form?

Answer 21

a criss-cross/lattice pattern (see diagram)

Question 22

what is so special about the hydrogen bonding of cellulose into microfibrils and then into the lattice pattern?

Answer 22

due to hydrogen bonding that forms the microfibrils and the fact that these microfibrils are laid downin a right-angled criss-cross pattern, it i very difficult for enzymes to access the 1,4 glycosidic bonds. hence cellulose is extremely difficult to digest, and although high in energy, that energy is not readily accessed. cellulose structure lends itself to support and strengthening.

Question 23

what are lipids?

Answer 23

lipids are commonly known by the terms ‘fats and oils’. fats are saturated lipids, which are solid at room temperature. oils are unsaturated lipids, which are liquid at room temp.

Question 24

what are the main components/functions of lipids

Answer 24

cholesterol = sex hormones, e.g., testosterone and oestrogen
surrounds nerve cells
insulation layer
secondary enegy source
phospholipids = necessary for plasma membranes

Question 25

what is a term for a basic lipid structure?

Answer 25

triglycerides

Question 26

what is the components of a triglyceride?

Answer 26

one glycerol molecule + three fatty acids

See diagram

Question 27

how is a triglyceride formed? what is its structure?

Answer 27

via condensation reaction. Three ester bonds are formed from the glycerol bonding to the fatty acid chains. (see diagram) 3 water molecules are also formed

Question 28

what does unsaturated mean? in relation to lipids

Answer 28

unsaturated fatty acid (derived from vegetable products, e.g., corn oil, canola oil, sesame seed oil, peanut oil, etc.) Unsaturated lipids are liquid at room temp. Have double bonds

Question 29

what does saturated mean? in relation to lipids

Answer 29

saturated means saturated with hydrogen (i.e., no double bonds between carbon atoms). saturated fatty acids (derived from animls) are solid at room temp

Question 30

What are some example of unsaturated fats?

Answer 30

Olive oil, peanut oil, mayonnaise, most margarines.