Carbon, carbs, lipids and proteins WK 1

Question 1

What are the 4 categories of carbon compounds

Answer 1

carbohydrates
lipids
proteins
nucleic acids

Question 2

Describe carbons structure and binding abilities

Answer 2

-four valence e (binds w/other atoms that provide 4 more valence e to fill outer shell)
-carbons bind readily to form long chains, branched molecules/rings (carbon backbone)
-form covalent bonds with H, O, N, S and other

Question 3

Listen carbons functional groups

Answer 3

-hydroxyl (-OH)
-carboxyl (-COOH)
-methyl (-CH3)
-amino (-NH2)
-phosphate (-H2PO4)

Question 4

Describe carbohydrates and their general formula (providing examples)

Answer 4

hydrophilic organic molecules e.g. sugars/starches
-formula: (CH2O)n, n=number of C atoms
e.g. glucose n=6 so formula C6H12O6

Question 5

Describe the three major monosaccharides and their similarities

Answer 5

glucose, galactose, fructose
- formula: C6H12O6 (isomers of each other)
- produced by digestion of complex carbohydrates (starch/disaccharides)
-small intestine/liver convert galactose and fructose=glucose

Question 6

Define disaccharide. Describe the three important types

Answer 6

sugar made of 2 monosaccharides
-sucrose: table sugar (glucose+fructose)
-lactose: sugar in milk (glucose+galactose)
-maltose: grain products (glucose+glucose)

Question 7

Describe the difference between oligosaccharides and polysaccharides

Answer 7

olig.-short chains of 3 or more monosaccharides (at least 10)
poly-long chains of monosaccharides (at least 50)

Question 8

What are three examples of polysaccharides? Define their functions

Answer 8

glycogen: energy storage in cells of liver, muscle, brain, uterus, vagina

starch: energy storage in plants

cellulose - structural molecule in plants important for human dietary fibre

Question 9

Describe carbohydrates. What occurs when it is digested/oxidised?

Answer 9

quickly mobilised source of energy
-when digested=glucose
-oxidised to =ATP

Question 10

Define conjugated carbohydrates

Answer 10

covalently bound to lipid or protein moiety

Question 11

Define glycolipids, glycoproteins, and proteoglycans

Answer 11

Glycolipids: external surface of cell membrane

Glycoproteins: external surface of cell membrane, mucus of respiratory and digestive tracts

Proteoglycans: Gels holding cells and tissue together. Gelatinous filler in eye, joint lubrication and cartilage texture

Question 12

Define lipids. What are the 5 types in the body

Answer 12

-hydrophobic molecules (higher H to O ratio)
-more calories per gram than carbs=better energy storage
types:
fatty acids, triglycerides, phospholipids, eicosanoids, steroids

Question 13

Describe and define fatty acids. What are it’s types

Answer 13

chains of 4-24 C atoms with end carboxyl (-cooh) group
-essential fatty acids obtained from food
-saturated: no double cov bonds
-unsaturated: 1/+ double cov bonds
-polyunsaturated: multiple double

Question 14

Describe triglycerides and structure

Answer 14

store energy, insulate, an act as shock absorption
-3 fatty acids linked to glycerol
-bonds formed by dehydration synthesis
-hydrolysis break down

Question 15

Describe phospholipids. What is meant by amphipathic

Answer 15

similar to neutral fats but one fatty acid replaced by phosphate group (PO4)
amphipathic:
-hydrophobic fatty acid tails
-hydrophilic phosphate head

Question 16

Describe eicosanoids

Answer 16

2- carbon compounds derived from arachidonic acid
-hormone like chemical signals between cells e.g. inflammation, blood clotting

Question 17

Describe steroids

Answer 17

lipid with 17 C atoms in four rings
-role in nervous system function and cell membrane structural integrity

Question 18

Describe cholesterol. What is meant by HDL and LDL

Answer 18

parent steroid from which others are synthesised

HDL: high density lipoprotein/good cholesterol
lower ratio of lipid to protein-may help prevent cardiovasc. disease

LDL: low density lipoprotein/bad cholesterol
high ratio lipid to protein-contributes to cardiovasc. disease

Question 19

Define protein in terms of amino acids, peptide, peptide bonds

Answer 19

polymer of amino acids
a.acid: central C with 3 attachments amino, carboxyl, radical group (determines properties of amino)

peptide: molecule comprising two/more amino acids joined by pep. bond

pep. bond: joins amino acid to carboxyl group of next amino (formed by dehydration synthesis)

Question 20

Describe protein structure (not the 4 types). Define denaturation

Answer 20

unique, three dimensional shape crucial to function
-reversibly change conformation therefore function
e.g. muscle contraction

denaturation (extreme conformational change that destroys function)

Question 21

Describe protein primary structure

Answer 21

sequence of amino acids encoded in genes

Question 22

Describe protein secondary structure

Answer 22

coiled/folded shape held together by H bonds between slightly neg (C=O) and slightly pos (N-H) groups
-alpha helix (spring like) or beta helix (pleated, ribbon like)

Question 23

Describe protein tertiary structure

Answer 23

further bending/folding of proteins into globular shapes due to hydrophobic-hydrophilic interactions and Vander Waals force

Question 24

Define globular and fibrous proteins

Answer 24

globular: within cell membrane/move freely in body fluids

fibrous: slender filaments suited for roles in muscle contraction and skin/hair strengthening

Question 25

Describe protein quaternary structure

Answer 25

associations of two or more polypeptide chains due to ionic bonds and hydrophobic-hydrophilic interactions
-only occurs in some proteins

Question 26

Describe 4 protein functions

Answer 26

structure: keratin- tough structural protein of nails/skin surface
collagen- deeper layers of skin, bones, cartilage

cell adhesion: protein bind cells together, keeps tissues from falling apart

membrane transport: channel proteins in cell membrane govern passage
e.g. carriers- transport solutes to other side of membrane

recognition: glycoproteins important for immune recognitions (antibodies=proteins)