Carbon, carbs, lipids and proteins WK 1 Flashcards
What are the 4 categories of carbon compounds
carbohydrates
lipids
proteins
nucleic acids
Describe carbons structure and binding abilities
-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
Listen carbons functional groups
-hydroxyl (-OH)
-carboxyl (-COOH)
-methyl (-CH3)
-amino (-NH2)
-phosphate (-H2PO4)
Describe carbohydrates and their general formula (providing examples)
hydrophilic organic molecules e.g. sugars/starches
-formula: (CH2O)n, n=number of C atoms
e.g. glucose n=6 so formula C6H12O6
Describe the three major monosaccharides and their similarities
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
Define disaccharide. Describe the three important types
sugar made of 2 monosaccharides
-sucrose: table sugar (glucose+fructose)
-lactose: sugar in milk (glucose+galactose)
-maltose: grain products (glucose+glucose)
Describe the difference between oligosaccharides and polysaccharides
olig.-short chains of 3 or more monosaccharides (at least 10)
poly-long chains of monosaccharides (at least 50)
What are three examples of polysaccharides? Define their functions
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
Describe carbohydrates. What occurs when it is digested/oxidised?
quickly mobilised source of energy
-when digested=glucose
-oxidised to =ATP
Define conjugated carbohydrates
covalently bound to lipid or protein moiety
Define glycolipids, glycoproteins, and proteoglycans
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
Define lipids. What are the 5 types in the body
-hydrophobic molecules (higher H to O ratio)
-more calories per gram than carbs=better energy storage
types:
fatty acids, triglycerides, phospholipids, eicosanoids, steroids
Describe and define fatty acids. What are it’s types
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
Describe triglycerides and structure
store energy, insulate, an act as shock absorption
-3 fatty acids linked to glycerol
-bonds formed by dehydration synthesis
-hydrolysis break down
Describe phospholipids. What is meant by amphipathic
similar to neutral fats but one fatty acid replaced by phosphate group (PO4)
amphipathic:
-hydrophobic fatty acid tails
-hydrophilic phosphate head
Describe eicosanoids
2- carbon compounds derived from arachidonic acid
-hormone like chemical signals between cells e.g. inflammation, blood clotting
Describe steroids
lipid with 17 C atoms in four rings
-role in nervous system function and cell membrane structural integrity
Describe cholesterol. What is meant by HDL and LDL
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
Define protein in terms of amino acids, peptide, peptide bonds
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)
Describe protein structure (not the 4 types). Define denaturation
unique, three dimensional shape crucial to function
-reversibly change conformation therefore function
e.g. muscle contraction
denaturation (extreme conformational change that destroys function)
Describe protein primary structure
sequence of amino acids encoded in genes
Describe protein secondary structure
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)
Describe protein tertiary structure
further bending/folding of proteins into globular shapes due to hydrophobic-hydrophilic interactions and Vander Waals force
Define globular and fibrous proteins
globular: within cell membrane/move freely in body fluids
fibrous: slender filaments suited for roles in muscle contraction and skin/hair strengthening
Describe protein quaternary structure
associations of two or more polypeptide chains due to ionic bonds and hydrophobic-hydrophilic interactions
-only occurs in some proteins
Describe 4 protein functions
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)
