Optional: Biochemistry Flashcards
Define Km
Inverse measure of affinity of enzyme for a substrate
How to convert between exponenital and log form?
a^x = b
x = loga b
Iodine number
(Mass of iodine reacted/mass of lipid) *100
Site of reactivity and conditions that favour oxidative and hydrolytic rancidity
Oxidative: Carbon=carbon unsaturated bond and light
Hydrolytic: ester and high heat and temperature
Describe the function of chlorophyll in photosynthesis. (2)
Aborbs light energy and transfers electrons
Bonding in cellulose, starch and glycogen
Cellulose: straight chain 1-4 beta
Starch: Amylose 1-4 alpha straight, branched chain amylopectin alpha 1-4 and 1-6
Glycogen: Highly branched like amylopectin but more 1-6 bonds
Suggest why glycine and isoleucine separate slightly at pH = 6.5
They are different sizes/molar masses so they move at different speeds
Functional group responsible for holding protein in secondary structure
Carboxamide
Explain why linoleic acid, C18H32O2, is a more efficient energy storage molecule than raffinose, C18H32O16 (2)
Linoleic acid is more exothermic and less oxidized so can be oxidized and lose more e providing energy
What does water solubility depend on
Forming MANY hydrogen bonds with water
Whcih fat has highest boiling point?
Straight chain, saturated, more LDF
General formula of carbohydrate
Cx(H2O)y
Why is Vitamin D soluable in fats?
Hydrcarbon chain forms LDF with fats
How do heavy metals decrease enzyme action?
They react with enzyme, breaking disulfide bonds
Suggest one challenge scientists face when scaling up synthesis of a new compound
Minimizing negative impact on environemnt and considering atom economy
Why is DNA negatively charged
Phosphate group ionized
Why do anthocyanins absorb visible light?
Extensive conjugation
Explain the shape of the oxygen dissociation curve at the start (low oxygen partial pressure?
Oxygen binds to first active site of hemoglobin which alters shape of other active sites
Cooperative binding causes increased affinity of hemoglobin to O2
**no coperative binding in mygolbin cause only 1 heme group
Outline how the formation of 11-trans-retinal results in the generation of nerve signals to the brain (2)
11 trans retinal no longer fits into rhodspin, leading to conformational change in rhodospin to opsin generating signals
What allows rhodospin to abosrb visible light?
Extensive conjugation
Vision cycle (3)
Extensive conjugation. Vitamin A is oxdized to 11-cis retinal. Cis retinal binds to opsin forming rhodospin . When visible light absorbed, cis-retinal changes to trans retinal which triggers nerve signal. Trans retinal detatches from opsin and is converted back to cis retinal
Determine iodine number when given molar mass of compound
1) mass of iodine x number of double bonds
2) (1)/molar mass of compounds * 100
How can inclusion of starch in plastics make them biodegradable?
- Carbohydrates make plastic more hydrophillic
- Carbohydrates are broken down by bacteria
- Carbohydrates weakens LDF between polymer chains in the plastic
Define GMO
Organism whose DNA has been altered by genetic engineering techniques
Wedge and dash of amino acids?
Wedge: Nh2
Dash R group
Diffeence between glucose and galactose
H and OH are reversed on C-4
D vs L sugars and alpha vs beta
On chiral carbon furthest from aldehyde or ketone group
D - hydrxoyl right
L - hydroxyl left
Alpha - OH below plane C1
Beta - OH above plane C1
Why are cellulose fibers strong?
Long straight chains, held by lots of H bonds that make microfibrils
Why is cellulose important part of diet?
Adds fiber and prevents obesity
Convert between straight chain and cyclic
1) carbon in straight chain, carbonyl group highest priority
2) hydroxyl on second last carbon
3) O from hydroxyl bonds with c 2 and H joins with carbonyl oxygen to form hydroxyl on second carbon
Why is atom economy not always a good measure of sustainability
Doesnt take into account catalysts which are renewable and promote pathway of less energy
Hemoglobin vs myoglibin
Hemo - 4 polypeptide chains and 4 heme groups, transport O2 and CO2 in bloodstream
Myo - 1 polypeptide chain and 1 heme goup, store O2
Heme group binds to oxygen for hemoglobin to transfer which causes oxidation from iron II to iron III then reduction when oxygen released to cell for respiration, myoglobin
why do lipids produce more energy than carbs?
Larger number of reduced carbons so can be oxidized easier
Does quinodal base or flavilum red predominent at pH 12
Quinodal loss of proton and positive ion unlikely
Similarity between myoglobbin and hemoglbin
Fe cation
