Exam Five Flashcards
(37 cards)
1
Q
enzymes
A
- referred as biological catalysts
- often end in “ase”
- named often based on the reaction they catalyze
2
Q
enzyme urease accepts only one specific substrate, considered:
A
absolute specificity
3
Q
enzyme alcohol dehydrogenase can oxidize many alcohols, considered:
A
relative specificity
4
Q
cofactors
A
- some enzymes need cofactors to function
- can be inorganic ions
- can be organic compounds/coenzymes
(derived from vitamins)
5
Q
the optimum pH of most enzymes is about
A
7
6
Q
the optimum pH of pepsin is about
A
1.5
7
Q
temperature optimum of most enzymes
A
typically 37 degrees celcius
8
Q
Michaelis menten enzymes
A
- has two parameters: Km and Vmax
- Km: the affinity between an enzyme and substrate
- Vmax: maximum velocity or reaction rate
9
Q
enzyme inhibitors
A
- compounds that reduce an enzyme’s activity
- IRREVERSIBLE INHIBITORS: react covalently with enzymes (ex. aspirin)
- REVERSIBLE INHIBITORS: bind to enzyme and interfere with its activity (temporary inhibitory effect)
10
Q
competitive inhibitors & noncompetitive inhibitors
A
- COMPETITIVE:
binds to the substrate binding site & also affects affinity or Km - NONCOMPETITIVE:
binds tp site different that active site & also affects the Vmax
11
Q
allosteric enzymes
A
- consists of more than one polypeptide chain
- cooperative behavior: binding of substrate to the active site that affects binding of the substrate at other subunits
- has positive and negative effectors (enhance-increase rate/reduce-slow)
12
Q
negative effectors
A
helps prevent its own overproduction
through FEEDBACK INHIBITION
13
Q
activity of some enzymes is controlled by the formation of inactive enzyme precursors:
A
- zymogens
14
Q
lipids
A
insoluble in water and found in a living system
15
Q
fatty acids
A
- have even number of carbons
- have around 12-20 carbons
- insoluble in water
16
Q
types of fatty acids
A
- saturated fatty acids
higher melting & boiling points due to packed tails through london forces - monosaturated fatty acids
cannot pack well due to cis double bonds - polyunsaturated fatty acids
will have lowest boiling points due to cis double bonds
17
Q
omega 3 fatty acids
A
- between 1st double bond between C3-C$
18
Q
waxes
A
- esters
- made from a FA and a very long chain alcohol
- serve as protective barriers
19
Q
triglycerides
A
- made from 3 FA and 1 glycerol
- provide energy
provide 2x more calories vs. carbs and proteins
stored in adipose tissue
20
Q
fats
A
- more SATURATED FATTY ACIDS
- solids
- melting points above room temp.
21
Q
vegetable oils
A
- more UNSATURATED FATTY ACIDS
- liquids
- melting points below room temp.
22
Q
cell membranes
A
has double layer of lipids
23
Q
cholesterol
A
- made in the liver
- transported in body by lipoproteins
- precursor to all other steroids
24
Q
lipoproteins
A
- four types based on density
carry lipids between different organs and tissues - chylomicrons, VLDLs, LDLs, and HDLs
25
entire set of chemical reactions occurring in a living system
metabolism
26
anabolism
- biosynthesis of large cmpds from small ones
- energy required
- reductive gaining of electrons
27
catabolism
- large cmpds are broken down into smaller ones
- released energy
- oxidative release of electrons
28
metabolic pathways
- groups of chemical reactions
- only few are regulated by allosteric enzymes
- can be linear, circular or spiral
29
ATP
- stored in the phosphodiester bond/high-energy bond
30
starch digestion
- begins in mouth
- hydrolysis of alpha (1-4) glycosidic bonds
- unhydrolyzed starch is broken in SI
31
triglyceride digestion
- begins in the stomach
- requires emulsification of triglycerides by bile salts
- fatty acids released
32
33
glycolysis
- universal pathway
- 10 step linear pathway
- requires 2 atp
first 5 steps: investment phase
6-10 steps: pay-off phase
- “energy rich” - turned on
- “energy poor” - turned off
34
Cori cycle
- lactate: formed in muscles -liver
liver: lactate - pyruvate
glycogenesis (pyruvate - glucose)
glucose - blood and muscles
(glucose-pyruvate) glycolysis
35
pyruvate
aerobic conditions: converted to acetyl coA
anaerobic conditions: converted to lactate (intense exercise)
36
gluconeogenesis
- making of glucose from lactate or other amino acids
- within liver
occurs during exercise or fasting
37
citric acid cycle
- krebs cycle
- takes place in mitochondria
- 8 step circular pathway
- produces a lot of energy
- energetically favorable
