Module 6 (Biochem Bioenergetics) Flashcards
What is the first law of thermodynamics?
energy cannot be created or destroyed
cannot gain or lose energy in a closed system
What does conversion of one form of energy to another lead to?
a loss of energy in the form of heat
High or low potential energy: high organized system
high potential energy
What is entropy?
high chaos, high measure of disorder
High or low potential energy: disorganized
system (high entropy)
low potential energy
What is the natural trend toward?
towards high chaos (en-
tropy) and low potential energy
to find the most stale state
in a system
Metabolism=
catabolism + anabolism
Define metabolism
sum of all biochemical re-
actions
Define catabolism
sum of all degradative reactions
Define anabolism
sum of all biosynthetic re-
actions
What do catabolic pathways result in?
generation of energy (ATP)
Anabolic pathways:
require ATP and reduced
electron carriers
Citrate is a C____ compound
6
What catalyzes the transfer of phosphate
groups from one organic molecule to another?
kinases
In the CAC cycle, what does acetyl-CoA get
combined with to form citrate?
oxaloacetate
Fermentation converts NADH to NAD+ so it
can be used in:
glycolysis
What coenzyme relies on fiboflavin?
FAD
What metabolite is the point of convergence
of carbohydrate, fat, and protein catabolism
for the purpose of ATP production?
acetyl-CoA
In what way do catabolic pathways deliver
chemical energy?
in the form of:
ATP. NADH, NADPH,
FADH2
What pathway converts small precursor molecules into cellular macromolecules?
anabolic
Where do anabolic pathways get electrons
from to reduce carbon?
NADH, NADPH, FADH2
What do anabolic pathways do?
require energy and reduce
carbon
What is the most highly oxidized form of carbon found in living systems?
CO2
What compounds have the highest potential
to be oxidized?
hydrocarbons
What type of organisms use photosynthesis?
phototrophs
What type of organisms use cellular respiration?
heterotrophs
What happens during cellular respiration to
glucose?
it is oxidized all the way to
CO2 and H2O
results in ATP
Relationship between photosynthesis and
cellular respiration
same contents, go in oppo-
site directions
photo = sunlight
resp = ATP
What happens to CO2 in photosynthesis?
gets reduced back to organic carbon
What pathway is cellular respiration?
catabolism
What macronutrients are used in cellular respiration?
amino acids (proteins)
fatty acids (fats)
glucose (carbs)
Stage 1 of cellular respiration:
oxidation of macronutrients
to get acetyl-CoA
produces some electrons
Stage 2 of cellular respiration:
oxidation of acetyl groups
in CAC
What happens to carbon in step 2 of cellular
respiration?
carbon gets oxidized
lots of electrons are produced
What are the universal electron carriers/re-
duced electron carriers?
NADH
FADH2
How many steps are there in the CAC which
abstract electrons?
4
What carries the electrons from stage 2 to
stage 3 of cellular respiration?
NADH and FADH2
Stage 3 of cellular respiration:
electron transfer and oxidative phosphorylation
In stage 3, where do the electrons go?
funneled into respiratory
(electron-transfer) chain
What do the electrons in stage 3 do?
attach to oxygen (reducing
it), forming H2O
What does the flow of electrons in stage 3
produce?
drives production of ATP
What stages of cellular respiration oxidize
carbon?
1 and 2
What stages of cellular respiration reduce
oxygen?
3
What is the macronutrient make-up of ATP?
nucleotide
What stages do the electrons come from in
cellular respiration?
1 and 2
What is the universal energy carrier?
ATP
What is the purpose of cellular respiration?
energy production in the
form of ATP
What type of process is glycolysis?
catabolic
What is glycolysis and how many phases?
splitting of sugar
2 phases
How many enzymatic steps take place in glycolysis?
10
What is special about the enzymes in glycolysis?
magnesium dependent
What is a cofactor of many enzymes in glycolysis?
magnesium
In glycolysis, what is produced for each glu-
cose molecule?
2 NADH
2 ATP
What is the primary source of metabolic en-
ergy in mammalian tissues and cell types?
glycolysis
What happens to glucose in glycolysis?
oxidized to 2 molecules of
pyruvate
What is energy conserved as in glycolysis?
ATP and NADH
What is required for glycolysis to start?
2 NAD+
Reversible or not: kinase activity
non-reversible
Reversible or not: phosphatase activity
non-reversible
Reversible or not: isomerase reactions
reversible
What removes a phosphate group, yielding
inorganic phosphate (Pi)?
phosphatase
What catalyzes the formation of an isomer of
the substrate (requires breaking a bond)?
isomerase
What catalyzes the redox reactions of coen-
zyme NAD+/NADH, FAD/FADH2?
dehydrogenase
What stage of cellular respiration does gly-
colysis occur for glucose?
1
What stage does the CAC occur in cellular
respiration?
2
Where does the CAC/Kreb’s cycle occur?
mitochondrial matrix
What process involves going from large molecules to smaller ones?
catabolic
What is the CAC yield per acetyl-CoA?
2 CO2 (waste)
3 NADH
1 FADH2
1 ATP
Where do the products of NADH and FADH2
from the CAC go?
into electron transport
chain in stage 3 of cellular
respiration to produce ATP
How do you find the glucose yield of the
CAC?
multiply its products from
acetyl-CoA by 2
Practice CAC diagram
Most of the reactions in the CAC are…
reversible
What is carbon oxidized to in stages 1 and 2
in cellular respiration?
completely oxidized to
CO2
Which of the following cannot be a cofactor
or coenzyme?
a polypeptide
Vitamins that can be micronutrients requirements
B1-5
Minerals that can be micronutrient require-
ments
magnesium, iron, copper
B1, thiamin
coenzyme TPP
B2, riboflavin
coenzyme FAD
B3, niacin
coenzymes NAD+ and
NADP+
B5, pantothenic acid
coenzyme A
When does fermentation occur?
anaerobic conditions in
skeletal muscle
no mitochondria (red blood
cells)
What do RBCs use to produce ATP?
fermentation
What happens during the fermentation
process?
NADH is recycled back into
NAD+ to be used in glycol-
ysis
citric acid formula
citrate formula
The reactants of cellular respiration of glu-
cose + 6O2 have…
high potential energy
The products of cellular respiration equation
of 6CO2 + 6H2O have…
low potential energy
What are the links between oxidation and re-
duction?
NADH and FADH2
Where does oxidative phosphorylation take
place?
inner membrane of mito-
chondria
Oxidative phosphorylation =
ETC + ATP synthesis
What are the micronutrients for the ETC?
iron, copper, riboflavin
(FMN, FAD)
How many metabolites are in the Kreb’s cycle?
8
How many enzymes are in the Kreb’s cycle?
8
What type of process is the Kreb’s cycle?
anabolic
going from 2 smaller molecules to 1 larger
Where does the energy come from to de-
crease entropy in the Kreb’s cycle?
high energy bond between
acetyl group and coenzyme A
Stages of fatty acid oxidation
- CAC
- oxidative phosphorylation
Stage 1 of fatty acid oxidation
4 recurring enzymatic reactions
long chain fatty acid oxidized to yield acetyl-coA
What is required for stage 1 of fatty acid oxi-
dation?
must be at least 4 satu-
rated carbons or saturated
fatty acids
What breaks down triacylglycerols?
lipases
Triacylglycerol –>
3 fatty acids + glycerol
What is the cost of activation for fatty acid
catabolism?
2 ATP
Fatty acid –>
fatty acyl-CoA
(then goes to beta oxida-
tion)
What does beta oxidation of fatty acyl-CoA
yield?
1 NADH
1 FADH2
1 acetyl-coA
What does the last cycle of fat catabolism
lead to?
2 acetyl-CoA
What breaks down protein in amino acid ca-
tabolism?
proteases
Protein –>
amino acids
Amino acids –>
NH4 + metabolites (C, H,
O)
What does NH4 get converted to?
nontoxic urea (waste) and
disposed
What do the metabolites from amino acid catabolism get converted into?
pyruvate to acetyl-CoA
or just straight to
acetyl-CoA
Once something is converted to acetyl-CoA,
where does it go?
Kreb’s cycle, then oxidative
phosphorylation
Overall yield of ATP per glucose
30-32 ATP
What does ATP per fatty acid depend on?
size of fatty acid produced
in beta oxidation
physiological state of the
human body
What does ATP per amino acid depend on?
which amino acid
physiological state of hu-
man body
What happens chemically during fermentation?
keytone group in pyruvate
gets reduced to hydroxyl
group
How many electrons are needed to re-
duce carbonyl group in pyruvate to hydroxyl
group?
2 electrons from NADH
Where does glycolysis take place?
cytosol
What is the starting point of the preparatory
phase of glycolysis?
glucose
What is the end point of the preparatory
phase of glycolysis?
glyceraldehyde 3-P
What is the starting point of the pay-off phase
of glycolysis?
glyceraldehyde 3-P
What is the cost of glucose being energetical-
ly activated or to make it more reactive?
2 ATP
What happens during the preparatory phase
of glycolysis?
phosphorylation of glucose
and its conversion to glyceraldehyde 3-phosphate
For each glucose molecule, how many glyc-
eraldehyde 3-P molecules are formed?
2
How many ATP are produced in the payoff
phase of glycolysis?
4
What are the 2 regulated enzymes involved in
the preparatory phase of glycolysis?
hexokinase
phosphofructokinase
Isomer of glyceraldehyde 3-P
dihydroxyacetone phosphate
Which enzyme is involved in the first priming
reaction of the preparatory phase of glycolysis?
hexokinase
What is produced during the first and second
priming reaction?
ATP to ADP
Which enzyme is involved in the second priming reaction of the preparatory phase of glycolysis?
phosphofructokinase
During the preparatory phase of glycolysis, 2
ATP are invested to activate glucose to:
fructose 1,6-biphosphate
Glucose
C6
Pyruvate
C3
What is the starting point of the glycolysis
pay-off phase?
glyceraldehyde 3-P
What is the end point of the glycolysis pay-off
phase?
pyruvate
What is the regulated enzyme involved in the
glycolysis pay-off phase?
pyruvate kinase
The potential energy of the 2 molecules of
glyceraldehyde 3-P metabolite can be reaped
as:
2 NADH and 4ATP per glucose
What is glyceraldehyde 3-P derived from?
glucose
Where does glyceraldehyde 3-P get oxidized
at in the payoff phase of glycolysis?
C-1
What is the yield per 1 glyceraldehyde 3-P
metabolite in pay off phase:
1 NADH and 2 ATP
What phase of glycolysis: oxidative conver-
sion of glyceraldehyde 3-P to pyruvate and
the coupled formation of ATP and NADH
pay off phase
How many pyruvate are reaped from 1 glu-
cose in glycolysis?
2 pyruvate
What can glycolysis be revered into in order
to increase blood glucose level in times of
starvation?
gluconeogenesis
What happens during the last step in stage 1
after glycolysis?
pyruvate dehydrogenase
complex
Where is the pyruvate dehydrogenase com-
plex located?
matrix of mitochondria
What is the first step in the PDH complex?
decarboxylation, removal
of a carbon atom from
pyruvate
What does the pyruvate dehydrogenase com-
plex do?
catalyzes the conversion of
pyruvate into acetyl-CoA
What does the oxidative decarboxylation pro-
duce?
NADH, CO2
