Topics 3d, 3e, 3f Flashcards
Potential energy is…?
stored energy
- energy of position
- chemical energy
Kinetic energy is…?
energy of motion
- light (photons)
- heat (molecules)
- electricity (electrons)
- movement of large objects
1st law of thermodynamics?
conservation of energy (energy cannot be created or destroyed)
2nd law of thermodynamics?
entropy is always increasing (closed system tend towards disorder)
If energy is liberated by a chemical reaction, it is said to be what? Give example.
exergonic/exothermic
glucose + O2 = CO2 + H2O + energy
If energy is required by a chemical reaction, it is said to be what? Give example.
endergonic/endothermic
CO2 + H2O + energy = glucose + O2
What is an energy carrier molecule? Eg…
molecules that carry energy in cells in the form of high-energy chemical bonds
eg. ATP
High energy molecules…
ATP
glucose
protein
low energy molecules…
ADP + P
CO2 + H2O
animo acids
Endergonic & exergonic reactions are coupled by …? What happens to this product?
ATP which gets ‘recycled’ and reused
What do catalysts do to activation energy?
lower it (interact with reactants to make chemical interactions energetically more favourable)
T or F - catalysts can participate in reactions repeatedly
true
T of F - catalysts get changed during a reaction
false
A bit about enzymes…
biological catalysts
made up of proteins (mainly)
generally very specific activity
end in …ase
Metabolism is defined as …?
…the sum of all biochemical reactions
Which factors regulate reactions?
enzyme concentration (more enzymes => faster reaction) enzyme activity (certain conditions eg pH) competitive/noncompetitive inhibition
Competitive inhibition occurs how?
competitive inhibitor binds to active site preventing entry of substrate
Noncompetitive inhibition occurs how?
noncompetitive inhibitor binds to substrate (away from active site) changing the shape of the molecule so substrate does not ‘fit’
Give example of allosteric regulation
+ve & -ve feedback loops
Major environmental variables that influence enzyme function?
temp
pH
[salt}
What is protein denaturation?
change in 3D shape of a protein
amino acid sequence remains UNCHANGED
is sometime reversible
For most cellular enzymes (human), max activity occurs at what pH/temp?
pH: ~7.4
temp: 37 degrees c
The breakdown of glucose to pyruvate costs/yields how many ATP molecules? Net ATP?
costs 2ATP (for activation energy) total yields 4 ATP net = 2 ATP
Compound losing an electron is …?
oxidised
Compound gaining an electron is…?
reduced
where does glycolysis occur?
cytosol
T or F - glycolysis requires O2
false
T or F - glycolysis has efficient energy recovery
fale - inefficient 2%
Other products of glycolysis that can recover energy?
pyruvate
NADH
Net products yielded from 1 glucose molecule in glycolysis…?
2 ATP
2NADH
2 pyruvate
What is the role of O2 in the electron transport chain?
ultimate electron acceptor (the main reason we need to breath, and to expel CO2)
Celular resp occurs in which organisms? Where?
Only in eukaryotes - mitochondria
2 key parts of cellular respiration?
Krebs cycle
electron transport chain
Krebs cycle inputs…?
input: 2-carbon molecules (acetyl Co-A); NAD+/FAD; ADP
Krebs cycle outputs…?
coenzyme A
CO2
NADH/FADH2
ATP
What are NADH & FADH2?
reduced electron carriers that transport e’s to ETC for ‘work’
Total products yielded from Krebs cycle alone…?
3 NADH
1 FADH2
1 ATP
Define the chemiosmotic theory
proton gradient created during transit of e’s thru ETC is utilised by ATP synthase in the phosphorylation of ADP -> ATP
3 requirements for chemiosmosis…?
chemical gradient (H+ gradient) isolated location (inter membrane space of mitochondria) enzyme (ATP synthase)
Total yield from glucose thru cellular respiration…?
36-38 ATP (32 or 34 ATP NET)
6H2O
6CO2
Total molecules yielded from glucose -> ETC…?
36-38 ATP
10 NADH
2 FADH2
Light reaction inputs…?
H2O
light
ADP
NADP+
Light reaction outputs…?
ATP
NADPH
O2
Where does the light-dependent reaction take place?
thylakoid membrane inside chloroplasts
What happens in light-independent reactions?
Energy from ATP & NADPH -> Calvin cycle -> 6 molecules of G3P -> 1 G3P leaves cycle (5 stay) -> 1 G3P + 1 G3P = 1 glucose molecule
Light-independent reaction inputs…?
ATP
NADPH
CO2
Light-independent reaction outputs…?
glusose
ADP
NADP+
