Download File - Mrs Jones A

Remind yourselves using whiteboards of
alcoholic and lactate fermentation
 You are then going to compare
anaerobic respiration in yeast and
mammals

Reduced
NAD
CO2
Pyruvate
Pyruvate
decarboxylated
Catalysed: Pyruvate
decarboxylase
2H
Ethanal
Reoxidised
NAD NAD can
accept
more H
atoms
Ethanol
Ethanal accepts H atoms
from reduced NAD.
Catalysed by Ethanol
dehydrogenase
Reduced
NAD
Pyruvate is the H
acceptor (H
atoms) from
reduced NAD
NAD is now
reoxidised and
can accept more H
atoms from
glucose
SO GLYCOLYSIS
CAN CONTINUE
NAD
2H
Pyruvate
Lactate
Catalysed by Lactate
dehydrogenase
YEAST
Hydrogen acceptor
Is carbon dioxide
produced
Is ATP produced
Is NAD reoxidised
End products
Enzymes involved
MAMMALS
Hydrogen
acceptor
Is carbon dioxide
produced
Is ATP produced
Is NAD reoxidised
YEAST
MAMMALS
Ethanol
Pyruvate
Yes
No
Yes 2x in glycolysis Yes 2x in glycolysis
Yes
Yes
End products
Ethanol and
carbon dioxide
Lactate
Enzymes involved
Pyruvate
decarboxylase/
ethanol
dehydrogenase
Lactate
dehydrogenase
Diving mammals,
such as this
Galapagos sea lion,
evolved adaptations
allowing them to stay
underwater for
prolonged periods of
time
 Suggest what they
could be..apply your
learning!






What physical adaptations?
Lower metabolic rate: Diving mammals will slow
their heart rate, stop their breathing, and shunt
blood flow from their extremities to the brain,
heart, and muscles when starting a dive
Diving mammals—including whales, seals and
otters, have more haemoglobin/myoglobin
(oxygen store) in their muscles.
Haemoglobin has a higher affinity for oxygen
Respiration: large supplies of NAD, so more
glycolysis, less build up of lactate; more pH
buffers
Examination
1.
2.
3.
4.
questions!
Organisms require energy..(4)
(b) In anaerobic conditions compound
F.. (5)
(b) Yeast cells carry out anaerobic
respiration (4)
(c) If oxygen is not present (4)
17 marks…
When is the majority of ATP produced in
respiration???
 HOW?
 What conclusion can you make about
the best respiratory substrate?

Oxidative phosphorylation
 Protons flow through channels
associated with ATP synthase on inner
mitochondrial membrane
 The more protons=more ATP produced!
 So more protons in respiratory substrate=
more TP when the substrate is respired
 More H atoms per mole of substrate=
more oxygen (final acceptor) needed to
respire the substrate!

Define the term respiratory substrate;
 Explain the difference in relative energy
values of carbohydrate, lipid and protein

So define ……
 A respiratory substrate is an organic
substance that can be used for
respiration

How many hydrogens!
Glucose (C6H12O6)
C6H2OH
H
C1
O
H
C2
OH
HO
C3
H
H
C4
OH
H
C5
OH
H
C6
OH
H
Chain form
C5
H
O
H
H
C4
OH
C1
OH
C3
H
Ring Chain
H
C2
OH
OH
•
•
•
•
•
•
•
Glucose is the most common substrate for most
mammalian cells
Animals store glucose as glycogen, and plants
store it as starch
Theoretical maximum energy yield for one
mole of glucose is 2870 kJ
It takes 30.6 kJ to produce 1 mol ATP
Respiration of 1 mol glucose should produce
nearly 94 mol ATP, but the actual yield is more
like 30, as it has an efficiency of 32%
Remaining energy used to generate heat
Maintains suitable temperature for all the
enzyme controlled reactions
Draw the amino acid glycine
 R=H
 How many hydrogens??

H
O
H
N
C
C
OH
H
H
•
•
•
•
•
•
Excess amino acids are deaminated (removal of
amine group converted to urea)
Rest is changed to glycogen or fat
During fasting/starvation /prolonged exercise:
Protein is then hydrolysed (split with water) to
amino acids which can be respired
Some can be converted to pyruvate, or acetate
and then is carried to Krebs cycle
Some can enter Krebs directly
Number of hydrogen atoms per mole accepted
by NAD then used in electron transport chain is
slightly more than the number of hydrogen atoms
per mole of glucose, so proteins release slightly
more energy than equivalent masses of glucose
Pyruvate
Acetate
Directly
Draw a glycerol molecule
 How many hydrogen's????
 Draw a triglyceride


Lipids are formed by joining fatty acids to a glycerol
backbone. Glycerol molecule is same in all fats, so it is
the fatty acid that gives fats their different properties
O
H
H
C
OH
H
C
OH
H
C
OH
H
HO
C
O
C17H35
HO
C
O
C17H35
HO
C
C17H35
CARBOXYL
GROUP
(acid)
Condensation reaction: Acid group on fatty acid
Glycerol (C3H8O3)
+ OH Hydroxyl group of glycerol =Covalent
bond= ester bond

Palmitic acid: a fatty acid
•
•
•
•
•
Made of fatty acids and glycerol
Glycerol can be converted to glucose,
fatty acids can’t
Contain many carbon atoms and
hydrogen atoms
SO SOURCE OF MANY PROTONS= Much
ATP!
What happens to the fatty acids??
•
•
•
•
•
Fatty acids combined with CoA after ATP is
used to hydrolyse (split using water) to AMP
(adenosine monophosphate) + 2 Pi
Fatty acid CoA complex taken to matrix
and broken down into 2- carbon acetyl
groups that are attached to CoA
Reduced NAD and FAD are formed
Acetyl groups are released from CoA and
enter Krebs producing 3 NADH, 1 FADH and
1 ATP (slp)
NADH can then go to electron transport
chain
• ATP produced by chemiosmosis
Coenzyme A
Fatty Acid
Fatty Acid Coenzyme A
complex
NAD + FAD
Reduced NAD +
FAD
Many 2-carbon acetyl groups
2-carbon acetyl
groups go to the Krebs
Cycle
Coenzyme A

How the respiratory substrates are used
Glycogen or starch
Protein
Glucose
Lipid
Amino Acids
Pyruvate
fatty Acids
Acetylcoenzyme A
Krebs cycle
Respiratory Substrate
Carbohydrate
Lipid
Protein

Guess??
Mean energy value/kJ g-1
Respiratory Substrate
Mean energy value/kJ g-1
Carbohydrate
15.8
Lipid
39.4
Protein
17.0

Key terms mix and match
 Individually 5 minutes
 Pairs 5 minutes
 Table groups
WWW/EBI
Examination
1.
2.
3.
4.
questions!
Organisms require energy..(4)
(b) In anaerobic conditions compound
F.. (5)
(b) Yeast cells carry out anaerobic
respiration (4)
(c) If oxygen is not present (4)
17 marks…
Your tasks
 Using LO sheet: what have we covered
in class?
 Get notes up to date
 Complete exam question pack
 TEST..
 Left to do respirometer practical
 Next week: recap lesson, practical
lesson, test the next Tuesday (24th March)
