Download Lesson 4.4 Anaerobic Respiration version 2

Respiration
Anaerobic Respiration
Settler
Write down 3 things you remember from KS4
anaerobic respiration
Feedback to the rest of class
Learning outcomes
Success criteria
By the end of this lesson
• All students will know that
ethanol and lactate are
produced in anaerobic
respiration
• Most students will be able to
explain how ethanol and
lactate are produced in
respiration
• Some students will know
how energy is released in
respiration in the absence of
oxygen.
I will achieve these outcomes by• Consolidate knowledge from
KS4 on anaerobic
respiration
• Complete word equations for
anaerobic respiration in
plants and animals
• Using keywords write down
an explanation of why
anaerobic respiration is
important and peer assess
• Complete application for
how science works
Starter
• How much ATP is generated during each stage of
respiration?
Glycolysis
Link reaction
Krebs cycle
Electron Transport Chain
• Which stages depend on oxygen (aerobic) and
which occur in the absence of oxygen
(anaerobic)?
Energy yields from aerobic and
anaerobic respiration
• Glycolysis
2 ATP
• Link reaction
• Krebs cycle 2 ATP
• Electron transport chain
28 ATP
Anaerobic respiration
Why is oxygen important?
Oxygen is important so the H ions produced in glycolysis
and krebs cycle can be converted to water and drive
the production of ATP.
What happens in the absence of oxygen?
Krebs cycle and electron transport chain can’t take place
and pyruvate builds up in the cell
Anaerobic process of glycolysis is the only source of ATP
So what happens to the pyruvate?
Glycolysis
Glycogen
2 ATP
4 ADP + 4Pi
Triose
Phosphate
(3C x 2)
Glucose
(6C)
2 ADP
4 ATP
Pyruvate
(3C x2)
NAD
Reduced NAD
NAD+ + 2H

(oxidised form )
NADH + H+
(reduced form)
Production of lactate in animals
• Human cells do this by converting pyruvate to
lactate. This reaction uses reduced NAD by
oxidising it to NAD once more.
• NAD is now available again to accept electrons
and protons so glycolysis continues.
• If NAD is not regenerated, even glycolysis would
have to stop, because there would be no
oxidised NAD available to accept these
electrons and protons.
• Write down the word equation to show how
lactate is made in anaerobic respiration.
• Pyruvate + reduced NAD
Lactate + NAD
Anaerobic Respiration in animals
Production of ethanol in plants and some
microorganisms
• Pyruvate loses a molecule of carbon dioxide and
accepts hydrogen from reduced NAD to produce
ethanol.
• Write down the word equation for this process
• Pyruvate + reduced NAD
ethanol + Carbon dioxide + NAD
Anaerobic Respiration in
microorganisms and plants
Why is anaerobic respiration important?
• Using the keywords below write down what
happens in anaerobic respiration (in animals)
and why it is important.
pyruvate
oxygen debt
oxygen
glycolysis
muscles
NAD
Glycogen
cramp
fatigue
Reduced NAD
lactate
• Peer assess explanations
What happens in anaerobic respiration and why it
is important.
• Anaerobic respiration occurs mostly in the muscles when
oxygen is being used up quicker than it can be supplied,
so an oxygen debt occurs. In the absence of oxygen
glycolysis would usually stop as there would be a build
up of reduced NAD. For glycolysis to continue, reduced
NAD must be converted into NAD. This happens when
pyruvate takes up 2 hydrogen atoms from reduced NAD
to make lactate. Lactate causes cramp and fatigue in
muscle tissue so this must be removed. It can be
oxidised back to pyruvate or it is taken to the liver and
converted to glycogen.
Removing Lactate
Why does oxygen uptake remain higher than normal
following exercise?
Lactate is oxidised back to pyruvate
Plenary – True and False
• More ATP is produced during anaerobic
respiration
• Anaerobic respiration in yeast has been
exploited by humans for the brewing industry.
• The krebs cycle and electron transport chain can
not occur without oxygen
• NAD is an important product of glycolysis
• The replenishment of NAD for use in glycolysis
is achieved by pyruvate accepting hydrogen
from reduced NAD
How Science works task.
• Unit 5 synoptic paper requires knowledge from
AS Biology. Using information from topics 3.1
and 2.7 complete the following application
• Investigating where certain respiratory pathways
take place in cells.
• Page 60 – answer questions
Class and Homework Tasks
1. Using the textbook complete the summary
question on page 59 and the ‘Application
and How Science Works’ questions on
page 60
2. Complete the practice exam questions on
respiration
Learning outcomes
Success criteria
By the end of this lesson
• All students will know that
ethanol and lactate are
produced in anaerobic
respiration
• Most students will be able to
explain how ethanol and
lactate are produced in
respiration
• Some students will know
how energy is released in
respiration in the absence of
oxygen.
I will achieve these outcomes by• Consolidate knowledge from
KS4 on anaerobic
respiration
• Complete word equations for
anaerobic respiration in
plants and animals
• Using keywords write down
an explanation of why
anaerobic respiration is
important and peer assess
• Complete application for
how science works