Transcript Molecules of Life

Respiration
Part 2
Learning Objectives
• Understand why exercise changed breathing
and pulse rate.
• Learn about the difference between aerobic
and anaerobic respiration.
• Learn about oxygen debt. (Higher only)
Success Criteria
• I can find and measure my own pulse rate.
• I can explain the link between increased
exercise and increased pulse/breathing rate.
• I can explain the link between anaerobic
respiration and build up of lactic acid.
Starter
• Look at the pictures below and use them to help you detect your
own pulse.
• Measure your pulse rate by counting the number of beats in one
minute.
• Why might your pulse rate not be at the normal rate right now?
Starter
• Think about an average weekday and all of the things you might do
during the course of the day.
• List what activities can raise or lower your pulse rate…
Exercising and Feeling Tired
• Let’s look back at the equation for aerobic respiration…
glucose + oxygen  carbon dioxide + water
When we exercise, we
need more of these
two.
This means more of
this is produced. It
must be removed.
• When we exercise, our cells work harder and require more energy
to be released. (respiration)
• Therefore, the cells need more glucose and oxygen.
• Because of this, our breathing rate and pulse rate increase to
satisfy the demand.
1. Cells need more
glucose + oxygen
for respiration
2. Breathing rate + Pulse rate
increase in order to deliver
glucose + oxygen to cells
4. The high breathing and pulse rate
means that the carbon dioxide can be
removed as quickly as possible.
Write out
these steps
under the
heading
‘Exercise &
Respiration’.
3. High rate of respiration
means lots of waste carbon
dioxide is produced
Recovery Rate
• Before a game of football, if you were to measure your pulse rate,
the reading would be called the “resting rate”.
• After a game of football, the time taken for the pulse rate to
return to the resting rate, is called the recovery rate.
pulse rate
What do you think
each time period
represents? Fill in
your own blank
graph.
A
B
C
time
D
B:
• The number of beats during exercise.
• Lots of glucose/oxygen required by
cells, so heart pumps blood faster.
pulse rate
A:
• Resting rate.
• The normal number of beats per
minute when not doing exercise.
A
B
C
D
time
C:
• The recovery rate.
• This is the time taken for the pulse rate
to return back to normal.
D:
• This is the resting rate again.
• The pulse rate has returned back to
normal.
Anaerobic Respiration
• Anaerobic respiration is a type of respiration that can release
energy without needing any oxygen.
• It occurs during hard exercise, when not enough oxygen can
supplied for aerobic respiration to occur.
glucose  lactic acid
(that’s it!)
• The equation is very different to aerobic respiration and produces
much less energy per glucose molecule.
• The lactic acid is poisonous and builds up in muscles after hard
exercise.
Lactic Acid & Muscle Fatigue
• After intense exercise, lactic acid
build-up causes muscles to stop
working.
• This is called muscle fatigue.
• It is also known as cramp and can be
very painful.
• You need to rest in order for the
lactic acid to be broken down.
• Remember, lactic acid is only
produced during hard exercise.
Practical: Fist Clenching!
• Place your hand (palm-side up) on the desk.
• One person in the group needs to have the
stopwatch. Ask them to count down ‘3, 2, 1, go!’
and then start the stopwatch to time 1 minute.
• When they say ‘go!’, start clenching your fist as
fast as you can while your partner counts how
many times you can open and close your hand in
1 minute. Do not stop! Keep going for the whole
minute.
• Record how many times you managed to make a
fist in the table on worksheet b3_c_02.
• Now repeat the experiment so that everyone in
the group does the fist clenching.
• Repeat the experiment again, but this time the
action should be raising your hand above your
head and making fists.
• Record your results in the table worksheet
b3_c_02.
• If you have time each group member should do
the exercises again to see if they can improve on
their previous scores.
Task
1. What type of respiration is used to release energy while you are
asleep?
2. What type of respiration is used to release energy when you are
sprinting?
3. What chemical is produced during anaerobic respiration?
4. Why do your muscles hurt after a hard game of football?
5. Explain the difference between aerobic and anaerobic
respiration.
HIGHER
Oxygen Debt
• The lactic acid that has built up during anaerobic respiration needs
to be broken down.
It gets broken down in
the liver.
The blood carries the
lactic acid there.
• Oxygen is required in the breakdown of lactic acid.
• Heavy breathing after exercise provides the extra oxygen required
to break down lactic acid, and is known as the oxygen debt.
• This is followed by panting to allow aerobic respiration to resume.
PLENARY
In your books, describe what will happen to
your breathing rate and pulse rate as you
move towards your next destination in the
college.
Explain the changes.