Transcript What is Energy Used For?

KS4 Biology
What is Energy
Used For?
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Contents
What is Energy Used For?
Processes that use energy
Contracting muscles
Building large molecules
Thermoregulation
Active transport
Summary quiz
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How does the body use energy?
Respiration occurs in all body cells to release energy.
What is this energy used for?
This energy is used by the many processes that sustain life,
such as…
muscle contraction
maintaining a steady body temperature
building large molecules from smaller ones
the active transport of substances within the body
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Contents
What is Energy Used For?
Processes that use energy
Contracting muscles
Building large molecules
Thermoregulation
Active transport
Summary quiz
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Muscles use energy to contract
Muscles work by contracting. When a muscle contracts it
pulls a bone, creating lever.
muscle
bone
Using the energy generated in muscle cells, muscle
contraction alters the position of the bones. This means
that work can be done, such as something can be lifted.
muscle
relaxed
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energy
muscle
contracted
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Contents
What is Energy Used For?
Processes that use energy
Contracting muscles
Building large molecules
Thermoregulation
Active transport
Summary quiz
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The seven main food groups
In order for the human body
to maintain the metabolic
processes in its cells, it must
obtain nutrients from the seven
food groups.
What are these food groups?
fats
proteins
minerals
vitamins
water
fibre
carbohydrates
A balanced diet should be made up of food from all seven
food groups.
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Converting food into respiration materials
The digestion of food produces many useful substances.
digestion
respiration
energy
useful raw
materials
The body uses the energy from respiration to turn
these raw materials into useful substances.
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Building a new protein molecule – step 1
An example of this use of energy is how the body
builds new proteins from amino acids.
Step 1
Proteins are eaten as part of our food (e.g. protein in eggs).
albumin is the main
protein in egg-whites
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Building a new protein molecule – step 2
Step 2
These proteins are made of amino acid chains.
The order of the amino acids is specific to the protein.
amino acids
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Building a new protein molecule – step 3
Step 3
This protein may not be the one that the body requires.
Therefore, the digestive system uses protease enzymes
to break up the amino acid chain.
enzyme
action
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Building a new protein molecule – step 4
Step 4
This digestive process releases the individual amino acids.
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Building a new protein molecule – step 5
Step 5
With the raw materials now free, the body can use energy
from respiration to assemble them into new proteins.
A new protein will have a different order of amino acids.
energy
respiration
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new protein
(old)
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Building a new protein molecule – step 6
Step 6
This new protein, and others like it, will now be used in
different ways by the body.
The energy from respiration makes this possible.
protein moved to
and then used
elsewhere in the
body
new protein
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Contents
What is Energy Used For?
Processes that use energy
Contracting muscles
Building large molecules
Thermoregulation
Active transport
Summary quiz
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Thermoregulation
The conditions outside your
body are constantly changing.
One minute they can be hot,
the next cold.
Despite these changes, your body must be kept at a
constant temperature of…
o
37 C
The body needs to remain at 37oC is because this is the
temperature at which our enzymes work most effectively.
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Temperature and enzymes
Enzymes are temperature-sensitive chemicals that control
many of the chemical reactions in the body.
How are enzymes are affected when body temperature
changes?
colder
Enzymes work
slowly and the
body is
suffering.
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37oC
Enzymes work
most effectively
and body is fine.
hotter
Enzymes are
heat-damaged
and body can
become ill.
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Sensing body temperature
Body temperature is controlled by a region of the brain.
As blood flows
around the body,
it passes through the
thermoregulatory
centre in the brain.
rest of
the
body
The brain senses
body temperature
by sensing the
temperature of
the blood.
Once the brain knows what the body temperature is, it can
act to keep it steady.
How does the body react to hot and cold temperatures?
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Feeling the heat
When you feel too hot, how
does your body react?
You sweat, which helps
to cool you down.
Another cooling effect is that blood vessels in the skin
expand.
This means that more blood gets near the surface of the skin,
which is why some people go red when they are too hot!
The expansion of blood vessels uses some of the energy
released by respiration.
How do blood vessels use this energy?
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How do blood vessels use energy?
An artery wall is made of a thick inner layer of muscle.
muscle cells
blood
outer wall
The muscle cells are able to contract and relax using
energy from respiration.
How does the contraction and relaxation of these muscles
affect the blood flow through this blood vessel?
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Blood vessels and blood flow
If the muscle lining a blood vessel contracts, the blood
vessel becomes narrower and blood flow is constricted.
blood flow
constricted
If the muscle lining a blood vessel relaxes, the blood vessel
becomes wider and the blood flow increases.
blood flow
increased
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Blood vessels in the skin
How do blood vessels affect blood flow in the skin?
skin surface
blood
vessels
direction of
blood flow
The brain can cause the contraction and relaxation of the
muscles within the walls of these blood vessels.
This means that blood can be forced to take different routes
through the blood vessels in the skin.
What happens to blood flow when the body is too hot?
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Increasing blood flow to the skin
When the brain senses that the body is too hot, it acts to
redirect the blood flow towards the surface of the skin.
increased
blood flow
to the surface
of the skin
blood vessel
widens
blood vessel
constricts
The contraction and relaxation of these blood vessels
forces more blood to flow within the surface of the skin.
Energy from respiration is used to power the contraction
of the muscle cells that allows this redirection to happen.
How does this help to increase heat loss from the body?
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Increasing heat loss from the skin
When blood flows to the surface of the skin, it passes near
the air surrounding the body.
This air is much cooler than the temperature of the blood.
air
heat
heat
heat
skin
blood
The heat within the blood escapes to the cool air.
This causes body temperature to drop and you feel cooler.
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Contents
What is Energy Used For?
Processes that use energy
Contracting muscles
Building large molecules
Thermoregulation
Active transport
Summary quiz
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Comparing active transport and diffusion
Diffusion is the movement of substances down a
concentration gradient from high to low concentration.
high concentration
diffusion
active transport
low concentration
Sometimes substances move up a concentration
gradient from low to high concentration.
This process is called active transport and requires
energy to make it happen.
Where does the energy for active transport come from?
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When does diffusion happen?
diffusion
Usually, substances move
in and out of cells by
diffusion from areas of
high to low concentration.
high
concentration
low
concentration
As an example, this particle
could be an oxygen molecule
in the lungs that is moving
from an alveolus into a
blood capillary.
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When does active transport happen?
active transport
Sometimes, substances
have to move in the
opposite direction to the
concentration gradient
from areas of low to high
concentration.
This is active transport,
which needs energy from
respiration to take place.
high
concentration
low
concentration
An example of active transport
occurs can occur in the lungs
when the oxygen supply is low
but is still needed by the blood.
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Contents
What is Energy Used For?
Processes that use energy
Contracting muscles
Building large molecules
Thermoregulation
Active transport
Summary quiz
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Multiple-choice quiz
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