© boardworks ltd 2004 1 of 30 ks4 biology what is energy used for?
TRANSCRIPT
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KS4 Biology
What is Energy Used For?
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Contents
What is Energy Used For?
Contracting muscles
Active transport
Thermoregulation
Processes that use energy
Building large molecules
Summary quiz
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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…
How does the body use energy?
building large molecules from smaller ones
the active transport of substances within the body
maintaining a steady body temperature
muscle contraction
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Contents
What is Energy Used For?
Contracting muscles
Thermoregulation
Building large molecules
Summary quiz
Processes that use energy
Active transport
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Muscles work by contracting. When a muscle contracts it pulls a bone, creating lever.
bone
muscle
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.
Muscles use energy to contract
muscle relaxed
energy
muscle contracted
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Contents
What is Energy Used For?
Contracting muscles
Thermoregulation
Building large molecules
Summary quiz
Processes that use energy
Active transport
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fats
proteins
minerals
vitamins carbohydrates
water fibre
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?
A balanced diet should be made up of food from all sevenfood groups.
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The digestion of food produces many useful substances.
The body uses the energy from respiration to turn these raw materials into useful substances.
energy
respiration digestion
useful raw materials
Converting food into respiration materials
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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).
Building a new protein molecule – step 1
albumin is the main protein in egg-whites
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Step 2
These proteins are made of amino acid chains.
The order of the amino acids is specific to the protein.
amino acids
Building a new protein molecule – step 2
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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.
Building a new protein molecule – step 3
enzymeaction
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Step 4
This digestive process releases the individual amino acids.
Building a new protein molecule – step 4
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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.
new protein (old)
energy
respiration
Building a new protein molecule – step 5
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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.
new protein
protein moved to and then used
elsewhere in the body
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Contents
What is Energy Used For?
Contracting muscles
Thermoregulation
Building large molecules
Summary quiz
Processes that use energy
Active transport
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The conditions outside your body are constantly changing.
One minute they can be hot, the next cold.
Thermoregulation
37oCThe body needs to remain at 37oC is because this is the temperature at which our enzymes work most effectively.
Despite these changes, your body must be kept at a constant temperature of…
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Enzymes are temperature-sensitive chemicals that control many of the chemical reactions in the body.
How are enzymes are affected when body temperature changes?
37oC37oC
Enzymes work most effectively and body is fine.
Enzymes work slowly and the
body is suffering.
Enzymes are heat-damaged and body can
become ill.
Temperature and enzymes
hotterhottercoldercolder
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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.
Sensing body temperature
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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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?
How do blood vessels use energy?
outer wall
blood
muscle cells
An artery wall is made of a thick inner layer of muscle.
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If the muscle lining a blood vessel relaxes, the blood vessel becomes wider and the blood flow increases.
Blood vessels and blood flow
If the muscle lining a blood vessel contracts, the blood vessel becomes narrower and blood flow is constricted.
blood flowconstricted
blood flowincreased
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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.
Blood vessels in the skin
How do blood vessels affect blood flow in the skin?
blood vessels
direction of blood flow
skin surface
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
Energy from respiration is used to power the contraction of the muscle cells that allows this redirection to happen.
The contraction and relaxation of these blood vessels forces more blood to flow within the surface of the skin.
How does this help to increase heat loss from the body?
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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.
The heat within the blood escapes to the cool air.
This causes body temperature to drop and you feel cooler.
bloodskin
air heat heat heat
Increasing heat loss from the skin
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Contents
What is Energy Used For?
Contracting muscles
Thermoregulation
Building large molecules
Summary quiz
Processes that use energy
Active transport
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Diffusion is the movement of substances down a concentration gradient from high to low concentration.
Comparing active transport and diffusion
diffusion active transport
high concentration
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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high concentration
When does diffusion happen?
As an example, this particle could be an oxygen molecule in the lungs that is moving from an alveolus into a blood capillary.
Usually, substances move in and out of cells by diffusion from areas of high to low concentration.
low concentration
diffusion
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When does active transport happen?
This is active transport, which needs energy from respiration to take place.
Sometimes, substances have to move in the opposite direction to the concentration gradient from areas of low to high concentration.
high concentration
low concentration
active transport
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?
Contracting muscles
Thermoregulation
Building large molecules
Summary quiz
Processes that use energy
Active transport
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Multiple-choice quiz