Learning objectives:
How does food energy get to our cells?
How do our cells release the energy in our food?
What do cells need the energy in food for?
How can we compare the energy content of different foods?
1 of 39 © Boardworks Ltd 2007

How do our cells get the energy out of our food?
Digestion (break food into small pieces)
Chemical & mechanical
2 of 39 © Boardworks Ltd 2007

How do our cells get the energy out of our food?
Digestion (break food into small pieces)
Chemical & mechanical
Absorption of digested
food into blood stream http://www.youtube.com/watch?
v=b20VRR9C37Q
3 of 39 © Boardworks Ltd 2007

How do our cells get the energy out of our food?
Digestion (break food into small pieces)
Chemical & mechanical
Absorption of digested
food into blood stream
Transport to every cell in the body
Food “burnt” by cells to release energy
© Boardworks Ltd 2007 4 of 39

Respiration means “burning food to release energy”
Respiration happens in every cell of the body 24/7
Respiration is GO!
5 of 39 © Boardworks Ltd 2007

Glucose
Molecules of glucose have
……….. stored in the bonds which hold them together.
Breaking up the molecule breaks ………. and releases the stored ……………
6 of 39 © Boardworks Ltd 2007

2 answers!
7 of 39 © Boardworks Ltd 2007

Mitochondria are full of enzymes which can help oxygen break down g................. and release its stored e...............
The breakdown of glucose inside our cells, releasing energy is called “cellular respiration”
To 1.13
Video to recap respiration key ideas http://www.youtube.com/watch?v=JEnjph9miK4
8 of 39 © Boardworks Ltd 2007

Digested sugars are carried in our blood to every cell in our body.
9 of 39 © Boardworks Ltd 2007

Digested sugars are carried in our blood to every cell in our body.
The blood also delivers
............ to every cell in our body. http://www.youtube.com/watch?
v=WXOBJEXxNEo
© Boardworks Ltd 2007 10 of 39

The oxygen is used to break the
.............
molecules down and release the ..............
stored in them
+
11 of 39 © Boardworks Ltd 2007

The process of releasing the energy stored in sugar is known as
+
The reaction produces 2 waste substances...........
& ....................................
12 of 39
Carbon dioxide water
© Boardworks Ltd 2007

glucose
+ oxygen carbon dioxide
+ water
+
(energy)
13 of 39 © Boardworks Ltd 2007

All organisms need energy to survive.
• A lot of our food contains glucose which acts as a small store of …………………
• Plants and animals continually release the………………. stored in glucose in a process called ………………………
• Respiration happens in ………………….. cell of the body
• The glucose breaks up when its hit by …………………..
The process releases ………… …………………and water.
14 of 39 © Boardworks Ltd 2007

On this journey Ranulph
Fiennes consumed an average of 10,000 calories per day.
1. What did he need these calories for?
2. What types of food would you recommend for Ranulph to eat on his journey?
Ranulph Fiennes on a solo walk across the Arctic
15 of 39 © Boardworks Ltd 2007

• What is the energy released in respiration used for?
Enable muscles to contract
Build larger molecules from smaller ones
All organisms
Plants only
Animals only
Mammals and birds only
Combine sugars and nitrates to make protein
16 of 39
Maintain body temperature
© Boardworks Ltd 2007

Independent
Variable
Question
Dependent
Variable
Reliability
If results are “reliable” it means
....................................
.......................................
.......................................
..................
You can check the reliability of your results by ..................................
…………………………..
…………………………..
17 of 39
Control variables If control variables are not all kept the same they might
...................................
...................................
...................................
...................................
...................................
© Boardworks Ltd 2007