Getting energy from food Why do we need

Getting energy from food

Why do we need energy? Building up of proteins from amino acids. Contraction of muscle cells Energy Conduction of electrical impulses

What is this process called? Energy is released from food by RESPIRATION

What is the difference between the process of breathing and respiration? Respiration Process where a series of chemical reactions take place to break down food and release energy. Breathing Process where air is taken into and out of the lungs. The oxygen inhaled (from the air) is then used during the process of respiration.

Experiment What you will need: �Spring operated clothes peg (plastic) �Stopwatch or cell phone (for timing). �Paper and pen (for recording data). �Graph paper (for results).

Experiment: Work in pairs. 2. Hold the clothes peg comfortably with the thumb and forefinger. 3. Make sure you open it all the way each time you do it. 4. Your partner will be the timekeeper and will count the number of times you can open and close the clothes peg in 30 second intervals. Before you start, draw Person 60 s 90 s up a table 30 s for your data: 1. 1 2

Experiment When your timekeeper says go, open and close the peg as fast as you can. Count out loud each time you repeat the movement. 6. The timekeeper will write down the numbers at 30 s, 60 s and 90 s intervals. 7. Repeat the experiment switching timekeeper and clothes peg squeezer roles with your partner. Record their number of squeezes. 8. Draw and plot a graph of the two sets of results. (X axis = 30 s, 60 s, 90 s. Y axis = number of squeezes per 30 s 5.

Discussion �What can we conclude from the graph? �Why do the numbers decrease by time? �What happens when all the oxygen is used up? Can respiration take place in the absence of oxygen?

Aerobic and Anaerobic respiration Aerobic respiration • Releases energy in the presence of oxygen • Produces a large amount of energy • Produces carbon dioxide and water Anaerobic respiration • Releases energy in the absence of oxygen • Produces a small amount of energy • Produces carbon dioxide and alcohol/lactic acid

Aerobic respiration �This is the release of relatively large amounts of energy by using oxygen to break down food. �The process takes place in several steps releasing energy at each stage. All the steps can be summed up in the following equation: Enzymes

Energy of the cell �The chemical energy released during aerobic respiration is called ATP. �ATP= ATP Adesonine Tri. Phoshpate. �ATP is found in cells which require a lot of energy. �Can you think of any examples? �ATP can be regarded as stored energy. �When energy is needed, ATP changes to ADP. The overall reaction results in the release of energy. �ATP ADP + Energy

Summary so far: Respiration The energy is then used by the body as needed. ATP breaks down into ADP and the reaction results in a release of energy. Aerobic respiration Produces energy in the form of ATP

Where does aerobic respiration take place? MITOCHONDRIA