Cell Respiration and Glucose in Biology

National 5 Biology Unit 1: Cell Biology Key Area 1.6 Respiration KA1.6a Introduction and glucose - the release of chemical energy 4/4/2025 Mrs Smith - National 5 Biology 1

National 5 Biology Learning Intentions By the end of today s lesson you shuld know: Your prior learning fromS1/S2 Specifically that respiration is the process by which chemical energy is released during the breakdown of food such as gluocose. Respiration occurs in every living cell Oxygen + Sugar Carbon Dioxide + Water + Energy Now in N5 The chemical energy stored in glucose must be released by all cells through a series of enzyme-controlled reactions called respiration, 4/4/2025 Mrs Smith - National 5 Biology 2

Glucose Facts Glucose is a type of sugar. It is an energy-rich substance. It is the most common end- product from the digestion of complex carbohydrates such starch. Glucose is the main source of energy in all living things

Release of chemical energy When food is burned in air or in oxygen, its chemical energy is released rapidly as heat and light. (we can do an experiment to show this). In a living cell, the chemical energy stored in food is not released as rapidly. Instead an orderly release of energy takes place relatively slowly through a series of enzyme-controlled reactions.

Respiration The chemical energy stored in glucose must be released. This orderly release of energy which takes place relatively slowly through a series of enzyme- controlled reactions is called RESPIRATION. Respiration occurs in ALL living cells.

Measuring the energy content of food

Investigation: Aim: To determine how much energy is in different foods What s your Hypothesis: Which food do you think contains the most energy? Type of Food Initial Temp ( C) Final Temp ( C) Temp Rise ( C) Crisps Pasta Bread Cereal What type of food has the most energy?

Aerobic Respiration Aerobic Respiration

Junior Phase revision: Can your remember the equation for respiration. Junior Phase revision: Can your remember the equation for respiration.

Food Calormeter The energy content of a food can be measured accurately using a food calorimeter. This equipment overcomes the limitations of the experimment we completed using the burning food to heat water. the food It is more accurate because The food sample is enclosed; therefore loss of heat energy is reduced to a minimum. The stirrer and coiled chimney bring about even distribution of the heat energy released during burning the oxygen supply ensures that the peanut burns completely. This time the temperature of the water is found to rise by 6 C, showing that 1 g of peanut has released 25.2 kJ of energy. Torrance, James. National 5 Biology with Answers: Second Edition (p. 37). Hodder Education. Kindle Edition.

National 5 Biology Have you achieved your Learning Intentions CAN YOU..... Describe that respiration is the process by which chemical energy is released during the breakdown of food such as gluocose. Explain that respiration occurs in every living cell Write the word equasion for respirario as Oxygen + Sugar Carbon Dioxide + Water + Energy Reacll that the chemical energy stored in glucose must be released by all cells through a series of enzyme-controlled reactions called respiration., 4/4/2025 Mrs Smith - National 5 Biology 11

TYK: Torrance pg 38 1. Which sugar is the most common source of energy in living cells? (1) 2. What name is given to the series of enzyme- controlled reactions by which energy stored in sugar is released? (1) 3. Where does this process occur in living organisms? (1) Torrance, James. National 5 Biology with Answers: Second Edition (p. 38). Hodder Education. Kindle Edition.

TYK: How did you do? 1. Which sugar is the most common source of energy in living cells? (1) GLUCOSE 2. What name is given to the series of enzyme- controlled reactions by which energy stored in sugar is released? (1) RESPIRATION 3. Where does this process occur in living organisms? (1) IN ALL LIVING CELLS