Ch. 9 Cellular Respiration• Food and drink provide a source of

energy for your cells that is used to make ATP

• calorie – the amount of energy needed to raise one gram of water one °C

• Kilocalorie (on labels) – 1000 calories

• Food provides the building blocks for your cellular products (proteins, hormones, etc.)

Overview of C. R.• Cellular respiration can be aerobic (with O2)

or anaerobic (without O2)

• Aerobic respiration has 3 steps:

1. Glycolysis

2. Krebs Cycle

3. Electron

Transport Chain

Equation for C. R. 6O2 + C6H12O6 6CO2 + 6H2O + 36 ATP

• Oxygen and Glucose react or form carbon dioxide, water and ATP

• Other sugars, starch, fats and proteins can also be used as energy sources.

• Glucose is the simplest energy form

***Some energy released as heat

Let’s review….• Write the reaction equation for cellular

respiration.

• What is the first step of C.R. called?

• Where does this step take place?

• What is broken down/What is formed?

• What is the net gain for ATP?

• Is oxygen needed?

Glycolysis (splitting glucose)

• Occurs in the cytoplasm

• One glucose molecule split into two molecules of pyruvic acid

• Uses 2 ATP but makes 4 ATP.

• ATP net gain = _____

• Makes 2 NADH

• Does NOT require oxygen

The Krebs Cycle• In the matrix of the mitochondria

• Pyruvic acid enters the cycle, where a series of enzyme-controlled reactions create NADH and FADH (energy carriers)

• Carbon dioxied (CO2) is a waste product

The Electron Transport Chain

• H+ ions made in Krebs cycle build up outside the inner mitochondrial membrane

• The H+ ions are forced through ATP synthase making 3 ATPs for each turn

E.T.C.• Oxygen is used as the final electron

acceptor

• H+ and oxygen combine to form water (a waste product)

• Without oxygen the process backs up and ATP can’t be made

Summary of Cellular Respiration

• Glucose is split into _________________ in the cytoplasm

• In the mitochondria, the _____________ makes CO2 and NADH and FADH

• ___________________ makes ATP on the inner membrane of the mitochondria

• Oxygen and hydrogen make water

• Total – 36 ATPs made by aerobic resp.

Anaerobic Respiration

• If your body uses energy very quickly, pyruvic acid can build up

• ATP is produced anaerobically by turning the pyruvic acid into lactic acid

• Lactic acid builds up in muscles and hurts!

• Intake of oxygen (heavy breathing) removes lactic acid from your muscles

Pyruvic acid + NADH lactic acid + NAD+

• Fermentation is a valuable anaerobic process used to make ATP by yeasts and bacteria

• Fermentation produces CO2 and ethyl alcohol as by-products

• Valuable in food/drink industry: yogurt, cheese, sauerkraut, and others

Pyruvic acid + NADH

alcohol + CO2 + NAD+

• *Fermentation releases energy from food molecules by making ATP w/o oxygen