Download Chapter 9 Notes: Cellular Respiration

Chapter 9 Notes: Cellular Respiration
A. Energy in food (sugar)
1. A calorie is the amount of energy needed to raise the temperature of 1
gram of water 1 degree Celsius
2. Food labels tell you how many calories are in the food products that you
eat. The average adult requires about 2000 calories from food each day.
B. Cellular Respiration - the process that releases energy from glucose and
other food molecules
1. The Equation for cellular respiration is:
Oxygen + Glucose
6O2
---------> Carbon dioxide + Water + ATP
+ C6H12O6 --------->
6CO2
+ 6H2O
+ 36ATP
2. Process of cellular respiration:
a. Glycolysis: the breakdown of glucose (a 6 carbon molecule)
Steps:
i. Glucose is split into two, 3 carbon molecules, called
pyruvate
ii. Occurs in cytoplasm
iii. This process is anaerobic – it does not require
oxygen
b. Steps of Oxidative Respiration:
i. This process is aerobic- it requires oxygen
ii. Pyruvate is broken down into pyruvic acid.
iii. Krebs Cycle - pyruvic acid is broken down into CO2 in a
series of energy-extracting reactions; high-energy electrons from
this process are used in the next step
iv. Electron Transport Chain – high-energy electrons
change ADP into ATP. The electron transport chain
produces a large amount of ATP!
v. Oxidative respiration occurs in mitochondria
3. If oxygen is not present during oxidative respiration, then
fermentation will occur
a. Fermentation – releases a small amount of energy from food
when oxygen is not present
Two types:
i. alcoholic fermentation – occurs in yeast (living,
unicellular organisms); makes CO2 and alcohol; causes bread
dough to rise when yeast in bread run out of oxygen
ii. lactic acid fermentation – lactic acid is produced when
your muscle cells do not get enough oxygen, causing a
painful, burning sensation
Bacteria are used make lactic acid in foods such as cheese
and yogurt, giving them a unique taste
Summary of Cellular Respiration:
GLYCOLYSIS
KREB’S
CYCLE
ELECTRON
TRANSPORT
CHAIN