UNIT 1
Chapter 2: The Cell Up Close: Processes That Sustain Life
Concept 2.7
2.7 Cells use ATP molecules to get energy.
Cells need energy for many functions. The source of energy is
ATP (adenosine triphosphate).
• ATP undergoes a chemical reaction that releases energy.
ATP + H2O → ADP + P + energy
TO PREVIOUS
SLIDE
UNIT 1
Chapter 2: The Cell Up Close: Processes That Sustain Life
Concept 2.7
Pause and Check
19. What does ATP stand for, and what type of molecule is it?
20. How is ATP used in cells?
21. Describe the reaction in which ATP releases energy.
TO PREVIOUS
SLIDE
UNIT 1
Chapter 2: The Cell Up Close: Processes That Sustain Life
Concept 2.8
2.8 Cellular respiration makes ATP.
Aerobic cellular respiration is one way plant and animal
cells make ATP. The overall process is
The numerous reactions involved occur in two stages:
1. Glycolysis, which takes place in the cytosol.
2. Oxidative respiration, which takes place in mitochondria.
TO PREVIOUS
SLIDE
UNIT 1
Chapter 2: The Cell Up Close: Processes That Sustain Life
Glycolysis
• occurs in the cytosol
• involves many reactions that
o split each glucose molecule into two 3-carbon
molecules (pyruvate)
o form 2 molecules of ATP
TO PREVIOUS
SLIDE
Concept 2.8
UNIT 1
Chapter 2: The Cell Up Close: Processes That Sustain Life
Concept 2.8
Oxidative Respiration
• Pyruvate from glycolysis enters the mitochondrion.
• A series of chemical reactions involving oxygen break
pyruvate down to carbon dioxide and water.
• As many as 34 ATP molecules can be produced for each
glucose molecule.
TO PREVIOUS
SLIDE
UNIT 1
Chapter 2: The Cell Up Close: Processes That Sustain Life
Overall process of aerobic cellular respiration
TO PREVIOUS
SLIDE
Concept 2.8
UNIT 1
Chapter 2: The Cell Up Close: Processes That Sustain Life
Food Molecules and the Production of ATP
TO PREVIOUS
SLIDE
Concept 2.8
UNIT 1
Chapter 2: The Cell Up Close: Processes That Sustain Life
Concept 2.8
Cellular Respiration and Photosynthesis
• Some organisms, such as plants, produce their own food
by photosynthesis.
• Photosynthesis takes place in chloroplasts and involves
using energy from the Sun to convert carbon dioxide and
water into glucose and oxygen.
Plants also use oxygen to
make ATP by aerobic cellular
respiration, but they produce
more oxygen than they use.
TO PREVIOUS
SLIDE
UNIT 1
Chapter 2: The Cell Up Close: Processes That Sustain Life
Concept 2.8
Fermentation
• Some organisms can survive where there is little or no oxygen.
• Fermentation is the production of ATP in the absence of
oxygen.
• Glycolysis produces two pyruvates from each glucose
molecule. Then reactions such as alcoholic fermentation or
lactic acid fermentation produce ATP.
This is how
alcohol is
made – yeast
ferment the
wheat, grapes
etc.
TO PREVIOUS
SLIDE
This what your
muscles do if
you exercise too
strenuously.