Page 120 - Fundamentals of anatomy physiology

Chapter 3 The Cellular Level of Organization 107

Figure 3–9 Mitochondria. Inner membrane Mitochondrial Cytosol
Matrix ribosomes Cristae
Organic molecules 3
and O2
Outer
CO2 membrane
ATP

Matrix Cristae Enzymes

Mitochondrion TEM × 46,332

a Shown here is the three-dimensional organization and a color-enhanced
TEM of a typical mitochondrion in longitudinal section.

CYTOSOL Glucose Glycolysis
CO2 Pyruvate ATP

Enzymes
and
ADP +
phosphate coenzymes O2
Citric Acid of cristae H2O
Cycle
b This is an overview of the role
of mitochondria in energy MATRIX H
production. Mitochondria
absorb oxygen and short MITOCHONDRION
carbon chains, such as
pyruvate, and they generate
carbon dioxide, ATP, and water.

released as carbon dioxide, which diffuses out of the cell. The Checkpoint
hydrogen atoms are delivered to carrier protein complexes in
the cristae. There the electrons are removed from the hydrogen 5. Differentiate between the cytoplasm and the cytosol.
atoms and passed along a chain of coenzymes and ultimately 6. What are the major differences between cytosol and
transferred to oxygen atoms. The energy released during these
steps indirectly supports the enzymatic conversion of ADP to extracellular fluid?
ATP. p. 84
7. Identify the nonmembranous organelles, and cite
Because mitochondrial activity requires oxygen, this a function of each.
method of ATP production is known as aerobic metabolism
(aer, air + bios, life), or cellular respiration. Aerobic metabolism 8. Identify the membranous organelles, and cite their
in mitochondria produces about 95 percent of the ATP needed functions.
to keep a cell alive. (Enzymatic reactions, including glycolysis,
in the cytoplasm produce the rest.) 9. Explain why certain cells in the ovaries and testes contain
large amounts of smooth endoplasmic reticulum (SER).

1 0. What does the presence of many mitochondria imply
about a cell’s energy requirements?

See the blue Answers tab at the back of the book.