Mitochondria And Chloroplast Essay

I. Introduction

Out of all the organelles there
are two that have fascinated microbiologists for the past hundred years. The
first is the mitochondria, nicknamed the "powerhouse of the cell." The second
is the chloroplast in plant cells that have functions similar to those of the
mitochondria. What do these organelles do? What are the similarities and differences
of these organelles? This essay will help you to understand these two fascinating
organelles.

II. Mitochondria

Mitochondria are small cytoplasmic organelles.
They are five to 10 micrometers long and one to .5 micrometers wide. They main
function is to provide energy for cell activities. They house the respiratory
enzymes that convert oxygen and the products of fat, carbohydrate, and protein
metabolism into adenosine triphosphate (ATP) and guanosine triphosphate (GTP),
chemicals that have high-energy bonds. They are hollow all except for a folded
line of matter that contains the   ribonucleic acid (RNA) or deoxyribonucleic
acid (DNA) of the cell.

Mitochondrion make use of a process known as oxidation
to make fat acids and pyruvate acid into (indirectly) ATP and Pi (inorganic
phosphate). The process goes as follows:

1) Oxidation of pyruvate acid
into acetyl coenzyme A.
2) Oxidation of fat acids into acetyl coenzyme A.
3) Oxidation
of acetyl coenzymes from step one and two into CO2 and NADH2.
4) Oxidation
of NADH2 by oxygen forming water.
5) Synthesis of ATP coupled to NADH2 oxidation
by process of oxidative phosphorylation.

Most of this is self explanatory
except for the last step (5). The final step contains a phrase "coupled to."
This means that the compound (NADH2) must be present and have been oxidized
for the synthesis of ATP, similar to a   catalyst"s presence of some reactions.

Although
the mitochondrion"s major purpose is to supply the cell with the much needed
ATP, it has others. Included in this list are nitrogen metabolism, porphyrin...