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MCAT
Test Introduction
25 Free Chemistry Practice Questions 25 Free Physics Practice Questions MCAT Test Physical Sciences Chemistry MCAT Test Physical Sciences Physics MCAT Test Biological Sciences Part I MCAT Test Biological Sciences Part II MCAT Study Guide Recommendations *MCAT is a registered trademark of the Association of American Medical Colleges, which does not endorse this site.
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MCAT Test Biological Sciences I
(Organic Chemistry and Biology)
The MCAT test biological sciences test covers organic chemistry
and biology. This section has five
answer choices per question and are level 2 type questions.
You have to understand enough basic knowledge about these subject areas
and then apply that knowledge to a higher level question.
If you don’t know the underlying basic knowledge then you have little
hope of answering the questions correctly on the MCAT test.
The below information is a partial review of mitochondria.
MCAT
Mitochondria
Review
Mitochondria are the best known of the cellular organelles.
They had been described during the 19th century, notably by Kollicker
and Fleming. Altman, using Janus green, was able to stain them in 1890.
Structually, the mitochondrion is composed of an outer trilaminar membrane and
an inner trilaminar membrane; the inner one forms folds which are known as cristae.
The space between the two membranes is about 6-10 nm wide.
Mitochondria as a whole and specifically the cristae vary
in size, shape and number not only in different cells but also in the same cell
depending on its functional state. Mitochondria are present in greater numbers
in cells exhibiting high levels of activity and having more energy requirements.
Muscle and grandular tissues fall in the above category.
DNA has been found in the mitochondria of animals and
the chloroplasts of plants. Mitochondria are capable of division and are
not generated de novo.
Granules have been observed in the mitochondria Matrix.
Their identity is in question, however; some believe they might be reservoirs of
calcium and other divalent ions. Phosphate is taken up with Ca²+ and calcium
phosphate deposit may be the end result.
Mitochondria are the biochemical power plants of the cell. They recover energy from food stuffs ( via krebs cycle, or citric acid cycle; tricarboxylic acid cycle and the respiratory chain) and convert it via phosphorylation into adenosine triphosphate ( ATP). In this manner they produce the energy necessary for the metabolic processes.