Page 304 - ABCTE Study Guide_Neat

The process of meiosis is essentially the same as mitosis except that the other major phases are
repeated resulting in two divisions of the cell.

Question

Which of the following statements is true of mitosis?

A Anaphase occurs at the end of the process.

B It contains one more step than meiosis.

C It occurs in the somatic cells.

D It produces ATP.

Answer

Answer C is correct. Mitosis only occurs in somatic, or body, cells. Choice A is incorrect, as anaphase is
the second-to-last stage. Choice B is incorrect. it’s actually meiosis that contains one more step than
mitosis. Choice D describes photosynthesis, not mitosis.

Fighting Diseases

Although we do get sick, our bodies fight a continuous battle against various infections and diseases from
many sources. The two most common include bacteria and viruses.

• Bacteria are single celled prokaryotic organisms (cells lacking a true nucleus); some of
which are capable of invading our bodies.
• Viruses are (debatable) entities consisting of RNA in some type of protein coating.

Viruses are capable of penetrating living cells in order to use the cell’s biochemical resources to
reproduce themselves.

Fungi also can invade as can some protists such as giardia.

Our bodies mount several types of responses to infection. Nonspecific defenses are those that respond
no matter which type of infection we face, whereas specific defenses recognize specific invading entities.

Nonspecific Defenses

Our biggest nonspecific defense is our biggest organ: our skin. Intact skin is one of the most important
and initial defense mechanisms; it allows almost no bacteria to pass through it. Excretions
from exocrine glands in the skin provide chemical defenses against invading organisms. Ciliated mucous
membranes act to literally sweep airborne invaders from the respiratory tract. The gastrointestinal system
has digestive acids capable of destroying many types of pathogens that enter the stomach with food. The
intestinal tract also contains necessary bacteria that make it more difficult for invading bacteria to obtain
food and survive.

If you were to cut your skin and allow pathogens to bypass the external defenses, several internal
defenses are ready. For example: