20 Antigens are substances that the immune system does notrecognize as self. Whi

Question

20 Antigens are substances that the immune system does notrecognize as self. Which of the following are antigens?

Select one:

a. All of these can act as antigens.

b. cancer cells in the lung

c. strep throat bacteria

d. HIV

21 A(n) pandemic is a global outbreak of disease.

Select one:

True

False

22 A virus differs from a bacterium in that a virus is a living organism

Select one:

True

False

23 Which of these conditions is a cancer that causes uncontrolled division of white blood cells, such that the number of cells greatly increases?

Select one:

a. iron-deficiency anemia

b. mononucleosis

c. leukemia

d. sickle-cell anemia

24 George is stuck out in the hot, dry desert without any water, and he is sweating a lot. Which of these components of the blood should decrease?

Select one:

a. plasma

b. platelets

c. red blood cells

d. glucose

25 Because the sinoatrial node sends out impulses that initiate each heartbeat, it is often referred to as the pacemaker of the heart.

Select one:

True

False

26 Pathogens are disease-causing organisms that invade a person's body.

Select one:

True

False

27 Which substance is released by motor neurons to stimulate a contraction?

Select one:

a. dopamine

b. myosin

c. calcium

d. acetylcholine

28 The lowest blood pressure that occurs when the ventricles are relaxing is known as ________.

Select one:

a. diastolic pressure

b. systolic pressure

c. aneurysm

d. arterial pressure

29 Juana is exhibiting redness, swelling, and elevated temperature in one area of her arm. She has a condition known as ________.

Select one:

a. asthma

b. anaphylactic shock

c. inflammation

d. passive immunity

30 Which protein transports oxygen in the bloodstream?

Select one:

a. hemoglobin

b. erythropoietin

c. plasminogen

d. thrombin

Explanation / Answer

20) Option a: all of these can act as antigens. Step throat bacteria (A streptococcus) and HIV both display antigens on their surfaces against which body shows immune response. Similarly lung cancer cells show some tumor associated antigens that illicit immune response in the body.

21) Option a: true- pandemic is the world wide spread or outbreak of a disease. It is different from endemic disease which exists in a particular region of a population.

22) Option b: false- Virus cannot replicate on its own. It can do so only when present in other living cells. So they are considered as being in a gray area between living and nonliving. Bacteria on the other hand are universally considered as living organisms.

23) Option c: leukaemia- It is a group of cancers affecting blood and bone marrow resulting in overproduction of abnormal white blood cells (leukocytes).

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