The mitotic spindle first appears during

26 Jun The mitotic spindle first appears during

Question
21: The mitotic spindle first appears during

A: prophase

B: metaphase

C: anaphase

D: telophase

22: Chromosomes line up in the center of the cell during

A: prophase

B: metaphase

C: anaphase

D: telophase

23: During mitosis, chromosomes begin to separate during

A: prophase

B: metaphase

C: anaphase

D: telophase

24: Which of the following is true regarding cytoplasmic division?

A: It occurs during the early part of mitosis

B: It is caused by microfilaments that lie beneath the plasma membrane

C: It begins during metaphasis

D: None of the above

25: Germ cells

A: in humans contain 46 chromosomes

B: are diploid

C: contain half the number of chromosomes of somatic cells

D: None of the above

26: Meiosis

A: occurs in all body cells

B: produces diploid gametes

C: involves two cell divisions

D: is identical to mitosis in all respects

27: Human somatic cells

A: contain 23 chromosomes from the mother and 23 from the father

B: are best described as haploid

C: undergo meiotic divisions

D: are genetically identical to germ cells

28: Meiosis I

A: is identical to mitosis

B: lacks a distinct metaphase

C: reduces the number of chromosomes in humans from 46 to 23

D: None of the above

29: In the ovary, the number of ova produced during meiosis is

A: one

B: two

C: three

D: four

30: The zygote produced during fertilization

A: divides my meiosis

B: is haploid

C: divides by mitosis

D: None of the above

31: The risk of a mistaken identity using DNA fingerprinting is _____ compared to a risk of error in blood typing of 1 in 1000

A: 1 in 4000

B: 1 in 4 million

C: 1 in 4 billion

D: 1 in 4 trillion

32: DNA

A: consists of two polynucleotide strands

B: is identical to RNA except that RNA consists of a single strand

C: contains two types of bases: purines and pyrimidines

D: a and b

E: a and c

33: A molecule that is not part of a nucleotide is

A: Phosphate

B: ribose

C: nitrogenous base

D: glucose

34: In DNA, hydrogen bonds are

A: nonexistent

B: found between the bases on opposing polynucleotide chains

C: found between sugars and phosphates

D: found between the nitrogen bases and sugar molecules

35: The DNA molecule contains

A: uracil

B: ribose

C: equal numbers of cytosine and thymine

D: contains equal numbers of purines and pyrimidines

36: Viruses

A: are submicroscopic organisms that lack organelles and can only reproduce inside other cells

B: are structurally very similar to eukaryotic cells

C: are considered living organisms

D: are not attacked by the immune system, which is why they are so dangerous

37: Bacteria

A: are eukaryotes that lack nuclei

B: are structurally identical to viruses

C: are prokaryotes that lack distinct organelles

D: cause disease

38: Which of the following is not part of the first line of defense against microorganisms?

A: The skin

B: The lining of the respiratory tract

C: The lining of the intestinal tract

D: The inflammatory response

39: During the inflammatory response

A: mast cells release histamine, causing the blood vessels to constrict

B: the release of prostaglandins at the site of the wound causes pain

C: blood flow to the injured area is reduced to prevent blood loss

D: all of the above

E: none of the above

40: Pyrogens

A: act on the temperature-regulating region of the hypothalamus, raising body temperature

B: are chemicals that lower body temperature, thus protecting the body in case of an invasion by bacteria

C: are one class of interferons

D: increase iron availability, which is detrimental to bacteria

41:A student performs an experiment to test the effects of a special diet on the cholesterol content of chicken eggs. He obtained 20 chickens from two different breeders. Half of the chickens were fed the special diet, and half were fed a diet of standard chicken feed, purchased at a local feed store. The student found that cholesterol levels in the eggs from chickens fed the special diet were lower than the levels found in the eggs of the other group, and he concludes that his special diet should be marketed to farmers. Do you see any problems with this study? How would you improve the design?

42: If you were considering becoming a strict vegetarian, eating no animal products, even milk or eggs, how would you be assured of getting all of the amino acids your body needs? What specific dietary components (not vitamin supplements) would your body require?

43: Give two examples of negative feedback loops in the endocrine system: 1) a simple feedback mechanism, and 2) a more complex one that operates through the nervous system.

44: Why is the heart described as a double pump? Describe the general structure of arteries and veins. How are they similar? How are they different? How do arteries and veins (and the blood they carry) contribute to homeostasis?

45: The immune system in the human body consists of three lines of defense. What are they and how do they operate?

46: Explain the difference between active and passive immunity and give an example of each.

47: Your friend is thinking about using anabolic steroids to improve his gymnastics performance. He argues that he is young and will only be taking the drug for a year or so. What are three “pros” and three “cons” associated with using steroids? What final advice would you give him based on your data?