Chapter 2: Week 1

Question 1

A 20-year-old woman presents at the emergency department with severe abdominal pain on the right side with signs of internal bleeding. She indicated that she has been sexually active without contraception and missed her last menstrual period. Based on this information, which of the following disorders must be included as an option in the diagnosis?

(A) Ovarian cancer
(B) Appendicitis
(C) Normal pregnancy
(D) Ectopic tubal pregnancy 
(E) Toxemia of pregnancy

Answer 1

(D) Ectopic tubal pregnancy

Question 2

When does a secondary oocyte complete its second meiotic division to become a mature ovum?

(A) At ovulation
(B) Before ovulation 
(C) At fertilization 
(D) At puberty
(E) Before birth

Answer 2

(C) At fertilization

Question 3

How soon after fertilization occurs within the uterine tube does the blastocyst begin implantation?

(A) Within minutes 
(B) By 12 hours
(C) By day 1
(D) By day 2
(E) By day 7

Answer 3

(E) By day 7

Question 4

Where does the blastocyst normally implant?

(A) Functional layer of the cervix
(B) Functional layer of the endometrium 
(C) Basal layer of the endometrium
(D) Myometrium
(E) Perimetrium

Answer 4

(B) Functional layer of the endometrium

Question 5

Which of the following events is involved in cleavage of the zygote during week 1 of development?

(A) A series of meiotic divisions forming blastomeres
(B) Production of highly differentiated blas- tomeres
(C) An increased cytoplasmic content of blastomeres
(D) An increase in size of blastomeres
(E) A decrease in size of blastomeres

Answer 5

(E) A decrease in size of blastomeres

Question 6

Which of the following structures must degenerate for blastocyst implantation to occur?

(A) Endometrium in progestational phase 
(B) Zona pellucida
(C) Syncytiotrophoblast
(D) Cytotrophoblast
(E) Functional layer of the endometrium

Answer 6

(B) Zona pellucida

Question 7

Which of the following is the origin of the mitochondrial DNA of all human adult cells?

(A) Paternal only
(B) Maternal only
(C) A combination of paternal and maternal 
(D) Either paternal or maternal
(E) Unknown origin

Answer 7

(B) Maternal only

Question 8

Individual blastomeres were isolated from a blastula at the 4-cell stage. Each blastomere was cultured in vitro to the blastocyst stage and individually implanted into four pseudo- pregnant foster mothers. Which of the follow- ing would you expect to observe 9 months later?

(A) Birth of one baby
(B) Birth of four genetically different
babies
(C) Birth of four genetically identical babies 
(D) Birth of four grotesquely deformed
babies 
(E) No births

Answer 8

(C) Birth of four genetically identical babies

Question 9

Embryonic carcinoma (EC) cells were isolated from a yellow-coated mouse with a teratocarcinoma. The EC cells were then microinjected into the inner cell mass of a blastocyst isolated from a black-coated mouse. The blastocyst was subsequently implanted into the uterus of a white-coated foster mouse. Which of the following would be observed after full-term pregnancy?

(A) A yellow-coated offspring
(B) A black-coated offspring
(C) A white-coated offspring
(D) A yellow- and black-coated offspring 
(E) A yellow- and white-coated offspring

Answer 9

(D) A yellow- and black-coated offspring

Question 10

10. In oogenesis, which of the following events occurs immediately following the completions of meiosis II?

(A) Degeneration of the zona pellucida
(B) Sperm penetration of the corona radiata 
(C) Formation of a female pronucleus
(D) Appearance of the blastocyst
(E) Completion of cleavage

Answer 10

(C) Formation of a female pronucleus