BRS- HISTO CH 2

Question 1

The nuclear pore complex
(A) permits free communication between the nucleus and the cytoplasm.
(B) is bridged by a unit membrane.
(C) islocatedonlyatspecificnuclearpore sites.
(D) permits passage of proteins via receptor- mediated transport.
(E) has a luminal ring that faces the cytoplasm.

Answer 1

D

Question 2

Which one of the following nucleotides is present only in RNA?
(A) Thymine (B) Adenine (C) Uracil (D) Cytosine (E) Guanine

Answer 2

C

Question 3

Anticodons are located in

(A) mRNA. (B) rRNA. (C) tRNA. (D) snRNP. (E) hnRNP.

Answer 3

C

Question 4

DNA is duplicated in the cell cycle during the

(A) G2 phase. (B) S phase. (C) Mphase. (D) G1 phase. (E) G0 phase.

Answer 4

B

Question 5

A male child at puberty is determined to have Klinefelter syndrome. Although the parents have been informed of the clinical significance, they have asked for an explana- tion of what happened. Identify the item that should be discussed with the parents.
(A) Trisomy of chromosome 21
(B) Loss of an autosome during mitosis
(C) Loss of the Y chromosome during meiosis (D) Nondisjunction of the X chromosome
(E) LossoftheXchromosome

Answer 5

D

these men have an XXY genotype (bar body)

Question 6

Which one of the following is an inclusion not bounded by a membrane that is observ- able only during interphase?
(A) Nuclear pore complex
(B) Nucleolus
(C) Heterochromatin
(D) Outer nuclear membrane (E) Euchromatin

Answer 6

B

Question 7

A structure that is continuous with RER is the
(A) nuclear pore complex. (B) nucleolus.
(C) heterochromatin.
(D) outer nuclear membrane. (E) euchromatin.

Answer 7

D

Question 8

Identify the structure that controls move-
ment of proteins in and out of the nucleus.
(A) Nuclear pore complex
(B) Nucleolus
(C) Heterochromatin
(D) Outer nuclear membrane (E) Euchromatin

Answer 8

A

Question 9

The site of transcriptional activity is the
(A) nuclear pore complex. (B) nucleolus.
(C) heterochromatin.
(D) outer nuclear membrane. (E) euchromatin.

Answer 9

E

The pale-staining euchromatin is the transcriptionally active chromatin in the nucleus (see Chapter 2 V A).

Question 10

Clumps of nucleoprotein concentrated near the periphery of the nucleus are called
(A) nuclear pore complex. (B) nucleolus.
(C) heterochromatin.
(D) outer nuclear membrane. (E) euchromatin.

Answer 10

C
Heterochromatin is the dark-staining nucleoprotein near the periphery of the nucleus. It is transcriptionally inactive but may be responsible for proper chromosome segregation