Question 1

What is the average length of interphase?

Accepted Answer

A) It is exactly 10 hours in all cells. 
B) It is 12 hours long. 
C) There is not a good average since it may extend for days,weeks or longer depending on the cell type and the conditions. 
D) It may last up to a day. 
E) On average,it lasts about 3 hours.

Question 2

What holds together the chromatid from one homologous chromosome to a non-sister chromatid of the other homologue at the site of a chiasma?

Accepted Answer

A) H bonds 
B) ionic bonds 
C) covalent bonds 
D) disulfide linkages 
E) van der Waals forces

Question 3

Organisms in which meiotic divisions are closely linked to gamete formation,as in the case where meiosis occurs just prior to the differentiation of the spermatozoa,exhibit ___________.

Accepted Answer

A) initial meiosis 
B) terminal meiosis 
C) zygotic meiosis 
D) sporic meiosis 
E) intermediate meiosis

Question 4

Synapsis is accompanied by the formation of a complex,ladderlike structure made of three parallel bars with transverse protein filaments connecting its central element with two lateral elements.What is the name of this structure?

Accepted Answer

A) synaptonemal ladder 
B) ladderellen 
C) synaptonemal complex 
D) nuclear complex 
E) nucleolar complex

Question 5

The current view of the fate of the ER during mitosis is that ________.

Accepted Answer

A) the ER network remains relatively intact during mitosis 
B) the ER is broken into its component macromolecules during mitosis,but it is built up from scratch after mitosis 
C) the ER is broken up into small vesicles that reassemble later 
D) the ER becomes part of the Golgi complex during mitosis 
E) the ER joins with mitochondria at the beginning of mitosis

Question 6

The nuclear lamina are disassembled _________.

Accepted Answer

A) as the interactions between nucleoporin complexes are disrupted and the proteins dissociate into the surrounding medium 
B) by depolymerization of the lamin filaments 
C) as their integrity is disrupted mechanically as holes are torn in the complexes by cytoplasmic dyneins associated with the outer nuclear membrane 
D) by cytoplasmic dyneins 
E) by cytoplasmic microtubules and microfilaments

Question 7

The total length of the cell cycle of cells in a cell culture is 24 hours.M phase is found to be 1 hour,S phase is found to be 9 hours and G2 is found to be 4.5 hours.How long is G1?

Accepted Answer

A) 24 hours 
B) 9.5 hours 
C) 9 hours 
D) 1 hour 
E) 4.5 hours

Question 8

What happens if any of the condensin proteins are removed from the frog egg extracts within which chromosome compaction can occur in vitro?

Accepted Answer

A) Compaction continues unabated. 
B) Compaction occurs more quickly than normal. 
C) Compaction is prevented. 
D) The DNA expands further and fills the entire cell. 
E) Compaction occurs but occurs more slowly.

Question 9

What stimulus can induce liver cells to proliferate?

Accepted Answer

A) interaction with an appropriate antigen 
B) interaction with an appropriate antibody 
C) surgical removal of part of the liver 
D) a buildup of bile in the liver 
E) glycogen buildup in the liver

Question 10

What triggers the start of centrosome duplication?

Accepted Answer

A) phosphorylation of a centrosomal protein by ATPase 
B) phosphorylation of a centrosomal protein by Cdk2 
C) dephosphorylation of a centrosomal protein by Cdk2 
D) dephosphorylation of a centrosomal protein by ATPase 
E) phosphorylation of a centrosomal protein focal adhesion kinase

Question 11

Which of the following is a multiprotein complex that acts primarily during interphase to ubiquitinate proteins and target them for destruction by a proteasome?

Accepted Answer

A) SCF 
B) APC 
C) anaphase promoting complex 
D) both SCF and APC 
E) proteasomal activating complex

Question 12

What must happen in order for a cell to move to S phase from G1?

Accepted Answer

A) It must divide. 
B) It must generate an external signal. 
C) It must receive a growth-promoting signal. 
D) It must divide and receive a growth-promoting signal. 
E) It must grow greatly.

Question 13

The process of centriole "replication" begins in the cytoplasm with the appearance of a small ________.

Accepted Answer

A) pericentriole 
B) procentriole 
C) precentriole 
D) procentrosome 
E) pericentrosome

Question 14

What is an alternative to the classical view of the fate of the membranous portion of the nuclear envelope?

Accepted Answer

A) fragmentation into a population of small vesicles that disperse throughout the mitotic cell 
B) absorption of the membranes of the nuclear envelope into the membranes of the Golgi complex 
C) absorption of the membranes of the nuclear envelope into the membranes of the peroxisomes 
D) absorption of the membranes of the nuclear envelope into the membranes of the ER 
E) absorption of the membranes of the nuclear envelope into the membranes of the nucleoplasm

Question 15

What are the three major components of the nuclear envelope?

Accepted Answer

A) nuclear pore complex,nuclear lemina,nuclear membranes 
B) RER,nuclear lamina,Na+-K+ pump 
C) nuclear pore complexes,nuclear lamina,nuclear membranes 
D) mitotic kinases,nuclear lemina,nuclear pore complexes 
E) phospholipids,nuclear pore complexes,nucleoplasm

Question 16

Which of the cells below normally possess a relatively high level of mitotic activity?

Accepted Answer

A) stem cells of various adult tissues 
B) hematopoietic stem cells that give rise to red and while blood cells 
C) stem cells at the base of numerous epithelia that line the body cavities 
D) the relatively unspecialized cells found near the tips of plant roots and stems 
E) All of these are correct.

Question 17

Movement past the transition point near the end of G2 that moves cells on to mitosis requires cdc2 activation by _______.

Accepted Answer

A) Na+ ions 
B) mitotic cyclins 
C) ATP 
D) Na+-K+ ATPase 
E) mitotic chromatin

Question 18

Anaphase I is the cytological event that corresponds to which scientific law?

Accepted Answer

A) the first law of thermodynamics 
B) the second law of thermodynamics 
C) Mendel's law of segregation 
D) Mendel's law of independent assortment 
E) the Lambert - Beer law

Question 19

What is the function of the synaptonemal complex presently thought to be?

Accepted Answer

A) It serves to initiate genetic recombination. 
B) It maintains RNA in association with the chromosomes. 
C) It functions primarily as a scaffold to allow interacting chromatids to complete crossover activities. 
D) It prevents the breakage of the DNA double helix at the wrong place. 
E) It assures that the DNA double helix breaks at exactly the right place.

Question 20

Which of the following has been implicated as a possible linker of a kinetochore to dynamic microtubules?

Accepted Answer

A) motor proteins 
B) a rod-shaped protein called Ndc80 
C) a member of the kinesin superfamily,CENP-E 
D) Dam-1 
E) All of these are correct.

Exam 14: Cellular Reproduction