Chromosome number is reduced during meiosis because the process consists of:
(1) Two cell divisions without any chromosome replication
(2) A single cell division without any chromosome replication
(3) Two cell divisions in which half of the chromosomes are destroyed
(4) Two cell divisions and only a single round of chromosome replication
Which of the following is false?
(1) The mitotic spindle is composed of microtubules
(2) In plant cells, cytokinesis is accomplished by the formation of a cell plate
(3) The distribution of mitochondria between the daughter cells during cytokinesis is random
(4) Chromatin condenses to form discrete, visible chromosomes early in G1
A reduction step during meiosis is important because:
(1) It returns the chromosome number to normal before fertilization
(2) There is a mechanism for this
(3) Only one copy of each chromosome is necessary
(4) Otherwise chromosome copies would double each fertilization
Which of the following statements about meiosis is false?
(1) Haploid cells cannot divide meiotically
(2) DNA replication does not occur during interkinesis
(3) Assortment of homologous chromosomes on the equatorial plate during metaphase I is independent
(4) Of the four cells produced by meiosis, none are genetically identical to the parent cells but two are identical to each other
D, E, F and G are the four daughter cells resulting when cell A undergoes meiosis as shown in the following diagram. If no crossing over has occurred which cells listed below, if any, are genetically identical?
(1) Cells B and C
(2) No two cells
(3) Cells D and E, cells F and G
(4) Cells D, and F, Cell E and G
The DNA content of individual cells and the number of cells in each phase of a "cell cycle" can be determined, using flow cytometry. Which of the following combinations of "phase of a cell cycle and its corresponding DNA content" can be considered normal?
A. Diploid cells found in the Go or G1 phase.
B. Cells with twice the normal DNA content in the early M phase.
C. Cells with intermediate amounts of DNA in the S Phase.
D. Cells with twice the normal DNA content in the G2 phase.
(1) A and B
(2) B and C
(3) C and D
(4) All are correct
Let a cell's generation time is 1 minute. In 20 minutes a culture tube (culture medium) is 1/8th filled with cells. When the tube will be fullfilled?
(1) 21 minutes
(2) 23 minutes
(3) 60 minutes
(4) 160 minutes
The following diagram refers to a typical cell cycle.
Identify the parts marked as X, Y and Z.
1. X - G1; Y - S; Z - G2 2. X - G2; Y - S; Z - G1
3. X - G0; Y - S; Z - G2 4. X - G1; Y - G2; Z - G0
Identify the meiotic stage in which the homologous chromosomes separate while the sister chromatids remain associated at their centromeres:
(1) Metaphase I
(2) Metaphase II
(3) Anaphase I
(4) Anaphase II
At which stage of meiosis does the genetic constitution of gametes is finally decided:
(1) Metaphase I
(2) Anaphase II
(3) Metaphase II
(4) Anaphase I