1. Biology Brooker/Widmaier/Graham/Stiling 1st Edition Chapter 15
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2. Question 1
Which one of the following statements about eukaryotic chromosomeorganization is incorrect?
A) Complexes of DNA and protein are called chromatin.
B) A core of 8 histone proteins and 146 base pairs of DNA wrapped around them is referred to as a nucleosome.
C) When DNA is wrapped around a protein core it has an approximate diameter of 11 nanometers.
D) In the "beads on a string" model, the amount of linker DNA between "beads" varies depending on species and cell type.
E) All of the above statements about eukaryotic chromosome organization are correct.

3. Question 2 Which one of the following events occurs during M- phase?
A) nuclear division
B) genome replication
C) cytoplasmic division
D) (A) and (C)
E) (A), (B) and (C)

4. Question 3
The process by which haploid cells are produced from a cell that was originally diploid is most accurately referred to as:
A) asexual reproduction.
B) mitosis.
C) meiosis.
D) cytokinesis.
E) fertilization.

5. Question 4
Which one of the following is not a classification of chromosomes based on centromere location?
A) acrocentric
B) submetacentric
C) subacrocentric
D) telocentric
E) metacentric

6. Question 5
Radial loop domains are formed by the interaction of ________ with ________.
A) 30-nm fibers; the nuclear matrix
B) 11-nm fibers; linker proteins
C) 300-nm structures; histones
D) nucleosomes; histones
E) mitotic chromosomes; mitotic spindle

7. Question 6
Less condensed regions of DNA are called ________ and typically have a diameter of approximately ________.
A) euchromatin; 700 nm
B) euchromatin; 30 nm
C) heterochromatin; 700 nm
D) heterochromatin; 30 nm

8. Question 7
True or False: The degree of chromatin compaction can be regulated by covalent modification of the amino terminal tails of histone proteins.
A) True
B) False

9. Question 8
During which phase of the cell cycle is gene expression least likely to be observed?
A) S-phase
B) G1
C) G2
D) M-phase
E) Gene expression and protein synthesis are equally likely in all phases of the cell cycle.

10. Question 9
A diploid organism which has 12 chromosomes in its gametes would have how many chromosomes in its somatic cells?
A) 2
B) 6
C) 12
D) 24
E) 48

11. Question 10
Following DNA replication, the identical copies of the original double helix are referred to as ________ and are tightly associated at the ________.
A) homologous chromosomes; centromere
B) sister chromatids; telomeres
C) sister chromatids; centromere
D) homologous chromosomes; kinetochore
E) sister chromatids; centrosome

12. Question 11
Match the type of microtubule above with the appropriate description below it.
positioning the spindle apparatus within the cell
binding to centromeric regions on each chromosome
extend into center of the cell and overlap with other microtubules
A) i = b; ii = a; iii = c
B) i = c; ii = b; iii = a
C) i = a; ii = b; iii = c
D) i = b; ii = c; iii = a
E) i = c; ii = a; iii = b

13. Question 12
True or False: Not all eukaryotic species require a pair of centrioles in a centrosome for proper spindle formation.
A) True
B) False

14. Question 13
During mitosis, the "ballet" of sister chromatids being tugged back and forth between the spindle poles is most accurately occurring in:
A) prophase.
B) prometaphase.
C) metaphase.
D) anaphase.
E) telophase.

15. Question 14
Which one of the following statements about crossing over is correct?
A) Crossing over is common to both meiosis and mitosis.
B) Crossing over typically occurs during Metaphase II.
C) Chiasmata are formed when segments of DNA are exchanged between sister chromatids.
D) After crossing over, the arms of the chromosomes remain fully attached at the synaptonemal complex.
E) The number of crossing over events differs among species, but is a carefully regulated process.

16. Question 15
Match the event on the left with the molecules that are separated on the right.
Mitosis a. bivalents
Meiosis I sister b. chromatids
Meiosis II
A) i = b; ii = a; iii = a
B) i = a; ii = b; iii = a
C) i = b; ii = a; iii = b
D) i = a; ii = a; iii = b
E) i = a; ii = b; iii = b

17. Question 16
True or False: DNA replication between Meiosis I and Meiosis II ensures that the gametes receive a full complement of the genome prior to fertilization
A) True
B) False

18. Question 17
A diploid species in which haploid gametes are a specialized cell used for sexual reproduction is most accurately referred to as a:
A) gametophyte.
B) sporophyte.
C) haploid dominant.
D) diploid recessive
E) diploid dominant.

19. Question 18
Match the change in chromosome structure above (i, ii, or iii) with the appropriate description below it (a, b, or c).
simple translocation
inversion
reciprocal translocation
moving of a segment of a chromosome to a different chromosome
exchange of pieces between two different chromosomes
region of a chromosome is flipped into the opposite orientation
A) i = a; ii = b; iii = c
B) i = c; ii = a; iii = b
C) i = b; ii = a; iii = c
D) i = c; ii = b; iii = a
E) i = a; ii = c; iii = b

20. Question 19
True or False: Nondisjunction refers to an event in which the chromosomes do not sort properly during cell division.
A) True
B) False

21. Question 20
Which one of the following statements about changes in chromosome number is incorrect?
A) Aneuploidy typically has detrimental consequences regardless of the eukaryotic species.
B) Male bees are haploid, while female bees are diploid.
C) Polyploid strains of plants commonly are larger and more robust.
D) Cells in a human affected with Down Syndrome produce 50% of the protein from chromosome 21 that an unaffected individual produces from the same chromosome.
E) All of the above statements about changes in chromosome number are correct.

22. Answer Key 1. E 11. B 2. D 12. A 3. C 13. B 4. C 14. E 5. A 15. C 6. B