MCQ on Chromosome Structure

A homologous chromosome is a pair of each type of chromosome in each cell. Chromatin, which contains a single molecule of DNA and related proteins, makes up chromosomes. Hundreds of thousands of genes are found on each chromosome, each of which can code for many proteins in the cell. A chromosome’s structure is best seen during cell division. The primary function of chromosomes is to transmit genetic information from one generation to the next. They also serve as a guiding force in the growth, reproduction, repair, and regeneration processes, all of which are critical for their existence. Chromosomes safeguard DNA from becoming distorted and damaged. Histone and non-histone proteins play a role in gene regulation. The centromere’s spindle fibres aid in the movement of the chromosome during cell division. Thousands of genes are found on each chromosome, each of which codes for several proteins found in the body.

1. DNA filaments that develop inside the nucleus during cell division?

(a) Spindle fibres

(b) Chromosomes

(c) Centrioles

(d) Asters

Sol: (d) Chromosomes. A chromosome is a DNA structure that resembles a thread and carries genetic information in the form of genes.

2. Which of the following does not belong to a significant chromatin protein class?

(a) Histones

(b) Topoisomerases

(c) SMC proteins

(d) Cohesins

Sol: (d) Cohesins. The SMC family of proteins includes cohesions.

3. Which of the following plays a significant role in the initial joining of sister chromatids after replication?

(a) Cohesins

(b) Topoisomerases

(c) Condensins

(d) Histones

Sol: (a) Cohesins. Sister chromatids are bound together by cohesins during replication and are kept together as the chromosomes condense to metaphase.

4. Which of the following is required for chromosomal condensation as cells enter mitosis?

(a) Condensins

(b) Histones

(c) Cohesins

(d) Topoisomerases
Sol: (c) Cohesins. Cohesins are critical right after replication.

5. Chromatin is made up of_________

(a) DNA, RNA and proteins

(b) DNA and proteins

(c) DNA

(d) None

Sol: (a) DNA, RNA and proteins. The combination of DNA and histones is referred to as chromatin.

6. Which of the histones below binds to linker DNA?

(a) H1

(b) H3

(c) H2A

(d) H2B

Sol: (a) H1. Each nucleosome has eight histone molecules in its bead: two copies of H2A, H2B, H3, and H4.

7.Which of the following has a strong structure with beads on it?

(a) Chromosomes

(b) Heterochromatin

(c) Chromatin 

(d) Nucleosomes

Sol: (d) Nucleosomes. When DNA wraps around histone proteins like beads on a thread, nucleosomes form.

8. Which of the following histones has the most comparable sequence across eukaryotic species?

(a) H1

(b) H3

(c) H2A

(d) H2B

Sol: (b) H3. The amino acid sequences of H3 and H4 histones are nearly identical in all eukaryotes.

9.The sister chromatids split at the____________

(a) Prophase

(b) Anaphase

(c) Metaphase

(d) Telophase
Sol:(b) Anaphase. Each chromosomal pair is divided into two identical and independent chromosomes during anaphase.

10. Throughout ____________, cellular DNA is uncondensed.

(a) Prophase

(b) Interphase

(c) Telophase

(d) Anaphase
Sol: (b). Interphase. The DNA of the cell is not compacted during interphase.

11. __________ coined the term “chromosome”.

(a) Waldeyer

(b) Hoffmeister

(c) Sutton 

(d)  Boveri 

Sol:(a). Waldeyer

12. Color blindness is caused by a mutation in the________ gene in males.

(a) Y-chromosome

(b)X-chromosome

(c) Both X and Y chromosome

(d) Either X-chromosome or Y-chromosome

Sol: (b). X-chromosome

13. Who first presented the chromosomal theory of inheritance? Boveri

(a) Correns

(b) Sutton

(c) Both (a) and (b)

(d) None of the above

Sol: (c). Both (a) and (b)

14. The sex-linked sickness is referred to as which of the following?

(a) Leukemia

(b) Colour blindness

(c) Alzheimer’s

(d) Malignancy

Sol:(b). Colour blindness.

15. Which of the following claims concerning chromosomal ends is correct?

(a) Satellites are the endpoints of the chromosome.

(b) Centromeres are the endpoints of the chromosome.

(c) Telomeres are the ends of the chromosome.

(d) Kinetochore are the ends of the chromosome.

Sol: (c) The ends of the chromosome are called Telomeres.

16. In a human individual, how many sex chromosomes are there?

(a) one pair 

(b) two pairs 

(c) three pairs 

(d) four pairs

Sol: (a) 1 pair.

17. Who was the first person to observe the chromosomes?

(a) Fleming

(b) Waldeyer

(c) Strasburger

(d) Hofmeister

Sol: (d) Hofmeister.

18. Which of the following statements is true about the metaphase?

(a) A chromosome is the thickest during the metaphase

(b) A chromosome is the shortest during the metaphase

(c) A chromosome is the longest during the metaphase

(d) Both (a) and (b)

Sol: (d) Both (a) and (b).

19. A fully expressed allele is referred to as ____.

(a) Dominant

(b) Recessive

(c) Homologous

(d) Heterozygous

Sol: (a) Dominant.

20. Each of the chromosomes in a bone marrow cell has reached anaphase during this stage___.

(a) No chromatids

(b) One chromatid

(c) Two chromatids

(d) Several chromatids

21. The majority of genetic illnesses are caused by___.

(a) Mutation

(b) The gender of an individual

(c) The gross chromosomal abnormalities

(d) All of the above

Sol: (a) Mutation.

22. The thread-like structures, which appear inside the nucleus at the time of cell division, are called ____.

(a) Asters

(b) Centrioles

(c) Chromosomes

(d) Spindle fibers

Sol: (c) Chromosomes.

23. Which of the following statements is true about the chromatin composition?

(a) DNA

(b) RNA

(c) DNA and proteins

(d) DNA, RNA and proteins

Sol: (d) DNA, RNA and proteins.

24. How many autosomes are present in a human being?

(a) 20 pairs

(b) 22 pairs

(c) 23 pairs

(d) 44 pairs

Sol: (b) 22 pairs.

25. Which of the following living species comprises more than 200 chromosomes?

(a) Amoeba

(b) Buffalo

(c) Chicken

(d) Giraffe

Sol: (a) Amoeba.