Quiz  /  Chromosomes Class 12 MCQ Questions With Answers

  • 1. 
    The diploid number of human chromosomes is

  • 23
  • 46
  • 92

  • 2. 
    Which of the following statements about homologous chromosomes is correct?

  • Each gene is at the same locus on both chromosomes.
  • They are two identical copies of a parent chromosome which are attached to one another at the centromere.
  • They come from the same parent.
  • They are chromosomes that have identical genes and alleles.

  • 3. 
    The position of a gene on a chromosomes is the _______.

  • allele
  • gene locus

  • 4. 
    How many DNA molecules make up a chromosome?

  • 1
  • 2
  • 23
  • 46

  • 5. 
    A _______ is an egg that has been fertilized by a sperm cell.

  • gene
  • chromosome
  • zygote
  • embryo

  • 6. 
    A nondisjunction resulting in three chromosomes in one position is called

  • monosomy
  • disomy
  • trisomy
  • polysomy

  • 7. 
    If a gene is found only on the X chromosome and not the Y chromosome, it is said to be what?

  • sex-linked trait
  • polygenic trait
  • codominant trait
  • incomplete dominance trait

  • 8. 
    How many autosomes are there in a human sperm?

  • 1
  • 22
  • 23
  • 46

  • 9. 
    The two sister chromatids are attached to each other at a point called the __________ of a chromosome.

  • zygote
  • autosome
  • gene
  • centromere

  • 10. 
    The 23rd pair of chromosomes that do determine the sex of an individual are called ___________.

  • sex chromosomes
  • autosomes
  • homologous
  • genes

  • 11. 
    An abnormality in which homologous chromosomes fail to separate properly is called

  • glue syndrome
  • sticky-osis
  • nondisjunction
  • telophase

  • 12. 
    The structure that holds two chromosomes together until they separate for cell division is the

  • chromatid
  • chromatin
  • centromere
  • cytoplasm

  • 13. 
    Based on the Karyotype shown, at which chromosome pair can we identify a genetic disorder?

  • Chromosome pair 5
  • sex chromosomes
  • Chromosome pair 21
  • There are no chromosomal disorders

  • 14. 
    How many chromosomes does a human body cell have, total?

  • 48
  • 46
  • 23
  • 47

  • 15. 
    A _________ is DNA tightly coiled around proteins.

  • gene
  • chromosome
  • trait
  • mutation

  • 16. 
    The structure labeled A is a(n)

  • chromatid
  • centriole
  • centromere
  • chromophere

  • 17. 
    The 2 female sex chromosomes are ___.

  • XY
  • XX

  • 18. 
    The 2 exact copies of DNA in a chromosome are called ________.

  • chromatids
  • genes
  • mutations
  • pathogens

  • 19. 
    Autosomes are

  • chromosomes found in autotrophs, only
  • chromosomes that automatically correct all errors in the DNA
  • chromosomes that determine traits other than sex
  • chromosomes that determine the sex of the individual

  • 20. 
    Cells that contain only ONE set of chromosomes are called ________ (n).

  • diploid
  • polyploid
  • triploid
  • haploid

  • 21. 
    The 2 male sex chromsomes are _____.

  • XY
  • XX

  • 22. 
    The structures labeled B are

  • centrioles
  • chromatids
  • centromeres
  • chromopheres

  • 23. 
    When DNA is in its less coiled, "relaxed," state, between cell divisions, it is called

  • autosomes
  • chromatid
  • chromatin
  • centromere

  • 24. 
    Genes that are located on the same chromosome

  • human genome project
  • pedigree
  • biology
  • linked genes

  • 25. 
    What is a nucleosome?

  • All the DNA and histones in a cell
  • chromatin that has been condensed
  • a histone with two coils of DNA wrapped around it

  • 26. 
    A nondisjunction resulting in one chromosome in one position is called

  • monosomy
  • disomy
  • trisomy
  • polysomy

  • 27. 
    Which statement is NOT true about Karyotypes

  • Chromosomes (pairs 1-22) are arranged by size
  • Sex chromosomes are found at the end
  • A normal karyotype has 46 chromosomes or 23 pairs
  • Having missing or extra chromosomes does not indicate a disorder

  • 28. 
    The haploid number of human chromosomes is

  • 11
  • 12
  • 23
  • 46

  • 29. 
    Cells that contain 2 sets of chromosomes are called _________ (2n).

  • diploid
  • haploid
  • triploid
  • polyploid

  • 30. 
    Chromosomes that have the same sequence of genes and the same structure are ___________.

  • homologous chromosomes
  • alleles
  • phenotypes
  • genotypes
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