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Free Cell Structure and Function MCQs with Answers

2,478 Cell Structure and Function MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.

Animal, plant, prokaryotic and eukaryotic cells are compared through their membranes, cell walls, nuclei and cytoplasmic organelles. The work includes the structures and functions of mitochondria, chloroplasts, ribosomes, endoplasmic reticulum, Golgi apparatus and lysosomes, as well as chromosome organization and the distinction between chromatin and chromosomes.

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Animal and Plant CellProkaryotic and Eukaryotic CellsCytoplasmic OrganellesChromosomes
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1861. The process in which a complementary copy of the code from a gene is produced by RNA Polymerase in the nucleus:

  • A. Transcription
  • B. Translation
  • C. Proofreading
  • D. DNA Replication

Explanation: Transcription, is when RNA polymerase makes a copy of a gene on a template DNA strand in the nucleus; this copy is messenger RNA.

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Correct answer: Transcription

1862. Sequence of amino acids, in a polypeptide chain of protein molecule, corresponds to the sequence of nucleotides on mRNA for that protein. If the reading frame of mRNA for a human protein is 993 nucleotides, including a stop codon at the end, how many amino acids would be incorporated in the polypeptide chain?

  • A. 93
  • B. 330
  • C. 331
  • D. 993

Explanation: Codon consists of three nucleotides, and each codon corresponds to a single amino acid.

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Correct answer: 330

1863. As a result of replication, parental DNA would become completely dispersed and that each strand of all the daughter molecules would be a mixture of old and new DNA. This is called as:

  • A. Dispersive idea
  • B. Conservative idea
  • C. Disruptive idea
  • D. Semi-conservative idea

Explanation: It is 'dispersive replication', which involves each daughter strand containing both parental and new DNA, as the old DNA is broken up and…

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Correct answer: Dispersive idea

1864. Extremely long molecule of DNA that is tightly folded to fit inside the cell component is called?

  • A. Nucleus
  • B. Chromosome
  • C. Chromatin body
  • D. Chromatid

Explanation: In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes.

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Correct answer: Chromosome

1865. Which of the following genetic diseases is caused by mutations in a membrane protein?

  • A. Alzheimer's disease
  • B. Parkinson's disease
  • C. Anemia
  • D. Hemolytic anemia

Explanation: Mutations probably include a combination of age-related changes in the brain along with genetic, environmental, and lifestyle factors.

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Correct answer: Hemolytic anemia

1866. A complete turn of the double helix of DNA comprises of:

  • A. 34 nanometer
  • B. 3.4 Angstrom
  • C. 3.4 nanometer
  • D. 34 micrometers

Explanation: At a distance of 3.4nm, the double helix DNA produces one full turn. Each full turn of DNA consists of 10 base pairs.

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Correct answer: 3.4 nanometer

1867. Single ringed pyrimidines are:

  • A. Uracil, Cytosine and Thymine
  • B. Cytosine, Guanine and Uracil
  • C. Adenine and Guanine
  • D. Cytosine, Adenine and Thymine

Explanation: The pyrimidines, Thymine, Cytosine and Uracil, are smaller and have a single ring, while the purines, Adenine and Guanine, are larger and…

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Correct answer: Uracil, Cytosine and Thymine

1868. The types of gametes produced by two pairs of chromosomes can be?

  • A. 2
  • B. 4
  • C. 6
  • D. 8

Explanation: Humans have 2 pairs of chromosomes. So for each pair, there are two options available.

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Correct answer: 4

1869. Chromosomes that have different alleles of a given gene at locus is called?

  • A. Homozygous
  • B. X chromosomes
  • C. Y chromosomes
  • D. Heterozygous

Explanation: Correct option is D. Humans have two sets of chromosomes. Homozygous and heterozygous are terms that are used to describe allele pairs.

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Correct answer: Heterozygous

1870. The ultimate source of all the change is

  • A. Migration
  • B. Mutation
  • C. Genetic drift
  • D. Selection

Explanation: Random mutations are the ultimate source of genetic variation. Mutations are likely to be rare and most mutations are neutral or…

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Correct answer: Mutation

1871. The 23rd pair of chromosomes in man is:

  • A. Polymorphic
  • B. Heteromorphic
  • C. Homomorphic
  • D. Automorphic

Explanation: The 23rd pair in man is heteromorphic and defines the gender of the person.

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Correct answer: Heteromorphic

1872. Which of the following best describes the impact of purifying selection?

  • A. It increases frequency of an allele.
  • B. It is the same as disruptive selection.
  • C. It increases genetic diversity.
  • D. It removes variation from the population.

Explanation: The statement that best describes the impact of purifying selection is: "It removes variation from the population." Purifying selection…

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Correct answer: It removes variation from the population.

1873. The doubling of DNA material occurs in the process of

  • A. Mitosis
  • B. Meiosis
  • C. Cytoplasm
  • D. Nucleus

Explanation: The doubling of DNA material occurs in the process of mitosis as parent cell divides into two daughter cells having same number of…

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Correct answer: Mitosis

1874. The term 'chromosome' was coined by:

  • A. Mendel
  • B. Boweri
  • C. Sutton
  • D. Fleming

Explanation: The term was discovered by the German scientist Heinrich Wilhelm Waldeyer in 1888, it referred to chromatin at the time which was later…

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Correct answer: Fleming

1875. Who proposed the chromosomal theory of inheritance for the first time?

  • A. Sutton
  • B. Sutton and Walther Flemming
  • C. Correns and Robert Brown
  • D. Einstein and Mendel

Explanation: The chromosomal theory of inheritance was proposed by Walter Sutton which states that chromosomes are the units of genetic heredity.

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Correct answer: Sutton

1876. The ends of chromosomes are called:

  • A. Telomeres
  • B. Centromeres
  • C. Kinetochores
  • D. Satellites

Explanation: The ends of chromosomes are called telomeres. They consist of repeating non-coding nucleotide sequences.

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Correct answer: Telomeres

1877. How many sex chromosomes are present in a human?

  • A. 3 pairs
  • B. 4 pairs
  • C. 2 pairs
  • D. 1 pair

Explanation: Humans have 2 sex chromosomes (1 pair), i.e. the X and Y chromosomes. Females have XX chromosomes whereas males have XY chromosomes.

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Correct answer: 1 pair

1878. The first person to observe chromosomes was:

  • A. Waldeyer
  • B. Coloumb
  • C. Strasburger
  • D. Flemming

Explanation: Walther Flemming was the first person to observe chromosomes while examining the rapidly dividing cells of salamander larvae and described…

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Correct answer: Flemming

1879. The term 'chromosome' was first time proposed by:

  • A. Sutton
  • B. Flemming
  • C. Boweri
  • D. Mendel

Explanation: The term 'chromosome' was first time proposed by Walther Flemming. Chromosomes are thread-like structures that appear inside the nucleus…

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Correct answer: Flemming

1880. Conversion of ssRNA (-) to ssRNA (+) mediated by:

  • A. DNA dependent DNA polymerase
  • B. DNA dependent RNA polymerase
  • C. RNA dependent DNA polymerase
  • D. RNA dependent RNA polymerase

Explanation: Conversion of - ssRNA to +ssRNA is mediated by "RNA-dependent RNA Polymerase".

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Correct answer: RNA dependent RNA polymerase
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