Biology – Genetics MCQ

Genetics is a fascinating branch of biology that studies heredity, or how characteristics are passed down from one generation to the next. This post contains a collection of multiple-choice questions designed to test and deepen your understanding of basic genetic principles.

1. What did Gregor Mendel use for his genetics experiments?

(a) Pea plants
(b) Fruit flies
(c) Mice
(d) Yeast

Answer:

(a) Pea plants

Explanation:

Gregor Mendel, the father of genetics, used pea plants to study the inheritance of traits.

2. Which base pairs with Adenine in DNA?

(a) Thymine
(b) Cytosine
(c) Guanine
(d) Uracil

Answer:

(a) Thymine

Explanation:

In DNA, Adenine (A) always pairs with Thymine (T).

3. What type of genetic material is found in a virus?

(a) DNA only
(b) RNA only
(c) Both DNA and RNA
(d) Neither DNA nor RNA

Answer:

(c) Both DNA and RNA

Explanation:

Different viruses can have either DNA or RNA as their genetic material.

4. Which genetic disorder is characterized by a person having an extra chromosome 21?

(a) Turner syndrome
(b) Klinefelter syndrome
(c) Down syndrome
(d) Hemophilia

Answer:

(c) Down syndrome

Explanation:

Individuals with Down syndrome have three copies of chromosome 21 instead of the usual two.

5. Which process creates gametes?

(a) Mitosis
(b) Meiosis
(c) Translation
(d) Transcription

Answer:

(b) Meiosis

Explanation:

Meiosis is the process of cell division that produces gametes, or sex cells.

6. Which of the following is not a type of mutation?

(a) Insertion
(b) Deletion
(c) Replication
(d) Substitution

Answer:

(c) Replication

Explanation:

Replication refers to the copying of DNA. It is not a type of mutation.

7. Who is known as the “Father of Genetics”?

(a) Charles Darwin
(b) James Watson
(c) Gregor Mendel
(d) Francis Crick

Answer:

(c) Gregor Mendel

Explanation:

Gregor Mendel is known as the “Father of Genetics” for his pioneering work on the inheritance of traits in pea plants in the mid-1800s. His experiments and observations established many of the rules of heredity, which are now referred to as the laws of Mendelian inheritance.

8. In which phase of meiosis do homologous chromosomes separate?

(a) Anaphase I
(b) Anaphase II
(c) Prophase I
(d) Metaphase II

Answer:

(a) Anaphase I

Explanation:

During Anaphase I of meiosis, homologous chromosomes are separated to opposite poles of the cell.

9. The alternate form of a gene is called?

(a) Chromosome
(b) Allele
(c) Genotype
(d) Phenotype

Answer:

(b) Allele

Explanation:

An allele is one of two or more versions of a gene. An individual inherits two alleles for each gene, one from each parent. Alleles are responsible for variations in traits and the genetic diversity within a population. Different alleles of the same gene will have variations in the sequence of DNA bases, which can lead to variations in traits and characteristics.

10. What is the shape of DNA?

(a) Triple helix
(b) Single strand
(c) Double helix
(d) Quadruple helix

Answer:

(c) Double helix

Explanation:

The DNA molecule is shaped like a double helix, often described as a "twisted ladder."

11. What is the name of the process by which DNA is copied?

(a) Transcription
(b) Translation
(c) Replication
(d) Mutation

Answer:

(c) Replication

Explanation:

DNA replication is the process by which DNA makes a copy of itself during cell division.

12. What type of mutation occurs when a piece of a chromosome is transferred to another chromosome?

(a) Translocation
(b) Deletion
(c) Insertion
(d) Inversion

Answer:

(a) Translocation

Explanation:

Translocation is a type of chromosomal abnormality in which a chromosome breaks and a portion of it reattaches to a different chromosome.

13. Which of the following represents a homozygous recessive genotype?

(a) AA
(b) Aa
(c) aa
(d) AAaa

Answer:

(c) aa

Explanation:

A homozygous recessive genotype consists of two recessive alleles, represented as 'aa'.

14. Which scientist(s) is/are credited with the discovery of the structure of DNA?

(a) Gregor Mendel
(b) Rosalind Franklin
(c) Watson and Crick
(d) Barbara McClintock

Answer:

(c) Watson and Crick

Explanation:

James Watson and Francis Crick, with contributions from Rosalind Franklin, are credited with discovering the double helix structure of DNA.

15. What is the role of tRNA in protein synthesis?

(a) Carrying amino acids to the ribosome
(b) Copying the DNA code
(c) Forming peptide bonds
(d) Translating mRNA into DNA

Answer:

(a) Carrying amino acids to the ribosome

Explanation:

Transfer RNA (tRNA) is responsible for bringing amino acids to the ribosome during protein synthesis.

16. Which genetic law states that allele pairs separate independently during the formation of gametes?

(a) Law of Dominance
(b) Law of Segregation
(c) Law of Independent Assortment
(d) Law of Unit Characters

Answer:

(c) Law of Independent Assortment

Explanation:

Mendel's Law of Independent Assortment states that different genes and their alleles are inherited independently within sexually reproducing organisms.

17. What is a genotype?

(a) Physical appearance of an organism
(b) Genetic makeup of an organism
(c) Ratio of dominant to recessive genes
(d) Type of genes present in DNA

Answer:

(b) Genetic makeup of an organism

Explanation:

A genotype refers to the set of genes in our DNA which is responsible for a particular trait.

18. What is the main function of the ribosome in the cell?

(a) DNA replication
(b) Lipid synthesis
(c) Protein synthesis
(d) Respiration

Answer:

(c) Protein synthesis

Explanation:

Ribosomes play a crucial role in the synthesis of proteins by translating messenger RNA (mRNA) into proteins.

19. How many chromosomes are in a human somatic cell?

(a) 23
(b) 46
(c) 92
(d) 44

Answer:

(b) 46

Explanation:

Human somatic cells (body cells) have 46 chromosomes, organized into 23 pairs.

20. What is the term for the alternative forms of a gene?

(a) Alleles
(b) Genotypes
(c) Phenotypes
(d) Homologues

Answer:

(a) Alleles

Explanation:

Alleles are alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.

21. Which of the following is a frame shift mutation?

(a) Substitution
(b) Deletion
(c) Insertion
(d) Both (b) and (c)

Answer:

(d) Both (b) and (c)

Explanation:

Both deletion and insertion mutations can cause a shift in the reading frame, leading to a frame shift mutation.

22. Which of the following processes results in genetically identical offspring?

(a) Sexual reproduction
(b) Asexual reproduction
(c) Meiosis
(d) Crossing over

Answer:

(b) Asexual reproduction

Explanation:

Asexual reproduction involves only one parent and produces offspring that are genetically identical to the parent.

23. What is the name of the enzyme that adds nucleotides to the growing DNA chain during replication?

(a) DNA polymerase
(b) RNA polymerase
(c) Ligase
(d) Helicase

Answer:

(a) DNA polymerase

Explanation:

DNA polymerase is the enzyme responsible for adding nucleotides to the growing DNA chain during replication.

24. In a Punnett Square, what does a capital letter represent?

(a) Recessive allele
(b) Dominant allele
(c) Genotype
(d) Phenotype

Answer:

(b) Dominant allele

Explanation:

In a Punnett Square, capital letters are used to represent dominant alleles, while lowercase letters represent recessive alleles.


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