All Free Biology MCQs with Answers

• A. And when I moved in particular direction, this time to the south and east, it shone out like a light.
• B. And when I moved in a particular direction, this time to south and east, it shone out like a light.
• C. And when I moved in a particular direction, this time to the south and the east, it shone out like a light.
• D. And when I moved in a particular direction, this time to the south and east, it shone out like a light.

Explanation: The correct answer is C. And when I moved in a particular direction, this time to the south and the east, it shone out like a light.

• A. Viruses
• B. Bacteria
• C. Higher plants
• D. Lower animals

Explanation: Both prokaryotic and eukaryotic cells contain structures known as cilia and flagella.

• A. Primary cell wall
• B. Secondary cell wall
• C. Middle lamellae
• D. Cell surface membrane

Explanation: The outermost layer in a typical plant cell would be primary cell wall.

• A. ATP
• B. DNA
• C. RNA
• D. ADP

Explanation: ATP is called the cell's energy currency because energy released from cellular reactions is temporarily stored in its phosphate bonds and…

• A. Thyroxin
• B. Triiodothyronine
• C. Calcitonin
• D. Glucagon

Explanation: The correct answer is Glucagon. Glucagon is secreted by the pancreas, not the thyroid gland.

• A. Hypothalamus
• B. Pitutary gland
• C. Thyroid
• D. Parathyroid gland

Explanation: Hypothalamus is the part of the brain that releases a variety of hormones.

• A. Respiratory system
• B. Nervous system
• C. Endocrine system
• D. Both b and c

Explanation: Animal coordination depends on both the nervous system, which sends rapid electrical signals, and the endocrine system, which releases…

• A. It produces amino acids
• B. It produces messenger RNA
• C. It results in increased DNA synthesis
• D. It is a semi conservative process

Explanation: Transcription of DNA means the formation of mRNA out of DNA. Translation is the synthesis of proteins using these mRNAs.

• A. Continuous and conservative
• B. Discontinuous and semiconservative
• C. Semidiscontinuous and semiconservative
• D. Conservative and semidiscontinuous

Explanation: Replication is semiconservative because the new daughter DNA synthesized is composed of one parent DNA and one newly synthesized…

• A. mRNA
• B. rRNA
• C. tRNA
• D. Polysome

Explanation: Option A is messenger RNA, the transcript of a segment of DNA that serves as the code which is then translated by the ribosomes.Option B…

• A. Deoxyribose sugar
• B. Ribose sugar
• C. Phosphate group
• D. Sequence of nitrogenous bases

Explanation: The genetic information of DNA is encoded as the sequence of nitrogenous bases.

• A. TACGGATCCTG
• B. UAGCGAUCCUG
• C. AUGCCUAGGAC
• D. UACCGAUCCUG

Explanation: DNA strand serves as the template for RNA synthesis. The RNA nucleotide sequence is complementary to that of DNA template strand except…

• A. 5th
• B. 4th
• C. 3rd
• D. 1st

Explanation: A nucleotide consists of a sugar molecule (either ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a…

• A. Heterochromatin
• B. Nucleosome
• C. Super coils
• D. None of these

Explanation: Heterochromatin represents the highly condensed portions of chromatin. This dense packing makes the DNA inaccessible to the transcription…

• A. 44 + XY
• B. 44 + XXY
• C. 44 + XO
• D. 44 + XXX

Explanation: The genotype of a normal male contains 44 autosomes and two sex chromosomes, which are XY.

• A. Only one daughter cell will have heavy DNA
• B. Two daughter cells have normal DNA and the other two have heavy DNA
• C. All daughter cells have heavy DNA
• D. All daughter cells contain hybrid DNA

Explanation: Duplication of DNA is by the semi-conservative method that was first shown in escherichia coli and later it was observed in higher…

• A. Down's Syndrome
• B. Turner's Syndrome
• C. Klinefelter's Syndrome
• D. Sickle Cell Anemia

Explanation: Klinefelter syndrome is a genetic condition in which a boy is born with an extra X chromosome.

• A. 10
• B. 30
• C. 40
• D. 44

Explanation: Haploid cells are formed by reduction division, which has half the number of chromosomes than diploid cells.

• A. 1
• B. 2
• C. 3
• D. 4

Explanation: The zygote, formed by the fusion of a sperm and an ovum, is the first cell to contain the diploid number of chromosomes.

• A. Complementary strand of mRNA which codes for one amino acid
• B. tRNA molecule where the amino acid is attached
• C. tRNA molecule which recognizes the appropriate sequence of bases on the mRNA
• D. mRNA molecule which instructs the ribosomes to initiate

Explanation: The correct answer is Option D. An anticodon is a sequence of three nucleotides on a tRNA molecule that recognizes and pairs with a…