All Free Biology MCQs with Answers

• A. Cleavage
• B. Fertilization
• C. Differentiation
• D. Spermatogenesis

Explanation: Cleavage, fertilization and regenerations all are the gifts of mitosis, while spermatogenesis is the sperm production process in human male that occur by meiosis.

• A. Prophase
• B. Anaphase
• C. Metaphase
• D. Telophase

Explanation: During meiosis, chromosomal condensation and crossing over occur in prophase I, while nuclear envelope will disappear at the start of metaphase I.

• A. Animals
• B. Fungi
• C. Plants
• D. Prokaryotes

Explanation: Meiosis is the special type of cell division in which the number of chromosomes in daughter cells is reduced to half as compared to the parent cell. Each diploid cell after meiosis produces four haploid cells because it involves two consecutive divisions after single replication of DNA.

• A. 2
• B. 92
• C. 23
• D. 46

Explanation: In the case of human cells, the total number of tetrads formed during zygotene is 23.

• A. Non specific but exactly pointed
• B. Highly specific and exactly pointed
• C. Non specific and non pointed
• D. Highly specific but fused

Explanation: The first essential phenomenon of meiosis i.e., pairing of homologous chromosomes called synapsis starts. This pairing is highly specific and exactly pointed, but with no definite starting point (s.) Each paired but not fused, complex structure is called a bivalent or tetrad.

• A. Mitosis
• B. Karyokinesis
• C. Cytokinesis
• D. None of these

Explanation: M phase of cell cycle is divided into karyokinesis and cytokinesis. Karyokinesis is the division of nucleus. It is further divided into prophase, metaphase, anaphase and telophase while cytokinesis refers to the division of whole cell.

• A. Smooth Endoplasmic Reticulum
• B. Golgi Complex
• C. Ribosome
• D. Rough endoplasmic reticulum

Explanation: Phragmoplast is formed from vesicles that originate from the Golgi complex during metaphase and line up in the centre of the cell where they fuse to form a phragmoplast at the end of telophase.

• A. M phase
• B. S phase
• C. G1 phase
• D. G2 phase

Explanation: Following the G1 is the S-phase (synthesis phase) during which the DNA is synthesised and (chromosome are replicated) which initiates G2 phase (pre- mitotic phase), thus preparing the cell for division e.g., energy storage for chromosome movements, mitosis specific proteins, RNA and microtubule subunits (for spindle fibres) synthesise.G2 phase is the second growth phase. It occurs after the synthesis phase in a typical cell cycle. In the G2 phase synthesis of tubulin protein which is the major component of microtubules takes place. The spindle fibres are made of microtubules.

• A. Crossing Over
• B. Attachment
• C. Pairing
• D. Leptotene

Explanation: Chiasmata are the X-shaped structure formed due to the point of contact between paired chromatids during meiosis. It is the point representing the crossing over where the homologous chromosomes are joined to each other.

• A. G2 phase
• B. G1 phase
• C. S phase
• D. C phase

Explanation: As the cell grows and expands after cell division, that is the point when the nucleus is most active, i.e. during the first stage of interphase.G1(Gap 1) is the period of extensive metabolic activity, in which cell normally grows in size, specific enzymes, are synthesized and DNA base units are accumulated for theDNA synthesis.