All Free Biology MCQs with Answers
Every Biology question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
19,844 questions · page 935 of 993
- A. Chromosomal rearrangement
- B. Transposition of gene
- C. Chromosomal aberration
- D. Point mutation
Explanation: Option [A] chromosomal rearrangement includes inversions,reciprocal translocations that can have effect on gene expression through…
Correct answer: Point mutation- A. Number
- B. Types
- C. Number, types and chemical composition
- D. Number and types
Explanation: [A] Does not refer only on number of chromosome[B] does not refer to the type of chromosomes only[C] does not refer to chemical…
Correct answer: Number and types- A. Prophase I
- B. Metaphase I
- C. Telophase I
- D. Anaphase I
Explanation: [A] During prophase no separation of chromosomes occurs instead they only condense and thicken during prophase[B] During Metaphase the…
Correct answer: Anaphase I- A. 11
- B. 22
- C. 21
- D. 12
Explanation: [A] Gene for albinism, sickle cell anaemia and leukaemia is present at chromosomes number 11.[B] Not present at chromosomes 22.[C] Not…
Correct answer: 11- A. Mitosis
- B. Interphase
- C. Meiosis
- D. Cell Cycle
Explanation: The period of life cycle of cell (cell cycle) between two consecutive divisions is termed as the interphase or misleadingly called resting…
Correct answer: Interphase- A. Prophase
- B. Metaphase
- C. Telophase
- D. Anaphase
Explanation: Telophase is the fifth and final phase of mitosis, the process that separates the duplicated genetic material carried in the nucleus of a…
Correct answer: Telophase- A. Down's syndrome
- B. Klinefelter's syndrome
- C. Turner's syndrome
- D. XYZ syndrome
Explanation: In Down's syndrome, there are three copies, either complete or partial, of chromosome 21.
Correct answer: Down's syndrome- A. Klinefelter's syndrome
- B. Down's syndrome
- C. Turner's syndrome
- D. Edward's syndrome
Explanation: The correct answer is Klinefelter's syndrome. Klinefelter's syndrome is characterized by the presence of an additional X chromosome in…
Correct answer: Klinefelter's syndrome- A. 7
- B. 18
- C. 21
- D. 19
Explanation: Down's syndrome is a genetic condition in which the 21st chromosome fails to segregate, leading to physical and mental developmental delay…
Correct answer: 2118690. Down's syndrome is a result of non-disjunction of_ pair of chromosomes that fails to segregate:
- A. 21st
- B. 22nd
- C. 18th
- D. 24th
Explanation: Down's syndrome, also known as trisomy 21, is a result of the non-disjunction of the 21st pair of chromosomes.
Correct answer: 21st- A. Prophase
- B. Metaphase
- C. Anaphase
- D. Telophase
Explanation: The third stage of cell division, between metaphase and telophase, during which the chromosomes move away from one another to opposite…
Correct answer: Anaphase- A. Turner's syndrome
- B. Klinefelter's syndrome
- C. Down syndrome
- D. Jacob's syndrome
Explanation: Down syndrome is usually caused by an error in cell division called "nondisjunction." Nondisjunction results in an embryo with three…
Correct answer: Down syndrome- A. Down's Syndrome
- B. Turner's Syndrome
- C. Klinefelter's Syndrome
- D. Phenylketonuria
Explanation: Klinefelter's Syndrome is a genetic disorder that affects males and is characterized by the presence of an extra X chromosome (XXY instead…
Correct answer: Klinefelter's Syndrome- A. Trisomy 21
- B. 44 + XXY
- C. Trisomy
- D. 44 + XO
Explanation: Turner's Syndrome is characterized by the complete or partial loss of one of the X chromosomes in females.
Correct answer: 44 + XO- A. Down's syndrome
- B. Turner's syndrome
- C. Klinefelter's syndrome
- D. Jacob's syndrome
Explanation: Klinefelter's syndrome is a genetic disorder that affects males, characterized by the presence of an extra X chromosome.
Correct answer: Klinefelter's syndrome- A. Trisomy
- B. Monosomy
- C. Polysomy
- D. Disomy
Explanation: In Down syndrome, there is an additional copy of chromosome 21, resulting in three copies instead of the normal two.
Correct answer: Trisomy- A. Turner's Syndrome
- B. Jacob's Syndrome
- C. Metastasis
- D. Down's syndrome
Explanation: Non-disjunction causes an abnormal number of chromosomes in all cells, called aneuploidy, or in some cells, called mosaicism.
Correct answer: Down's syndrome- A. Turner's
- B. Down's
- C. Edward's
- D. Patau's
Explanation: Turner syndrome, a condition that affects only females, results when one of the X chromosomes (sex chromosomes) is missing or partially…
Correct answer: Turner's- A. Anaphase
- B. Metaphase
- C. Prophase
- D. Telophase
Explanation: Anaphase is the most critical phase of the mitosis, which ensures equal distribution of chromatids in the daughter cells.
Correct answer: Anaphase- A. XXX
- B. XYY
- C. XO
- D. XXY
Explanation: XO refers to a specific chromosomal condition known as Turner syndrome, which occurs in females.
Correct answer: XO