All Free Biology MCQs with Answers

• A. RNA coiling
• B. Gene expression
• C. DNA formation
• D. Protein synthesis

Explanation: Histones are involved in gene expression, as they play a role in regulating the accessibility of DNA to the transcriptional machinery.

• A. Diploid cells
• B. Polyploid cells
• C. Both Options A and B are correct
• D. None of these options is correct

Explanation: All cells have homologous chromosomes except for the reproductive cells of higher organisms. Cells with homologous chromosomes are diploid. Polyploidy is a condition in which the cells of an organism have more than one pair of (homologous) chromosomes. Homozygous will have the same colour alleles on homologous pairs, i.e. 'RR' or 'rr' and the heterozygous will have different alleles on homologous pair of chromosomes, i.e., Rr.

• A. Transduction
• B. Transformation
• C. Binary fission
• D. Conjugation

Explanation: Option A: Transduction is a method of genetic transfer in bacteria mediated by bacteriophages (viruses that infect bacteria). It involves the transfer of genetic material from one bacterium to another through the infection of a bacteriophage. This process was not demonstrated in the Frederick Griffith experiment. Option B: The Frederick Griffith experiment demonstrated bacterial transformation, where genetic material from one bacterium is taken up and incorporated by another bacterium, leading to a change in its characteristics. Option C: Binary fission is a form of asexual reproduction in which a single cell divides into two identical daughter cells. It does not involve the transfer of genetic material between different bacteria. Option D: Conjugation is a process of genetic transfer in bacteria that involves the direct physical contact between two bacterial cells. Conjugation was not observed in the Frederick Griffith experiment.

• A. 8
• B. 18
• C. 16
• D. 32

Explanation: Somatic cells are diploid cells and if one of an organism's gametes contains 16 chromosomes then one of its somatic cells will contain 32. 16x2= 32

• A. Hybrid
• B. The P generation
• C. Mutants
• D. The F2 generation

Explanation: When two individuals of different pure breeding strains or genotypes are crossed, their offspring are known as hybrids. The offspring of the first generation (F1 generation) resulting from the cross between two parental strains are all hybrids, which have a mixed genetic makeup from both parents.

• A. Haploid
• B. Diploid
• C. Single nucleus
• D. None of these

Explanation: Most multicellular organisms are diploid (2n). Because the diploid stage is the most obvious stage in the life cycle, usually only gametes are haploid.

• A. 30,000 to 40,000
• B. 40,000 to 50,000
• C. 10,000 to 15,000
• D. 20,000 to 25,000

Explanation: Scientists estimate that the human genome, for example, has about 20,000 to 25,000 protein-coding genes.

• A. Diploid
• B. Haploid
• C. Unicellular
• D. None of these

Explanation: Organisms that have one copy of each gene on each chromosome are called haploid organisms. Haploid organisms have a single set of chromosomes, whereas diploid organisms have two sets of chromosomes (one from each parent). In haploid organisms, each gene is represented by a single allele. Examples of haploid organisms include bacteria, some fungi, and gametes (sperm and egg cells) of higher organisms.

• A. 44
• B. 45
• C. 46
• D. 43

Explanation: A diploid cell has two complete sets of chromosomes. Most cells in humans are diploid, comprising 23 chromosome pairs, so 46 chromosomes in total. This is 22 pairs of autosomes and a pair of sex chromosomes. One copy of each chromosome pair came from the individual's mother and the other from the individual's father. The other options have incorrect values.

• A. They lack cytoplast.
• B. They have a cell wall.
• C. They cannot create proton gradients.
• D. They can conduct mRNA translation simultaneous to transcription.

Explanation: They can conduct mRNA translation simultaneous to transcription is unique to prokaryotes.