All Free Agriculture MCQs with Answers
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2,315 questions · page 70 of 116
1381. A child is born with an extra chromosome in each of it cells, the reason is___________________?
- A. Crossing over
- B. Segregation
- C. Hybridization
- D. Non-disjunction
Explanation: Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate properly, producing a gamete with an extra…
Correct answer: Non-disjunction- A. Balbiani (1881)
- B. Mendel (1810)
- C. Allard (1910)
- D. Baranetzky (1910)
Explanation: Polytene chromosomes were first described by Édouard-Gérard Balbiani in 1881 from the salivary glands of dipteran larvae.
Correct answer: Balbiani (1881)- A. Heptose
- B. Hexose
- C. Pentose
- D. Triose
Explanation: DNA contains deoxyribose, a five-carbon sugar, so it is classified as a pentose.
Correct answer: Pentose- A. Solution
- B. Semi-solid
- C. Colloidal solution
- D. Crysto colloidal solution
Explanation: Protoplasm is a complex colloidal system containing water, dissolved crystalloids and suspended colloids, so it is described as a…
Correct answer: Crysto colloidal solution- A. Chromosome movementOrder DNA Kits
- B. Nucleolus formation
- C. Chromosome replication
- D. Spindle formation
Explanation: The centromere forms the chromosome region where spindle fibres attach through the kinetochore, allowing chromosomes to move during cell…
Correct answer: Chromosome movementOrder DNA Kits- A. metaphase I
- B. Auaphase I
- C. Metaphase II
- D. Anaphase II
Explanation: Homologous chromosome pairs separate during anaphase I of meiosis, while sister chromatids remain joined.
Correct answer: Auaphase I- A. Two
- B. Eight
- C. Six
- D. Four
Explanation: RNA contains four nitrogenous bases: adenine, guanine, cytosine and uracil. Uracil replaces the thymine found in DNA.
Correct answer: Four- A. 5 carbon sugars
- B. 4 carbon sugars
- C. 3 carbon sugars
- D. 6 carbon sugars
Explanation: RNA contains ribose, a five-carbon pentose sugar. DNA also contains a five-carbon sugar, but it is deoxyribose rather than ribose.
Correct answer: 5 carbon sugars- A. Plasmalemma
- B. Ribosomes
- C. Nuclcolus
- D. Chromosome
Explanation: The plasmalemma, or plasma membrane, is made mainly of lipids and proteins and does not contain RNA as a structural or genetic component.
Correct answer: Plasmalemma- A. Rice
- B. Cabbage
- C. Maize
- D. Tomato
Explanation: Self-incompatibility prevents self-fertilization and forces pollen from another plant, making it useful for hybrid seed production in…
Correct answer: Cabbage- A. Mendel lan monohybrid
- B. Mendelian dihybrid
- C. None of the above
- D. Incomplete dominance
Explanation: With incomplete dominance, the three genotypes produce three visibly different phenotypes, so both genotype and phenotype ratios are…
Correct answer: Incomplete dominance- A. Crossingover
- B. Polyploidy
- C. Mutations
- D. Linkage
Explanation: Crossing over creates new combinations of genes and therefore contributes to variation among offspring.
Correct answer: Crossingover- A. Dominance
- B. Liukage
- C. Independent assortment
- D. Purity of gametes
Explanation: Linkage is an exception to Mendel’s law of independent assortment because genes located close together on the same chromosome tend to be…
Correct answer: Liukage- A. Genetics
- B. Mutation
- C. Evolution
- D. Polyploidy
Explanation: Evolution is the gradual change in populations through successive generations, driven partly by genetic variation and selection.
Correct answer: Evolution- A. 1:1:1:1
- B. 1:2:3
- C. 3:1
- D. 1:2:1
Explanation: The all-tall, all-red F1 indicates that tall and red are dominant and that the F1 is heterozygous for both traits.
Correct answer: 1:1:1:1- A. 6
- B. 12
- C. 24
- D. 36
Explanation: In gymnosperms, the endosperm is a haploid female gametophyte rather than the triploid tissue found in angiosperms.
Correct answer: 12- A. Dominance
- B. Independent assortment
- C. Segregation
- D. Incomplete dominance
Explanation: Selfing a heterozygous tall plant (Tt × Tt) separates the two alleles and produces tt dwarf offspring along with tall plants.
Correct answer: Segregation- A. 25%
- B. 50%
- C. 75%
- D. 100%
Explanation: The cross Tt × tt produces Tt, Tt, tt and tt in the expected ratio, so half the progeny are homozygous dwarf.
Correct answer: 50%- A. Segregation, independent assortment and dominance recessive ness
- B. Gene linkage, dominance and segregation
- C. Segregation, independent assortment and gene linkage
- D. Gene linkage, character se gregation and independent assortment
Explanation: Mendel’s three principles are dominance, segregation and independent assortment.
Correct answer: Segregation, independent assortment and dominance recessive ness- A. Gametes will have 8 chromosomes
- B. Zygote will have 4 chromosomes
- C. Gametes will have 4 chromosomes
- D. Zygote will have 16 chromosomes
Explanation: Leaf cells are normally diploid somatic cells, so their chromosome number is 2n = 8.
Correct answer: Gametes will have 4 chromosomes