Quick revision: every question with its correct answer. For the full explanation, open the test and tap View Solution.
7.3 Extrachromosomal (Cytoplasmic) Inheritance — Test 2
Q1. Cytoplasmic male sterility (CMS) in maize is caused by a mutation in the:✓ Mitochondrial genome
Q2. Reciprocal crosses give DIFFERENT results in:✓ Cytoplasmic (extrachromosomal) inheritance
Q3. Extrachromosomal inheritance is best detected experimentally by:✓ Reciprocal crosses
Q4. A gene for fungal resistance lies in the chloroplast. If a susceptible female is crossed with a resistant male, the progeny will be:✓ All susceptible
Q5. A petite (slow-growing) yeast crossed with wild type yields no petite progeny. This indicates the petite trait is:✓ Mitochondrial (cytoplasmic)
Q6. In Neurospora, 'poky × normal → all poky' but 'normal × poky → all normal' (poky used as the maternal/protoperithecial parent). This pattern is:✓ Maternal inheritance
Q7. A characteristic feature of the mitochondrial genome is:✓ Polycistronic transcription
Q8. In the snail Limnaea, shell coiling shows maternal effect: a homozygous dextral male (DD) crossed with a homozygous sinistral female (dd) gives F1 that are sinistral, and the F1 selfed give all dextral F2. This is because:✓ The nuclear genotype of the mother determines the offspring's coiling
Q9. In a maternal-effect cross of Limnaea (dextral D dominant), the F1 of a heterozygous (Dd) mother, when selfed, gives an F2 genotype ratio of:✓ 1:2:1
Q10. Cytoplasmic male sterility (CMS) is restored by a dominant nuclear gene Rf. A male-sterile plant pollinated by a heterozygous (Rf rf) fertile plant gives progeny that are:✓ 50% fertile and 50% male sterile
Q11. The killer trait in Paramecium, transmitted through cytoplasmic kappa particles, is an example of:✓ Cytoplasmic (endosymbiont) inheritance
Q12. Leaf variegation in Mirabilis jalapa (the four-o'clock plant), studied by Correns, is inherited:✓ According to the maternal (egg) parent's plastids
Q13. Human mitochondrial diseases are transmitted:✓ From the mother only
Q14. The fact that mitochondria and chloroplasts have their own circular DNA, ribosomes and are inherited maternally supports the:✓ Endosymbiont theory
Q15. A 'maternal-effect' gene differs from organelle (cytoplasmic) inheritance in that a maternal-effect gene is:✓ A nuclear gene whose product is deposited in the egg by the mother
Q16. In yeast, a 'segregational' petite (caused by a nuclear gene) crossed with wild type gives diploids that, on sporulation, segregate:✓ 2 petite : 2 grande
Q17. The 'iojap' trait in maize, which causes striped leaves and is transmitted through the maternal cytoplasm once induced, involves:✓ Defective plastids
Q18. Why does the male (pollen/sperm) parent usually contribute little to cytoplasmic inheritance?✓ It contributes very little cytoplasm to the zygote
Q19. A Neurospora mitochondrial mutant (stp) used as the maternal (protoperithecial) parent crossed to a normal male gives progeny that are:✓ All stp mutant
Q20. Match each example with its mechanism and select the correct option.✓ A-ii, B-i, C-iv, D-iii