100 DAYS ACTION PLAN - MARCH 2026
UNIT 4 – HEREDITY
1 Marks Questions
3. What is Heredity?
Passing of traits from parents to offspring.
5. Who is called the Father of Genetics?
Gregor Johann Mendel.
6. Mention any two recessive traits of a garden pea.
Wrinkled seeds and short (dwarf) plants.
7. What is the genotypic ratio of a monohybrid cross?
[Image of Mendel's monohybrid cross Punnett square]
1 : 2 : 1
8. What is the phenotypic ratio of a dihybrid cross?
9 : 3 : 3 : 1
9. Which of the gametes - sperm or egg decides the sex of the child?
Sperm (because it carries either an X or a Y chromosome).
11. Name two organisms in which sex determination is regulated entirely on environmental cues.
• Environmental: Snails, Turtles.
• Not genetic: Crocodiles, some reptiles.
• Not genetic: Crocodiles, some reptiles.
12. Write any two slogans on female foeticide.
"Save girl child – save future."
"Let daughters live."
"Let daughters live."
15. Males are called heterogametic. Why?
Because they produce two different types of gametes (one carrying the X chromosome and one carrying the Y chromosome).
17. What is the scientific name of the plant used by Mendel for his experiments?
Pisum sativum
19. In a Mendel experiment, breeding a tall plant (violet flowers) with a short plant (white flowers) resulted in all violet flowers, but half were short. What is the genetic make-up of the tall parent?
TtWW
21. Which is the information source for making proteins in the cells?
DNA (Genes).
27. A Boy said 22 pairs of autosomes are present in adult boys. Raju said one pair of autosomes are present in human sperm. Who is correct?
The Boy is correct. (Sperms contain 22 single autosomes, not pairs).
31. Identify the monohybrid phenotypic ratio from the common experiment figure?
3 : 1
32. Sex is determined by different factors in various species. Do you agree?
Yes. In humans, it is genetic (X and Y chromosomes), while in animals like snails and some turtles, it is determined by environmental factors like temperature.