CBSE Class 6 Science Advanced Biology Getting to Know Plants Long Answer Questions Set 01

Long Answer Type

Question 1. Describe the structure of a root with the help of a labelled diagram.
Answer:

Primary root: the main, thick root that grows from the radicle straight into the soil.
Secondary roots: side branches of the primary root; tertiary roots are branches of secondary roots.
Root cap: a cap-like cover on the tip of each root branch that protects the soft growing tip as it pushes through the soil.
Root hairs: fine hair-like outgrowths on the roots that absorb water and minerals from the soil.
Roots have no nodes or internodes. They grow towards water and soil and away from light.
In simple words: A root has a main root, branches, a root cap at the tip and root hairs for absorption.

Teacher's Note:
1. Label the diagram neatly: primary root, lateral root, root hairs, root tip, root cap.
2. Write one use for each part.

Question 2. Describe the functions of a leaf with the help of a labelled diagram.
Answer:

1. Manufacture of food (photosynthesis): the leaf takes in carbon dioxide from the air and water from the roots and, with chlorophyll and sunlight, makes food and releases oxygen.
2. Transpiration: the extra water taken up by the roots is lost as vapour through the stomata of leaves.
3. Gaseous exchange: gases enter and leave through the stomata during photosynthesis and respiration.
In simple words: A leaf makes food, gives out water vapour and exchanges gases.

Teacher's Note:
1. Use arrows in the diagram for CO₂, O₂ and water.
2. Mention stomata for the last two functions.

Question 3. Describe the parts of a typical flower with the help of a diagram.
Answer:

A flower stands on a stalk, the pedicel, whose swollen tip, the thalamus, holds four whorls.
1. Calyx: the outer whorl of green sepals that protect the bud and may make food.
2. Corolla: the second whorl of coloured petals; colour, scent and nectar attract insects for pollination.
3. Androecium: the male part made of stamens. Each stamen has a filament and an anther that holds pollen grains.
4. Gynoecium: the female part in the centre made of pistils. Each has a stigma (receives pollen), a style (raises the stigma) and an ovary (holds the ovules).
In simple words: A flower has sepals, petals, stamens and pistil on a stalk.

Teacher's Note:
1. Learn the order from outside: calyx, corolla, androecium, gynoecium.
2. Stamens and pistil are the essential whorls.

Teacher's Note:
1. Pull the flower apart gently and count each whorl.
2. Do not pluck flowers from public gardens.