Differentiate between the following pairs of terms based on the clues given in parentheses: Class 9

Differentiate between the following pairs of terms based on the clues given in parentheses: Class 9

Revise, Reflect, Refine (Page 24-26)

Question 1.

Differentiate between the following pairs of terms based on the clues given in parentheses: Class 9

(i) Cellmembrane andcell wall (permeability)

Answer:

1. The cell membrane is selectively permeable - it allows only certain substances to pass through while blocking others, thus controlling what enters and exits the cell.
2. The cell wall, on the other hand, is fully permeable - it allows water and dissolved minerals to pass through freely without any selectivity. It acts as a structural support rather than a control barrier.

(ii) RER and SER (structure)

Answer:

Rough Endoplasmic Reticulum (RER) has ribosomes attached to its surface, which give it a rough, bumpy appearance under an electron microscope. These ribosomes are responsible for protein synthesis.

Smooth Endoplasmic Reticulum (SER) lacks ribosomes on its surface, making it appear smooth. Because of this structural difference, RER is involved in protein synthesis and secretion, while SER is involved in the synthesis and storage of fats and hormones,

(iii) Chloroplasts and chromoplasts (pigments)

Answer:

1. Chloroplasts contain the green pigment chlorophyll, which absorbs sunlight for photosynthesis. They are found in the green parts of plants, mainly leaves.
2. Chromoplasts contain pigments other than chlorophyll, such as yellow, orange, or red pigments called carotenoids. They are found in flowers and fruits and are responsible for their bright colours, which attract pollinators and seed-dispersing animals.