Embibe Experts Solutions for Chapter: Cell – Structure and Functions, Exercise 1: Exercise

Refer to the given paragraph.
X and Y are the two type of cells. The X have a well-organised nucleus which is separated from the cytoplasm by the nuclear membrane. On the other hand, Y do not have a true nucleus and their nuclear material is in direct contact with cytoplasm. Identify X and Y and select the correct option.

Read the given statements and select the option that correctly identifies them as true (T) and false (F) ones.
(i) Granum is the site of dark reaction during photosynthesis, whereas stroma is the site of light reaction during photosynthesis.
(ii) Lysosomes are formed by the joint activity of endoplasmic reticulum and Golgi complex.
(iii) Each $70 \mathrm{S}$ ribosome consists of a large $50 \mathrm{S}$ subunit and a small $30 \mathrm{S}$ subunit.
(iv) The chromosome in which the centromere is near the end and consequently its one arm is very short and the other arm very long, is called acrocentric chromosome.

Red blood cells are also known as erythrocytes, is one of the major components of the blood. RBCs are red in colour because of the presence of a red colour pigment called haemoglobin. The haemoglobin carries oxygen to all parts of the body from the heart and contains iron in its molecules. RBCs are biconcave disc in structure. These cells are living, but do not contain mitochondria and nucleus. 

What would have happened if RBCs had mitochondria?

Robert Hooke was the first cytologist to identify cells under his microscope in 1665. He decided to call this shapes that he saw in a slice of cork "cells" because the shapes reminded him of the cells (rooms) that the monks in the nearby monastery lived in. All living organisms, including plants, animals, bacteria and fungi, are made up of cells. Cells are the smallest parts of all living organisms. We can say that cells are the basic structural and functional units of all living organisms.

How do you appreciate the fact that a huge elephant, giraffe, trees and even a Paramecium are made of cells, which are very small and we can look at them through the microscope?

Living things have cells that range in size from a millionth of a metre (micrometre or micron) to a few centimetres. However, the majority of the cells are microscopic and cannot be seen with the human eye. They require enlargement or magnification with a microscope.

Charan said, "Bigger Elephants have larger cells when compared to the cells of smaller Elephants"! Do you agree with his statement or not. Explain Why?

Cell is called a structural and functional unit of life of all living organisms capable of independent existence and can perform all functions of life. Both plant and animal cells are eukaryotic, so they contain membrane-bound organelles like the nucleus and mitochondria. However, plant cells and animal cells do not look exactly the same or have all of the same organelles, since they each have different needs. For example, plant cells contain chloroplasts since they need to perform photosynthesis, but animal cells do not.

What would have happened if there had been no difference between mitochondria and plastids in plant cells?

The circulatory system in animals and human beings is made up of blood vessels that carry blood away from and towards the heart. Arteries carry blood away from the heart and veins carry blood back to the heart. The circulatory system carries oxygen, nutrients, and hormones to cells, and removes waste products, like carbon dioxide. Plants do not have a circulatory system like that of animals for transportation of food and minerals within the body then how cells manage intercellular transport?

Cell is called a structural and functional unit of life of all living organisms capable of independent existence and can perform all functions of life.

Is the function performed by an organ the same as the function of its constituent tissues? What is the advantage of organs with the same function working together as a system?