Organization in the Living World-Conceptual Questions
Question 1. While studying the slides made from different parts of the body of the frog, the cells appear different. Why?
Answer.
In multicultural organisms the cells from different parts of the body appear different in structure. The shape and size of cells depend upon the function they perform.
Their peculiar shape and size helps the cells to perform function of different body parts. For example, the cells of digestive system have particular type of shape and structure that helps them in digesting the food.
Question 2. A girl cuts thin slices of cucumber for preparing salad and sprinkles some table salt on it. After sometimes she found some water in the plate. From where does this water came?
Answer.
Sprinkling the salt made the outside medium of cucumber more concentrated than the inside. As a result, the cucumber cells looses water through osmosis (exosmosis) leading to shrinkage of protoplasm away from cell wall. We call this phenomenon plasmolysis. Due to this phenomenon the girl observed water in the plate.
Question 3. Sohan wants to study the structure of endoplasmic reticulum. Which kind of microscope would you suggest him for the purpose and why?
Answer.
Cell organelles like endoplasmic reticulum, ribosomes, plastids etc. are clearly visible under an electron microscope. They are too small to be seen from compound microscope. The resolving power of electron microscope is high and it can magnify any object several times more than a compound microscope.
Question 4.
Study the above figure and answer the following questions-
(i) Label (1) and (2)
(ii) Name the process shown.
(iii) Name the organism shown in the figure.
Answer (i)
(1) Cell membrane or plasma membrane.
(2) Food particle.
Answer (ii)
The process of intake of food with the help of plasma membrane in Amoeba is called endocytosis.
Answer (iii)
Unicellular organism — Amoeba.
Question 5. The given flow chart gives information about the mode of arrangement of hereditary material within the nucleus. What B, C and E indicate?
D E
Answer.
B- Chromatin material or chromatids
C- Chromosomes
E- Genes.
Question 6. A leaf appears green in colour while a tomato appears red. Why?
Answer.
The colour of plant parts is due to pigments present in chloroplasts. The green coloured pigment chlorophyll is abundantly present in leaves so they appear green. In tomato, a red coloured carotenoid “Lycopene” is found which gives red colour to tomato. Lycopene is an antioxidant and protects our body from cancer and heart diseases.
Question 7.
Answer the following questions regarding the above figure –
(i) What kind of cellular organisation of the cell appears?
(ii) Name the structure indicated by arrow.
(iii) What is its significance.
Answer.
Answer (i)
The cell shows prokaryotic organization. It is a bacterial cell with poorly defined nucleus not surrounded by nuclear membrane called nucleoid. It also shows absence of other membrane-bound cell organelles like mitochondria, chloroplast etc.
Answer (ii)
The structure indicated by arrow is mesosomes. It is formed by infoldings of plasma membrane.
Answer (iii)
Mesosomes contain respiratory enzymes and are site of respiration as bacterial cell lacks mitochondria.