Title Ex-3 Cell The unit of life Reviewed.pdf ✅

30 CELL THE UNIT OF LIFE EXERCISE – 3: Advanced Objective Questions Introduction to Cells 1. Match Column - I with Column - II and select the correct option from the codes given below. Column I Column II A. Leeuwenhoek (i) First saw and described a living cell B. Robert Brown (ii) Presence of cell wall is unique to plant cells C. Schleiden (iii) Discovered the nucleus D. Schwann (iv) All plants are composed of different kind of cells (a) A-(i), B-(iii), C-(iv), D-(ii) (b) A-(i), B-(iii), C-(ii), D-(iv) (c) A-(iii), B-(i), C-(iv), D-(ii) (d) A-(i), B-(iv), C-(iii), D-(ii) Ans. (a) Sol. The first man to see and describe a live cell under the microscope was Antonie van Leeuwenhoek. Robert Brown discovered the cell nucleus. Schleiden stated that all plants are composed of different kinds of cells. Schwann studied the cell wall and stated that the presence of the cell wall is unique to plant cells. 2. Read the following statements and find out the correct statements. (a) The shape of cell may vary with the function they perform. (b) The prokaryotic cells lack all membrane bound organelles. (c) Schleiden, a German botanist concluded, based on his studies on plant tissues, that the presence of cell wall is a unique character of the plant cells. (d) Based on their studies on plant and animals, Schwann, a British zoologist, proposed the hypothesis that the bodies of animals and plants are composed of cells and products of cells. (e) Rudolf Virchow modified the hypothesis of Schleiden and Schwann and gave the cell theory a final shape. (a) b, d, e (b) a, c, d (c) a, b, e (d) a, b, d Ans. (c) Sol. In the given question, statements (a), (b) and (e) are correct. Statement (c) is incorrect as it was Schwann who discovered that cell walls are unique to plant cells. Statement (d) is incorrect as Schwann was a German zoologist who proposed the given hypothesis and not a British zoologist. 3. Match the columns I, II and III, and choose the correct combination from the options given. Column I Column II Column III a. 1. Mesophyll cell K. Elongated b. 2. Tracheid L. Round and biconcave c. 3. Red blood cells M . Amoeboid d. 4. White blood cells N. Round and oval (a) a–3–M, b–4–L, c–1–K, d–2–N (b) a–4–M, b–3–L, c–2–K, d–1–N (c) a–3–L, b–4–M, c–1–N, d–2–K (d) a–4–L, b–3–M, c–2–N, d–1–K Ans. (c)
CELL THE UNIT OF LIFE 31 Sol. The figure 'a' depicts red blood cells which are round and biconcave which permits oxygen exchange over a larger surface area. The figure 'b' depicts White blood cells which are amoeboid in shape aiding the process of phagocytosis. The figure 'c' depicts round and oval Mesophyll cells which provide large spaces for carbon dioxide during photosynthesis. They figure ‘d' depicts Tracheid which is elongated thus carrying out water conduction in the xylem. 4. Which of these statements is/are true? (i) The surface area available for cellular functions in a prokaryotic cell is less than in a eukaryotic cell. (ii) The total genome size of a prokaryotic cell is always less than that of a eukaryotic cell. (iii) Unlike eukaryotes, no special respiratory organelles are found in prokaryotes. Hence, they respire at a much lesser rate than eukaryotes. (iv) Eukaryotic cells show various membrane bound organelles such as chloroplasts and nucleus while ribosomes are the only membrane bound organelles found in prokaryotes. (a) (i) and (ii) (b) (iv) only (c) (iii) only (d) (i), (ii) and (iv) Ans. (a) Sol. Statements (i) and (ii) are correct. Statement (iii) is incorrect as even though prokaryotes do not have mitochondria, they do have respiratory enzymes to fasten up the process of respiration. Statement (iv) is incorrect as prokaryotic ribosomes are not membrane bound. 5. Different cells have different sizes. Arrange the following cells in an ascending order of their size and select the correct option. (i) Mycoplasma (ii) Ostrich eggs (iii) Human RBCs (iv) Bacteria (a) (i)  (iv)  (iii)  (ii) (b) (i)  (iii)  (iv)  (ii) (c) (ii)  (i)  (iii)  (iv) (d) (iii)  (ii)  (i)  (iv) Ans. (a) Sol. Mycoplasma is the smallest bacterium with a size of 0.1-0.5μm as it lacks a cell wall. A typical bacterial cell measures 3-5μm in length. Erythrocytes or red blood cells are 6-8μm in diameter. The largest cell is the egg of Ostrich which can measure up to 170 mm x 130 mm. Hence, the ascending order of size is: Mycoplasma
CELL THE UNIT OF LIFE 33 which are responsible for the transport of molecules across the membrane. C is the lipid layer. 11. Match the columns I and II, and choose the correct combination from the options given. Column I Column II A. Neutral solutes 1. Active transport B. Water 2. Passive transport C. Polar molecules 3. Osmosis (a) A–1, B–2, C–3 (b) A–2, B–3, C–1 (c) A–3, B–1, C–2 (d) A–2, B–1, C–3 Ans. (b) Sol. Neutral solutes move spontaneously down their concentration gradient (i.e., from a region of higher to a region of lower concentration) by passive transport, either by simple diffusion or facilitated by a carrier protein. The diffusion of water through the plasma membrane is termed osmosis. Polar molecules can be moved across the membrane through channel proteins, by the process of active transport. This process requires the expenditure of energy (usually from ATP) and is a highly selective, specific process. Eukaryotic Cells (Endomembrane System) 12. Recognise the figure and find out the correct matching (a) e–Rough endoplasmic reticulum, c–Smooth endoplasmic reticulum, a–Ribosome, d–Nucleus, b–Nuclear pore (b) c–Rough endoplasmic reticulum, e–Smooth endoplasmic reticulum, a–Ribosome, b–Nucleus, d–Nuclear pore (c) c–Rough endoplasmic reticulum, e–Smooth endoplasmic reticulum, a–Ribosome, d–Nucleus, b–Nuclear pore (d) e–Rough endoplasmic reticulum, b–Smooth endoplasmic reticulum, c–Ribosome, e–Nucleus, d–Nuclear pore Ans. (b) Sol. The diagram is an illustration of the endoplasmic reticulum (ER) (a) depicts the ribosomes attached to RER (b) depicts the nucleus of the cell in the centre (c) depicts the RER attached to the nucleus (d) depicts the nuclear pore of the nucleus (e) depicts the SER 13. Select the correct matching in the following pairs: (a) Rough ER – Synthesis of glycogen (b) Rough ER – Oxidation of fatty acids (c) Smooth ER – Oxidation of phospholipids (d) Smooth ER – Synthesis of lipids Ans. (d) Sol. Lipids (cholesterol & phospholipids) are synthesized by the agranular portion of the endoplasmic reticulum (Smooth endoplasmic reticulum). The major lipids synthesized by the smooth endoplasmic reticulum are phospholipids and cholesterol. The Rough ER, on the other hand, synthesizes proteins.