All Free Biology MCQs with Answers
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19844 questions · page 614 of 1985
6131. The ability to distinguish between two separate points/ objects is:
- A. Magnification
- B. Fractionation
- C. Centrifugation
- D. Resolution
Explanation: Resolution is the shortest distance between two points that a user can still see as separate images under the microscope
Correct answer: Resolution6132. If 15 mm size object is observed under light microscope using 5X eyepieces and 10X objective, its magnified image size will be:
- A. 250 um
- B. 50 um
- C. 750 um
- D. 500 um
Explanation: To calculate the total magnification of an object observed under a microscope, you need to multiply the magnification of the eyepiece (ocular lens) by the magnification of the objective lens. In this case, you're using a 5X eyepiece and a 10X objective lens. Total magnification = Eyepiece magnification × Objective magnification Total magnification = 5X × 10X Total magnification = 50X So, the object will be magnified 50 times under the given microscope setup. If the object's actual size is 15 mm, its magnified image size will be: Magnified image size = Actual size × Total magnification Magnified image size = 15 mm × 50X Magnified image size = 750 mm The magnified image size will be 750 mm.
Correct answer: 750 um6133. Shape of the maturing face of the golgi apparatus is?
- A. Biconcave
- B. Convex
- C. Spherical
- D. Concave
Explanation: The shape of maturing phase of the golgi apparatus is concave or the inner concave.
Correct answer: Concave6134. In which model do proteins float in membrane like icebergs in sea:
- A. Lock and key model
- B. Induced fit model
- C. Fluid mosaic model
- D. Lotka volterra model
- E. All of these
Explanation: As per the fluid mosaic model cell membranes have proteins as icebergs in a sea of lipids (lipid). Hence option C is correct.
Correct answer: Fluid mosaic model6135. A group of cells performing same function are known as:
- A. Organelles
- B. Tissues
- C. A system
- D. Both A and B
Explanation: The group of cells that perform the same function is called tissue (OPTION B). Many different tissues combine to form organs, that can perform multiple functions. Different organs combine to form a system. An organelle is a subcellular structure that performs specific functions.
Correct answer: Tissues6136. The cells are held together by a Ca-pectate layer are called as:
- A. Primary cell wall
- B. Secondary cell wall
- C. Middle lamella
- D. Tertiary cell wall
Explanation: The plant cell is surrounded by cellulosic cell walls. The cell walls of two adjacent cells are separated by middle lamella which literally means middle plate or middle membrane. Middle lamella is actually the cementing layer between two plant cells. It is absent on the outer surface. It ruptures to create intercellular spaces wherever required. It is formed of calcium and magnesium pectate.
Correct answer: Middle lamella6137. Lysosomes are also called:
- A. Suicide Sacs
- B. Chondriosome
- C. Storage organelle
- D. Dicytosome
- E. Power house of a cell
Explanation: Lysosomes are sphere-shaped sacs filled with hydrolytic enzymes that have the capability to break down many types of biomolecules. Lysosomes are known as suicide sacs of the cell because they contain lytic enzymes capable of digesting cells and unwanted materials.
Correct answer: Suicide Sacs6138. Which one of the following organelles is required for aerobic respiration?
- A. Nucleus
- B. Mitochondrion
- C. Endoplasmic reticulum
- D. Plastids
- E. Cytoskeletons
Explanation: Aerobic respiration consists of glycolysis, Calvin cycle, Kreb's cycle, and oxidative phosphorylation. All of these processes require the presence of Mitochondria.
Correct answer: Mitochondrion6139. The diagram shows an apparatus set up to investigate the effect of changing the concentration of glucose in the surrounding solution on the movement of molecules through a selectively permeable membrane (Visking tubing) in 15 minutes. As the concentration of glucose solution in the surrounding solution increases, which of the following statements are correct? Net diffusion of water increases. Glucose molecules reach an equilibrium quicker. There is less change in the volume of the surrounding solution. Net diffusion of glucose increases.
- A. I, II, III and IV
- B. I, II and IV only
- C. I and III only
- D. II and III only
Explanation: Looking at the diagram, it is apparent that increasing glucose concentration in the surrounding tube will decrease the difference in the concentration of glucose between the surrounding liquid and inside the visking tubing. As there is less concentration gradient, the net diffusion of water would decrease so statement I is incorrect. The time to reach equilibrium would decrease as there is less difference in concentration of glucose, so statement II is correct. As the concentration gradient is less, less net movement of water would be needed to reach equilibrium, so volume would also change less, hence statement III is correct. There is no movement of glucose molecules, so statement IV is incorrect.
Correct answer: II and III only6140. Which of the following cell organelles involved in the synthesis of cell wall and middle lamella?
- A. Endoplasmic reticulum
- B. Golgi apparatus
- C. Lysosomes
- D. Peroxisomes
Explanation: The Golgi and plasma membranes are the two main sites where constituents of cell wall are synthesized. The Golgi body is also known as Golgi apparatus. It synthesizes vesicles which then fuse to form the middle lamella as shown below.
Correct answer: Golgi apparatus