1.
How many classes of lipids are contained in the cell membrane?
Correct Answer
A. 3
Explanation
The cell membrane is composed of various types of lipids, including phospholipids, cholesterol, and glycolipids. These lipids are arranged in a bilayer structure, with hydrophobic tails facing inward and hydrophilic heads facing outward. Therefore, the correct answer is 3, as there are three main classes of lipids present in the cell membrane.
2.
Which of these is not an amphipathic lipid?
Correct Answer
D. pHospHolipids
Explanation
Phospholipids are not an amphipathic lipid because they have a polar head and two nonpolar tails. Amphipathic lipids have both hydrophilic and hydrophobic regions, allowing them to interact with both water and lipid environments. Amyloids, sterols, and glycolipids all have both hydrophilic and hydrophobic regions, making them amphipathic lipids.
3.
How many amphipathic lipids exist?
Correct Answer
C. 3
Explanation
There are three types of amphipathic lipids. Amphipathic lipids have both hydrophobic and hydrophilic regions, allowing them to interact with both water and lipid molecules. The three types of amphipathic lipids are phospholipids, glycolipids, and cholesterol. Phospholipids are the most common type and make up the majority of the lipids in cell membranes. Glycolipids contain a carbohydrate group and are found on the outer surface of the cell membrane. Cholesterol is a lipid that helps maintain the fluidity and stability of the cell membrane. Therefore, the correct answer is 3.
4.
Which of these account for over 50% concentration in lipids concentration in the membrane?
Correct Answer
D. pHospHolipids
Explanation
Phospholipids account for over 50% concentration in lipids concentration in the membrane. This is because they are the main component of the lipid bilayer that forms the cell membrane. Phospholipids have a hydrophilic (water-loving) head and hydrophobic (water-hating) tails, which allows them to arrange themselves in a double layer, with the hydrophilic heads facing the aqueous environment both inside and outside of the cell, and the hydrophobic tails facing each other in the interior of the membrane. This arrangement provides stability and fluidity to the cell membrane, making it crucial for its structure and function.
5.
How many lipid percentage does the membrane have?
Correct Answer
B. 30%
Explanation
The correct answer is 30%. The lipid percentage in the membrane refers to the proportion of lipids present in the membrane compared to other components. In this case, the membrane has 30% lipids, indicating that lipids make up 30% of the total composition of the membrane.
6.
What area of the living cells does the cell membrane surround?
Correct Answer
B. Cytoplasm
Explanation
The cell membrane surrounds the cytoplasm, which is the gel-like substance inside the cell that contains various organelles and is responsible for many cellular processes. The cell membrane acts as a protective barrier, regulating the movement of substances in and out of the cell, and maintaining the integrity of the cell's internal environment.
7.
Which of these is a transport mechanism in the membrane?
Correct Answer
A. Osmosis
Explanation
Osmosis is a transport mechanism in the membrane. It is the movement of water molecules from an area of lower solute concentration to an area of higher solute concentration, through a selectively permeable membrane. This process helps maintain the balance of water and solutes inside and outside of cells.
8.
What is the process by which cells absorb molecules?
Correct Answer
A. Endocytosis
Explanation
Endocytosis is the process by which cells absorb molecules. It involves the formation of a vesicle around the molecules outside the cell, which then fuses with the cell membrane and brings the molecules into the cell. This process is important for the uptake of nutrients, hormones, and other substances by cells. Exocytosis, on the other hand, is the opposite process where molecules are released from the cell. Photosynthesis is the process by which plants convert sunlight into energy. Diffusion is the passive movement of molecules from an area of higher concentration to an area of lower concentration.
9.
Which of these is not part of a cell membrane‘s structure?
Correct Answer
D. Membrane model
Explanation
The correct answer is "Membrane model". This is because the other three options - Membrane polarity, Lipid bilayer, and Fluid mosaic model - are all components or concepts related to the structure of a cell membrane. The membrane model, on the other hand, is not a recognized term or concept in the context of cell membrane structure.
10.
Which of these is a cell membrane not made of?
Correct Answer
D. Membra
Explanation
The given options are Caveola, Postsynaptic density, Podosome, and Membra. Among these options, the cell membrane is not made of Membra. The other options, Caveola, Postsynaptic density, and Podosome, are all structures that are found within or associated with the cell membrane. Therefore, the correct answer is Membra, as it is not a component of the cell membrane.