Cell Membrane

Q.

Mention the functions of following:

Cell membrane

Q. The barrier which separates the protoplasm from the external environment is known as___.

1. plasma membrane
2. chlorophyll
3. ribosome
4. nucleus

Q.

Why the plasma membrane must be a bilayer?

Q.

The cell membrane has holes.

1. True
2. False

Q. The plasma membrane consists mainly of

1. Phospholipids embedded in a protein bilayer
2. Proteins embedded in a phospholipid bilayer
3. Proteins embedded in a polymer of glucose molecules
4. Proteins embedded in a carbohydrate bilayer

Q. Plasma membrane is selectively permeable because

1. Osmosis has to take place
2. The membrane is thin
3. It has pores in it
4. Both (a) and (c) in water

Q. Which one of the following is not a constituent of the cell membrane?

1. Phospholipids
2. Cholesterol
3. Glycolipids
4. Nucleic acids

Q. Gases like carbon dioxide and oxygen can move across the cell membrane.

1. True
2. False

Q. A cell observed under a microscope has circular DNA, 70S ribosomes, and chromatophores. The observed cell is

1. plant cell
2. protist cell
3. cyanobacterial cell
4. mycoplasma cell

Q.

‘Fluid mosaic model’ of plasma membrane was given by

1. Robertson

2. Gorter and Grendel

3. Singer and Nicolson

4. Danielli and Davson

Q.

The bilayer has a ________ layer sandwiched between it

1. Basic

2. Acidic

3. Hydrophilic

4. Hydrophobic

Q. Select the correct statement from the following regarding cell membrane:

1. Lipids are arranged in bilayer with polar heads towards the inner part
2. Fluid mosaic model of cell membrane was proposed by Singer and Nicholson
3. $N{a}^{+}$ and $K^{+}$ ions move across cell membrane by passive transport
4. Proteins make up 60 to 70% of the cell membrane

Q. Which of the following statement(s) is/are false regarding fluid mosaic model of cell membrane?

1. The cell membrane is composed of lipids bilayers with the proteins floating on it
2. The polar heads face towards the inside and the hydrophobic tails face towards the outer part
3. Peripheral proteins lie on the surface of membrane while the integral proteins are partially or totally buried in the membrane
4. The cell membranes also possess carbohydrate in addition to lipids and proteins

Q. According to widely accepted "Fluid mosaic model", the cell membranes are semi-fluid, where lipids and integral proteins can diffuse randomly. In recent years, this model has been modified in several respects. In this regard, which of the following statements is incorrect?

1. Proteins can also undergo flip -flop movements in the lipid bilayer
2. Many proteins remain completely embeded within the lipid bilayer
3. Proteins in cell membranes can travel within the lipid bilayer
4. Proteins can remain confined within certain domains of the membranes

Q.

‘Fluid mosaic model’ of plasma membrane was given by

1. Robertson

2. Gorter and Grendel

3. Singer and Nicolson

4. Danielli and Davson

Q.

Cell membranes are

1. Impermeable

2. Freely permeable

3. Selectively permeable

4. None of these

Q.

Which of the following processes does not involve osmosis?

I. Entry of water from soil into root

II. Movement of water between xylem elements.

III. Opening and closing of stomata

IV. Sleeping movement of leaves

V. Transport of water through root cortex

1. I $\&$ III

2. III, IV $\&$ V

3. III $\&$ II

4. II only

Q. Gases like carbon dioxide and oxygen can move across the cell membrane.

1. True
2. False

Q. According to the widely accepted theory "the fluid mosaic model", cell membranes are semi-fluid, where lipids and integral proteins can diffuse randomly. In recent years, this model has been modified in several aspects. In this regard, which of the following statements is incorrect?

1. Proteins in cell membranes can travel within the lipid bilayer
2. Proteins can also undergo flip-flop movements in the lipid bilayer
3. Proteins can remain confined within certain domains of the membranes
4. Many proteins remain completely embedded within the lipid bilayer

Q.

Which one of the following is a mismatch?

1. Cisternae – golgi

2. Cristae – mitochondrion

3. Thylakoids - chloroplast

4. Fluid mosaic model – cell wall

Q. The fluid mosaic model was proposed by Singer and Nicolson to explain the structure of

1. cell wall
2. cell membrane
3. glycocalyx
4. capsule

Q. Potato spindle tuber disease is caused by an organism which has:

Q. Which of the following are non-membrane bound organelles?

1. Nucleolus
2. Ribosomes
3. Centrosome
4. All of these

Q. The fluidity of membranes in a plant in cold weather may be maintained by

1. increasing the number of phospholipids unsaturated hydrocarbon tails
2. increasing the proportion of intergral proteins
3. increasing concentration of cholesterol in membrane
4. increasing the number of phospholipids with saturated hydrocarbon tails

Q. According to the widely accepted theory "the fluid mosaic model", cell membranes are semi-fluid, where lipids and integral proteins can diffuse randomly. In recent years, this model has been modified in several aspects. In this regard, which of the following statements is incorrect?

1. Proteins in cell membranes can travel within the lipid bilayer
2. Proteins can also undergo flip-flop movements in the lipid bilayer
3. Proteins can remain confined within certain domains of the membranes
4. Many proteins remain completely embedded within the lipid bilayer

Q. Viroids were discovered by

1. Diener
2. Ivanowsky
3. Stanley
4. Pasteur

Q.

Why cell membrane is called selectively permeable?

Q. Monograph gives a complete global information about a single taxon of any rank.

Q. The mosaic nature of the plasma membrane structure is because of

1. Glycolipids
2. Phospholipids
3. Cholesterol
4. Proteins

Q.

Name the membrane that allows solvent molecules to pass through it.

1. Semi-permeable membrane

2. Selectively permeable membrane

3. Impermeable membrane

4. Both A and B