Tag: biology

Questions Related to biology

Channel proteins allow ions that would not normally pass through the cell membrane to go through the channel. What properties of the proteins are responsible for this? 

biology movement in and out of the cell transport of molecules osmosis and plasmolysis plant water relation

  1. The channels are often composed of charged or polar $R$ groups.

  2. The channels are often composed of hydrophobic $R$ group.

  3. $a$ and $b$

  4. None of these

Show answer
Correct Option: A
Explanation:

Facilitated diffusion, therefore, allows polar and charged molecules, such as carbohydrates, amino acids, nucleosides, and ions, to cross the plasma membrane. Two classes of proteins that mediate facilitated diffusion are generally distinguished.

So, the correct option 'The channels are often composed of charged or polar R groups'.

The movement of ions against the concentration gradient is

biology movement in and out of the cell transport of molecules osmosis and plasmolysis plant water relation

  1. Active transport

  2. Osmosis

  3. Diffusion

  4. All of the above

Show answer
Correct Option: A
Explanation:

Active transport is the movement of molecules across a cell membrane in the direction against their concentration gradient, i.e. moving from an area of lower concentration to an area of higher concentration. 

Osmotic theory for an active absorption of water was given by

biology movement in and out of the cell transport of molecules osmosis and plasmolysis plant water relation

  1. Thimann

  2. O. Hertwig

  3. Atkins and Priestley

  4. J. C. Bose

Show answer
Correct Option: C
Explanation:

There are two methods of water absorption active and passive. Active water absorption requires energy. Osmotic active absorption theory was advanced first by Atkins in 1916 and later on by Priestley, 1921, for the maintenance of high salt content in xylem channels.

Carrier ions like Na$^+$ facilitate the absorption of substances like 

biology movement in and out of the cell transport of molecules osmosis and plasmolysis plant water relation

  1. Fructose and some amino acids

  2. Amino acids and glucose

  3. Glucose and fatty acids

  4. Fatty acids and glycerol

Show answer
Correct Option: B
Explanation:

Absorption of glucose takes place with the help of a carrier protein that carries out the co-transport of glucose along with two sodium ions. Absorption of amino acids also takes place by a similar mechanism with the help of a sodium-dependent co-transporter. Absorption of fructose occurs by facilitated diffusion, and fatty acids and glycerol by a simple diffusion mechanism. 

So, the correct option is 'Amino acids and glucose'.

A student put five raisins each in two beakers A and B. Beaker A contained 50 ml of distilled water and beaker B had 50 ml of saturated sugar solution. After sometime, the student would observe that

biology movement in and out of the cell transport of molecules osmosis and plasmolysis plant water relation

  1. Raisins in beaker A were more swollen than those in beaker B.

  2. Raisins in beaker B were more swollen than those in beaker A.

  3. Raisins in both beaker A and B were equally swollen.

  4. Raisins in beaker A did not swell up at all.

Show answer
Correct Option: A
Explanation:

Raisins in the beaker A will swell as solution surrounding them is hypotonic in nature. Hypotonic solution contains lesser solute concentration. In such case, endosmosis will occur in which inward movement of the water molecules from the lower solute concentration to higher solute concentration through raisin covering. 
Raisins in the beaker B will shrink as solution surrounding them is hypertonic in nature. Hypertonic solution contains higher solute concentration. In such case, exosmosis will occur in which outward movement of the water molecules from the lower solute concentration to higher solute concentration through raisin covering. 

Transporting pull arise mainly from

biology movement in and out of the cell transport of molecules osmosis and plasmolysis plant water relation

  1. Roots

  2. Leaves

  3. Stems

  4. All

Show answer
Correct Option: B
Explanation:

As water is lost from the surface of the leaves due to transpiration a strong suction force is transmitted through the active mesophyll cells to the ends of the water column in the root. This is called transpiration pull. It caused the entire water column to be pulled upwards. When the rate of transpiration is very high and the rate of absorption is slow the water in the xylem elements of the leaf develops a state of tension.

So, the correct answer is B.

Which of the following does not operate in the carrier concept of active absorption of minerals?

biology movement in and out of the cell transport of molecules osmosis and plasmolysis plant water relation

  1. Electron transport

  2. Contractile protein

  3. Protein lecithin

  4. Ascending water stream

Show answer
Correct Option: D
Explanation:
Plants absorb minerals from the soil in the form of inorganic ions. The process of mineral absorption and water absorption are separate processes occur in plants. Water absorption takes place actively by root pressure whereas mineral absorption takes place actively with the help of carrier proteins.
So the correct answer is 'Ascending water stream'.

Mineral absorption is mostly

biology movement in and out of the cell transport of molecules osmosis and plasmolysis plant water relation

  1. Physical process

  2. Chemical process

  3. Active process

  4. Passive process

Show answer
Correct Option: C
Explanation:
Mineral absorption takes place in two phases: active absorption and passive absorption. It mostly occurs using active absorption phase because it is a fast process of mineral absorption, utilise energy and unidirectional. It is a biochemical process that occurs against the concentration gradient with the help of carriers and pumps.
So the correct answer is 'Active process'.

Which one is not connected with transport across the cell membrane?

biology movement in and out of the cell transport of molecules osmosis and plasmolysis plant water relation

  1. Osmosis

  2. Active transport

  3. Diffusion

  4. Surface tension

Show answer
Correct Option: D
Explanation:

(A) Osmosis is the movement of the solute molecule from lower concentration to higher concentration through a semi-permeable membrane.

(B) Active transport is the transport of molecules which is energy dependent.
(C) Diffusion is the movement of molecules from a higher concentration to lower concentration.
(D) Surface Tension is the elastic tendency of a fluid surface to cover the least possible surface area.
So, the correct answer is 'Surface Tension'.

Which of the following is correctly matched for diseases in humans?

biology body fluids and circulation cardiac disorders cardiac regulation and disorders the blood system

  1. Hypertension increase in sytolic blood pressure about 130-140 mm hg and diastolic blood pressure 90-100 mm hg.

  2. Arteriosclerosis hardening of arteries due to deposition of calcium salts resulting in plaque formation.

  3. Atherosclerosis inelastic arteries.

  4. All of the above.

Show answer
Correct Option: D
Explanation:

A. The systolic blood pressure is the pressure that develops in arteries when the ventricles contract and the diastolic pressure develops when the ventricles relax. The normal range of blood pressure is 120/80 mm Hg. In hypertension, the blood pressure elevates to 130-140 mm Hg systolic and 90-100 mm Hg diastolic pressure.

B. Arteriosclerosis occurs due to deposition of plaque in the arteries. This can occur due to deposition of calcium, cholesterol etc. It is linked with hypertension and Diabetes Miletus.
C. Atherosclerosis results due to building up of fatty deposits in arteries due to which they become inelastic. 
Hence, the correct answer is 'All of the above'.