Question Discussion & Solution

The correct answer is gain of oxygen

Concept:

Chemical Reactions:

• A process in which one or more compounds are formed as products completely different from the reacting substances is known as a chemical reaction.
• There is generally a change in heat, colour, or appearance when a chemical reaction takes place.
• The evolution of gas may also occur.
• A chemical reaction may be reversible or irreversible in nature.

Oxidation reaction:

• Oxidation Reaction refers to a reaction in which either the addition of Oxygen takes place or the removal of Hydrogen takes place.
• It can also be said as the process of loss of one or more electrons by atoms or ions.
• Example is:

Mg + O2 = Mg2O

Reduction Reaction:

• Reduction Reaction refers to a reaction in which either the addition of Hydrogen takes place or the removal of oxygen takes place.

• In the process of reduction, a chemical species also gains electrons.
• It is the reverse of the oxidation reaction.
• Example is:

H2 + F2 → HF

Explanation:

Oxidation is a chemical reaction that is characterized by 

• loss of electron
• addition of oxygen atom
• removal of the hydrogen atom 

The substance that undergoes oxidation is said to be oxidized.

The loss of electrons and an increase in the oxidation state are the characteristics of an oxidation reaction.

For example:

H2S + Cl2 → 2HCl + S

In this reaction, the chlorine is getting reduced to hydrochloric acid (HCl) on the addition of hydrogen provided by Hydrogen sulfide (H2S).

A storage unit is used to store information and instructions when they are not being used in memory.

Three kinds of storage devices are a flash drive, hard disks, and CD - ROM drives.

Data access time is the time taken by a computer, or a data storage device or medium, to respond to a user's request for data.

Typical access times for a CD-ROM drive, 200 milliseconds; hard drive, 15 milliseconds; Random Access Memory (RAM), 70 nanoseconds.

There is a trade-off among the three key characteristics of memory: namely, capacity, access time, and cost. A variety of technologies are used to implement memory systems, and across this spectrum of technologies, the following relationships hold:

• Faster access time, greater cost per bit
• Greater capacity, smaller cost per bit
• Greater capacity, slower access time

option(4)

CONCEPT:

• Solar cooker: It is a device that uses the energy of sunlight to heat or cook food
• Concave Mirror: Those mirrors have a reflecting surface as a curved inward that absorbs all the light coming towards them.
  • It is also known as a Converging mirror.
• Concave mirrors are used for solar energy storage in solar cookers.

EXPLANATION:

• A solar cooker contains a box made of insulating material, with its inner surfaces blackened. The top is closed by a glass sheet.

• Concave Mirror is used in solar cookers to absorbs all the light coming from the infinite which are brought together near at the focus, cause the production of lots of heat in it.
• The temperature at that point increases which heats and cooks the food placed at that point.
• The efficiency of this solar cooker can be increased by placing a plane mirror at some inclination with the glass top to enhance more trapping of sunlight. 

Explanation:

• The virus which infects the bacteria is called bacteriophage.
• Bacteriophage was discovered by Twort & Filix
• It was named bacteriophage by D. Herelle.
• A bacteriophage is generally a double-stranded DNA virus
• In QB - bacteriophage - ss RNA is present.
• In ϕ X 174 - bacteriophage - ss DNA is present.
• A bacteriophage is of two types- Non-infective phages and infective phage.

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Additional Information

• The animal virus was discovered by Loeffler & Frosch.

The correct answer is Bone-marrow.

Key Points

Red blood cell:

• Red blood cells (RBCs) are the most common type of blood cell and the vertebrate's principal means of delivering oxygen to the body tissues via blood flow through the circulatory system.
• RBC is formed in Bone Marrow.
• RBCs take up oxygen in the lungs, or in fish the gills, and release it into tissues while squeezing through the body's capillaries.
• The cytoplasm of erythrocytes is rich in hemoglobin, an iron-containing biomolecule that can bind oxygen and is responsible for the red color of the cells and the blood.
• Each human red blood cell contains approximately 270 million of these hemoglobin molecules.
• The cell membrane is composed of proteins and lipids, and this structure provides properties essential for physiological cell function such as deformability and stability while traversing the circulatory system and specifically the capillary network.

Additional Information

• Red blood cells are thus much more common than the other blood particles: there are about 4,000–11,000 white blood cells and about 150,000 - 400,000 platelets per microliter.
• Human red blood cells take on average 60 seconds to complete one cycle of circulation.
• The blood's red color is due to the spectral properties of the hemic iron ions in hemoglobin.
• Each hemoglobin molecule carries four heme groups; hemoglobin constitutes about a third of the total cell volume.
• The normal pH range of blood is between 7.35 to 7.45. This means that blood is naturally slightly alkaline or basic.