Question

During light reactions in photosynthesis, the following are formed:
A. ATP and sugar
B. Hydrogen, $O_2$ and sugar
C. ATP, hydrogen and $O_2$
D. ATP, hydrogen and $O_2$ donor

Answer 1

Process used by plants and other organisms to convert the light energy coming from the sun to chemical energy is called photosynthesis. This occurs through cellular respiration and can be used for the metabolic activities of an organism. Those organisms which are capable of photosynthesis are known as autotrophs because they can make their own food without depending on any other organism.

Complete answer:
Process used by plants and other organisms to convert the light energy coming from the sun to chemical energy is called photosynthesis. This process occurs because of the presence of a chlorophyll molecule inside the cell. The formed chemical energy is stored as carbohydrates in the form of sugar and starch, which are synthesized with use of carbon dioxide and water. In most organisms, oxygen gas is evolved as a form of by-product.
The process of photosynthesis is divided into two parts:
Light reaction (light dependent reaction),
Dark reaction (light independent reaction).
Option A is incorrect because ATP (Adenosine Triphosphate) also known as the energy currency of a cell is an energy carrying molecule which is found in each and every living organism. The chemical energy formed during respiration by the breakdown of food molecules is captured by ATP only. It is released to fuel other chemical processes and to obtain energy. Essential structural component of living cells and source of energy in many organisms is sugar. They are basically of three types: monosaccharide, disaccharide and polysaccharide. In monosaccharide only one unit is present, in disaccharide two units are present and in polysaccharide more than two units are present.
Option B is incorrect because hydrogen is a gas with very less viscosity. It is a direct source of clean energy and is used in many food industries, refineries and in metallurgy. This gas is mainly used to test leaks in containers. During a light reaction an electron gets stripped from the water molecule and it frees the hydrogen and oxygen atoms. One free oxygen atom combines with another free oxygen atom to form a $O_2$ molecule which is released directly in air. Essential structural component of living cells and source of energy in many organisms is sugar. They are basically of three types: monosaccharide, disaccharide and polysaccharide.
Option C is correct because, in light reactions of photosynthesis, the products formed are ATP, hydrogen and $O_2$. This process occurs inside the thylakoid of chlorophyll which is dependent on light. Water breaks into $H_2$ and $O_2$ and produces NADPH and ATP. The electrons released are picked by the photo centre of photosystem II.
Hence the formed products are ATP, hydrogen and $O_2$.
Option D is incorrect because ATP (Adenosine Triphosphate) also known as the energy currency of a cell is an energy carrying molecule which is found in each and every living organism. The chemical energy formed during respiration by the breakdown of food molecules is captured by ATP only. Hydrogen is a gas with very less viscosity. It is a direct source of clean energy and is used in many food industries, refineries and in metallurgy. This gas is mainly used to test leaks in containers. During a light reaction an electron gets stripped from the water molecule and it frees the hydrogen and oxygen atoms.

Therefore option C is the correct answer.

Note:
Process used by plants and other organisms to convert the light energy coming from the sun to chemical energy is called photosynthesis. This occurs through cellular respiration and can be used for the metabolic activities of an organism. In light reactions of photosynthesis, ATP, hydrogen and $O_2$ are formed. This process occurs inside the thylakoid of chlorophyll which is dependent on light.