Photosynthesis and Respiration Test - 6

Amphibians like frogs breathe through their skin when they are submerged in water. This is called cutaneous respiration. In the land, they breathe through their lungs. ∙ Gills are present in fishes. Trachea is the site of gaseous exchange in insects.  ∙ All mammals have lungs to breathe

In plants, carbohydrates are synthesised in the form of glucose by the process of photosynthesis in the chloroplast using the pigment chlorophyll. Chlorophyll molecules are present in and around the photosystems which are embedded in the thylakoid membranes of chloroplasts. Plants use carbon dioxide and water in presence of sunlight to synthesise glucose and release oxygen. There is no role of nitrogen. Thus the correct answer is option C.

The primary reason all living things need oxygen is to break down (or “burn”) food to release its stored energy to perform various life processes. This process is called cellular respiration. 

Our muscles generally respire aerobically. During heavy exercises, the demand for energy in these cells are high but the supply of oxygen to produce energy is limited. In such situations, the muscle cells turn to anaerobic respiration to fulfil the energy demands. The anaerobic breakdown of glucose produces lactic acid in muscles.

Water indirectly affects the process of photosynthesis by causing water stress due to its unavailability. It causes closing of stomata which further results in CO₂ unavailability and hence affecting photosynthesis.

During heavy exercise, fast running, cycling, walking for many hours or heavy weight lifting, the demand for energy is high but the supply of oxygen to produce the energy is limited. So, the heart rate increases to supply more oxygen and glucose to the respiring cells. Anaerobic respiration takes places in the muscle cells to fulfil the demand of energy.

Yeasts are single celled organisms. Yeasts can undergo both aerobic and anaerobic repsiration. during anaerobic respiration, yeasts produce alcohol. Glucose is broken down into ethanol and carbon dioxide with the release of energy. Lactic acid is produced in muscles when they respire anaerobically.

For the process of photosynthesis, oxygen is not required but is liberated as a by-product. \(\mathrm{CO}_{2}\) water and light are the main components required for the process and are even limiting factors. Thus, the correct answer is option (D).

Breathing involves the movement of both diaphragm and ribcage.

During inhalation, ribs move up and outwards and the diaphragm moves down. This movement increases the space in the chest cavity and air enters into the lungs.

During exhalation the ribs move down and inwards, while the diaphragm rises up. This reduces the size of the chest cavity and air is pushed out of the lungs.

Photosynthetic organisms, also known as photoautotrophs, are organisms that are capable of photosynthesis. Some of these organisms include higher plants, some protists, algae and bacteria.

Thus, the correct answer is 'Plants, algae and some bacteria.'

Transportation of food and waste other minerals takes place in the body of plants in the dissolved state. A large quantity of water gets evaporated from the plants as water vapour. It helps to water plants cool during hot weather.

Tracheas are tubes present in an insect and are the sites of gaseous exchange. Openings to these tubes are called spiracles. Oxygen rich air rushes through spiracles into the tracheal tubes, diffuses into the body tissue and reaches every cell of the body. Similarly carbon dioxide from the cells goes into the tracheal tubes and moves out through the spiracles. 

The respiratory organ present in fishes are known as gills. They breathe air that is dissolved in water through gills. Gills are well supplied with blood vessles for exchange of gases. When water passes over the gills, the dissolved oxygen in the water rapidly diffuses across the gills into the bloodstream.

Photosynthesis is a process utilized by plants to produce glucose using carbon dioxide, water and light energy. Thus light energy is converted into chemical energy and stored in the form of glucose. This glucose can be converted into ATP by the process of respiration as and when needed.

Hence the correct answer is 'Chemical energy'.

Aerobic respiration is the process of producing energy by breaking down glucose in the presence of oxygen. Carbon dioxide and water is also produced during this process.