Photosynthesis in Plants

Compensation point is the value of a factor where the rate of photosynthesis is equal to the rate of respiration.  At this point, carbon dioxide released from respiration is equivalent to that which is taken up during photosynthesis. When the light intensity increases, the compensation point is reached. When light intensity is increased beyond the compensation point, the rate of photosynthesis increases proportionally until the point of light saturation is reached. Beyond light saturation point, the rate of photosynthesis is no longer affected by light intensity. Compensation point varies in different species of plants. It even varies in response to changes in temperature and other environmental factors.

The compensation point is the light intensity on the light curve for which the rate of photosynthesis is equal to the rate of respiration in the plant cell i.e., the rate of cellular fixation of Carbon dioxide through photosynthetic pathway is equal to the respiratory release of Carbon-dioxide and the release of Oxygen by photosynthesis is equals to the rate of consumption by respiration in a plant cell. At the compensation point, the organism is not building any biomass nor consuming any biomass.

About $1-5\%$ of incident solar energy or $2-10\%$ of PAR is captured by the photosynthetic organisms for the synthesis of organic matter(Gross primary productivity). Roughly $20\%$ of it is consumed in respiration so that net capture of energy(net primary productivity) is $0.8-4\%$ of incident radiation or $1.6-8\%$ of PAR.

The nutrient synthesized by plants through photosynthesis is carbohydrates. Plants are autotrophs and they synthesize their own food by the process of photosynthesis. During photosynthesis, they convert carbon dioxide and water in presence of sunlight and chlorophyll to produce carbohydrates (glucose) and oxygen. 

The major pigments present in algae is chlorophyll. It is a photosynthetic pigment. Apart from it, algae contain carotenoids and phycobilins pigments. Haemoglobin pigment is present in the red blood cells. It carries oxygen from the lungs to different parts of the body. Plasma is the colourless liquid part of the blood which contains all the components of blood except red blood cells, white blood cells and platelets.

So, the correct answer is ' Anthocyanin'.

The members of Rhodophyceae are commonly called red algae because of the predominance of the red pigment r-phycoerythin in their body. Apart from this, other major pigments found in them are chlorophyll a and chlorophyll d.

Transpiration results in loss of water in vapour form. Water vapours are a prominent green house gas, responsible for maintenance of temperature on earth.

Metabolism refers to series of reactions in which product of one reaction becomes reactant for the next one. It includes catabolism (degradative pathways) and anabolism (synthetic pathways). Digestion is the process in which complex compounds are broken down into the simpler form. Hence, option C is the correct answer. 

Bundle sheath cells in C4 plants are involved in the Calvin cycle (CO2 fixation) and are specialized for this purpose, similar to mesophyll cells in C3 plants. They do not have grana (in C4 plants) and are not involved in the initial CO2 fixation (which is done by PEP carboxylase in mesophyll).

Photosynthesis is the process by which green plants make their own food from carbon dioxide and water in the presence of sunlight. The prepared food is glucose. To prepare one molecule of glucose, by the process of photosynthesis six molecules of carbon dioxide and six molecules of water is required. Six oxygen molecule is released as a waste product. This oxygen is produced due to splitting of water by the process of photolysis during light reaction. So, the correct answer is option 'Oxygen'.

In physiology, respiration is defined as the movement of oxygen from the outside air to the cells within tissues, and the transport of carbon dioxide in the opposite direction. The physiological definition of respiration should not be confused with the biochemical definition of respiration, which refers to cellular respiration. The metabolic process by which an organism obtains energy by reacting oxygen with glucose to give water, carbon dioxide and 38 ATP (energy). Although, physiologic respiration is necessary to sustain cellular respiration and thus life in animals, the processes are distinct: cellular respiration takes place in individual cells of the organism, while physiologic respiration concerns the bulk flow and transport of metabolites between the organism and the external environment. 

Lenticels are involved in gaseous exchange between internal tissues and atmosphere. These are porous tissues present in periderm that are developed during secondary growth.