Photosynthesis and Respiration Test - 7

Photosynthesis is a chemical reaction that takes place inside a plant, producing food for the plant to survive. Carbon dioxide, water and light are all needed for photosynthesis to take place.

During photosynthesis, the plant uses the energy of sunlight and convert carbon dioxide and water into carbohydrates and oxygen. Thus, oxygen is released during photosynthesis.

So, the correct answer is 'Photosynthesis'.

Characteristics like intensity and quality of light affect the photosynthesis in plant. This in turn affects the growth and morphology of the plant. Monochromatic light reduces the growth in plants. Also, red and blue wavelengths of light have positive effect on photosynthesis. At high light intensity, the rate of photosynthesis decreases as it may damage the chlorophyll.

Thus, the correct answer is 'Intensity and quality.'

Chlorophyll is the light-absorbing pigment found in chloroplast. Since it is a light-absorbing pigment, it is also called as photoreceptor. It absorbs mostly blue light followed by red light hence it is green in color. It is of two types chlorophyll a and chlorophyll b. Thus the correct answer is option A.

Photosynthesis (Photo means light). Most plants are autotrophs (ability to make their own food) which utilize the light from the sun, water and minerals from the soil to make their food.  The leaves of the plants contain a pigment called chlorophyll (green color pigment) which requires the light for the synthesis/production of the food. Thus, the correct option is A.

Cytokinins are plant hormones that cause increased cell division by stimulating the process of mitosis. Hence they are not essential for opening stomata.

So, the correct option is 'Cytokinin'

Guard cells are normal plant cells that are kidney shaped.

Like all other plant cells, it also has a Nucleus, a large central vacuole and chloroplast for photosynthesis.

So the correct answer is 'All of the above'.

CO₂, H₂O are raw material for photosynthesis. Photosynthesis occurs in the presence of chlorophyll.

Opening and closing of stomata is related to turgidity and flaccidity of the cells when turgor pressure of the two guard cells changes, opening, and closing of stomata takes place. Opening and closing of stomata can take place in the process of transpiration but it is related to turgidity and flaccidity of cells. The opening of stomata is due to when water is freely available and the guard cells become turgid and closed when water availability is low and guard cells become flaccid.  

So the correct option is B.

Stomata are the major structure for exchange of gases like carbon dioxide in plants.

Root hair involves the exchange of water and minerals from the soil.

Lenticels are present on the barks of trees but their major function is to make available oxygen from the atmosphere for the cells in the stem to respire.

Hence the correct answer is 'Stomata'.

Since photosynthesis takes place in the chloroplast that has chlorophyll, the rate of photosynthesis is affected by the colour of light that is absorbed the best by the chlorophyll pigment. Chlorophyll absorbs blue and red light energies the best. The colour that has highest influence on photosynthesis thus is blue which is why many plant growers use blue lights to grow indoor plants. Red light is next best for photosynthesis. 

The leaves of a plant are green because the chlorophyll within them absorb all other wavelengths of light and reflects green light. In the absorption spectrum, it can be shown that red light and blue light are the most absorbed whereas the green light is most commonly reflected. Therefore minimum photosynthesis takes place in green light.

Photosynthesis is carried out by green plants to synthesize organic compounds. Raw materials of photosynthesis are water which plants absorb from soil and carbon dioxide which plants get from the atmosphere. During photosynthesis light energy in sunlight is converted into chemical energy present in bonds of organic compounds and oxygen is released as a by-product. If there is less rainfall, the rate of photosynthesis will decrease because water is one of the substrates used in the process of photosynthesis.

So, the correct answer is option B.

A stoma (stomata) is a tiny opening or pore that is used for gas exchange. They are found on the under-surface of plant leaves. Each stoma remains surrounded by two kidneys or bean shaped epidermal cells the guard cells. 

These adjust the size of the opening by opening or closing.

Air enters the plant through these openings. Also, water vapor goes into the atmosphere through these pores in transpiration. 

Stomata are the major structure for exchange of gases and water vapour with the atmosphere. Stomata release water vapour into the atmosphere in the process of transpiration.

Lenticels are present on the surface of the stem that provides a medium for gaseous exchange especially oxygen for respiration.

The epidermis is the upper outer layer of cells present on the plant. It doesn't provide significant exchange activity.

So the correct answer is 'Stomata'.

Stomata is surrounded by two highly specialized guard cells. Guard cells have cytoplasmic inclusions in the nucleus, chloroplasts, starch grains, mitochondria, endoplasmic reticulum, Golgi apparatus, and ribosomes. Hence, they are living cells. They regulate the rate of transpiration by opening and closing the stomata.  Thus, the correct answer is option D.

Guard cells are highly specialized epidermal cells that in pairs form stomatal pores in aerial organs of plants. Each pair of guard cells forms a pore through which water and CO22 exchange occurs. Guard cells modulate stomatal pore size by co-coordinating responses to environmental and physiological factors including light, temperature, Ca2+ and the plant hormone abscisic acid. These factors induce dynamic changes in the intracellular concentrations of inorganic and organic ions. Stomatal opening occurs by osmotic swelling of guard cells, caused by K+ uptake. Stomatal closure results from anion and K⁺ release from guard cells and conversion of malate to starch. 

Thus, the correct answer is option D.