Question

Q.1) Justify the statement – (5)

a. In Glycolysis pathway 2 ATP of energy released.

b. Plant respire in day time mostly.

c. Cardiac Mussels work through out the life.

d. Xylem is a conducting Chanel for plants

e. Guard cells work both in day and night time.​

Answer 1

Explanation:

a.

• Glycolysis occurs in the cytoplasm of the cell and is present in all living organisms.
• In this process, glucose undergoes partial oxidation to form two molecules of pyruvic acid.
• One ATP is produced by oxidation of PGAL and with inorganic phosphate to get converted into BPGA. The conversion  of BPGA to 3-phosphoglyceric acid (PGA), is also an energy yielding process; this energy is trapped by the formation of ATP.
• Another ATP is synthesised during the conversion of PEP to pyruvic acid.

b.

• Photosynthesis, takes place within the chloroplasts , whereas the breakdown of complex molecules to yield energy takes place in the cytoplasm and in the mitochondria.
• The breaking of the C-C bonds of complex compounds through oxidation within the cells, leading to release of considerable amount of energy is called respiration.
• Since photosynthesis require sunlight, plants mostly respire during day time.

c.

• Cardiac muscles are the muscles of heart.
• Many cardiac muscle cells assemble in a branching pattern to form a cardiac muscle.
• Based on appearance, cardiac muscles are striated.
• They are involuntary in nature as the nervous system does not control their activities directly.
• The refractory period of the cardiac muscles is high, so they do not undergo fatigue and work through out life.

d.

• The path of water movement is through the vascular bundles, more specifically, the xylem.
• Water and minerals, and food are generally moved by a mass or bulk flow system.
• Mass flow is the movement of substances in bulk from one point to another as a result of pressure differences between the two points.
• Bulk flow can be achieved either through a positive hydrostatic pressure gradient or a negative hydrostatic pressure gradient.

e.

• The immediate cause of the opening or closing of stomata is a change in the turgidity of the guard cells.
• The inner wall of each guard cell, towards the pore or stomatal aperture, is thick and elastic.
• Transpiration is affected by several external factors: temperature, light, humidity, wind speed.
• Hence the guard cells work both day and night depending upon the above factors.

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