Pteridophytes (ferns and their relatives) are the first terrestrial plants to possess vascular tissues (xylem and phloem) for water and nutrient transport. However, they do not produce seeds or flowers and reproduce via spores. Hence, they are called 'vascular cryptogams'. Bryophytes are called 'amphibians of the plant kingdom'.
Explanation:
The Fluid Mosaic Model of the plasma membrane was proposed by S. Jonathan Singer and Garth Nicolson in 1972. It describes the cell membrane as a dynamic, fluid structure composed of a phospholipid bilayer with globular proteins embedded or attached, moving laterally within the lipid matrix.
Consider the following statements about the pancreas:
1. It has both endocrine and exocrine functions.
2. Alpha cells secrete insulin.
3. Beta cells secrete glucagon.
Which of the above is/are correct?
Explanation:
Ethylene is a gaseous plant hormone that is widely known for its role in promoting the ripening of fruits. It increases the respiration rate during fruit ripening (climacteric rise) and breaks down cell walls, converting starches to sugars, making the fruit softer and sweeter. It is also involved in leaf abscission and the triple response in seedlings.
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