1. What is endocytosis? State its significance. Why is it found in animals only?
2. If you are provided with some vegetables to cook, you generally add salt into the
vegetables. After adding salt, vegetables release water. Why?
3. How is bacterial cell different from onion peel cell?
4. Draw neat and well labeled diagrams of bacterial cell, plant cell and animal cell.
5. Why does the skin of your finger shrink when you wash clothes for a long time?
6. Differentiate between Parenchyma, collenchyma and sclerenchyma.
7. Why is the epidermis present as thick waxy coating of cutin in desert plants?
8. Why are xylem and phloem called as complex tissues? How are they different from e
other?
9. Draw a well labeled diagram of meristematic tissue.
10. Give reasons:
a. Branches of a tree move and bend freely in high wind velocity.
b. It is difficult to pull out the husk of a coconut.
Answers
Answer:
1. What is endocytosis? State its significance. Why is it found in animals only?
Endocytosis is found only in the animal cells because animal cells lack a cell wall outside the plasma membrane. It is not associated with plant cells. They get their nutrients mostly by osmosis and plasmodesmata.
2. If you are provided with some vegetables to cook, you generally add salt into the
vegetables. After adding salt, vegetables release water. Why?
On adding salt, the external medium is made hypertonic, i.e., concentration of water is lowered as compared to the concentration of water inside the cell. Thus, water is released from the vegetables due to exosmosis (water molecules goes out of the cell resulting in shrinkage of cell).
3. How is bacterial cell different from onion peel cell?
4. Draw neat and well labeled diagrams of bacterial cell, plant cell and animal cell.
They are the prokaryotic cells. They do not have organelles bounded with membranes as they do not have a complex body. They even lack membrane around the nucleus. Onion cell is a eukaryotic cell with well-defined membranes around the organelles.
Answer:
1. Endocytosis: Endocytosis definition and purposes. Endocytosis is the process by which cells take in substances from outside of the cell by engulfing them in a vesicle. These can include things like nutrients to support the cell or pathogens that immune cells engulf and destroy
Endocytosis is found only in the animal cells because animal cells lack a cell wall outside the plasma membrane. It is not associated with plant cells. They get their nutrients mostly by osmosis and plasmodesmata.
2. You generally add salt into the vegetables during cooking process. After adding salt, vegetables release water. ... Thus, water is released from the vegetables due to exosmosis (water molecules goes out of the cell resulting in shrinkage of cell).
3. They are the prokaryotic cells. They do not have organelles bounded with membranes as they do not have a complex body. They even lack membrane around the nucleus. Onion cell is a eukaryotic cell with well-defined membranes around the organelles.
5. When we wash clothes, our hands are exposed to water for a long time. Our hands behave as a hypertonic solution and the outside of our hands behave as a hypotonic solution. ... So actually the water is not absorbed here just leaving and thus it shrinks.
6. Parenchyma cells are found in every soft part of the plant, but collenchyma cells are found in specific part of the plant like leaves, stems, and petioles, whereas sclerenchyma cells are found in mature parts of the plants or trees.
Parenchyma has a thin cell wall of their cells, and are made up of cellulose.
7. Desert plants are subjected to high temperatures and scarcity of water. To prevent the loss of water through transpiration or evaporation desert plants have leaf modified into spines and the epidermis is covered with a thick waxy coating.
8. Xylem and phloem are an example of complex permanent tissues. These tissues are named so because they are made up of more than one type of cells and all these different types of cells coordinate to perform the same function. They ultimately achieve the same goal despite their different structures and function.
10.a) Collenchyma is present at junction of a branch. Collenchyma provides rigidity with flexibility. Due to this, branches of tree move and bend freely in high wind velocity.
b) Intercellular spaces in sclerenchyma are absent because they have lignin around which makes them hard. - Sclerenchyma in plants supports tissue composed of any of various kinds of hard woody cells. - So, it is difficult to pull out the husk of a coconut tree due to the Presence of Sclerenchyma