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Previous Chapter 4 | Next Chapter 6
Q1. Make a comparison and write down ways in
which plant cells are different from animal cells.
Answer:
|
Animal Cell
|
Plant Cell
|
|
Animal cells do not have cell wall
|
Plant cell have
cell wall made up of cellulose
|
|
It does not have chloroplast
|
It contains
chloroplast
|
|
They contain small
vacuoles
|
Contain large
vacuoles
|
|
Have centro-some
|
Does not have
centrosome
|
Q2. How is prokaryotic cell different from a
eukaryotic cell?
Answer:
|
Prokaryotic cell
|
Eukaryotic cell
|
|
These cell are
small in size (1-10um)
|
Eukaryotic cell
are larger than prokaryotic cells (5-100 um)
|
|
Nuclear region in
not surrounded by nuclear membrane
|
Nuclear material
surrounded by a nuclear membrane
|
|
They have single
chromosome
|
More than one
chromosome
|
|
Nucleolus is
absent
|
Nucleolus is
present
|
|
Membrane bound
cell organelles are absent
|
Membrane bound
cell organelles are present
|
|
Division of cell
happens by fission or budding
|
Cell division
happens by mitotic mode
|
Q3. What would happen if the plasma membrane
ruptures or breakdown?
Answer: Plasma membrane is a selectively
permeable membrane. If the plasma membrane is ruptured then the cytoplasm will
come in direct contact with the surrounding medium and the act of selection
will stop.
Q4. What would happen to the life of a cell if there
was no Golgi apparatus?
Answer:
If the cell does not have Gogli apparatus then
the life of the cell will reduce. In the absence of Gogli apparatus the
materials synthesized in the endoplasmic reticulum will not be carried to
intracellular and extracellular targets. The lysosomes will not be formed and
due to all this various enzymes and hormones will not form that helps in the
excretion of waste matter.
Q5. Which organelle is known as the powerhouse of
the cell? Why?
Answer:
Mitochondria are called as the powerhouse of the
cell. The energy produced by the mitochondria is stored in ATP molecules and
used in several life processes.
Q6. Where do the lipids and proteins constituting
the cell membrane get synthesized?
Answer:
They are synthesized in the endoplasmic
reticulum.
Q7. How does amoeba obtain its food?
Answer:
Amoeba envelopes its prey and through food vacuole its absorbs its food.
Q8. What is osmosis?
Answer:
The movement of water molecules through a
selectively permeable membrane from an area of higher concentration to an area
of lower concentration is called osmosis. The movement of water depends on the
substances dissolved in it.
Q9. Carry out the following osmosis experiment:
Take four peeled potatoes halves and scoop each
one out to make potato cups. One of these potato cups should be made from a
boiled potato. Put each potato cup in a trough containing water. Now,
a. keep cup A empty
b. put one teaspoon salt in B
c. put one teaspoon salt in cup C
d. Put one teaspoon sugar in boiled potato cup D.
Keep these for four hours. Then observe the four
potato cups and answer the following:
a. Explain why water gathers in the hollowed portion B and C
b. Why is potato A necessary for this experiment
c. Explain why water does not gather in the hollowed out portion of A and D.
Answer:
a. The water will collect inside the cups B and C. The inside of the cups B
and C is filled with sugar and salt respectively and the outside of these cups is
in contact with water. Since the concentration of water is more outside than
inside the cups, due to osmosis the water will move inside the cup through the
cell membrane which is selectively permeable.
b. The cup A is important to this experiment as no movement of water takes
place in cup A. It shows that no osmosis takes place when solution with equal
concentration is on both the sides of the permeable membrane.
Water does not collect in the cup A (which is empty
)because the concentration is equal on both the sides and hence no osmosis
takes place. Whereas in the case of boiled cup D, the cells are dead after
boiling and hence the cell membrane is no longer selectively permeable and thus
no osmosis takes place. Previous Chapter 4 | Next Chapter 6
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