YASH CLASSES
THE FUNDAMENTAL UNIT OF LIFE
Q. 1. What
is eukaryotic cell ?
Ans.
A cell that contains membrane bound organelles in
its cytoplasm is called Eukaryotic
cell. A eukaryotic
cell has definite nucleus with nuclear
membrane.
Q.2.What
is nucleoid?
Ans.
Nucleoid. It is the nuclear region that contains a
single chromosome which is in direct contact
with
cytoplasm. Nucleoid is found in a
prokaryotic cell.
Q.3. Give two
examples of prokaryotic organisms.
Ans.
Bacteria and Cyanobacteria (earlier called blue green
algae) e.g., Nostoc are prokaryotic
unicellular organisms.
Q.4. What
is a prokaryotic cell ?
Ans.
A cell which lacks nuclear membrane, contain a single
chromosome and also lacks membrane bound
organelles.
Q.5.
What is cytoplasm?
Ans.
The part of protoplasm which remains after excluding
nucleus,
is known as cytoplasm. Cytoplasm contains
an aggregate molecule of various chemical
and cell
organelles. Most of the biochemical
reactions such as
protein synthesis, release of energy etc. take place in
cytoplasm or organelles present in the
cytoplasm.
Q.6.
List four major functions of a cell.
Ans. Functions of Cell:
(1) Synthesis of substances.
(2) Digestion (lysis) of substances.
(3)
Generation of energy for vital functions.
(4)Secretion.
Q.7.Differentiate
between prokaryotic cell and eukaryotic cell.
Ans.
Prokaryotic
Cell Eukaryotic Cell
1. Cell size is generally small 1. Cell is generally
large
(1-10 µm) (5-100 µm)
2. Nuclear region called 2. Nuclear material
is surrounded
nucleoid
and not surrounded by a nuclear membrane.
by a nuclear membrane
3. Only a single
chromosome 3. More than one chromosome
is
present. are present.
4. Nucleolus is absent. 4. Nucleolus is present.
5. Membrane bound cell 5. Cell organelles
bounded
organelles are absent. by membrane are
present.
6. Cell division by
fission or 6. Cell division mitotic or meiotic.
budding (no mitosis).
INTEXT
BOOK QUESTIONS
1. Fill in the
gaps in the following table illustrating
differences between prokaryotic and eukaryotic
cells.
Ans. Prokaryotic Cell
Eukaryotic
Cell
1.
Size: generally small 1. Size: generally
(1-10 μm) 1 µm = 10-6 m large (5-100 μm)
2. Nuclear region:
is poorly 2. Nuclear region: well-defined
defined due to absence and surrounded
of a
nuclear membrane by a nuclear membrane.
and
known as nucleoid.
3. Chromosome: single 3. More than one
chromosome.
4. Membrane-bound cell 4. Membrane bound
cell
organelles absent. organelles are
present.
Q.2. Can you name the two organelles we have
studied
that contain their own genetic.
Ans.
a. Mitochondria and b. Plastid
(chloroplast).
Q3. The organisation of a cell is destroyed
due to some
physical or chemical influence, what will
happen?
Ans.
Each cell has got certain specific cell organelles. Each cell
organelle
performs a special function, e.g., making of new
material,
removal waste from the cell, release of energy etc.
If the organization of a cell is destroyed,
the functioning of
the cell organelle will be disturbed, control
of the nucleus
will be lost. Ultimately cell die.
Q.4.Why are
lysosomes known as suicide bags?
Ans. A Lysosome is membrane bound bag
like which contains
powerful
enzymes. If lysosome burst, its enzymes eat up
(digest) other organelles of its own cell. Therefore,
they are
known as 'suicide bags'.
Q.5. Where are proteins synthesised inside the cell?
Ans. Ribosomes.