10 – Cell and Cell Organelles
Q.
1 Who gives me the colour? (Select the correct option)
Column 'A' Column 'B'
(1)
Red tomato (a)
Chlorophyll
(2)
Green leaf (b) Carotene
(3)
Carrot (c)
Anthocyanin
(4)
Violet (d)
Lycopene
Ans.
(1) Red tomato - Lycopene
(2)
Green leaf - Chlorophyll
(3)
Carrot - Carotene
(4)
Violet - Anthocyanin
Q.
2 Find the odd one out by giving suitable
reasons :
(1)
Nucleolus, mitochondria, plastids, endoplasmic reticulum
(2)
DNA, Ribosomes, Chlorophyll
Ans.
(1) Nucleolus. (All the others are cell organelles but nucleolus is not a cell
organelle present in cytoplasm.)
(2)
Chlorophyll. (DNA and Ribosomes are present in plant as well as in animal
cells. Chlorophyll is present only in plant cells.)
Q.
3 Who am I?
(1)
I am ATP producing factory.
(2)
I am single layered, but maintain cellular osmotic pressure.
(3)
I support the cell, but I am not cell wall. I have a body resembling net. (4) I
am chemical factory of the cell.
(5)
Leaves are green because of me.
Ans.
(1) Mitochondria
(2)
Vacuole
(3)
Endoplasmic reticulum
(4)
Chloroplasts in case of plant cells can be called chemical factory as they
synthesise carbohydrates. Ribosomes also synthesise proteins, so those can also
be called chemical factory. Golgi complex is secretory in function, hence it
can be also called factory. Mitochondria though mainly referred to as
powerhouse of the cell, it is also mentioned as chemical factory by some authors.
(5)
Chloroplast.
Q. 4 What would have happened? If...
(1)
RBCs had mitochondria.
Ans.
Mitochondria continuously carry out oxidation and form energy inside the cell.
They produce energy rich compound, ATP. In this process, they utilize
carbohydrates, fats and proteins present in the cell. If RBCs has mitochondria,
they would have used oxygen for this purpose than carrying it to all the cells
of the body. The cells would not have obtained oxygen.
(2)
There had been no difference between mitochondria and plastids.
Ans.
Mitochondria carry out oxidation of carbohydrates, fats, etc. with the help of
enzymes. Plastids are synthesising carbohydrates with the help of solar energy
and chlorophyll. Both the cell organelles have their own sets of different
enzymes as per their role. If there would have been no difference between
mitochondria and plastids, the specific functions would not have been taken
place.
(3) Genes had been
absent on the chromosomes.
Ans.
Genes are functional segments on the chromosomes which are responsible for
transmitting the hereditary information is synthesis process also The protein
initiated due to genes. If genes were absent these processes will be ended.
(4) Plasma membrane
had not been selectively permeable.
Ans.
Selectively permeable membrane allows some substances to enter the cell. while
prevents other unwanted or harmful substances. If plasma membrane would not
have been selectively permeable, there would be no control over entry and exit
of any substances. The process of osmosis
would
also be erroneous in such case.
(5) Plants lacked
anthocyanin.
Ans.
If plants lacked anthocyanin, no part of the plant would display purple or blue
colour. Anthocyanin attracts the insects for pollination and seed dispersal. These
processes will be affected due to lack of anthocyanin. These pigments are also
sala to be protective in nature for the plant. Thb protection will not be given
to the plant in absence of anthocyanin.
Q.
11 Give functions:
(1) Plasma membrane.
Ans.
Plasma membrane acts as selectively permeable membrane. It allows entry of
those useful substances which are needed for the cell. It does not allow entry
of the harmful and unwanted substances.
(2)
Plasma membrane keeps the homeostasis in the cell. The cell is kept in steady
state even if the external environment changes.
(3)
Plasma membrane is responsible for processes of endocytosis and exocytosis.
(4)
The processes of diffusion and osmosis are possible only due to plasma
membrane.
(5)
In animal cells, plasma membrane is the outermost protective covering of the
cell.
(2) Cytoplasm.
Ans.
(1) All the cell organelles are spread in the cytoplasm of a cell.
(2)
The cytoplasm is the medium for many cellular chemical reactions.
(3)
The cytosol which is the part of cytoplasm other than cell organelles stores
many vital substances like amino acids. glucose, vitamins, etc.
(4)
Cytosol also helps in the cellular movements.
(3) Nucleus.
Ans.
(1) Nucleus is the controlling centre for the entire cell.
(2)
It controls all metabolic activities of the cell.
(3)
The cell division is possible due to the
(4) The chromosomes present in the nucleus carry the
genes. These genes are responsible for the transmission of hereditary
characters from parental generation to the next generations.
(4) Lysosome.
Ans.
(1) Lysosome helps in the destruction of attacking viruses and bacteria and
thereby help in the immune response.
(2)
Lysosomes act as demolition squads. They destroy worn out cellular organelles
and organic debris. This process is called autolysis which means
self-destruction.
(3)
They are also called suicide bags as in a worn out, damaged or old cell,
lysosomes automatically burst. The lytic enzymes present in the lysosome digest
their own cells.
(4)
Lysosomes can digest stored proteins, fats during starvation.
(5) Vacuole.
Ans.(1)
Vacuoles maintain the osmotic pressure of the cell.
(2)
Various metabolic byproducts and end products such as glycogen, proteins,
water, etc. are stored in the lysosome.
(3)
In food vacuole of amoeba, the food is temporarily stored till digestion. In
other animal cells, vacuoles can store waste products and food.
(4)
Vacuoles of plant cells can provide turgidity and rigidity as it contains good
amount of cell sap.
