NCERT Class 11 Biotechnology Second Chapter Cellular Organelles Solution
NCERT Class 11 Biotechnology Chapter 2 Solution: Dear students Here in this post we are posted Second Chapter Cellular Organelles full exercise questions & answer by our arts teacher. This Solution is helpful for CBSE English medium students. Download this 2nd Chapter Biotechnology solution & prepare your homework.
Q1. The Fluid Mosaic model was proposed by
(d) Singer and Nicolson.
Q2. Ribosomes are composed of
(b) rRNA and proteins.
Q3. Tonoplast is
(c) a membrane covering the vacuoles.
Q4. Describe the various mechanisms of transport across plasma membrane with the help of labelled diagram.
Ans- There are two mechanisms of transport across the plasma membrane they are as follows:
1.) Passive transport- Passive transport is a membrane transport in which the molecules move passively without any expenditure of energy across the membrane along concentration gradient. This passive movement occurs by the process of diffusion and osmosis. In passive transport the charged or uncharged molecules cannot cross plasma membrane by simple diffusion. For the movement of such molecules carrier proteins and channel proteins are facilitated, this is known as facilitated movement. In passive transport one of the critical channel protein called aquaporin’s is used for transport of water in plant and animal cell across the plasma membrane.
2.) Active transport- Active transport is a membrane transport in which the molecules are transported against the concentration gradient which require utilization of energy from ATP molecules. E.g. Na+-K+ pump. In active transport some are the ATP independent molecules, which are transported against the concentration gradient without using any energy from ATP hydrolysis. Active transport of ions, sugars, and amino acids using energy derived from the Na+ gradient is a coupled transport.
Q5. Match the following:-
Column 1 | Column 2 |
Nucleolus | Synthesis of rRNA |
Mesosome | Membranous extension of plasma membrane |
Vacuoles | Storage and structural support |
Cristae | Infoldings of inner mitochondrial membrane |
Ribosomes | Protein synthesis |
Thylakoid | Membranous sacs in chloroplast |
Cisternae | Disc shape sacs in Golgi |
Q7. State importance of cell wall in prokaryotic cell.
Ans – Cell wall is a protective layer for the cell which not only determines the shape of cell but also protects the cell from bursting. The prokaryotic cells have two types of cell wall which are know as gram negative and gram positive cell wall in bacterial cell wall. The bacterial cell wall is a sturdy covalent shell of linear peptidoglycan chain which is cross linked by tetrapeptides. The cell wall in prokaryotes especially in bacteria has the cell wall covered with heavily glycosylated proteins called as glycosylic. This is involved in cell to cell interaction. Gram positive bacteria has a thick cell wall with the single plasma membrane and gram-negative bacteria has thin cell wall with dual plasma membrane.
Q8. A eukaryotic cell contains organelles which may be bound by a single-membrane; double-membrane or nonmembrane bound organelles. Classify the various eukaryotic organelles into these three types.
Ans- The eukaryotic cell has all cell organelles. In this some organelles are bounded by single membrane and some are bounded by double membrane, some are without membrane also present in the cell. According the membrane bounded the cell organelles are classified as below:-
- Bounded by single membrane- The organelles bounded by single membrane are vacuole, lysosome, Golgi apparatus and endoplasmic reticulum.
- Bounded by double membrane- The organelles bounded by double membrane are nucleus, mitochondria and chloroplast.
- Nonmembrane organelles- The organelles which don’t have membrane they are non membrane organelles. Ribosomes and cytoskeleton are non membrane organelles.
Q9. Mention different types of vacuoles.
Ans- There are different types of vacuoles which are given below:
- Central vacuoles
- Lytic vacuoles
- Protein storage vacuoles
- Storage vacuoles
- Fungal vacuoles
- Food vacuoles
- Contractile vacuoles.
Q10. Peroxisomes share similarities as well as differences with mitochondria and chloroplast. Comment?
Ans- Peroxisomes are the organelles which are small and bounded with membrane. These are involved in energy metabolism in cell by which they serve as a site for enzymes involved in metabolic reaction. These share similarities as well as differences with mitochondria and chloroplast in terms of assembly and replication i.e. fission, they are derived from endoplasmic reticulum and replicate by fission.
Q11. What are glyoxysomes? Where are these present? Mention their functions.
Ans- Glyoxysomes are the specialized peroxisomes. These glyoxysomes are found in fungi and other higher plants especially found in the fat storage tissues in the
germinating seeds. It functions in conversion of lipids into glucose. These contain all enzymes necessary for fatty acid oxidation, glyoxylate cycle and gluconeogenesis.
In case you are missed :- Previous Chapter Solution
Q12. Cell is structural and functional unit of life. Justify the statement.
Ans- We humans do many tasks at a time in many ways in our day to day life. The tasks like food digestion, sending electrical messages to nerves, pumping blood from the heart, circulating nutrients, synthesising proteins, filtering urine and many more. These tasks are done due to the cells in our body which functions according their structure. So the cell is considered as structural and functional unit of life.
Q13. Distinguish between:-
- Cilia and Flagella-
Cilia | Flagella |
Cilia are smaller in size and present in large number. | Flagella are larger in size and typically vary from one or two in number. |
These occurs throughout the surface of cell. | Flagella occurs at one end of cell. |
The size of cilia is upto 5-10 micro meter | The size of flagella is up to 150 micrometre. |
It moves in co-ordinated rhythm and it shows sweeping movement. | It moves independently and show undulatory movement. |
- Primary and secondary cell wall:-
Primary cell wall | Secondary cell wall |
Primary cell wall is thin layer cell wall. | Secondary cell wall is thick and rigid layer. |
This is surrounded to growing cell in plants. | It is formed between primary cell wall and plasma membrane. |
The primary cell wall has scope for cell expansion. | In secondary cell wall there is deposition of lignin. |
- Lysosomes and Vacuoles:-
Lysosomes | Vacuoles |
Lysosomes are small spherical vesicles. | Vacuoles are membrane bound organelles found in cytoplasm. |
The size of lysosomes is approximately 0.2-0.5 micron diameter. | The size and number of vacuoles varies per plant. |
They are bounded by single membrane containing hydrolytic enzymes. | Vacuoles function in storage and structural support and recycling. |
Lysosomes carry out intracellular digestion in a variety of circumstances. | Vacuoles are empty sacs which lack the cytoplasmic material. |
- Microtubules and Actin filaments:-
Microtubules | Actin filaments |
Microtubule is composed of globular protein called tubulin | Actin filament is found or observed in skeletal muscle. |
Microtubules are hollow, rodlike structure. | It plays important role in muscles contraction. |
Tubulin protein undergo polymerization to form a protofilament. | Actin filaments are mostly found closer to plasma membrane. |
It may contain 10-15 protofilaments. | These provides strength to the cell. |
5.Active and passive transport:-
Active transport | Passive transport |
The transport of molecules to the membrane against the concentration gradient is called as active transpor | The transport of molecules to the membrane along the concentration gradient is called as passive transportt. |
In this transport molecules utilise energy from ATP molecules. | This passive movement occurs by process diffusion and osmosis. |
Some molecules are ATP independent molecules. | Some movement of molecules is facilitated by carrier proteins. |
In case you are missed :- Next Chapter Solution