NCERT Class 11 Biotechnology Fifth Chapter Cellular processes Solution
NCERT Class 11 Biotechnology Chapter 5 Solution: Dear students Here in this post we are posted Fifth Chapter Cellular processes full exercise questions & answer by our arts teacher. This Solution is helpful for CBSE English medium students. Download this 5th Chapter Biotechnology solution & prepare your homework.
Q1. Give comparative account of the following:-
1.Apoptosis and Necros
Apoptosis is known as programmed cell death which has the property which enables the cell to die during development. This doesn’t occur randomly and it is highly controlled, energy dependent process. It is characterised by certain morphological and physiological change in cell.
Necrosis is the process when there is a physical injury due to this an immune response is triggered which result in inflammation of the injured area. Necrosis results in unregulated digestion of cell fragments. It is unplanned death of cells which occur as injury.
2.Autocrine and Paracrine signaling
Autocrine signalling is a signalling in which a cell secretes ligand, also possesses receptors specific for that ligand. The cancer cells, which are characterized by uncontrollable growth, hence they require a greater amount of growth factors for their proliferation.
Paracrine signalling is a signalling in which the communication between cells occur over relatively short distances. This is seen in the communication of neurons.
3.Anabolic and Catabolic pathways
In anabolic pathway, the larger and more complex molecules are synthesized from small molecules. These pathways are endergonic i.e. they consume energy.
In catabolic pathway, there is breakdown of larger molecules. These pathways are exergonic i.e. they release energy.
- Totipotent and Pluripotent cells
Totipotent cells are the cells which are able to differentiate into all possible cell types in an organism. This ability is known as totipotency. These cells exhibit highest differentiation potential and these cells can give rise to embryonic as well as extraembryonic cells.
Pluripotent cells are the cells which do not exhibit full potency i.e. they can’t produce all the tissues but can get differentiated into most tissues of the body.
Q2. Explain how stem cells are different from blood cells in terms of potency?
Ans- Stem cells are the cells which are unspecialized or undifferentiated cells and found to be present in organisms after attaining adulthood. Stem cells are unspecialized cells which divide to produce two daughter cells, in which one cell is stem cell and another cell gets differentiated. As compare to blood cells stem cells are considered as the potent cells because they give rise to any type of cells. The blood cells are multipotent cells which have limited range of tissues by which they can differentiate and they have lower cell differentiation potential.
Q3. How many mitotic divisions produce 64 cells out of a single cell?
Ans- In mitosis single cell produce two daughter cells by cell division. To produce 64 cells out of single cell there should be 6 mitotic divisions.
Q4. During cell division, assembly of mitotic spindle can be prevented by administration of drug called colchicine. Which stage of mitosis is most likely to be affected by this drug?
Ans- Colchicine is the drug which breaks the spindle fibres formed during cell division. This affects the metaphase stage most likely because in metaphase the spindle fibres are formed and the cells are in equatorial plate.
Q5. Match the following:-
1. Centromere | Holds the two sister chromatids together |
2. Kinetochore | Site of attachment of chromosomes to spindle fibres. |
3.Metaphase | Assembly of homologous chromosomes on metaphase plate. |
4. Zygotene | Pairing of homologous chromosomes. |
5. Pachytene | Crossing over between homologous chromosomes occur |
6.Meiosis 1 | Reductional division. |
7.Meiosis 2 | Equational division. |
Q6. How is cell migration is important for development of embryo?
Ans- Cell migration means the movement of cells from one place to another in the body. This occurs in unicellular and multicellular organisms. In some organisms it occurs under some conditions like to create layers in embryo during embryogenesis, organogenesis and regeneration to generate different organs. Cell migration play an important role in development of embryo. It play a fundamental role for developing morphological characteristics of embryo during gastrulation. The formation of embryonic layers in embryo has cell migration in organogenesis as well as formation of organs and tissue.
In case you are missed :- Previous Chapter Solution
Q7. What is significance of citric acid cycle?
Ans- Citric acid cycle is also known as Krebs cycle or TCA cycle. This is the process of metabolic reactions which include condensation, oxidation to form the end product. This cycle is sequence of reactions which occur in mitochondrial matrix. The reaction which oxidise acetyl the moiety of Acetyl Co-A and reduce NAD+ , this reoxidise through electron transport chain which is linked to the formation of ATP. In this cycle different enzymes condense the reaction to form end product. The end product formed is oxaloacetate in the mitochondrial matrix.
Q8. The first reaction in glycolysis is catalysed by which of following enzymes:
(C) Phosphofructokinase.
Q9. Which of the following statements regarding cell signalling is NOT true?
(C) ligands bind to receptors in a non specific manner.
Q10. Dark reaction in photosynthesis is named so because
(A) It occurs Independent of light energy.
Q11. Differentiate between cyclic and non cyclic phosphorylation.
Cyclic phosphorylation |
Non cyclic phosphorylation |
The process in which there is formation of ATP due to light induced cyclic flow of electron is called as cyclic phosphorylation. |
The process in which ATPs are synthesized by non cyclic electron flow is called as non cyclic phosphorylation. |
The PS1 is present in stromal lamellae or on the edge of the grana of thylakoid membrane. |
ATP is synthesized on CF1 subunit of ATP synthase by using ADP. |
ATP synthesis occur when there is back flow of proton. |
In this water oxidises and provide hydrogen ion as proton. |
Q12. Briefly explain Calvin’s cycle.
Ans- Calvin’s cycle takes place in the stroma of chloroplast. It has three main steps in the cycle :
- Fixation of CO2 into 3-phosphoglycerate:
This is the first step of the cycle in which carbon dioxide is fixed into stable organic intermediate. In this CO2 gets condensed to form 2 molecules with five carbon acceptor ribulose 1,5-bisphosphate and 3-phosphoglycerate is formed. 3 molecules of carbon are fixed to three molecules of ribulose 1,5-bisphosphate and form six molecules of 3- phosphoglycerate.
- Reduction of 3-phosphoglycerate to glyceraldehyde 3-phosphate:
This is a second step which is involved in reduction. In this step reactions are there which lead to reduction of 3-phosphoglycerate and form sugar. This require two molecules of ATP and two molecules of NADPH + H+ which is used in reduction of one CO2 molecule to be fixed.
- Regeneration of ribulose 1,5-bisphosphate from triode phosphatase:
This is a third step which is based on regeneration. For the flow of CO2 into carbohydrate, ribulose 1,5-bisphosphate should be regenerated. For this one ATP is used for phosphorylation to form ribulose-1,5 bisphosphate.
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