class 9 Holiday home work(work sheet)

1	Name the cell organelle which is termed as powerhouse of the cell.	1
2	Identify the single celled organisms from the following: Cockroach, Chlamydomonas, snake, mosquito, bacteria	1
3	Write any two differences between prokaryotic and eukaryotic cells.	1
4	When a living plant cell loses water through osmosis, there is contraction of the contents of the cell away from the cell wall. What is this phenomenon called?	1
5	What is the chemical composition of cell wall in plants and fungi?	1
6	Name the functional unit of DNA that carries genetic information.	1
7	Why is nucleus called “director of the cell”?	1
8	Name the cell organelle which is able to destroy a damaged cell.	1
9	In which parts of the plant are chromoplasts found ?	1
10	What is plasmolysis?	1

11	A plant cell is placed in a hypotonic solution. What will happen? Will the cell burst? Why or why not ?	2
12	List two main functions of plasma membrane.	2

13	Draw the diagram of a plant cell and label any three parts which make it different from an animal cell.	3
14	Distinguish between hypotonic solution, isotonic solution and hypertonic solution.	3
15	What is the difference between plasma membrane and cell wall? Give the functions of each one. OR State three differences between cell membrane and cell wall.	3
16	Define the following terms: Protoplasm, cytoplasm, nucleoplasm	3
17	Grass looks green, papaya appears yellow. Which cell organelle is responsible for this?	3
18	Differentiate between diffusion and osmosis.	3
19	Name: (a) An organelle which has its own genetic material (b) An organelle rich in digestive enzymes (c) Nucleic acid present in nucleus of cell	3

20	What are the main functions of each of the following cell components? (a) Plasma membrane (b) Chromosomes (c) Lysosomes (d) Ribosomes (e) Nucleus (f) Mitochondria (g) Nucleolus (h) Cell wall (i) Chloroplast ( j) Peroxisomes	5

class x Holiday home work (work sheet)

1	Name the component of blood that helps in the formation of blood clot in the event of a cut.	1
2	Which pigment is responsible for the transport of nutrients, respiratory gases, metabolites, hormones and waste products?	1
3	Select two non-biodegradable substances from the following wastes generated in a kitchen: spoilt food, paper bags, milk bags, vegetable peels, tin cans, used tea leaves.	1
4	Distinguish between biodegradable and non-biodegradable wastes.	1
5	List two natural ecosystems.	1
6	List two biotic components of a biosphere.	1
7	The depletion of ozone layer is a cause of concern. Why?	1
8	What will be the amount of energy available to the organism of the 2nd trophic level of a food chain, if the energy available at the first trophic level is 10,000 joules?	1
9	The first trophic level in a food chain is always a green plant. Why?	1
10	The following organisms form a food chain. Which of these will have the highest concentration of non-biodegradable chemicals? Name the phenomenon associated with it. Insects, Hawk, Grass, Snake, Frog.	1
11	List two components of an ecosystem.	1
12	Name the phenomenon in which non-biodegradable chemicals get accumulated progressively at each trophic level of a food chain.	1
13	What is the role of decomposers in the ecosystem?	1
14	Write the full name of the group of compounds mainly responsible for the depletion of ozone layer.	1
15	Expand the term: U.N.E.P.	1

16	Explain the mechanism of gaseous exchange between tissues and blood.	2
17	Why are the walls of ventricles thicker than the auricles ?	2
18	Government of India is imposing ban on the use of polythene bags for shopping. List four advantages of using cloth or jute bags over polythene bags.	2
19	Construct an aquatic food chain showing four trophic levels.	2

20	List the three kinds of blood vessels of human circulatory system and write their functions in tabular form.	3
21	Draw a diagram of human excretory system and label kidneys, ureters on it.	3
22	What is an ecosystem? List its two main components. We do not clean natural ponds or lakes but an aquarium needs to be cleaned regularly. Why is it so? Explain.	3
23	“Damage to the ozone layer is a cause for concern.” Justify this statement. Suggest any two steps to limit this damage.	3

24	(a) Explain how does the exchange of gases occur in plants across the surface of stems, roots and leaves. (b) How are water and minerals transported in plants?	5

class 12 biology holiday home work

.

1. What is meant by semi conservative replication?

2. How did Meselson and Stahl prove it experimentally?

 3.. What does the lac operon consist of? How is the operator switch turned on and off in the          expression of genes in this operon? Explain.

 4. State salient features of genetic code.

 5. Describe the process of transcription of mRNA is an eukaryotic cell.

 6. Describe the various steps involved in the technique of DNA fingerprinting.

7.‘Industrial Melanism’ in peppered moth is an excellent example of ‘Natural selection’. Justify the statement.

  8.. (i)In which part of the world, Neanderthal man lived? (ii)What was his brain’s capacity? (iii)Mention the advancement which Neanderthal man showed over Homo erectus.

 9.Is evolution a ‘process’ or the end result of a ‘process’? Discuss. Describe various factors that effect Hardy-Weinberg equilibrium
.
10.Briefly explain the various reproductive technologies to assist an infertile couple to have children.

11.Why is the sobriquet ‘The Evil Quartet’ used in context of biodiversity? Name the members of this quartet. Why do we grieve for the genes when a species is lost?

12.A dihybrid heterozygous round, yellow seeded garden pea (Pisum sativum) was crossed with a double recessive plant. (i) What type of cross is this? (ii) Work out the genotype and phenotype of the progeny. (iii) What principle of Mendel is illustrated through the result of this cross?

13.A woman with O blood group marries a man with AB blood group (i) work out all the possible phenotypes and genotypes of the progeny. (ii) Discuss the kind of dominance in the parents and the progeny in this case.

 14. Explain the cause of Klinefelter’s syndrome. Give any four symptoms shown by sufferer of this syndrome.

 15. In Mendel’s breeding experiment on garden pea, the offspring of F2 generation are obtained in the ratio of 25% pure yellow pod, 50% hybrid green pods and 25% green pods State (i) which pod colour is dominant (ii) The Phenotypes of the individuals of F1 generation. (iii) Workout the cross.

 16.How does primary sludge differ from activated sludge? What type of changes in the sludge are carried out in anaerobic sludge digester? Give the composition of biogas produced in the sewage treatment plant.

HOLIDAY HOME WORK FOR CLASS 10

Construct a food web ( use colorful pictures)

HAPPY

HAPPY HOLIDAYS

hi

hi all

   Class XI Biology----- DRAW AND LABEL TRANSVERSE SECTIONS OF DICOT AND                                                    MONOCOT STEM.

                                       Differentiate phellum, phellogen and periderm.