The Fundamental Unit of Life

1.Who discovered the cells first?
      Robert Hooke observed cells in a slice of cork in 1665.

2.Name unicellular organism.
   Amoeba, Chlamydomonas, Paramecium, Bacteria

3.Why is the cell called the structural and functional unit of life?
   A cell is able to live and perform all basic functions that are characteristic of all living forms. It is able to do this because of its organelles. All these organelles together constitute the basic unit called cell.

4.Which are the 3 functional regions (features) of the cell?
   Plasma membrane, cytoplasm and nucleus.

5. What is diffusion?
Ans. Diffusion is the spontaneous movement of molecules from a region of high concentration to region of low concentration.

6. What is Osmosis?
Ans. Osmosis is the movement of water molecules from a region of high water concentration to a region of low water concentration through a semi permeable.

7. What is a hypotonic solution?
Ans. If the medium surrounding a cell has high water concentration than the cell then the cell will gain water by osmosis. Such a solution is a hypotonic solution.

8. What is an isotonic solution?
Ans. If the medium has exactly the same water concentration as the cell
there will be no net movement of water molecules across the cell membrane. Such a
solution is called isotonic solution.

9. What is a hypertonic solution?
Ans. If the medium has a lower water concentration than the cell then the
cell will lose water by osmosis. Such a solution is known as hypertonic solution.

10.What is endocytosis
    Flexibility of plasma membrane enables the cell to engulf in food and other materials from the environment.
This process is called endocytosis.

11.How do substances like CO2 and water move in and out of the cell? Discuss.
Gases like CO2 and water move in and out of the cell by diffusion.  The concentration of CO2 inside the cell is more than the concentrations of CO2 in the external environment of the cell.  So CO2 moves from a place of its high concentration to a place of its low concentration by the process diffusion.
The movement of water also obeys laws of diffusion.  The movement of water through a selectively permeable membrane is called OSMOSIS.
Osmosis is the movement of water molecules from a region of high water concentration to a region of low water concentration through a semi permeable membrane.

12.  Why is the plasma membrane called a selectively permeable membrane?
The plasma membrane allows the entry and exit of some materials in and out of the cell.  It prevents the movement of some other materials. Therefore, cell membrane is called a selectively preamble membrane.

13. What is Plasmolysis?
When cell loses water through Osmosis there is shrinkage or contraction of contents of the cell away from the cell wall.  This phenomenon is called Plasmolysis.


14. What are Chromosomes?
Chromosomes are rod shaped structures visible only when the cell is about to divide.  Chromosomes are composed of DNA and proteins.

15. What is DNA? What is its function?
DNA is Dexoyribo Nucleic Acid DNA contains information for making and organizing the cell.  DNA transmits hereditary information from generation to generation.  Genes are segments of DNA.

16. What is the role of nucleus?
Nucleus controls all the chemical activities of the cell.  It plays a central role in cellular reproduction.

17. Write the differences between Prokaryotes and Eukaryotes.
Nuclear regions in prokaryotes are not surrounded by a nuclear membrane such an undefined nuclear region containing only nucleic acid is called a nucleoid.
Prokaryotes do not have organelles, chlorophyll in photosynthetic bacteria (Prokaryotes) are not present in plastids.

Eukaryotes have nucleus surrounded by nuclear membrane. Membrane bound all organelles are present in these cells.

PROKARYOTES   
1. Size generally small  
2. Nuclear region not surrounded by nuclear membrane and known as Nucleoid 
3. Single chromosome   
4. Membrane bound cell organelles absent  

EUKARYOTES
1. Generally large
2. Nuclear region well defined and surrounded by a nuclear membrane.
3. More than one chromosome
4. Membrane bound cell organelles present

18.What are cell organelles? Give examples
These are membrane bound structures in the cell doing particular functions. 
1. Endoplasmic reticulum 2. Golgi apparatus
3.Lysosomes 4.mitochondria 5.Plastids 6. Vacuoles.

19.What is endoplasmic reticulum?
Endoplasmic reticulum is a large network of membrane bound tubes and sheets in the cytoplasm.

20.Which are the two types of endoplasmic reticulum? What are its functions?
1. Rough endoplasmic reticulum (RER). Rough endoplasmic reticulum has ribosome's attached to its surface.  These ribosomes are sites of protein synthesis.  The manufactured proteins are then sent to various places in the cell using endoplasmic reticulum.

2. Smooth Endoplasmic Reticulum (SER): It helps in the synthesis of fat molecules or lipids.  Some of these lipids and proteins help in building cell membrane (membrane biogenesis).  Some other proteins and lipids function as enzymes and hormones.  In the liver cells of vertebrate animals SER plays a crucial role in detoxifying many poisons and drugs.

The endoplasmic reticulum serves as channels for transport of materials between various regions of cytoplasm.   It provides a surface for some of the biochemical activities of the cell.

21. What is Golgi apparatus? What is its function?
Golgi apparatus is a system of membrane bound vesicles arranged in stacks called Cisterns.
Golgi apparatus holds and stores materials made by endoplasmic reticulum and sends it to the necessary sites.  It stores, modifies and packages products in its vesicles. Eg.complex sugars are made from simple sugars in the Golgi apparatus.  Golgi apparatus is involved in the formation of Lysosomes.

22. What are Lysosomes? Why are they called digestive bags of the cell?
Lysosomes are membrane bound sacs filled with digestive enzymes made by RER.  Lysosomes are a kind of waste disposal system of the cell.  Lysosomes help to keep the cell clean by digesting any foreign material, bacteria and worn out cell organelle.  They are able to do this because they contain powerful digestive enzymes capable of breaking down all organic material.

23. Why are Lysosomes called suicide bags of the cell?
During a disturbances in cellular metabolism when the cell gets damaged, lysosomes may burst and digest the whole cell.

24. What are mitochondria? Write their structure and function.
Mitochondria are known as the powerhouses of the cell.  They have two membrane coverings; the outer membrane is very porous while the inner one is deeply folded.  These folds provide large surface area for ATP generating chemical reactions.

25. What is ATP?
ATP is Adenosine Triphosphate. It is the energy currency of the cell.

26. Why are mitochondria strange organelles?
Mitochondria have their own DNA and ribosomes.  They are able to make some of their own proteins.

27. What are the different types of plastids? Write their functions.
1. Chromoplasts (coloured plastids)
2. Leucoplasts (White or colourless plastids)
Chloroplasts are plastids containing the pigment chlorophyll.  Chloroplasts are important for photosynthesis.
Leucoplasts store starch, oils and protein granules.

Like mitochondria plastids have their own DNA and ribosomes.

28.What are vacuoles?
Vacuoles are storage sacs for solid or liquid contents.      Vacuoles are small in animal cells. Plant cells have large vacuoles.

29. Can you name the two organelles we have studied that contain their own genetic material?
Mitochondria, Plastids.

30.If the organizations of a cell are destroyed due to some physical or chemical influence what will happen?
Lysosome may burst and enzymes in it digest the cell.

31.Where are proteins synthesized inside the cell?
Proteins are synthesized by the ribosomes on the endoplasmic reticulum.  Ribosomes are present in mitochondria and plastids also.

32.How are plant cells different from Animal Cells?

33. How does an Amoeba obtain its food?
Amoeba obtains its food by endocytosis (phagocytosis).

34. Draw a plant cell and label the parts.

35. Draw an Animal cell and label the parts.

                   Improvement of Food Resources

1. What was the result of the Green Revolution?
Ans: The result of the Green Revolution was increased food grain production.

2. What was the effect of the White Revolution?
Ans: Better and most efficient use as well as availability of milk was the effect of White Revolution.

3. What is the ill-effect of Green Revolution and White Revolution?
Ans: Our natural resources are getting used more intensively. Our natural resources are damaged to the point of destroying their balance completely.

4. Increase in grain production did not solve the problem of mal nutrition and hunger.  Why?

                                                       Natural Resources

Q.1) What are Biogeochemical Cycles?
Ans) The cyclic flow of nutrients between non-living environment and living
organisms is known as Biogeochemical cycle.

Q.2) Draw and describe Carbon Cycle?
Ans) Carbon is the most significant element. The basic movement of Carbon is
from atmospheric reservoir (0.03%) to producers, to consumers and then to
decomposers. Other reservoirs of Carbon are water, fossil fuels and sedimentary rocks. Plants utilize the atmospheric CO2   in photosynthesis to produce carbohydrates. Plant food is taken by herbivores and passes to the carnivores. The respiratory activities at each level help in returning the CO2 quickly to the atmosphere. The CO2 is returned to the atmosphere by various activities such as respiration, decomposition, burning of fossil fuels and volcanic activities.

Q.3) Draw and describe Nitrogen Cycle?
Ans) Atmosphere is the reservoir for free Nitrogen (about 78%). Nitrogen in element form cannot be used by plants. First it has to be converted to nitrates, a process known as nitrogen fixation.
The three types of nitrogen fixations are:
i)  Atmospheric fixation.
ii)  Industrial fixations.
iii)  Biological fixations.

i) Atmospheric fixations: During lightning the high temperatures and pressures created in the air convert Nitrogen into Oxides of Nitrogen. These oxides dissolve in water to give nitric and nitrous acids and fall on land along with rain. These nitrate and nitric ions are then used up by the plants, convert them into amino acids and then make proteins.

ii) Industrial fixations: Commercial productions of nitrogenous fertilizers.

iii) Biological fixations: Free living and symbiotic nitrogen fixing bacteria in the root nodules of leguminous plants, convert Nitrogen to form nitrites and nitrates. Animals consume the plant proteins and build their animal proteins from them. The dead bodies of plants and the dead bodies and excretions of animals undergo ammonification and nitrification by bacteria and become nitrates and nitrites.

A different type of bacteria converts nitrates back to nitrogen. This process is called denitrification.

Q.4) The percentage of CO2 in the atmosphere doubled since the industrial revolution. Why?
Ans) Human beings started burning fossil fuels on a very large scale since industrial revolution.

Q.5) Draw the Oxygen Cycle.

Diversity In Living Organisms

1. Why do we classify organisms?
We classify organisms to put them into groups, to study the vast variety of life forms easily.

2. Give three examples of range variations that you see in life forms around you.
(1) Range of size: Microscopic bacteria of a few micrometer in size to blue whales and Redwood trees of California of approximate size of 30 meters and 100 meters respectively.
(2) Range of lifespan: Pine trees living for thousands of years to insects like mosquitoes which die within a few days.
(3) Range of colour: Life ranges from colourless worms to brightly coloured birds and flowers

3. On what basis did Aristotle classify organisms? Was it a correct way of 
classification? Why?
Aristotle classified organisms according to whether they lived on land in water or air.  It was not a correct way of classification because animals which live in water differ in many different ways. Same is the case with those in air and on land. Habitat is the only point they share in common.

4. What are the advantages of classifying organisms?
1. It makes the study of vast variety of organisms easy.
2. Inter relationships among organisms become clear.

5. What should be the guidelines followed in classifying organisms?
Decide which characteristic is to be used as the basis for making the broadest divisions. Pick the next set of characteristics for making subgroups within these divisions. This process can be continued using new characteristic each time.

6. What is a characteristic? Give example.
A characteristic is a particular form or function. For example five fingers on each hand is a characteristic.

7. What do you think is a basic characteristic for classifying organisms,
(a) the place where they live
(b) the kind of cells they are made of?  Why?
The kind of cells they are made of. This is because the nucleated cells can make multicellular organisms with tissues that can take up specialized functions.

8. What makes the basic distinction in the body design of organisms?
The type of cells whether prokaryotic or eukaryotic is a characteristic that makes a basic distinction in the body design of organisms.

9. Give three examples of characteristics used for hierarchical classification.
Whether they are (1) prokaryotic or eukaryotic
       (2) unicellular or multicellular
       (3) mode of nutrition autotrophic or heterotrophic.
     
10. The characteristics used for classification of plants will be very different from
those used for animals. Why?
The basic design in plants and animals is different based on the need to make their own food (in plants) or acquire it (in animals)

11. What is evolution?
Evolution is the gradual unfolding of organisms from the preexisting ones through
changes since the beginning of life.

12. Name the scientist who described the idea of organic evolution and the book in which he explained it.
Charles Darwin first described the idea of evolution in his book 'The Origin of Species'.

13. Name the scientists who classified organisms into kingdoms.
Ernst Haeckel, Robert Whittaker and Carl Woese.
   
14. Who proposed the 5 kingdom classification? Name the 5 kingdoms.
Whittaker. The 5 kingdoms are 1. Monera 2. Protista 3. Fungi 4. Plantae 5. Animalia

15. On what basis were the organisms classified into 5 kingdoms?
1. Cell structure 2.  Mode of nutrition 3.  Body organization.

16. Name the subgroups at various levels of classification.
Kingdom
Phylum
Class
Order
Family
Genus
Species

17. Which are the two divisions of Monera introduced by Woes?
Archaebacteria and eubacteria

18. Define species.
Species is a group of similar organisms which can naturally interbreed.

19. Which organisms are called primitive and how are they different from the so called advanced ones?
Primitive organisms have ancient body designs that have not changed much.
Primitive organisms have simple structure. Advanced ones are complex in their structure and body organization.

20) What are the features of Monera? Give examples.
Ans. a) Monera does not have a defined nucleus or organelles. (They are prokaryotic)
b) They do not have multicellular body design
c) Some have cell walls while others do not have them
d) Some are autotrophic, while others are heterotrophic (e.g. Bacteria, blue-green algae or cyan bacteria, mycoplasma)

21) What are the features of protista? Give examples
Ans.These organisms are unicellular and eukaryotic.
b) Some of them use cilia or flagella for movement.
c) Nutrition can be autotrophic or heterotrophic. E.g. Diatoms and protozoa.

22) What are fungi? Give examples.
Ans. a) Fungi are eukaryotic organisms.
b) Their mode of nutrition is heterotrophic.
c) They use decaying organic material for food and are called saprophytes.
d) They have tough cell walls made of tough complex sugars called chitin.
e) Some have the capacity to become multicellular organisms
e.g.) yeast, penicillium, aspargillus, mushrooms

23) What is symbiosis? What are lichens?
Ans. Symbiosis is a permanent mutually dependent relationship between two organisms. Lichens are symbiotic life forms. The mutually dependent and benefiting relationship is between algae and fungi.

24) What is the criterion for classification of organisms as belonging to kingdom monera or protista?

Ans. The criterion is whether they are prokaryotic or eukaryotic. Monera are prokaryotic and protista are eukaryotic.

25) What are the main features of kingdom plantae and animalia?
Ans. Plantae is multicellular eukaryotes with cell walls. They are autotrophs and use chlorophyll for photosynthesis. Animalia are multicellular eukaryotes without cell walls. They are heterotrophic.

26) Outline the five-kingdom classification (Refer Page No. 85)

27) What are the three levels in the classification of plantae?
Ans. The first level is whether the plant has well'differentiated distinct components (roots, stems and leaves). The next level is whether they have specialized tissues for the transport of water and minerals. The third level is the ability to bear seeds and then whether the seeds are enclosed in fruits or not.

28) Outline the classification of kingdom plantae. (Refer Page No. 88 & 95)

                        Why Do We Fall Ill?

1. What is health?
Health is the state of physical, mental and social well being.

2. State two conditions essential for good health
1. Disease free environment
2. Social equality and harmony.

3. State any two conditions essential for being free of disease.
1. Public cleanliness (community hygiene)
2. Good economic conditions to ensure good health.

4. What are signs and symptoms?
Symptoms of diseases are things that we feel as being wrong with our body.
E.g. ' head ache, loose motion, giddiness

5. How does a physician pinpoint a disease?
A physician pin points a disease by getting laboratory tests done on the basis of signs of the disease.

6. What are acute and chronic diseases?
Diseases that last for a short period are called acute diseases. Ailments which last for long time are called chronic diseases.

7. Differentiate between acute and chronic diseases
acute diseases last for a short duration. An acute disease which is over very soon will have not enough time to cause a major effect on the health. E.g.: Common cold
chronic diseases last for a long time or even a life time and it can cause major effects on health.
E.g. Elephantiasis
8. What are infectious diseases or communicable disease?
Diseases caused by microbes are called infectious diseases. Microbes can spread in community and the diseases caused by them spread with them.

9. Give two examples of non infectious diseases.

Cancer, High Blood Pressure.

10. What are the organisms that cause diseases?
Bacteria, fungi, virus, protozoa, and different kinds of worms

11.  Name 4 diseases caused by virus.
Common cold, dengue, AIDS and influenza

12. Name 4 diseases caused by bacteria.
Typhoid, cholera, tuberculosis, anthrax

13. What causes ringworm?
Fungus

14. Write one difference between virus and bacteria.
Virus lives and multiplies only in host cells, but bacteria can be grown by a culture medium.

15. How do antibiotics affect bacteria?
Antibiotics block bio chemical pathways important for bacteria. The antibiotic penicillin blocks the bacterial processes that build the cell wall. As a result the growing bacteria become unable to make cell walls that easily and they die.

16. What is the effect of Penicillin on bacteria?
The antibiotic penicillin blocks the bacterial processes that build the cell wall. As a result the growing bacteria become unable to make cell walls that easily and they die.

17. How does HIV (Human Immuno Deficiency Virus) infection affect the body?
In the HIV infection, the virus goes to the immune system and damages its function. Thus many of the effects of HIV ' AIDS are because the body can no longer fight off the many minor infections we face every day. A small common cold can become pneumonia; a minor gut infection can cause major diarrhea and blood loss. Ultimately these infections kill the people suffering from AIDS.

18. On what does the severity of a disease depend?
Severity of a disease depends on the type of microbe and the number of microbes in the body.

19. Give reason for why making of antiviral drug is difficult.
Viruses have very few biochemical mechanisms of their own. They use our cells and use our machinery. There are few virus specific targets to aim at.

20. How do infectious diseases spread?
1. Air ' By droplets thrown out by an infected person when he coughs or sneezes. This is more common in conditions of overcrowding. 
            Example ' pneumonia, tuberculosis
2. Water ' excreta from infected person get mixed with the drinking water. The microbes enter new hosts and cause diseases in them.
            Example ' typhoid, cholera
3. Sexual Contact ' Syphilis, AIDS 
4. Biological vectors - lice, fleas, mites and mosquitoes… Mosquitoes spread diseases like Filariasis, Dengue and Malaria.

21. How does AIDS spread?

1. Sexual Contact with an infected person
2. Blood to blood contact through contaminated injection needles, razors, etc.
3. Babies born to infected mothers are also infected with the disease during pregnancy or through breast feeding

22. What are the points of entry of the following microbes?
1. Tuberculosis causing Bacteria' they enter from the air through the nose.

2. Typhoid causing bacteria ' they enter the mouth through contaminated water or food.
3. Malaria causing microbe ' mosquito bites on the skin.

23. What are the symptoms
(1) if lungs are infected?

Cough and breathlessness
(2) if the liver is infected
the person will suffer from jaundice
(3) if the microbe targets the brain
headaches, fits, unconsciousness and vomiting will take place.

24. What are the common effects of diseases?
Inflammations, swelling, pain and fever

25. What is inflammation? What are its effects?
The immune system recruits many cells to the affected area to kill the microbes. This recruitment process is called inflammations.

 Local effects such as swelling and pain and general effects such as fever

26. What are the two ways in which we have to treat infectious diseases?
1. Symptoms directed treatment.
    Example ' to reduce fever, pain, to stop loose motions
2. To kill the microbe causing the disease. Medicines that can kill the specific group of organisms are used.

27. Why is prevention of disease better than cure?
Once a person has a disease the body functions are damaged and may never recover completely.
Treatment takes time.

The person affected by a disease is bedridden for some time.
Infected person is a source of infection to the other people.

28. Why are we asked to take bed rest during illness?
This is to conserve energy so that it will enable us to use this energy to help in the healing process.

29. How can we prevent diseases?
General ' We can prevent exposure to microbes. For air borne infections, have living conditions which are not overcrowded. For water borne microbes, provide safe drinking water. Treat the water to kill microbes.
Proper public hygiene, to dispose the wastes and to avoid mosquitoes, rats, etc., from breeding to prevent infectious diseases.
Second basic principle is the availability of proper and sufficient food for everyone.

Specific ' We can develop immunity to diseases by either having the diseases once, by getting exposed to the microbes or by vaccinations

30. List some diseases against which vaccines are available. Tetanus, Whooping Cough, Diphtheria, measles, polio, meningitis, Hepatitis A, T B, etc

31. Differentiate between vector and carrier

1. Vector is an organism which carries particular pathogen spreading a particular disease.

2. All vectors are carriers.

Example: Female anopheles mosquito is the vector which carries the pathogen Plasmodium which causes malaria.

1. Carrier is an organism which carries many pathogens spreading many diseases.

2. All carriers are not vectors

Example: Housefly helps to spread many diseases.

32. Differentiate between Vaccination and Antibiotics

Vaccination:

1. Process of injecting a part of the microbe dead or alive which will produce resistance against a particular disease.

2. It is used to prevent a disease and is given to a healthy person.

Example: BCG for TB, OPV for Polio

Antibiotics

1. It is a biochemical substance extracted from micro organisms like bacteria or fungi which could kill or inhibit the growth of other micro organisms.

2. It is used to cure a disease and is given to a sick person.

Example: Penicillin, Amoxyllin

33. Name the causative organism of the following diseases

Kala Azar ' Leishmania (protozoa)

Sleeping Sickness ' Trypanosoma (protozoa)

AIDS ' HIV (Human Immuno Deficiency Virus)

Acne ' Staphylococci bacteria  

34. How does HIV (causing AIDS) affect the body?

HIV damages immune system.

Reduces efficiency of body to fight off infections

35. What is vaccination? How does it prevent diseases Name 2 diseases for which vaccination are available?

 Process of injecting a part of the microbe dead or alive which will produce resistance against a particular disease

 It develops memory for a particular infection and prevents any subsequent exposure to infecting microbe from turning into disease.

Polio ' OPV

TB - BCG

TT 'Tetanus

MMR- Measles, Mumps,

36. List 2 principles of treatment of diseases?

How does penicillin kill bacteria?

Why does it have no effects on human and viral cells?

Reduce the effect of disease and kill the cause of disease.

Penicillin blocks bacterial process that build cell wall. So growing bacteria become unable to make cell walls and die.

It does not affect viral cell as they don't have a metabolism of their own.  Human cells don't make a cell wall, so they cannot have such an effect.

Syllabus for Second Terminal Examination