IMMUNE SYSTEM

 

IMMUNE SYSTEM

     After Covid-19 we all are familiar with the word-Immune system. The Immune System is a complex network of cells and proteins that defends the body against infections. The immune system detects a wide variety of agents from viruses to parasitic worms, known as pathogens. Immune system has the ability to distinguish pathogens from healthy tissue in our body.

     The main part of the immune system is white blood cells, which produces antibodies. Antibodies are chemically proteins. Antibodies fight with pathogens (microbes) or toxins (poisons) they produce. White blood cells are produced in bone marrow and move throughout the body looking for foreign bodies (microbes). Healthy diet and regular exercise boost up our immune system.

   The immune system keeps a record of every germ (microbe) it has ever defeated, so it can recognize and destroy the microbe quickly if it enters the body .“Vaccines” work on this principle.

    Vaccines contain a microorganism in a weekend live or killed state, or proteins or toxins from the organism, which stimulate the immune system to produce antibodies. The processes of administration of a vaccine are known as “Vaccination” (Immunization).

Q 2.1    Antibodies are chemically made up of:

    (a)   Sugar  

    (b)   Protein

    (c)   Vitamin

    (d)   Fat

Q2.2    Which part of blood forms antibodies?

    (a)    Red blood cells

    (b)   White blood cells

   (c)     Platelets

   (d)    Plasma

Q 2.3   In which part of our body are White blood cells formed?

Q 2.4   The Vaccine triggers -------------- to form antibodies.(fill in the blanks)

Q 2.5    Give two examples of common vaccines?

Answer and scoring--

1.1	Option   (d) Nitrogen
	Full credit: 2
	Any other option no credit
1.2	Option   (d) Cyanobacteria
	Full credit: 2
	Any other option no credit
1.3	Legumes
	Full credit: 2
	Half credit :1(for one example such as                          Pea, Gram)
1.4	Azotobacter, Anabaena, Nostoc (any one)
	Full credit: 2
	For any other suitable examples full credit
1.5	Full credit: 2     (for two reasons)
	Half credit :1    (for one reason)
2.1	Option   (b) Protein
	Full credit: 2
	Any other option no credit
2.2	Option   (b) White blood cells
	Full credit: 2
	Any other option no credit
2.3	Bone marrow
	Full credit: 2
2.4	White blood cells
	Full credit: 2
2.5	Full credit:2   (For two correct examples)
	Half credit :1   (For one correct example)

BIOFERTILIZERS

 

BIOFERTILIZERS

Bio fertilizers are artificially multiplied cultures of certain microorganisms that can improve soil fertility and crop productivity without polluting our environment. Some common microorganisms used as bio fertilizers are Rhizobium, Azotobacter, Azospirillum, Blue green algae (Cyanobacteria) etc. These microorganisms fix atmospheric nitrogen, converting insoluble phosphates into soluble and decomposable farm wastes, which results in the release of plant nutrients by their biological activities.

       Rhizobium forms nodules in the roots of legume plants and fixes atmospheric nitrogen symbiotically. Azotobacter is a free living nitrogen fixing bacteria present in soil which enhances the crop yield of cereals by fixing nitrogen non symbiotically. Anabaena & Nostoc belonging to Cyanobacteria are free living nitrogen fixing microbes mainly used in rice fields to enhance crop yield.

     These microbes are produced in large scale and used in crop fields as a bio- fertilizer to supplement the chemical fertilizers to maintain sustainability of the soil and environment. It is cheaper than chemical fertilizer.

Q 1.1 Bio fertilizers are used to maintain which element in soil:

 (a) Calcium    

 (b)  Magnesium

 (c)   Iron

 (d)   Nitrogen

 Ans- d

Q 1.2   Blue green algae are known as:

(a)     Bacteria

(b)    Algae

(c)     Lichen

(d)    Cyanobacteria

 Ans- d

Q 1.3 In which group of plants does Rhizobium form nodules?

Ans-legume plants

Q 1.4   Give one example of microbe which fixes nitrogen in cereal crops.

Ans- Azotobacter ,Anabaena & Nostoc

Q 1.5   How bio fertilizers are better than chemical fertilizers? Give two reasons.

Ans-   These microbes are produced in large scale and used in crop fields as a bio- fertilizer to supplement the chemical fertilizers to maintain sustainability of the soil and environment. It is cheaper than chemical fertilizer

REFRACTION OF LIGHT

Sameer performs an experiment with the help of clear round drinking glass, pencil and tap water. He fills the drinking glass about two-thirds of the way with water. Then he place the pencil inside the glass on an angle, so it’s resting on the rim.

 

                           

He then bends down until he is looking in line with the top of the water. He observes that the pencil is broken in two.

 

Question 1- A ray of light is travelling from a rarer medium to a denser medium. What will happen?

     …………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….

 

 

Question 2- A light ray enters from medium A to medium B as shown in figure. The refractive index of medium B relative to A

 

(a)   greater than unity

(b)   less than unity

(c)   equal to unity
(d)   zero

Question 3- The optical phenomena, twinkling of stars, is due to

(a)   Atmospheric reflection

(b)  Total reflection

(c)   Atmospheric refraction

(d)   Total refraction

 

Question 4- Which one is optically denser in between Water and air?

 

(a)  Water

(b) Air

(c)  Both are same

(d) None of these

MARKING SCHEME:

1-    When a ray of light is travelling from a rarer medium to a denser medium, it bends towards the normal.
Correct answer - FULL CREDIT                                    (1 marks)

      Any other response- NO CREDIT

2-    (a)- FULL CREDIT, Any other response- NO CREDIT              (1 marks)

3-    (c)- FULL CREDIT, Any other response- NO CREDIT               (1 marks)

4-    (a)- FULL CREDIT, Any other response- NO CREDIT               (1 marks)

 

  

Science in long Jumping

      The length of long jump by an athlete can be increased by keeping the jumper in air as long as possible and making him run forward as fast as possible before jumping. In these games the place is provided with a sand pit or straw bed to prevent the athlete from any injury.

 

While covering the long jump the athlete makes a projectile motion and lands on the surface.

 

Question 1:

Why does the athlete take a long run before jumping?

1. To increase the inertia of motion
2. To decrease the inertia of motion
3. To reduce the effect of gravity while jumping
4. To reduce air friction

 

Answer : a

 

Question 2:

What do you think the sand pit or the straw bed actually do to keep the athlete safe?

1. Provide time delay for the change in momentum
2. Soft surface of straw bed and sand pit
3. It is the techniques of athlete which prevent themselves
4. None of the above

Answer : a

Question 3:

What would be the angle of projection of jumping to cover maximum distance?

1. 30°
2. 45°
3. 60°
4. 90°

Answer : b

Question 4:

What would be the shape of the path of motion of the athlete during jumping in air?

1. Hyperbola
2. Parabola
3. Circular
4. Not specified path

Answer : b

PHOTOSYNTHESIS

            Photosynthesis is the process by which green plants, algae and some bacteria use sunlight, carbon dioxide and water to prepare their food. This is a biogeochemical processes. It takes place in the chloroplast. The chlorophyll pigments present in chloroplast traps light energy and converts it into carbohydrate(glucose then into starch). During the process water molecules splits by light energy , hydrogen is used for the reduction of carbon dioxide into glucose(sugar carbohydrate) with release of oxygen as a by product.  The carbon dioxide enters the leaf through small openings called as stomata. Each stomata is guarded by two guard cells.

Questions-:

1.What is the first step in photosynthesis ?

             a)  formation of glucose

             b)  formation of ATP

              c)   absorption of light by chlorophyll pigment

              d)   release of oxygen

2. Factors that influence the photosynthesis ----------------.

3.During photosynthesis oxygen releases comes from which compound .

4.Carnivores are also dependent on green plants even though they eat flesh.  Justify the statement.

5.During photosynthesis

            a)  light energy is converted into heat energy.

            b)  light energy is converted into chemical energy .

            c)  chemical energy is converted into heat energy .

            d)  heat energy is converted into light energy .

                               Answer Key

Q1.  Full credit - option(c) Absorption of light by chlorophyll

     No credit – any other option

Q2.  Full credit -  light, chlorophyll, water & carbon dioxide

      Half credit- for any two correct answer

Q3.  Full credit -  Water

      No credit - for any other answer

Q4.  Full credit -  animals depend on plants for their food ,because they

                         Have no chlorophyll

      Partial credit –if required

Q5.   Full credit - 

         Option (b) Light energy is converted into chemical energy.  

       No credit -  for any other option

Pesticides Vs Food

Pesticides Vs. Food

          Pesticides are used to protect crops against insects, weeds, fungi and other pests ie., Pesticides are substances that are meant to control pests. The term pesticide includes all of the following: herbicide, insecticides (which may include insect growth regulators, termiticides, etc.) nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, antimicrobial, and fungicide. Pesticides are potentially toxic to humans and can have both acute and chronic health effects, depending on the quantity and ways in which a person is exposed. Some of the older, cheaper pesticides can remain for years in soil and water. These chemicals have been banned from agricultural use in developed countries, but they are still used in many developing countries. People who face the greatest health risks from exposure to pesticides are those who come into contact with them at work, in their home or garden. Pesticides play a significant role in food production. They protect or increase yields and the number of times per year a crop can be grown on the same land. This is particularly important in countries that face food shortages. To protect food consumers from adverse effects of pesticides, WHO reviews evidence and develops internationally-accepted maximum residue limits.

Q.1.Pesticide have Chronic & Acute both Health effects. Its affect mostly

a. Consumers

b. Sellers

c. Farmers

d. None

Q.2. Countries that are facing food shortage are at high risk of getting the food items with high concentration of pesticides.  T/F

Q.3. Why do some of the older & cheaper pesticides have been banned in ……………….. Countries?  

Q.4. WHO reviews evidence and develops internationally-accepted maximum residue limits. Why?

Q.5.The best way to reduce the use of Pesticides in crops.

a. We should prefer consumption of seasonal Vegetable & Fruits

b. We should reduce the consumption of Non-seasonal Vegetable & Fruits

c. Ban the production & selling of pesticides.

d. We should increase the consumption of Non-seasonal Vegetable & Fruits.

Answer Key

Q.1. (c) Farmers (Full credit any other answer no Credit)

Q.2. (T) (Full credit any other answer no Credit)

Q.3. Developed countries (Full credit any other answer no Credit)

Q.4. To protect food consumers from adverse effects of pesticides(Full credit any other answer no Credit)

Q.5.(a) We should prefer consumption of seasonal Vegetable & Fruits(Full credit any other answer no Credit)

Matters- As pure and impure

 

Anything that occupies some space, having mass, volume and can be felt by one or more out of five senses is called matter. The purest form of matter is called an element. An element is a substance which cannot be split up into two or more simpler substances by the usual chemical methods of applying heat, light or electric energy.

A pure substance consists of a single type of particles. All the elements and compounds are pure substances because they contain only one kind of particles. eg. Hydrogen, Carbon, Oxygen, Carbon-monoxide,Copper, Gold, Silver.

 

A pure substance has a fixed composition as well as a fixed boiling point and melting point. The presence of impurities generally increases the melting and boiling point of the pure substances

 

Q: 8.1 Which of the statement is true about pure substances

a.     Homogeneous mixtures are pure as they have same composition throughout.

b.     22 carat goldis pure in nature.

c.     Elements are not pure in nature.

d.     Gold and carbon dioxide both are pure in nature.

 

Q: 8.2 The boiling point of pure water is 100^oC. What likely be the effect on the boiling point of water if 150 gm NaCl is added to one litre of water ?

______________________________________________________________________________________________________________________________.

 

Q: 8.3 Carbonmonoxide gas can be separated into carbon and oxygen gas by ________________.

     a.     Chemical methods

     b.     Applying heat,

     c.     Sunlight or electric energy

     d.     None of the above.

Q: 8.4The melting point of 1 Kg carbon dioxide is –79°C. What will be the melting point of 500gmCarbondioxide?

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Q: 8.5 Why table salt resist free flow and becomes damp during rainy season moisture if exposed to damp air although sodium chloride does not hygroscopic?

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Q: 8.6 Universe is made up of matter justify this statement?

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Answer Key and Credit:

ANSWER 8.1:-

 

Scientific Literacy:

FRAMEWORK	CHARACTERISTICS
Competency	Evaluate and design scientific enquiryExplain the phenomenon scientifically
Knowledge system	Knowledge of science-Physical
Context	Global
Cognitive demand	Low
Item format	Simple Multiple choice question.
Proficiency level	2

 

Credit Pattern:

Full Credit:	2
Partial Credit:	1
Nil Credit:	0

 

Full Credit:	(D)(d) Gold and carbon dioxide both are pure in nature.
Partial Credit:	Only if one factor is mentioned like Gold or Carbonmondioxide
Nil Credit:	Other responses.(A), (B) and (C)

 

ANSWER 8.2:-

Scientific Literacy:

FRAMEWORK	CHARACTERISTICS
Competency	Interpret data and evidencescientificallyEvaluate and design scientific enquiry
Knowledge system	Knowledge of science-Physical
Context	Global
Cognitive demand	Medium
Item format	Closed constructive
Proficiency level	4

Credit Pattern:

Full Credit:	2
Partial Credit:	1
Nil Credit:	0

 

Full Credit:	Boiling point of water will increase.
Partial Credit:	101oC or above
Nil Credit:	Boiling point of water will remains constant or decreasies.

 

ANSWER 8.3:-

Scientific Literacy:

FRAMEWORK	CHARACTERISTICS
Competency	Use scientific evidences to draw conclusion
Knowledge system	Procedural
Context	Global
Cognitive demand	Low
Item format	Simple Multiple choice question.
Proficiency level	2

Credit Pattern:

Full Credit:	2
Partial Credit:	1
Nil Credit:	0

 

 

Full Credit:	(D) None of the above.
Partial Credit:	------
Nil Credit:	Other responses.(A), (B) and (C)

 

ANSWER 8.4:-

Scientific Literacy:

FRAMEWORK	CHARACTERISTICS7
Competency	Interpret Data and Evidence Scientifically
Knowledge system	Physical
Context	Global
Cognitive demand	Low
Item format	Closed constructive
Proficiency level	1

Credit Pattern:

Full Credit:	2
Partial Credit:	1
Nil Credit:	0

 

 

Full Credit:	Same –79°C.
Partial Credit:	------
Nil Credit:	Other responses or missing

 

ANSWER 8.5:-

Scientific Literacy:

FRAMEWORK	CHARACTERISTICS7
Competency	Evaluate and design scientific enquiry
Knowledge system	Earth
Context	Global
Cognitive demand	High
Item format	Closed constructive
Proficiency level	5

Credit Pattern:

Full Credit:	2
Partial Credit:	1
Nil Credit:	0

 

Full Credit:	The presence of CaCl2 and MgCl2 impurities in table salt absorb moisture if exposed to moist air and resist free flow.
Partial Credit:	Due to the presence of impurities.
Nil Credit:	Any other or missing.

ANSWER 8.6:-

Scientific Literacy:

FRAMEWORK	CHARACTERISTICS7
Competency	Evaluate and design scientific enquiry
Knowledge system	Earth
Context	Global
Cognitive demand	High
Item format	Closed constructive
Proficiency level	5

Credit Pattern:

Full Credit:	2
Partial Credit:	1
Nil Credit:	0

 

Full Credit:	Space research have shown that all the star, planet and satellites are very big in size and made up of solid particle and sometimes possess (gaseous) atmosphere. Even our earth planet contains soil, mineral rocks, water and atmosphere therefore according to the definition mentioned anything that occupies some space, having mass, volume and can be felt by one or more out of five senses is called matter.
Partial Credit:	Universe is made up of solid liquid and gases.
Nil Credit:	Any other or missing.