Nutrition in Living Organisms

Question 1:

Classify according to food-type.
tiger, cow, vulture, bacteria, deer, goat, human, fungus, lion, sparrow, buffalo, frog, cockroach, tick.

ANSWER:

tiger- carnivore 
cow- herbivore 
vulture- scavenger
bacteria- decomposers
deer- herbivore
goat- herbivore
human- omnivore
fungus- decopmosers
lion- carnivores
sparrow- herbivore
buffalo- herbivore
frog- carnivore
cockroach- carnivore
tick- parasite

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Question 2:

Match the pairs.
 

Group 'A'		Group 'B'
(1)	Parasitic plant	(a)	Mushroom
(2)	Insectivorous plant	(b)	Lichen
(3)	Saprophytic plant	(c)	Drosera
(4)	Symbiotic plant	(d)	Cuscuta

ANSWER:

Group 'A'		Group 'B'
(1)	Parasitic plant	(d)	Cuscuta
(2)	Insectivorous plant	(c)	Drosera
(3)	Saprophytic plant	(a)	Mushroom
(4)	Symbiotic plant	(b)	Lichen

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Question 3:

Answer the following questions in your own words.
(a) Why do living organisms need nutrition ?
(b) Explain the process of production of food in plants.
(c) What is meant by parasitic plants ? Name their different types with examples of each.
(d) Explain the various steps of nutrition in animals.
(e) Name some unicellular organisms in which all life-processes take place within their unicellular body.

ANSWER:

a. Nutrition is the process of uptake of nutrients from food and utilizing them for various functions of the cells. Nutrition is required for purposes like:

• supplying the energy required for doing work
• for growth and development of the body
• to fight diseases
• to replace the damaged cells and repair tissues

b. Leaves are the food factories of plants. They are the sites where the synthesis of food occurs in plants. The leaves of plants contain a green pigment called chlorophyll. This pigment captures the sun’s energy, which is used to prepare food from carbon dioxide and water. The process of synthesis of food using sunlight, carbon dioxide, and water is known as photosynthesis. During the process of photosynthesis, the leaves containing chlorophyll convert carbon dioxide and water into carbohydrates in the presence of sunlight. Carbohydrates, which are produced during photosynthesis, are ultimately converted into starch to be stored in plants.This process can be represented in the form of the following equation:

c. Cuscuta survives by growing on the body of another plant and deriving nutrients from this plant in the process. This mode of nutrition is known as parasitic mode of nutrition. Cuscuta is known as a parasite as it depends on another plant for its survival. The plant on which it grows is known as the host. Cuscuta can be seen around in the form of yellow tubular structures growing on the stems of other plants. It is devoid of leaves. Another such example of parasitic plants is Loranthus.


 d.  The various steps of nutrition in animals are:

• Ingestion − The process of taking in of food into the body is called ingestion. Ingestion of food in humans is done with the help of the buccal cavity. 
• Digestion − The process where conversion of food into soluble form occurs.
• Absorption − The nutrients from the digested food are absorbed in the small intestine with the help of finger-like projections called villi.
• Assimilation − The absorbed nutrients are transported via the blood vessels to the different organs, to be utilised for different life processes. 
• Egestion − The process of removal of faecal matter through the anus is called egestion. 

e. The unicellular organisms in which all life processes take place within their body are- Amoeba, Paramoecium and Euglena.

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Question 4:

Give reasons.
(a) Insectivorous plants are attractively coloured.
(b) Butterflies have a long tube-like proboscis.

ANSWER:

a. Insectivorous plants are attractively coloured so that they can attract insects and feed upon them. Insectivorous plants grow in soil or water which are deficient in nitrogen compounds and in order to meet this deficiency, they feed on insects.

b.  Butterflies have a long tube like proboscis which is a straw-like structure which enables them to drink juices and nectar. It is coiled-up like a garden hose when it is not in use.

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Question 5:

Prepare and complete the flowchart according to type of nutrition.

ANSWER:

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Question 6:

Think and answer.
(a) We prepare a variety of foodstuffs and dishes at home. Are we then autotrophic organisms ?
(b) Which organisms are greater in number - autotrophs or heterotrophs ? Why?
(c) The number of heterotrophs found in desert regions is smaller. However, they are found in greater numbers in the sea. Why is this so ?
(d) What damage or harm do ectoparasitic and endoparasitic animals cause ?
(e) Why is plant food not produced in any other parts of the plant except the green ones ?

ANSWER:

a. By preparing variety of foodstuffs and dishes at home, we do not become autotrophic. Autotrophic is a term which is used for organisms which can produce their own food. We humans depend on plants for our food and the products which we get from them are used by us to make a variety of foodstuffs. Also, autotrophic organisms contain chloroplast which is an absolute necessity to be classified as an autotroph and we do not possess any such structures. So, we cannot be considered autotrophs.

b. Autotrophs are the organisms which are greater in number. It is because heterotrophs are dependant on autotrophs to meet their food requirements. If heterotrophs exceed the number of autotrophs, then all the autotrophs will vanish and so will be the heterotrophs. However, this is not the case because autotrophs are always more than heterotrophs so that they can help in sustaining the heterotrophs.

c. The conditions in deserts are extremely difficult for survival of organisms. Not all kinds of organisms can survive in such harsh climatic conditions, which means there are only few types of organisms which would be found in this region. Since, there are not many kinds of plants and animals which are found in this region, heterotrophs would not be able to survive and would die of starvation. That is why less heterotrophs are found in desert areas. However, in case of a habitat like sea, there are plenty of organisms which are found in region ranging from aquatic plants, to small fishes to big fishes. It is an environment which supports the survival of heterotrophs and thus more heterotrophs are found in this region.

d. Parasitism is a type interaction in which one of the partners is benefited because it resides outside or inside the body of the host and gets free accommodation and food while the host is affected due to loss of nutrients. Ectoparasites and endoparasites devoid the host of its nutrition. Some of the parasites are known to cause diseases like Ascaris/roundworm which is an endoparasite of intestine causes ascariasis. Another example is of Wuchereria which causes elephantiasis or filariasis. It is an endoparasite which lives in lymphatic vessels of lower limbs.
Lice or ticks which are found in humans and dogs respectively are examples of ectoparasites. They absorb the nutrients from their host.

e. Plant food is produced by a special process known as photosynthesis. The process of photosynthesis requires specialised structures called chloroplasts and these structures are found only in green regions of plants. The green colour of specific parts of plants is due to the presence of chlorophyll pigment present in these chloroplasts. Structures in plants which do not contain chloroplast, do not appear green in colour and are not capable of producing food.

Properties of Natural Resources

Question 1:

Fill in the blanks with the appropriate term.
(Temperature, volume, mass, density, humidity, acidic, weight, neutral, shape.)
(a) The capacity of air to hold moisture depends upon the ........... of the air.
(b) Water does not have a ........... but has definite ........... and ........... .
(c) While freezing, the ........... of water is lowered.
(d) ........... soil has pH 7.

ANSWER:

(a) The capacity of air to hold moisture depends upon the temperature of the air.
(b) Water does not have a shape but has definite mass and volume.
(c) While freezing, the density of water is lowered.
(d) Neutral soil has pH 7.

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Question 2:

Why is it said that –
(a) Air is a homogeneous mixture of various gases.
(b) Water is a universal solvent.
(c) There is no alternative to water for cleaning purposes.

ANSWER:

a. Air is a homogeneous mixture of gases as it is primarily made up of nitrogen and oxygen. Its elements are not readily separated or distinguished from one another.

b. Water is a very good solvent as it can dissolve almost every substance in it, therefore water is known as the “universal solvent”.

c. There is no alternative to water for cleaning purposes beacuse it dissolves everything that is added to it. The reason why it is called the universal solvent. The water dissolves all the dirt present in our clothes, the reason why we soak our clothes in detergent and water prior to washing. Also, water has a neutral pH which means it does not harm the object which has to be cleaned and also does not affect the skin.

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Question 3:

What will happen if....
(a) The amount of water vapour in the air increases.
(b) Only one crop is grown repeatedly

ANSWER:

a. The amount of water vapor in atmosphere determines the level of humidity. As the amount of water vapor in the atmosphere increases so does the level of humidity. Higher humidity levels result in excessive sweating and this sweat does not dry quickly leaving us feeling hot and sticky. 

b. If only one crop is grown repeatedly in the soil, it loses its fertility and gets devoid of nutrients. For this reason crop rotation is an important procedure, so that the fertility of the soil is retained and there is no loss of nutrients. For example, after cultivation of wheat, the fertility of soil decreases and thus leguminuos crops like peanut, moong etc. are cultivated after its harvest. These leguminous crops restore the fertility of soil.

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Question 4:

With whom should I pair up?
 

Group 'A'		Group 'B'
(1)	Air	(a)	Excretion
(2)	Water	(b)	Scattering of light
(3)	Soil	(c)	Plasticity

ANSWER:

Group 'A'		Group 'B'
(1)	Air	(b)	Scattering of light
(2)	Water	(a)	Excretion
(3)	Soil	(c)	Plasticity

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Question 5:

State whether the following statements are true or false.
(a) Sandy soil has low capacity for holding water.
(b) Sea water is a bad conductor of electricity.
(c) The substance in which a solute dissolves is called a solvent.
(d) The pressure exerted by air is called atmospheric pressure.

ANSWER:

(a) Sandy soil has low capacity for holding water.- False
(b) Sea water is a bad conductor of electricity.- False
(c) The substance in which a solute dissolves is called a solvent.- True
(d) The pressure exerted by air is called atmospheric pressure.- True

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Question 6:

Explain the picture in your own words.

ANSWER:

Image 'a' represents a crevice or crack which is filled with water wheras image 'b' represents a crevice which has ice. It is evident from both the images that in image 'b', the width of the crevice increases as the water in the crevice freezes. This is one of the properties of water due to which it expands upon freezing. This expansion in water after freezing results in the widening of the crack in image 'b'.

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Question 7:

Write answers to the following questions in your own words.
(a) How is light scattered by the air?
(b) Explain the various properties of water.
(c) Why is the density of seawater more than that of rain water?
(d) What is the importance of good soil structure?
(e) What are the various uses of soil?
(f) What is the need and importance of soil testing from the point of view of farmers?
(g) What is the importance of air in transmission of sound?
(h) Why should a glass bottle completely filled with water never be kept in a freezer?

ANSWER:

a. Scattering is the phenomenon of change in direction of light rays when they travel through Earth's atmosphere. Air is a mixture of gases, somke, dust and very fine particles. As the rays of light fall on these particles, these rays are spread/scattered in all directions. It is a natural phenomenon which is observed on our daily basis.


b. Properties of water: 

• Water is a colourless, tasteless, and transparent liquid. It also has no smell.
• Boiling point of pure water is 100°C at 760 mm of Hg pressure. However, boiling point of water increases due to increase in pressure and presence of dissolved impurities.
• Pure water freezes at 0°C at 760 mm of Hg pressure. However, freezing point of water decreases due to increase in pressure and presence of dissolved impurities.
• The state of water changes on heating or cooling. On heating, the state of water changes from liquid state to gaseous state (vapour). Similarly, on cooling, the state of water changes from liquid state to solid state (ice).
• Water is neither acidic nor basic. It is neutral.
• Water is a bad conductor of heat and electricity.
• Water is an universal solvent as it can dissolve many substances in it.

c. Sea water has more density than rain water because it contains salt ions. These salt ions make the seawater heavier, which means the mass of the water increases due to the presence of salt ions. From the relation, density= mass/volume, we can say that as the mass of an object increases, its density also increases simultaneously.


d. Soil stucture basically refers to the type of constituents and the ratio in which they are present in soil. The soil structure is important with respect to the growth of plants and the type of plantation which can occur in a particular area. Good soil structure has advantages like:

• roots get sufficient supple of oxygen
• it has good water drainage nad thus roots grow well

e. The following table represents the various types of soil: 

 

Soil type	Particle type	Properties
Sandy	Large	Loosely packed, with large air spaces. Water soaks into it easily. Thus it is dry, light and airy
Clayey	Fine, small	Tightly packed with no air spaces. This type of soil is heavy and holds more water.
Loamy/silt	A mixture of large and small particles	Holds water, contains humus.

f. Soil testing is a method of determining the constituents of soil.  A sample of soil is taken and is tested for its various characteristics for example, ph and electrical conductivity. It is important with respect to agricultural practices as it helps us in determining which crops can be grown in which region. It also gives us a knowledge about the deficient nutrients and this deficiency can then accordingly be dealt with. It is also useful in determining, if additional amounts of fertilizers are required.


g. Air acts as a medium for transmission of sound. When a sound wave passes through air, the particles of air vibrate back and forth, parallel to the direction of the sound wave. Thus, when a sound wave travels in the horizontal direction, then the particles of the medium also vibrate back and forth in the horizontal direction. Sound cannot travel without a medium and thus we cannot listen to sounds in the space because of absence of air. 


h. A glass bottle completely filled with water should not be kept in a freezer because the bottle can break and result in damage. We know that water expands after freezing and if a completely water filled glass bottle is placed in freezer, the water would freeze and would expand resulting in the bottle to break.

Std.8 Health and Diseases

Question 1:

Distinguish between- Infections and non infections diseases.
 

ANSWER:

Infectious diseases	Non infectious diseases
1. It can be passed from one person to another.	It cannot be passed from one person to another.
2. It is caused by a pathogen.	It is caused due to internal reasons like metabolic or genetic reasons.
3. They are classified as communicable disease.	They are classified as non communicable disease.
4. eg: diarrhoea, cholera, tuberculosis	eg: diabetes, hypertension, cancer

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Question 2:

Identity the odd term.
A. Malaria, hepatitis, elephantiasis, dengue.
B. Plague, AIDS, cholera, T.B.

ANSWER:

A. Malaria, hepatitis, elephantiasis, dengue- Hepatitis is the odd one out because it is a type of viral infection while the rest of three are spread through the bite of mosquitoes.
B. Plague, AIDS, cholera, T.B. - AIDS is the odd one out because it is a viral disease while the rest of them are bacterial diseases.

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Question 3:

Answer in one to two sentences.
A. Which are various media of spreading the infectious diseases ?
B. Give the names of five non-infections diseases other than given in the lesson.
C. Which are the main reasons of diabetes and heart diseases ?

 

ANSWER:

a. Infectious diseases can spread through air, water, blood to blood contact and animal vectors.

b. Non infectious diseases- arthiritis, cataract, osteoprosis, multiple sclerosis and Alzeimer's.

c. Reasons of heart diseases include smoking, alcoholism, diabetes, hypertension, obesity, lack of physical exercise, mental stress, anxiety and improper diet.

Reasons of diabetes include obesity, lack of physical exercise, mental stress, improper diet and hereditary.

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Question 4:

What can be achieved / can be prevented ?
A. Drinking boiled and filtered water.
B. Avoiding smoking and alcoholism.
C. Regular balanced diet and exercise.
D. Proper checking of blood before blood donation.

ANSWER:

a. Boiling and filteration are methods of purifying water which makes it suitable for consumption. Drinking boiled and filtered water can help in prevention of water borne diseases such as typhoid, cholera, etc. Most of the water borne diseases are transmitted through the consumption of contaminated water in some or the other form. 

b. Smoking and alcoholism are two of the devils of our health and society. Smoking leads to various kinds of respratory disorders and hinders the process of respiration. It can lead to diseases such as lung cancer. On the other hand, consumption of alcohol, effects the nervous as well as the digestive system of our body. Avoiding alcohol and smoking can protect indivisuals from various diseases and can help in living a healthy and stress free life.

c. Balanced diet and exercise are key to good health. Both of these in combination helps our systems to function properly, helps maintain a healthy weight, reduces body fat, provides the body with energy, promotes good sleep and makes us feel better about ourselves.

d. Proper checking of blood before blood donation is required to check that the blood to be transferred is safe in all respects. There are chances of transfer of infectious diseases form the donor, if he/she is suffering from any such diseases. Another important factor for checking of blood before donation is to check that the donor is not anemic (does not have anemia). 

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Question 5:

Read the passage and answer the questions.
Master 'X' is a 3 year old child. He is toiler with his family in a slum. Public toilet is present near his house. His father is drunkard. His mother does not know the importance of balanced diet.
A. Master 'X' can suffer from which different possible diseases in above conditions ?
B. How will you help him and hsi family in this situation ?
C. Which disease can occur to the father o master 'X' ?
 

ANSWER:

a. Since, the house of master X is near the toilet and he lives in a slum area, the chances are that there is less cleaniliness in that area. There are chances that he may suffer from diseases like salmonellosis, shigellosis, diarrhoea, trachoma, gastroenteritis, giardiasis, tapeworm infection and threadworm infection.

b. In this case, the famliy needs to be made aware about cleanliness in and around their houses. There is a need to explain them the importance of balanced diet for them and their child. Since, the father is a drukyard, he needs counselling and treatment to get rid of the habit of alcoholism.

c. The father of master X is a drunkyard which means he might suffer from diseases such as heart diseases, liver cirrhosis, ulcers and gastrointestinal ptoblems, brain damage etc.

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Question 6:

Give the preventive measures of following diseases.
A. Dengue
B. Cancer
C. AIDS

ANSWER:

 a. Dengue is a mosquito borne disease which is transmitted by Aedes mosquitoes which grow in clean and stagnant water. The breeding of this mosquito can be prevented by adopting the following steps:

• larve-eating fishes should be introduced in ponds
• collection and storage of water should always be done in closed vessels
• potted plants should have proper drainage to avoid collection of water in the pots
• pesticides should be used against mosquitoes as and when required

b. Preventive measures for cancer:

• have a healthy diet
• exercise regularly
• avoid smoking and alcohol
• 
  
• go for regular health checkups

c. Preventive measures for AIDS are:

• avoid sexual contact with unknown persons
• screening of blood before transfusion
• avoid sharing of needles

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Question 7:

Explain the importance.
A. Balanced diet.
B. Physical exercise / Yogasanas.

ANSWER:

a. A balanced diet is a diet containing all nutrients (carbohydrates, fats, proteins, vitamins, etc.) in the right quantities. A balanced diet helps us in various ways:

• provides us with important nutrients required for the growth of body
• helps us to stay fit and free from diseases
• helps in strengthening the immune system
• helps our systems to function properly
• helps maintain a healthy weight
• reduces body fat
• provides the body with energy
• promotes good sleep and makes us feel better about ourselves

b. Importance of exercise and yogasanas are:

• reduces the risk of heart attack
• helps in managing weight better
• helps in maintaining blood cholesterol level
• lowers the risk of type 2 diabetes and some cancers
• helps in maintaining the blood pressure levels
• helps in attaining stronger bones, muscles and joints and lowers the risk of osteoporosis
• boosts the energy levels, makes you feel relaxed

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Question 8:

Make a list.
A. Viral diseases.
B. Bacterial diseases.
C. Diseases spread through insects.
D. Hereditary diseases.
 

ANSWER:

Type of Disease	Example
Viral	Measels, Mumps, Swine flu, Chicken pox
Bacterial	Tuberculosis, Diptheria, Tetanus, Cholera, Typhoid
Insects	Dengue, Malaria, Plague
Hereditary	Diabetes, Hypertension, Cancer

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Question 9:

Write the information on modern diagnostics and treatments of cancer.
 

ANSWER:

Diagnostics of cancer:

There are many techniques whiich are used in the diagnosis of cancer and their application depends upon the type of cancer. Biopsy, histopathological studies of bone and blood, radiography (use of X-rays), CT (computed tomography) and MRI (magnetic resonance imaging) are used in diagnosis of cancer. Radiography, CT and MRI are the modern techniques used in cancer diagnosis.
Computed tomography uses X-rays to generate a three-dimensional image of the internals of an object. MRI uses strong magnetic fields and non-ionising radiations to accurately detect pathological and physiological changes in the living tissue.

Treatment of cancer:

Cancer is treated using 3 major approaches depending on the type of cancer. These 3 approaches are- surgery, radiotherapy and chemotherapy. In surgery, the tumor is removed surgically from its site and can be used in specific cases only. Radiotherapy is a technique in which the cancer cells are irradiated with radiations taking care of the normal tissues which surround the cancer cells.
Chemotherapy uses different kinds of drugs for the treatment of cancer. These chemotherapeutic drugs are specific for particular tumors and have side effects such as hair loss, anemia, etc.
Most of the cancers are treated by the combination of these 3 approaches.

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Question 10:

Enlist the names and composition of the medicines present at your home.

ANSWER:

The following medicines are found in our houses:

Paracip- Paracetamol/Acetaminophen
Digene-  Dried Aluminium Hydroxide, Magnesium Aluminium Silicate Hydrate, Magnesium Hydroxide, Simethicone
Volini- Diclofenac diethylamine BP, Linseed Oil BP (Oleum Lini), Methyl salicylate, Menthol IP, Benzyl Alcohol IP.
Vomikind- Ondansetron

Ch.5 Food safety (Std.7)

Question 1:

Complete the following statements by using the correct option from those given below.
(Irradiation, dehydration, pasteurization, natural, chemical)
(a) Drying the food grains from farms under the hot sun is called .......... .
(b) Materials like milk are instantly cooled after heating up to a certain high temperature. This method of food preservation is called .......... .
(c) Salt is a .......... type of food preservative.
(d) Vinegar is a .......... type of food preservative.

ANSWER:

(a) Drying the food grains from farms under the hot sun is called dehydration.
(b) Materials like milk are instantly cooled after heating up to a certain high temperature. This method of food preservation is called pasteurization.
(c) Salt is a natural type of food preservative.
(d) Vinegar is a chemical type of food preservative.

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Question 2:

Answer the following questions in your own words.
(a) How is milk pasteurized?
(b) Why should we not consume adulterated food materials?
(c) What precautions do your parents take to keep foodstuffs safe?
(d) How does food spoilage occur? Which are the various factors spoiling the food?
(e) Which methods of food preservation would you use?

ANSWER:

a. Milk is pasteurised in order to kill any kind of harmful microorganism present in it and to increase its shelf life. Pasteurisation is a process in which the milk is heated to a certain temperature for a fixed period of time and then is quickly cooled. For example, it may be heated at 80^oC for 15 minutes and then immediately cooled. This helps to kill any kind of microorganism which is present in milk. 

b. The process of substituting or concealing the quality of food, adding harmful or poisonous substances to food, and misbranding or giving false labels to food is known as food adulteration. the adulterants which are added to food products have harmful effects on our bodies. For example:

• vegetable oil is adulterated with cheaper and non-edible oils such as argemone oil which causes dropsy, which in turn leads to renal and cardiac failure.
• pulses are mixed with kesari dal or with metanil yellow to improve the colour which can cause carcinogenic disorder and it can also affect the nervous system.

We should be very careful in buying our food products and should be aware of our rights and actions which can be taken against people who are involved in this crime.

c. Precautions which are taken to preserve foods:

1. Storing fruits and vegetables in proper storage, for example, fruits like bananana are not stored in refrigerator while fruits like mangoes require refrigerator.
2. Storing grains, dals etc. in dry conditions and in air proof containers.
3. Making pickles and jams to increase their shelf life.

d. The undesirable or disagreeable change in the state of food which makes it unsuitable for human and animal consumption is termed as food spoilage. Spoilage of food can be caused by various factors like:

• Microorganisms: Growth of microorganisms like bacteria, fungi etc. can lead to spoilage of food. 
• Action of enzymes: Enzymes which are an inherent part of plant and animal tissue begin the decomposition process after the death of plant or animal. For example, a bananana starts to ripen and then spoil if it is not consumed on time.
• Infestation by insects: Insects like cockroaches may infest the food stuff and make them unsuitable for consumption. There is possiblity of transmission of pathogens from these insects.
• Wrong handling of products may also result in the spoilage of foodstuffs.
• Overcooking is another such reason for spoilage of foods.

e. The following methods of food preservation can be used:

• Preservation by common salt: Common salt is usually used to preserve meat and fish as it checks the growth of bacteria in these foods. It is also used to preserve amla, raw mangoes, and tamarind.

• Preservation by sugar: Sugar is usually used to preserve jam, jellies, and squashes. Sugar prevents spoiling of food by reducing the moisture content of food, which inhibits the growth of bacteria in it.

• Preservation by oil and vinegar: Oil and vinegar are used to preserve vegetables, fruits, fish, and meat. They prevent food from getting spoilt as micro-organisms cannot grow in such an environment.

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Question 3:

What shall we do?
(a) There are vendors selling uncovered sweetmeats in open places in the market.
(b) A 'pani-puriwalla' is serving the pani puri with dirty hands.
(c) We have purchased a large quantity of fruits and vegetables.
(d) We need to protect foodstuffs from pests like rats, cockroaches, wall-lizards, etc.

ANSWER:

a. We should not eat food from vendors who sell uncovered foods. We should try to talk to him and convince him to keep his food covered while selling it. Also, we should tell him the importance of clean and healthy food and how these habits can help him to gain profit for his business.

b. If a pani puriwalla is serving the pani puri with dirty hands, then we should not consume it. We sholud insist him to wash his hands and wear gloves while serving the pani puris.

c. If we have purchased large amounts of fruits and vegetables, then we need to store them properly. Some of the fruits can be used to make juices, jams and jellies which would increase their shelf life and also make it easy to store food. Vegetables can be cut and stored in deep freezers and then used as and when required. Some vegetables can also be used in making pickles.

d. Foodstuffs can be protected from rats, cockroaches etc. by storing them in proper conditions and proper areas. They should be stored in air tight containers and away from damp places which are the breeding places for these organisms.

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Question 4:

Find the odd-man-out.
(a) salt, vinegar, citric acid, sodium benzoate
(b) lakhi dal, brick dust, metanyl yellow, turmeric powder
(c) banana, apple, guava, almond
(d) storing, freezing, settling, drying

ANSWER:

(a) salt, vinegar, citric acid, sodium benzoate- salt is the odd one out beacuse it is natural preservative while rest of them are chemical preservatives.

(b) lakhi dal, brick dust, metanyl yellow, turmeric powder - turmeric powder is the odd one out because it is a type of spice while the rest of the three are adulterants.

(c) banana, apple, guava, almond- almond is the odd one our because it is a dry fruit whereas the rest of the three are fresh fruits..

(d) storing, freezing, settling, drying- settling is the odd one out because rest of the three are preservation methods.
 

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Question 5:

Complete the chart below.
 

S.No.	Foodstuff	Adulterant
1.	----------	Metanyl yellow
2.	Black pepper	----------
3.	----------	Iron filings
4.	Honey	----------

ANSWER:

S.No.	Foodstuff	Adulterant
1.	Turmeric powder	Metanyl yellow
2.	Black pepper	Papaya seeds
3.	Rava	Iron filings
4.	Honey	Sugar

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Question 6:

Explain why this happens and suggest possible remedies.
(a) Qualitative wastage of food.
(b) The cooked rice is underdone.
(c) The wheat that was bought is a bit moist.
(d) The taste of yoghurt is too sour/slightly bitter.
(e) Cut fruits have turned black.

ANSWER:

a. Wastage of food can either be qualitative or quantitative. Qualitative wastage of food is caused by:

• excessive use of preservatives
• over cooking of food
• washing vegetables after cutting them
• using wrong methods of protecting food
• mishandling of food products like fruits etc.

Qualitative wastage of food can be prevented by adopting steps like controlling the use of peservatives, taking care while cooking food to prevent it from being overcooked or undercooked, using proper methods of storage etc.

b. If the cooked rice is underdone, it can be used to make some foodstuff in which it can be reused. For example, underdone rice can be used to prepare kheer in which it can be cooked further with milk, or it can further be cooked to make papads or something else which would avoid its wastage.

c. If the wheat which was brought was little moist, it could be dried under the sun to remove this moisture. It is important to remove this moisture before grinding the wheat or storing it because it can act as a factor for the growth of microorganisms leading to its spoilage.

d. The taste of yoghurt could turn a little sour because it has undergone too much fermentation. The first thing would be to store this yoghurt in cold environment to stop further souring of the yoghurt. This yoghurt can then be used to make sweet lassi or some other delicacy like sindhi curry. 

e. Cut fruits turn black due to oxidation. Small amount of lemon juice should be applied to the surface of cut fruits as it prevents the oxidation of the fruits. 

Page No 40:

Question 7:

Give reasons.
1. Food remains safe at 5° Celsius.
2. Nowadays, food is served buffet style during large gatherings.

ANSWER:

a. Food remains safe at 5^oC because this temperature prevents the growth of microorganisms. Microorganisms usually require hot and humid places to grow whereas at this temperature they cannot grow and survive. Their metabolic activities are inhibited at this temperature.

b. Nowadays, foods are served in buffet style during large gatherings to prevent the wastage of food. Every indivisual can choose what to eat and how much to eat according to their wish and thus prevents the wastage of food.

Ch.7. Nutrition and Diet

Question 1:

Fill in the blanks.
(a) The process of intake of food and utilising it for all life processes is called .......... .
(b) All the substances in our food which are useful for various bodily processes are called .......... .
(c) Carbohydrates and .......... provide .......... to our body.
(d) In a balanced diet, all the nutrients are present in the ....... proportion.
(e) In the food pyramid, cereals are given the maximum space because they fulfil our .......... requirement.
(f) Intake of more food than necessary causes .......... .

ANSWER:

(a) The process of intake of food and utilising it for all life processes is called nutrition.
(b) All the substances in our food which are useful for various bodily processes are called nutrients.
(c) Carbohydrates and fats provide energy to our body.
(d) In a balanced diet, all the nutrients are present in the right proportion.
(e) In the food pyramid, cereals are given the maximum space because they fulfil our nutritional requirement.
(f) Intake of more food than necessary causes overnutrition.

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Question 2:

Spot the following in the table of vitamins and minerals.
(a) The nutrient present in citrous fruits.
(b) Vitamins / minerals present in milk.
(c) Causes and symptoms of night blindness, scurvy, rickets, beriberi.
(d) Foods required to prevent the above diseases.
(e) Causes of anaemia.
(f) Essential mineral for healthy bones and teeth.
(g) Sensory organ affected due to the deficiency of Vitamin A

ANSWER:

(a) The nutrient present in citrous fruits- Vitamin C
(b) Vitamins / minerals present in milk- Vitamin B₁₂ and Vitamin D.
(c) Causes and symptoms of night blindness, scurvy, rickets, beriberi
 

Disease	Causes	Symptoms
Night blindness	Deficiency of Vitamin A	Inability to see in dim light
Scurvy	Deficiency of Vitamin C	Bleeding of gums
Rickets	Deficiency of Vitamin D	Softening of pones causing pain and fractures
Beri beri	Deficiency of Vitamin B1	Nerve disorders

(d) Foods required to prevent the above diseases.
 

Disease	Foods to avoid these diseases
Night blindness	Carrot, milk, butter, dark green vegetables, sweet potato
Scurvy	Amla, kiwi, oranges, other citrus fruits, tomato, green leafy vegetables
Rickets	Milk, fish, eggs and butter
Beri beri	Milk, fish, meat, cereals, nuts, pulses

(e) Causes of anaemia- defeciency of iron can result in anaemia as it is required for the formation of red blood cells.
(f) Essential mineral for healthy bones and teeth- Vitamin D
(g) Sensory organ affected due to the deficiency of Vitamin A- Eyes

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Question 3:

Choose the correct alternative.

(a) Pulses are a very good source of .......... .

(1) carbohydrates	(2) proteins
(3) fats	(4) minerals

(b) .......... provide maximum energy to the body.

(1) Cereals	(2) Leafy vegetables
(3) Water	(4) Amla

(c) Goitre is caused by a deficiency of the mineral .......... .

(1) iron	(2) calcium
(3) iodine	(4) potassium

(d) .......... is a type of junk food.

(1) Orange	(2) Milk
(3) Bhakri	(4) Chocolate

ANSWER:

(a) Pulses are a very good source of proteins.
(b)Cereals provide maximum energy to the body.
(c) Goitre is caused by a deficiency of the mineral iodine.
(d) Chocolate is a type of junk food.

Page No 56:

Question 4:

Use the food pyramid to select food items of your choice for three days.
Conditions :
(1) The diet for all three days should be balanced.
(2) There should be variety in the items chosen for the three days.

ANSWER:

Day 1-
Cereal like cornflakes and milk, apple, roti, sabzi and dal

Day 2
Bread and butter with milk, rice/ roti and chicken, curd, any one type of fruit, salad

Day 3
Poha, green vegetable and dal with rice or roti, raita, one fruit, vegetable sandwich.

Current Electricity

Question 1:

Write proper words from the following group of words in the blanks.
(magnetism, 4.5V, 3.0V, gravitational attraction, potential differences, potential, higher, lower, 0V)

A.Water in the waterfall flows from a higher level to the lower level because of ____________.

B. In an electric circuit, electron flow a from of point of ________ potential to the point of ____________ potential.

C. The differences between the electrostatic potential of the positive end the negative end of an electric cell is the __________ of the cell.

D. Three electric cells of potential difference 1.5 V each have been connected as a battery. The potential differences of the battery will be ________ V.

E. An electric current flowing in a wire creates __________ around the wire. 

ANSWER:

A. Water in the waterfall flows from a higher level to the lower level because of potential differences.

B. In an electric circuit, electron flow a from of point of higher potential to the point of lower potential.

C. The differences between the electrostatic potential of the positive end the negative end of an electric cell is the potential of the cell.

D. Three electric cells of potential difference 1.5 V each have been connected as a battery. The potential differences of the battery will be 1.5 + 1.5 + 1.5 = 4.5 V.

E. An electric current flowing in a wire creates magnetic field around the wire. 

Page No 27:

Question 2:

A battery is to be formed by joining 3 dry cells with connecting wires. Show how will you connect the wires by drawing a diagram.

ANSWER:

or

Page No 27:

Question 3:

In an electric circuit, a battery and a bulb have been connected and the battery consists of two cells of equal potential difference. If the bulb is not glowing, then which tests will you perform in order to find out the reason for the bulb not glowing?

ANSWER:

The following test should be performed to find the reason why bulb is not glowing:

• Check how the terminals of the batteries are connected to each other: Ensure that the positive terminal of one battery is connected to negative terminal of other battery. If the batteries are connected in this this way and even then the bulb does not glow, go for the next test given below.
• Check for the broken wires in the circuit: Ensure that the wires used for connecting the various electrical components are nor broken in between i.e. ensure that the circuit is closed. Even after ensuring that the wires are not broken in between, the bulb does not glow, move to the next test.
• Check how the connecting wires are connected to the bulb: Ensure that the bulb is connected to the batteries using the connecting wires as shown below. Even now, if the bulb does not glow, replace the bulb or the batteries with a new one.

Page No 27:

Question 4:

Electric cells having 2 V potential difference each have been connected in the form of a battery. What will be the total potential difference of the battery in both cases ?
(i) 

(ii) 

ANSWER:

(i) Total potential difference = 2 + 2 + 2 = 6 V

(ii) Total potential difference = 2 + 2 + 2 + 2 = 8 V

Page No 27:

Question 5:

Describe the construction, working and usefulness of a dry cell, with the help of a diagram. 

ANSWER:

Construction of dry cell
The dry cell consists of following components:
Outer metal covering: The metal covering is made up of zinc metal and is whitish in appearance. It acts as a negative terminal of the cell.
Electrolyte: Inside the Zinc metal, there is the electrolyte filled between two layers. Electrolyte is a wet pulp of Zinc chloride (ZnCl₂) and Ammonium chloride (NH₄Cl). It is the charge carrier of electricity as it contains negatively charged and positively charged ions.
Metal rod: There is a graphite rod at the centre of the cell. It is surrounded by paste of Manganese dioxide (MnO₂). It acts as the positive terminal of the cell.

Working of dry cell: Chemical reactions take place between the electrolyte, zinc container and graphide rod. Because of this, electric charge is produced on the two terminals of the cell and electric current flows in the circuit.

Usefulness of dry cell: They are handy and portable. The life of dry cell is longer than cells using liquid electrolyte. Dry cells can be use in torch, T.V. or A.C remote controls, toys, etc.

Page No 27:

Question 6:

Describe the construction and working of an electric bell with the help of a diagram.

ANSWER:

Construction of an electric bell
Following are the components of electric bell:

• Electromagnet: A copper wire is wound around an iron piece which acts a magnet when current flows through it.
• Striker in touch with contact screw through an iron strip
• A metal gong
• A key or a switch

Working of an electric bell
When the switch is 'ON' and the screw is in contact with the iron strip, then electric current flows through the copper wire which gets magnetised because of electromagnetism. This magnetised copper wire (or the electromagnet) attracts the iron strip towards it, letting the striker hit the gong and thus sound is produced. As soon as the striker hits the gong, the screw loses its contact with the iron strip and therefore, current stops in the circuit. At this point, the electromagnet loses its magnetism and the iron strip moves back and comes in contact with the contact screw. The electric current is then restored in the circuit and again the striker hits the gong by the above process. This action repeats itself and the bell rings.

Ch.2 Parts of plants

Give examples of 3 plants that have :
(a) spiny fruits
(b) spiny stem
(c) red flowers
(d) yellow flowers
(e) leaves which close at night
(f) single-seeded fruits
(g) many-seeded fruits

ANSWER:

(a) spiny fruits- jackfruit, breadfruit and custard apple
(b) spiny stem- cactus, acacia and aloe vera
(c) red flowers- rose, hibiscus and carnations
(d) yellow flowers- marigold, sunflower and daffodil
(e) leaves which close at night- acacia, mimosa and albizia
(f) single-seeded fruits- mango, plum, cherries
(g) many-seeded fruits- watermelon, apple and kiwi

Page No 15:

Question 2:

Observe any one flower and its various parts and describe it in your own words.

ANSWER:

They different parts of a flower are:

1. Androecium (male reproductive organ) - The androecium consists of whorls of stamen. The stamen consists of the filament (long and slender stalk) and anther (bilobed structure). A typical anther is bilobed, which contains the pollen grains.

2. Gynoecium (female reproductive organ) − Gynoecium represents the female reproductive part made up of carpels. Carpel is made up of:

• Style − It connects stigma to the ovary.
• Stigma − It acts as a receptacle for the pollen grains.
• Ovary − It is the enlarged basal part on which style lies. Each ovary bears one or more ovules attached to cushion-like placenta. After fertilisation, ovules develop into seeds and ovary into fruit.

3. Calyx (accessory organ bearing sepals) − Calyx refers to the sepals.They are green in colour. They protect the plant in bud stage and also attract the insects for pollination.

4.Corolla (accessory organ bearing petals) − Corolla refers to the brightly coloured whorl of a flower. Individual unit of corolla is petals.Petals protect the inner essential organs (i.e., stamens and carpels) and attract pollinators since they are brightly coloured.​

Page No 15:

Question 3:

What are the similarities and differences between ?
(a) jowar and moong
(b) onion and coriander
(c) leaves of banana and mango
(d) coconut tree and jowar stalk plant

ANSWER:

a. 

Jowar	Moong
1. It is a type of monocot plant.	It is a type of dicot plant.
2. It has fibrous root system.	It has tap root system.
3. The leaves of jowar plant show parallel venation.	The leaves of moong plant show reticulate venation.

 
Similarity: Both jowar and moong are annual plants.

b. 

Onion	Coriander
1. It is a type of monocot plant.	It is a type of dicot plant.
2. It is a type of vegetable.	It is a type of herb.
3. The edible part is a bulb.	The edible part is leaf and stems.

Similarity: Both onion and coriander are annual plants.

​c. 

Leaves of Banana	Leaves of Mango
1. The leaves of banana are very long and have bifurcations on their edges.	Leaves of mango are short in size.
2. It has parallel venation.	It has reticulate venation.

Similarity: Both banana and coconut are perrenial plants.

d. 

Coconut tree	Jowar stalk plant
1. It can grow upto 15 - 23 metres.	It can grow upto 2 - 3 metres.
2. Leaves of coconut trees are arranged spirally.	Leaves of jowar stalk plants are arranged in opposite manner.

Similarity: Both have fibrous roots.

Page No 15:

Question 4:

Explain the following images in your own words.

ANSWER:

Image A represents a seed and its cross section. The seed consists of seed coat, cotyledon and an embryo. A seed coat is the outer covering of a seed. It is hard in nature and thus provide protection to the inner delicate parts of a seed. This embryo is thick and swollen due to the presence of food reserves.

Image B represents a monocot and a dicot seed. A monocot seed is made up of a single cotyledon called scutellum. It has a relatively small embryo which contains endosperm.

Page No 15:

Question 5:

Describe the functions of various parts of a plant.

ANSWER:

They different parts of a flower are:

• Androecium

• Gynoecium

• Calyx (accessory organ bearing sepals)

• Corolla (accessory organ bearing petals)

Calyx − Calyx refers to the sepals.They are green in colour. They protect the plant in bud stage and also attract the insects for pollination.

Corolla − Corolla refers to the brightly coloured whorl of a flower. Individual unit of corolla is petals.Petals protect the inner essential organs (i.e., stamens and carpels)andattract pollinators since they are brightly coloured.

Androecium (male reproductive organ) − The androecium consists of whorls of stamen. The stamen consists of the filament (long and slender stalk) and anther (bilobed structure). A typical anther is bilobed, which contains the pollen grains.

Gynoecium (female reproductive organ) − Gynoecium represents the female reproductive part made up of carpels. Carpel is made up of:

• Style − It connects stigma to the ovary.

• Stigma − It acts as a receptacle for the pollen grains.

• Ovary − It is the enlarged basal part on which style lies. Each ovary bears one or more ovules attached to cushion-like placenta. After fertilisation, ovules develop into seeds and ovary into fruit.

Page No 15:

Question 6:

Certain properties are mentioned be-low. Find a leaf corresponding to each property and describe those plants.
leaves with smooth surface, leaves with rough surface, fleshy leaf, spines on leaf.

ANSWER:

Fleshy leaves: Plants with fleshy leaves are called succulents and are usually found in areas like deserts. Their leaves are green and fleshy becuase they store water in them which can be used under adverse conditions. For example, opuntia.

Spines on leaf: Many plants have spines on their leaves. It is a way of protecting themselves from being eaten and destroyed by animals. For example, Acacia and aloe vera.

Leaf with rough surface: Asperifolia is a type of plant which has rough leaves. It belongs to the category of shrubs.

Leaf with smooth surface: Salix caroliniana or commonly known as Southern Willow is a plant which has smooth leaves. The simple smooth-edged narrow leaves are 2-4 m long, green above and whitish underneath.

Page No 15:

Question 7:

Find the plant parts.
 

r	b	u	d	x	s	r	f
o	w	p	y	e	t	a	1
o	l	1	d	n	e	d	o
t	a	o	i	1	m	i	w
c	n	e	t	a	1	c	e
a	v	o	v	u	m	l	r
p	e	t	a	1	s	e	o
r	o	o	t	h	a	i	r

ANSWER: