Question bank
Class 7. (Science)
Chapter 1 , 2 & 3
Q1 . What type of plants have Rhizobium bacteria in their root nodules ?
Q2. What is photosynthesis ?
Q3 . Name three plant nutrients commonly present in fertilizers and manures.
Q.4. Explain why we cannot make food ourselves by photosynthesis like the plants do.
Q5 . Proteins are nitrogenous food. How do plants get nitrogen for making proteins ?
Q6 . What are insectivorous plants ? Name an insectivorous plant
Q7 describe briefly how nutrients are replenished in the soil ? How is the growing of leguminous crop in the fields beneficial to the farmers ?
Chapter 2
Q1. The bacteria present on unclean teeth convert the sugar in food into a substance X which causes tooth decay name the substance x.
Q2. What is the special name of the animals which can chew the cud ?
Q3. Write the full form of ORS.
Q4. Name the condition in which a person passes out frequent watery stools.
Q5 . What is alimentary canal ? Name the various parts of alimentary canal and the associated glands.
Q6. Where is the bile produced ? which component of food does it digest .
Q7. How does Amoeba take in the food ? From which part of the body undigested
food is egested in amoeba ?
Q8. Draw a neat labelled diagram of the human digestive system.
Q9. What is meant by the term "rumination "name any two ruminants.
Ans: the process by which the cud (partially digested food) is brought back from the stomach to the mouth of the animal and chewed again is called rumination.
Cow and buffalo are the two ruminants.
Q10. Name the three things secreted by the inner lining of our stomach also state their functions. what is the function of large intestine ?
Ans:. The inner lining of stomach secrete mucus , hydrochloric acid , and digestive juices.
Mucus protects the lining of stomach.
Hydrochloric acid kills any bacteria which may enter the mouth with food . It also make the medium in the stomach acidic which is essential for proper action of digestive juices on protein in the stomach.
The digestive juices secreted by the stomach lining breaks down the proteins present in our food into simpler substances.
The large intestine absorbs most of the water from the undigested food material .This waste material is stored in the last part of the large intestine that is called rectum.
Chapter 3:
Q1. Name the tree whose leaves provide food for the silkworms .
Q2 . Name a natural fibre obtained from insects .
Q3 . What is meant by rearing and breeding of sheep ?
Q4. Name the most common Silk moth. What are the characteristics of silk fibres obtained from the cocoons of this Silk moth ?
Q5. Arrange the following steps in the correct order in which they are carried out during the production of woolen yarn from the Sheep :
Combing , shearing, dyeing , scouring , spinning ,sorting .
Q6. In what type of weather shearing of sheep is done ? why ? Why does shearing not hurt the Sheep ?
Ans:. The searing of ship is done in the hot weather of Summer so that sleep may survive without their protective coat of hair
Shearing does not hurt the Sheep because the uppermost layer of the skin of sheep is dead .
Q7. How will you distinguish between natural silk and artificial silk ?
Q8. What is meant by the following terms:
a. Shearing
b. Scouring
C. Sorting
.
Q9. The hair of animal A are cut from its body in one piece along with a thin layer of its skin in the form of B This process is called C .The B of this animal is then cleaned by using soap and a lot of water by a process D The clean B is then converted into yarn by the process of sorting ,Dyeing combing and spinning.
a. What could be A and B ?
b. Name the process C and D
C. What is yarn E
d . State one use of E. ( high order thinking skills *)
Answers
Answer:
Q. 1)
Rhizobium spp. are soil-dwelling α-Proteobacteria that can fix nitrogen in a symbiotic relationship with leguminous plants. Nodules develop on the roots of nitrogen-starved legumes such as peas, beans, clover, and soy. Within these nodules, rhizobia differentiate into bacteroids that fix atmospheric nitrogen using nitrogenase. The rhizobia–legume symbiosis is a widely studied example of mutualism because legumes are important food crops. In return for reduced nitrogen, plants provide carbon and energy in the form of organic acids to the bacteroids.
Q2) Silk is one of the oldest fibres known to man. It is an animal fibre produced by certain insects to build their cocoons and webs.
Q3) Most fertilizers that are commonly used in agriculture contain the three basic plant nutrients: nitrogen, phosphorus, and potassium.
Q4) Our body cells lack one cell organelle which is present in plants, that is, chloroplast. Chloroplast contains a pigment called chlorophyll which is necessary for the photosynthetic reactions to take place. ... Hence, these are various reasons why we cannot photosynthesize like plants but depend upon them for food.
Q5) Certain plants produce nitrogenous food known as proteins. Plants obtain nitrogen through soil. Gaseous nitrogen is converted to usable form by bacteria known as rhizobium present in soil. This process of conversion of nitrogen is known as nitrogen fixation.
Q6) Insectivorous plants are plants that derive some of their nutrients from trapping and consuming animals or protozoan. ... Insectivorous plants include the Venus flytrap, several types of pitcher plants, butterworts, sundews, bladderworts, the waterwheel plant, brocchinia and many members of the Bromeliaceae.
Q. 7)nutrients are replenished as in soil because of the leguminous plants, they have a bacteria called rhizobium in root nodules which helps in nitrogen fixation in the soil . thus this replenish the soil with furthermore nutrients.