DPS - MIS, DOHA - QATAR

ASSIGNMENT FOR PISA EXAM

SUBJECT: SCIENCE

FORCE

  1. A plastic comb when rubbed with hair can attract piece of paper. Name force and its nature?
  2. Why it is not easy to walk wearing high heels shoe?
  3. Give two uses of fluid pressure?
  4. Give reason:

(a)A rolling ball stops after moving some distance.

(b) Every object left above the surface of the earth without a support, fall downwards.

  1. Name one contact and one non-contact force?
  2. What is SI unit of Force?
  3. On what principal, Hydraulic Disk brakes based on?
  4. Two forces 200N and 300N acting on a body in same direction. What is resultant force?
  5. Give two examples each of situations in which you push or pull to change the state of motion of objects.
  6. State Pascal’s law.
  7. The S.I unit of pressure is ______

a) N/mb) Pac) Nd) m/N

  1. The force exerted by the muscles is______

a) Non-contact forceb) magnetic forcec) contact forced) none

  1. 1 kg weight equals to _____

a) 9.8Nb) 98Nc) 980Nd) 10m

  1. Hydraulic devices are based on______
  2. The total force acting per unit area of the surface is called______
  3. How does pressure exerted by a liquid increase with depth? Give reason.
  4. Calculate the weight of the body whose mass is 20kg?(take g=10mls2)
  5. Explain contact and non-contact forces. Give two examples for each.
  6. Lubrication reduces friction between surfaces in contact. Explain.
  7. Define different types of friction.
  8. What are ultrasonic and infrasonic sounds?
  9. Explain sound pollution. Give two reasons for sound pollution.
  10. Give two examples each for stringed and wind instruments.
  11. Sound cannot travel through:

a)water

b)air

c)vacuum

d)steel

  1. Which of the following characteristics of sound depends on the amplitude of vibrations?

a)speed

b)pitch

c)loudness

d)quality

  1. The special shape of the body due to which it experiences least fluid friction is called

a)Friction

b)Buoyancy

c)Upthrust

d)Streamlining

  1. The S.I unit of force is

a)Newton

b)Kg wt

c)Pascal

d)Kg m/s2

  1. Which physical quantity of a body always remains constant?

a)Weight

b)Speed

c)Mass

d)Force

  1. State the type of force acting in the following conditions-

a)Bullocks ploughing the field.

b)Attraction of paper bits towards a comb.

c)Stopping a goal by a goalkeeper.

d)Coming downwards of the object even when it is thrown upwards.

  1. Name one contact and one non-contact force?
  2. Two forces 200N and 300N acting on a body in same direction. What is resultant force?
  3. The force applied by the archer to stretch the bow is an example of ______force.
  4. The force exerted by the muscles is ______force.
  5. How would you show that like charges repel each other and unlike charges attract each other?

NATURAL PHENOMENA

  1. Write about the following in detail:
  1. Earth quake b. Volcano c.Tsunami
  1. What is the reason behind the lightning that we see in the sky during rainy season?
  2. Explain why a charged body loses its charge if we touch it with our hand.
  3. The upper solid layer of the earth is called___

a)Mantle

b)Core

c)Crust

d)Fault

  1. The electrical charge generated by rubbing is called ____

a)Current electricity

b)Static electricity

c)Earthing

d)None

  1. During earthquake students should crouch under their desks. (True or False)
  2. The seismic waves are seconded by an instrument called the seismograph.

(True or False)

MOTION

  1. Define the following: a) velocity b) acceleration c) uniform circular motion
  2. Distinguish between distance and displacement.
  3. Why is the motion in a circle at a constant speed called accelerated motion?
  4. On a 60 km track, a train travels the first 30 km with a uniform speed of 30 km/h. How fast must the traintravel the next 30km or so as to average 40 km/h for the entire trip? (Ans:60 km/h)
  5. Plot the distance-time in the following cases:
  1. For a stationary body
  2. For a body in uniform motion
  3. For a body in non-uniform motion
  1. An object goes from point X to Y and then come back from Y to X. What is the displacement and average velocity?
  2. Write down the difference between Scalars and Vectors?
  3. Four Cyclist A,B,C ,D starts at the same point and at the same time and move in a straight line to reach destination .They all move with uniform velocities. They reach the destination in the following order
    C→A→B→D
    Answer the following questions
    a. If the displacement-time graph is plotted for each cyclist, which will be having highest slope
    b. Arrange the cyclist in decreasing order of velocity
  4. What do you infer if?

1 / Distance –time graph is straight line
2 / Velocity –time graph is curved
3 / Displacement –time is zig zag
  1. State whether the following statements are true or false.
    A) Displacement can be zero but distance never
    B) Displacement magnitude can be greater than distance travelled by the object
    C) Time is a vector quantity
    D) If the velocity of the body decreases with time, the acceleration is negative (retardation), and the motion is called decelerated motion
    E) The area of the velocity time graph gives displacement of the body
    F) Acceleration is a scalar quantity
    G) Motion and rest are relative terms
    I) an object can be moving with Uniform speed but variable acceleration

CELL: STRUCTURE AND FUNCTION

1. Name the following:

(i)Smallest unit of life.

(ii)Scientist who discovered cell.

(iii)Organism in which metabolic functions like nutrition, respiration, reproduction etc. are carried-out by the single cell.

(iv) Longest cell in human body.

(v)Outermost layer in an animal cell.

(vi)The solution present in plant vacuoles.

(vii)Main component of cell walls in plants.

(viii)Full form of DNA.

(ix)Component in lysosomes that help them in cellular digestion.

(x)Function of rough endoplasmic reticulum.

(xi)Helps in transport of substances within the cell.

(xii)Present in abundance in red and orange coloured fruits.

(xiii)Site of cellular respiration.

(xiv)Site of photosynthesis.

(xv)Contains centrioles.

(xvi)Contains enzymes for cellular digestion.

(xvii)Stores excess materials.

(xviii)Synthesize, store and secrete enzymes and proteins.

(xx)The structure inside the nucleus concerned with protein synthesis.

(xxi)Group of similar cells that perform a particular function.

(xxii)This unit is used to measure the size of cell.

(xxiii)This cell in human body can change its shape.

(xxiv)Smallest cell.

(xxv)An instrument to view small objects by magnifying them.

(xxvi)Non-living substances in a cell.

(xxvii)Organisms that do not have a well-defined nucleus.

(xxviii)Hereditary units of chromosomes.

(xxix)This organelle in animal cells help in cell division.

(xxx)Golgi apparatus in plant cells are known as.

(xxxi)Cell organelle that stores excess materials.

(xxxii)Cell organelles that give colour to carrots.

2. Give reasons:

(i)A cell is defined as the smallest structural and functional unit of life.

(ii)Chloroplasts are called as the kitchen of a cell.

(iii)Lysosomes are called as the suicidal bags of a cell.

(iv)Mitochondria are referred to as the power house of the cell.

(v)Nucleus is known as the brain of the cell.

(vi)Ribosomes are called protein factories.

(vii)Offspring’s resemble their parents.

(viii)Cell is called the basic unit of life.

(ix)Plant cell needs a cell wall.

(x) Genes are called hereditary unit.

3. Differentiate between:

(i)Organ & Organelle

(ii)Chromoplast and Leucoplast

(iii)Plant cell and Animal cell

(iv)Bacterial cell and Nerve cell of human beings

(v)Plasma membrane and Cell wall

(vi)Ribosome and Lysosome

(vii)Nuclear sap and Cell sap

(viii)Nucleus and Nucleolus

(ix)Prokaryotes and Eukaryotes

(x)Chromosome and Deoxyribonucleic acid

(xi)Cell organelles and cell inclusions

4. Answer the following briefly:

(i)Arrange the following in the correct order of level of organization.

(a)Brain, Neuron, Nervous system, nervous tissue.

(b)Muscular tissue, Heart, Cardiac muscle cell, Circulatory system.

(ii) Classify the following terms into cells, tissues and organs and write in the tabular column given below.

RBC, WBC, Nerve cell, blood, muscle, blood vessels, brain, heart, hand

(iii)Which of the cells have larger vacuoles (a) plant cell or (b) animal cells, and why?

(iv)Name two cell organelles each exclusively found in plant and animal cells.

(v)Amoeba and Paramecium belong to which category of organisms?

(vi)We do not sense any pain when we clip our nails or cut our hair. Why?

(vii)Observe the following diagram and answer the following questions.

(a) Does it represent a plant cell or an animal cell? Give reasons.

(b) Does it represent a prokaryotic cell or an eukaryotic cell? Give reasons.

(viii)Label the parts A to E in the given diagram.

(ix)Is the following statement correct? If it is wrong, correct the statement

Statement: “Unicellular organisms do not respire, only multicellular organisms respire”

Long Answer Type Questions

(i) Cells consist of many organelles, yet we do not call any of these organelles as structural and functional unit of living organisms. Explain.

(ii) Why do plant cells have an additional layer surrounding the cell membrane? What is this layer known as?

(iii) The size of the cells of an organism has no relation with the size of its body. Do you agree? Give reason for your answer.

(iv)Draw the pyramid showing the different levels of organization in a living organism.

(v)What type of cell is shown below?

(a) Label A-J and X, Y and Z. Also write their important functions.

(b) Name the nucleoproteins present in Y.

6. Label the parts of the diagram.

1. Name the following:

(i)Golgi apparatus in plants.

(ii)The process of formation of cell membrane with lipids and proteins.

(iii)The energy currency of the cell.

(iv)The undefined nuclear region containing only nucleic acid.

(v)The process by which an amoeba engulfs liquid food.

(vi)The organelle that contains digestive enzymes.

(vii)Colourless plastid which stores proteins, lipids and starch.

(viii)The site of protein synthesis in the cell.

(ix)The finger-like folds of the inner membrane of mitochondria.

(x)The fluid present in the vacuole of a plant cell.

(xi)Membrane of the vacuole.

(xii)The chemical composition of plasma membrane.

(xiii)The process of reversal of a plasmolysed cell to its normal condition.

(xiv)The functional segments of DNA.

(xv)The membrane-bound vesicular structure of Golgi apparatus that are arranged parallelly.

(xvi)The organelles that have their own genetic material.

(xvii)The organisms with poorly defined nucleus.

(xviii)The type of solution which has more water molecules than the cell.

(xix)The scientist who proposed the term “protoplasm”.

(xx)A cell organelle without a membrane .

(xxi)Passage of water from a region of high water concentration through a semi-permeable membrane to a region of low water concentration.

(xxii)Shrinking of a plant cell when placed in a hypertonic solution.

(xxiii)The poorly defined nucleus of a bacterial cell.

(xxiv)An entangled mass of thread-like structures present in a eukaryotic nucleus.

(xxv)The phase when chromosomes become visible.

(xxvi)The region within the cell membrane that takes up a very light stain.

(xxvii)The energy currency of the cell.

(xxviii)The specialized vacuole found in some unicellular organisms that help in expelling excess water and wastes from the cell.

2. Answer the following questions:

(i)A red blood cell when placed in solution ‘A’ swells up. What happens if it is kept in solution A for a long time? What will happen if the same condition persists for a raisin? Explain

(ii)After eating cookies we feel thirsty. Explain the phenomenon responsible for this.

(iii)What will happen if the plasma membrane ruptures?

(iv)How is endocytosis different from active transport?

(v)Why do we stain cells while observing under the microscope? List some commonly used stains.

(vi)How do substances like Carbon di oxide and water move in and out of the cell?

(vii)Why plasma membrane is called a selectively permeable membrane?

(viii)Why are lysosomes known as suicidal bags?

(ix)Write the significance of osmosis in plants.

(x)What is a gene?

(xi)Name two nucleic acids present in the cells.

3. What happens when?

(i)Dry apricots are kept in pure water for some time and then transferred to sugar solution.

(ii)Rhoe leaves are boiled in water and then a drop of sugar syrup is put on it.

(iii)Golgi apparatus is removed from a cell.

(iv) A red blood cell is kept in concentrated salt solution.

(v)Plasma membrane of a cell breaks down.

4. Give reasons.

(i) Inner membrane of mitochondria has many folds.

(ii)Endocytosis is found only in animal cells.

(iii)Osmoregulation is necessary in case of unicellular aquatic organisms.

(iv)A de-shelled egg is placed in pure water, after 5 minutes it swells.

(v)When placed in hypotonic solution for a very long time, an animal cell bursts but a plant cell does not.

(vi)Mitochondria and chloroplasts can synthesize their own proteins.

(vii)In the laboratory, after removing the onion peel, it should immediately be transferred to water.

(viii)Plasma membrane is known as selectively permeable membrane.

(ix)While cooking any vegetable, when we put salt ,the vegetable releases water.

5. Name the cell organelles involved in the following functions.

(i)It produces vacuoles or secretory vesicles.

(ii)Secretes lipids.

(iii)Helps in membrane biogenesis.

(iv)Produces enzymes for lysosomes.

(v)Involved in active transport.

(vi)Forms spindle during cell division in animals.

(vii)Stores starch, oils and proteins.

(viii)Detoxification of poisons in the lungs of vertebrates.

(ix)Serves as channels for the transport of materials within the cytoplasm.

6. Differentiate between:

(i)Plant cell and Animal cell

(ii)Prokaryotic cell and Eukaryotic cell

(iii)Diffusion and Osmosis

(iv)Endosmosis and Exosmosis

(v)Cell wall and Cell membrane

(vi)SER and RER.

(vii)Hypotonic, Hypertonic and Isotonic solution

(viii)Multicellular and Unicellular organism

(ix)Chromosome and Chromatin

(x)Bacterial cell and Onion peel cell

(xi)Mitochondria and Chloroplast

7. Explain the phenomenon in the given pictures.

a)

b)

c)

8. Very short answer questions.

(i)What is cytoplasm?

(ii)What is a chromosome made up of?

(iii)Who discovered cell?

(iv)Name two cell organelles that have their own genetic material.

(v)Give the term for incipient nucleus of bacteria. What type of cell is it?

(vi)Who discovered nucleus?

(vii)Name two factors on which the shape of cell depends.

(viii)Every multicellular organism arise from single cell. Justify.

(ix)The synthesis, packaging and movement of proteins have stopped inside a cell. Which cell organelle/organelles could probably have stopped functioning?

(x) Name the 3 functional region of the cell.

9. Short answer questions.

(i)List two functions of plasma membrane.

(ii)What are the similarities between mitochondria and chloroplast?

(iii)What are plastids and what are their main kinds?

(iv)What are the different ways in which substances move across plasma membrane?

(v)What is cell theory and who proposed it?

(vi)How ER and Golgi body are functionally related?

(vii)Under what conditions can a plant cell become plasmolysed and deplasmolysed?

(viii)What features of the membrane of mitochondria and chloroplast make them suitable for their functions?

(ix)How is nucleus able to control all the activities of a cell?

(x)Why are viruses not able to show features of life outside a living cell?

(xi)What is the advantage of multicellularity over unicellularity?

(xii)Observe the diagram below and note down the differences between the two cells.

10. Identify the type of solution the cells are placed in the folowing three cases. Explain the changes taking place in the cells placed in solutions A, B & C.

A B C

11. Choose the keywords to link it to the given conditions.

{Endosmosis, Exosmosis, Endocytosis, Diffusion, Plasmolysis}

(i) Absorption of water by roots.

(ii) Engulfing of food by amoeba.

(iii) Mangoes shrinking in salt solution.

(iv) Entry of oxygen into the cell.

(v) Swelling of a marine fish when placed in fresh water.

DNA and chromosomes

  1. What are chromosomes?

Ans. Chromosomes are a thread-like structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.

  1. What is the function of chromosome?

Ans. I) As the genetic material passes from parents to child, the chromosomes are responsible for containing the instructions that make the offspring unique while still carrying traits from the parent.

ii) The structure of chromosomes helps ensure the DNA remains tightly wrapped around the proteins;otherwise, DNA molecules would be too large for the inside of the cells

iii) Chromosomes are important to this process to ensure the DNA is accurately replicated.

  1. What are different types of chromosomes?

Ans.Chromosomes are divided into four types based on the centromere position. These four types are as follows:

i)Metacentric Chromosome
The metacentric chromosome has its centromere centrally located between the two arms. This gives the chromosome a typical 'V' shape that is seen during the anaphase. The arms of this chromosome are roughly equal in length. In certain cells, fusion of two acrocentric chromosomes leads to formation of metacentric chromosome.

ii)Submetacentric Chromosome
The arms of the submetacentric chromosome are said to be unequal in length. This is because the kinetochore is present in the sub median position. This gives rise to the 'L' shape of the submetacentric chromosome.