Q17 of 36 Page 1

Read the following and answer any four questions from 17 (i) to 17 (v)

All living cells require energy for various activities. This energy is available by the breakdown of simple carbohydrates either using oxygen or without using oxygen


(i) Energy in the case of higher plants and animals is obtained by


a) Breathing


b) Tissue respiration


c) Organ respiration


d) Digestion of food


(ii) The graph below represents the blood lactic acid concentration of an athlete during a race of 400 m and shows a peak at point D.



Lactic acid production has occurred in the athlete while running in the 400 m race. Which of the following processes explains this event?


a) Aerobic respiration


b) Anaerobic respiration


c) Fermentation


d) Breathing


(iii) Study the graph below that represents the amount of energy supplied with respect to the time while an athlete is running at full speed.




(iv) The characteristic processes observed in anaerobic respiration are


i) presence of oxygen


ii) release of carbon dioxide


iii) release of energy


iv) release of lactic acid


a) i) ,ii) only


b) i), ii), iii) only


c) ii), iii), iv) only


d) iv) only


(v) Study the table below and select the row that has the incorrect information



(i) b) Tissue respiration


Solution: In higher animals and plants, the gases are transported via the circulatory system and then at the tissue level, the gases are exchanged by the mode of diffusion. The oxygen taken into the cells of the tissue near the components of the circulatory/transport system of the higher organism and energy will be generated and stored in the form of ATP.


(ii) b) Anaerobic respiration


Solution: Lactic acid formation takes place in the muscle cells of humans when there is insufficient supply of oxygen. The accumulation of lactic acid causes cramps and is reflected in the blood as well.


(iii)


Aerobic Respiration provides the maximum energy generation and consistently higher than the energy produced during Lactic acid fermentation in Anaerobic respiration. Hence, the graph A denotes Aerobic respiration (high and consistent) while the graph B denotes Anaerobic respiration (explosive energy production during the initial stages but as the lactic acid accumulates, the energy production also drops).


(iv) c) ii), iii), iv) only


Anaerobic respiration takes place in the absence of oxygen. Pyruvate is converted into lactic acid with the generation of low energy (~2 ATPs). While in the alcoholic fermentation during the anaerobic respiration, both Ethanol and CO2 are formed (as seen in Yeast) along with production of small amounts of ATPs.


NOTE : The option C is not absolutely correct in this question because in lactic acid fermentation, no CO2 is formed. But since no other correct option is given, we would have to choose Option C.


(v) a) Location Aerobic-Cytoplasm and Anaerobic-Mitochondria


Aerobic respiration takes place inside the mitochondria and not in the cytoplasm. It requires oxygen and the amount of ATP generated is higher than that in anaerobic respiration, that can occur in the cytoplasm. The final products of Aerobic respiration are CO2 and H2O whereas in anaerobic respiration, the final products may be alcohol and CO2 (alcoholic fermentation) or Lactic acid (lactic acid fermentation) along with production of a little amount of ATPs.


More from this chapter

All 36 →
15

Assertion: Food chain is responsible for the entry of harmful chemicals in our bodies.

Reason: The length and complexity of food chains vary greatly.


a) Both A and R are true, and R is correct explanation of the assertion.


b) Both A and R are true, but R is not the correct explanation of the assertion.


c) A is true, but R is false.


d) A is false, but R is true.


OR


Assertion: Greater number of individuals are present in lower trophic levels.


Reason: The flow of energy is unidirectional.


a) Both A and R are true, and R is correct explanation of the assertion.


b) Both A and R are true, but R is not the correct explanation of the assertion.


c) A is true, but R is false.


d) A is false, but R is true.


 16

Assertion: A geneticist crossed a pea plant having violet flowers with a pea plant with white flowers, he got all violet flowers in the first generation.

Reason: White colour gene is not passed on to the next generation.


a) Both A and R are true, and R is correct explanation of the assertion.


b) Both A and R are true, but R is not the correct explanation of the assertion.


c) A is true, but R is false.


d) A is false, but R is true.


 18

Read the following and answer any four questions from 18 (i) to 18 (v).

Metallic Character


The ability of an atom to donate electrons and form positive ions (cation) is known as electropositivity or metallic character. Down the group, metallic character increases due to increase in atomic size and across the period, from left to right electropositivity decreases due to decrease in atomic size.


Non-Metallic Character


The ability of an atom to accept electrons to form a negative ion (anion) is called non-metallic character or electronegativity. The elements having high electro-negativity have a higher tendency to gain electrons and form anion. Down the group, electronegativity decreases due to increase in atomic size and across the period, from left to right electronegativity increases due to decrease in atomic size.



(i) Which of the following correctly represents the decreasing order of metallic character of Alkali metals plotted in the graph?


a) Cs>Rb>Li>Na>K


b) K>Rb>Li>Na>Cs


c) Cs>Rb>K>Na>Li


d) Cs>K>Rb>Na>Li


(ii) Hydrogen is placed along with Alkali metals in the modern periodic table though it shows non-metallic character


a) as Hydrogen has one electron & readily loses electron to form negative ion


b) as Hydrogen can easily lose one electron like alkali metals to form positive ion


c) as Hydrogen can gain one electron easily like Halogens to form negative ion


d) as Hydrogen shows the properties of non-metals


(iii) Which of the following has highest electronegativity?


a) F


b) Cl


c) Br


d) I


(iv) Identify the reason for the gradual change in electronegativity in halogens down the group.


a) Electronegativity increases down the group due to decrease in atomic size


b) Electronegativity decreases down the group due to decrease in tendency to lose electrons


c) Electronegativity decreases down the group due to increase in atomic radius/ tendency to gain electron decreases


d) Electronegativity increases down the group due to increase in forces of attractions between nucleus & valence electrons


(v) Which of the following reason correctly justifies that “Fluorine (72pm) has smaller atomic radius than Lithium (152pm)”?


a) F and Li are in the same group. Atomic size increases down the group


b) F and Li are in the same period. Atomic size increases across the period due to increase in number of shells


c) F and Li are in the same group. Atomic size decreases down the group


d) F and Li are in the same period and across the period atomic size/radius decreases from left to right.


 19

Read the following and answer any four questions from 19 (i) to 19 (v)

Sumati wanted to see the stars of the night sky. She knows that she needs a telescope to see those distant stars. She finds out that the telescopes, which are made of lenses, are called refracting telescopes and the ones which are made of mirrors are called reflecting telescopes.



So she decided to make a refracting telescope. She bought two lenses, L1 and L2. out of which L1 was bigger and L2 was smaller. The larger lens gathers and bends the light, while the smaller lens magnifies the image. Big, thick lenses are more powerful. So to see far away, she needed a big powerful lens. Unfortunately, she realized that a big lens is very heavy.


Heavy lenses are hard to make and difficult to hold in the right place. Also since the light is passing through the lens, the surface of the lens has to be extremely smooth. Any flaws in the lens will change the image. It would be like looking through a dirty window.


(i) Based on the diagram shown, what kind of lenses would Sumati need to make the telescope?


a) Concave lenses


b) Convex lenses


c) Bifocal lenses


d) Flat lenses


(ii) If the powers of the lenses L1 and L2 are in the ratio of 4:1, what would be the ratio of the focal length of L1 and L2?


a) 4:1


b) 1:4


c) 2:1


d) 1:1


(iii) What is the formula for magnification obtained with a lens?


a) Ratio of height of image to height of object


b) Double the focal length.


c) Inverse of the radius of curvature.


d) Inverse of the object distance.


(iv) Sumati did some preliminary experiment with the lenses and found out that the magnification of the eyepiece (L2) is 3. If in her experiment with L2 she found an image at 24 cm from the lens, at what distance did she put the object?


a) 72 cm


b) 12 cm


c) 8 cm


d) 6 cm


(v) Sumati bought not-so-thick lenses for the telescope and polished them. What advantages, if any, would she have with her choice of lenses?


a) She will not have any advantage as even thicker lenses would give clearer images.


b) Thicker lenses would have made the telescope easier to handle.


c) Not-so-thick lenses would not make the telescope very heavy and also allow a considerable amount of light to pass.


d) Not-so-thick lenses will give her more magnification.