CHAPTER 6
A .MCQ
1.(b) 2. (b) 3. (b) 4.(c ) 5. (b) 6.(a) 7.(c) 8.(d) 9.(b)
B .VERY SHORT ANSWERS
(a) Autotrophs or green plants
(b) Chloroplast
(c) ATP
(d) Glucose
(e) Green plants
(f) Dissolved CO2
(g) Stroma
(h) Phloem(It’s a type of Vascular tissue or conductive tissue of plants)
C SHORT ANSWER
1.
(a) Respiration involves the intake of O2 and release of CO2. Photosynthesis involves the intake of CO2 and release of O2.
(b) The products of light reaction consists of NADPH, Oxygen& ATP
Glucose(Carbohydrate) is produced at the end of dark reaction.
(c )Producers prepare the food (glucose) by itself by using the raw material such as CO2,H2O,sunlight (autotrophs)whereas consumers directly or indirectly consume the food prepared by producers ( heterotrophs)
(c) Grass is a producer since it can trap sunlight as it has got chlorophyll in its cells, to prepare glucose by using the raw material such as CO2, H2O etc (autotrophs). Grasshopper is a heterotroph, as it is consuming the food prepared by the plants.
(d) Chlorophyll is a pigment, highly sensitive to light,& can trap solar energy as photons, the smallest unit of light energy. Chloroplast is a cell organelle of plant cell which is oval in shape contain chlorophyll .
2.IDENTIFY FALSE STATEMENTS & MAKE CORRECTIONS
(a) False . Dark reaction of photosynthesis occurs during night& day time
(b) True
(c ) False. Starch produced in a leaf remains stored in it for a short while, till night, and is transported to other parts to be used by other parts.
(d)True
(e ) False. Green plants are producers.
(f ) False-Photo synthesis results in gain of dry weight.( Normal weight without any extra water content)
(g) False. Photosynthesis stops above 400C.
(h) True
(i) True
(j) True
3 FILL IN THE BLANKS
(a) Grana
(b) Iodine solution
(c) Chloroplast
(d) Calvin cycle
(e) Sucrose
4. SAY TRUE OR FALSE WITH REASON
(a) False. Rate of photosynthesis increases with light intensity, till the availability of CO2 reaches upto 0.02%. Then further increase of light intensity has no effect on rate of photosynthesis. If the CO2 concentration raises further up to 0.05%, there will be again a raise in rate of photosynthesis.
(b)False .Rate of photosynthesis increases with temperature till it reaches 350C.
©False. A particular temperature is required for photosynthesis( optimum temperature)
(d ) False. Absence of sunlight (a dark room)is required for destarching.
(e ) False. Carbon cycle comprises of cyclic chemical reactions . Cycling of carbon in its various forms between atmosphere, living organisms (biosphere) & soil(lithosphere).
(f) False. Dark reaction is light independent reaction. Presence of light is not a must. It takes place even in the presence of light & absence of light.
(g) True. Plants are the only organisms able to trap sun’s energy as it has chlorophyll pigment molecule. This energy is being transferred to consumers of different levels through food chains.
5.(i) photons (ii)grana (iii)water molecules,(iv) hydrogen and hydroxyl ions,(v) oxygen
6. DIFFERENCES
Photosynthesis Respiration
(i ) Light is essential (i) Light is not essential
(ii) Making process (ii) Breaking process
(anabolic process) ( catabolic process)
(iii) Raw materials are CO2,H2O, sunlight&chlorophyll (iii)Glucose like biomolecules &O2
(iv) C6H12O6,O2 &H2O (iv) CO2 & H2O
(v) Takes in CO2 &gives out O2 (v) Takes inO2 & gives out CO2
7. Its not a waste product . But it’s the end product, which is essential for other living organisms for their survival.
8. Plant is kept in darkness in order to ensure that the entire starch is consumed by the plant itself. This makes it easier to find out the probability of formation of starch when the plant is shifted to the light. Further on conducting the entire series of procedures which involves boiling in water ,in methylated spirit with the support of water bath & again in water followed by iodine test will give conclusion about starch synthesis and essential factors of photosynthesis.
9. When a plant is kept in sunlight , CO2 released by respiration gets used by photosynthesis to synthesis food. So no CO2 is liberated, &respiration can’t be demonstrated.
10.Upper epidermis of leaf has cuticle & sometimes its waxy to prevent transpiration. Upper epidermis of dicot leaf is more green, as the palisade tissues which is near to upper epidermis has more chloroplast than spongy tissue which is near to spongy tissues.
11. With the help of Hydrilla experiment- Page 75-76 Expt:4
12.(i) Light reaction
STEP I Activation of chlorophyll. The chlorophyll on exposure to light energy becomes activated by absorbing photons.
STEPII Splitting of water. The absorbed light energy is used in splitting the water molecules (H2O) into its two components(hydrogen &oxygen)and releasing electrons.
(ii) Dark reaction. Involves transfer of hydrogen from NADPH through a series of chemical reactions, to combine with CO2 to produce C6 H 12 O6 (reduction of CO2 to glucose)by using energy fromATP.
13. (i)Grass— Rat—–Snake—–Hawk
(ii) Grains—Mouse—-Snake—-Peacock
14.Non green Plants like fungi& bacteria obtain their nourishment from decaying organic matter in the environment. This matter comes from dead animals & plants which in turn depend directly or indirectly on photosynthesis.
15. Chlorophyll is the only pigment or biomolecule which can trap sun’s energy . The makes it available for entire living world.
16 (1) to kill the cells of leaf
(2) to remove chlorophyll
(3) Iodine (4) non-green region (5) brown coloration