Which one of the following roles is not characteristic of an essential
Question: Which one of the following roles is not characteristic of an essential element? a. is a component of biomolecules b. changing the chemistry of soil c. being a structural component of energy-related chemical compounds d. activation or inhibition of enzymes Solution: Option (b)changing the chemistry of soil is the answer...
Read More →Differentiate:
Question: Differentiate: $e^{x} \cos x$ Solution: To find: Differentiation of $e^{x} \cos x$ Formula used: (i) (uv) = uv + uv (Leibnitz or product rule) (ii) $\frac{d e^{x}}{d x}=e^{x}$ (iii) $\frac{d \cos x}{d x}=-\sin x$ Let us take $u=e^{x}$ and $v=\cos x$ $u^{\prime}=\frac{d u}{d x}=\frac{d e^{x}}{d x}=e^{x}$ $v^{\prime}=\frac{d v}{d x}=\frac{d \cos x}{d x}=-\sin x$ Putting the above obtained values in the formula:- $(u v)^{\prime}=u^{\prime} v+u v^{\prime}$ $\left(e^{x} \cos x\right)^{\prim...
Read More →Water molecule is very polar.
Question: Water molecule is very polar. Polar end of molecule attracts opposite charges on another water molecule (acts like a magnet). How will you explain this property of water with reference to the upward movement of water? Comment on the upward movement of water given the intermolecular hydrogen bonding in water. Solution: The process by which water molecules remain attached to one another via hydrogen bonding in between them is known as the cohesion of the water molecules. The upward movem...
Read More →Evaluate the following integrals:
Question: Evaluate the following integrals: $\int \frac{1}{x(3+\log x)} d x$ Solution: Assume $3+\log x=t$ $\mathrm{d}(3+\log \mathrm{x})=\mathrm{dt}$ $\Rightarrow \frac{1}{\mathrm{x}} \mathrm{dx}=\mathrm{dt}$ Put $t$ and dt in given equation we get $\Rightarrow \int \frac{\mathrm{d} t}{t}$ $=\ln |t|+c .$ But $t=3+\log x$ $=\ln |3+\log x|+c$...
Read More →The radiolabelled carbon in carbon dioxide supplied
Question: The radiolabelled carbon in carbon dioxide supplied to potato plants in an experiment was seen in the tuber eventually. Trace the movement of the labelled carbon dioxide. Solution: When the potato plant carries out photosynthesis using the CO2 which is radiolabelled, it forms Oxygen and glucose (C6H12O6) where the carbon in the glucose molecule has the radiolabelled carbon present. The process of measuring is by autoradiography which detects the radioactive carbon and traces the compon...
Read More →Halophytes may show cell pressure very much higher
Question: Halophytes may show cell pressure very much higher than atmospheric pressure. Explain how this can happen? Solution: Due to the higher concentration of salt, their cell cytoplasm is hypertonic causing water from the surrounding cells or region to enter the cell cytoplasm. The pressure exerted by the cell will be higher. Salt secreting glands will be present for controlling this pressure that removes excess of salts....
Read More →Why are natural membranes selectively
Question: Why are natural membranes selectively permeable. Give examples. Solution: Natural membranes like the cell membrane are selectively permeable, which means that it allows only certain molecules to get in or go out of the cell. Example of a cell membrane is where it allows only non-polar and small molecules through the lipid bilayer along the concentration gradient....
Read More →Plants show temporary and permanent wilting.
Question: Plants show temporary and permanent wilting. Differentiate between the two. Do any of them indicate the water status of the soil? Solution: In temporary wilting, plants lose turgidity when the rate of transpiration is more than the rate of water absorption from the soil but in permanent wilting, wilting of the plant occurs and is a permanent phenomenon as the soil is unable to meet the water requirement of the plant....
Read More →Evaluate the following integrals:
Question: Evaluate the following integrals: $\int \frac{\sec x \operatorname{cosec} x}{\log (\tan x)} d x$ Solution: Assume $\log (\tan x)=t$ $d(\log (\tan x))=d t$ $\Rightarrow \frac{\sec ^{2} x}{\tan x} d x=d t$ $\Rightarrow \sec x \cdot \operatorname{cosec} x \cdot d x=d t$ Put $\mathrm{t}$ and $\mathrm{dt}$ in given equation we get $\Rightarrow \int \frac{\mathrm{dt}}{\mathrm{t}}$ $=\ln |t|+c$ But $t=\log (\tan x)$ $=\ln |\log (\tan x)|+c$...
Read More →Differentiate:
Question: Differentiate: $x^{2} \sin x$ Solution: To find: Differentiation of $x^{2} \sin x$ Formula used: (i) (uv) $^{\prime}=u^{\prime} v+u v^{\prime}$ (Leibnitz or product rule) (ii) $\frac{d x^{n}}{d x}=n x^{n-1}$ (iii) $\frac{d \sin x}{d x}=\cos x$ Let us take $u=x^{2}$ and $v=\sin x$ $u^{\prime}=\frac{d u}{d x}=\frac{d\left(x^{2}\right)}{d x}=2 x$ $v^{\prime}=\frac{d v}{d x}=\frac{d(\sin x)}{d x}=\cos x$ Putting the above obtained values in the formula:- $(u v)^{\prime}=u^{\prime} v+u v^{\...
Read More →Minerals are present in the soil in sufficient amounts.
Question: Minerals are present in the soil in sufficient amounts. Do plants need to adjust the types of solutes that reach the xylem? Which molecules help to adjust this? How do plants regulate the type and quantity of solutes that reach xylem? Solution: Yes, plants need to adjust the type and quantity of solutes that reach the xylem. The transport proteins of end dermal cell help in maintaining and adjusting solute movement. Mineral ions are frequently remobilised particularly from older senesc...
Read More →Define Uniport, Symport and Antiport.
Question: Define Uniport, Symport and Antiport. Do they require energy? Solution: 1. Uniport: When a single substance moves in a single direction across a cell membrane, it is called uniport. 2. Antiport: When two substances move in the opposite direction across a cell membrane, it is called antiport. 3. Symport: When two substances move in the same direction across a cell membrane, it is called symport They do not need energy directly....
Read More →Explain the mass flow hypothesis
Question: Explain the mass flow hypothesis of transport in phloem Solution: In 1930, Munch proposed the mass flow hypothesis which explains the movement of sap through the phloem. When there is a high concentration of sugar present in the source (which is where the food is prepared) then a diffusion gradient gets created between the sugar source and the sugar shrink where the sugar is stored. This is responsible for drawing water into the cells from the neighbouring xylem. When this happens, tur...
Read More →How is facilitated diffusion different
Question: How is facilitated diffusion different from diffusion? Solution: Diffusion occurs through phospholipid layer and facilitated diffusion occurs through membrane proteins...
Read More →Differentiate between diffusion
Question: Differentiate between diffusion and translocation in plants. Solution: Diffusion is the movement of substances from a region of their higher concentration to a region of their lower concentration Translocation is the bulk transport of material in solution inside plant channels....
Read More →We know that plants are harmed by excess water.
Question: We know that plants are harmed by excess water. But plants survive under flooded condition. How are they able to manage excess water? Solution: There is a deprivation of oxygen in the plant roots causing an anaerobic condition. Thus aeration is affected....
Read More →ABA (Abscisic acid) is called a stress hormone.
Question: ABA (Abscisic acid) is called a stress hormone. a. How does this hormone overcome stress conditions? b. From where does this hormone gets released in leaves? Solution: (a) Abscisic acid is a stress hormone and during stress conditions, it induces changes like the closing of stomata to prevent further water loss during the scarcity of water, aids in seed germination when conditions are favourable and dormancy when not and other changes as and when required. (b) This hormone, abscisic ac...
Read More →Find the derivation of each of the following from the first principle:
Question: Find the derivation of each of the following from the first principle: $\tan (3 x+1)$ Solution: Let f(x) = tan (3x + 1) We need to find the derivative of f(x) i.e. f(x) We know that, $\mathrm{f}^{\prime}(\mathrm{x})=\lim _{\mathrm{h} \rightarrow 0} \frac{\mathrm{f}(\mathrm{x}+\mathrm{h})-\mathrm{f}(\mathrm{x})}{\mathrm{h}}$ (i) $f(x)=\tan (3 x+1)$ $f(x+h)=\tan [3(x+h)+1]$ Putting values in (i), we get $\mathrm{f}^{\prime}(\mathrm{x})=\lim _{\mathrm{h} \rightarrow 0} \frac{\tan [3(\math...
Read More →What are ‘aquaporins’?
Question: What are aquaporins? How does the presence of aquaporins affect osmosis? Solution: Aquaporins are a kind of membrane proteins that form channels in the membrane and are usually facilitating the transport of water between cells. Presence of aquaporins would increase the rate of osmosis thus facilitating it....
Read More →Evaluate the following integrals:
Question: Evaluate the following integrals: $\int \frac{1-\cot x}{1+\cot x} d x$ Solution: Convert $\cot x$ in form of $\sin x$ and $\cos x$. $\Rightarrow \cot x=\frac{\cos x}{\sin x}$ $\therefore$ The equation now becomes $\Rightarrow \int \frac{1-\frac{\cos x}{\sin x}}{1+\frac{\cos x}{\sin x}} d x$ $\Rightarrow \int \frac{\frac{\cos x-\sin x}{\sin x}}{\frac{\cos x+\sin x}{\sin x}} d x$ $\Rightarrow \int \frac{\cos x-\sin x}{\cos x+\sin x} d x$ Assume $\cos x+\sin x=t$ $\therefore \mathrm{d}(\c...
Read More →What is the chemical composition
Question: What is the chemical composition of xylem and phloem sap? Solution: Xylem sap: Water and concentration of minerals in dilute form. It is mildly acidic. Phloem sap: traces of minerals, water, sucrose and amino acids In some species, it also transports fructose or raffinose etc...
Read More →Salt is applied to tennis lawns to kill weeds.
Question: Salt is applied to tennis lawns to kill weeds. How does salting tennis lawns help in the killing of weeds without affecting the grass? Solution: The salt solution being hypertonic causes exo-osmosis in plants. 1 cup salt in 2 cups of water, fairly well dissolved when sprayed on weed plants, start killing them....
Read More →Evaluate the following integrals:
Question: Evaluate the following integrals: $\int \frac{\sec x \tan x}{3 \sec x+5} d x$ Solution: Assume $3 \sec x+5=t$ $d(3 \sec x+5)=d t$ $3 \sec x \tan x=d t$ $\operatorname{Sec} x \tan x=\frac{\mathrm{dt}}{3}$ Substitute $t$ and $d t$ We get $\Rightarrow \frac{1}{3} \int \frac{\mathrm{dt}}{\mathrm{t}}$ $\Rightarrow \frac{1}{3} \ln |\mathrm{t}|+\mathrm{c}$ But $t=3 \sec x+5$ $\therefore$ the equation becomes $\Rightarrow \frac{1}{3} \ln |3 \sec x+5|+c$...
Read More →Evaluate the following integrals:
Question: Evaluate the following integrals: $\int \frac{e^{3 x}}{e^{3 x}+1} d x$ Solution: Assume $e^{3 x}+1=t$ $\Rightarrow \mathrm{d}\left(\mathrm{e}^{3 \mathrm{x}}+1\right)=\mathrm{dt}$ $\Rightarrow 3 \mathrm{e}^{3 \mathrm{x}}=\mathrm{dt}$ $\Rightarrow \mathrm{e}^{3 \mathrm{x}}=\frac{\mathrm{dt}}{3}$ Substituting $t$ and dt in the given equation we get $\Rightarrow \int \frac{\mathrm{dt}}{3 \mathrm{t}}$ $\Rightarrow \frac{1}{3} \int \frac{\mathrm{dt}}{\mathrm{t}}$ $\Rightarrow \frac{1}{3} \ln...
Read More →Find the derivation of each of the following from the first principle:
Question: Find the derivation of each of the following from the first principle: $\sin (2 x+3)$ Solution: Let $f(x)=\sin (2 x+3)$ We need to find the derivative of $f(x)$ i.e. $f^{\prime}(x)$ We know that, $\mathrm{f}^{\prime}(\mathrm{x})=\lim _{\mathrm{h} \rightarrow 0} \frac{\mathrm{f}(\mathrm{x}+\mathrm{h})-\mathrm{f}(\mathrm{x})}{\mathrm{h}}$ (i) $f(x)=\sin (2 x+3)$ $f(x+h)=\sin [2(x+h)+3]$ Putting values in (i), we get $\mathrm{f}^{\prime}(\mathrm{x})=\lim _{\mathrm{h} \rightarrow 0} \frac{...
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