Q: What will happen if a healthy plant is supplied with excess
essential elements.
A: If excess of Nitrogen is supplied to a healthy plant, its
Vegetative growth is more but reproductive growth is inhibited. It
results in poor yield.
Moderate increase in the concentration of micronutrients causes toxicity.
Any mineral ion concentration in tissues that reduces dry weight of
tissues by about 10% is considered toxic.
Excess of one element may inhibit the uptake of another element.
Excess of Manganese shows Brown spots in the leaf surrounded by
chlorotic veins. Excess of Manganese competes with other micro
elements (Fe, Ca and Mg) and inhibits their uptake. So symptoms of Mn
toxicity
also results in the deficiency symptoms of Fe, Ca and Mg.
Q: Explain the steps involved in the formation of root nodule?
A: The following steps are observed in the formation of root nodule:
1) Bacteria are attracted by sugars, amino acids and flavonoids
secreted by the roots of leguminous plants.
2) Legumes select compatible strains of Rhizobium by specific proteins
called Lectins.
3) Bacteria multiply and secrete curling factor. Root hair shows
curling which is called Shepherd's crook.
4) Bacteria invade the root hair and produce cellulase, pectinase to
digest the cell wall.
5) Bacteria breach the cell wall. Plasma membrane invagination forms
infection thread and carries bacteria into cortical cell.
6) Cortical cells produce Auxins, multiply and root nodule is formed
into which bacteria are released.
7) Bacteria also stimulate pericycle cells to divide.
8) The nodule develops vascular connection.
9) It consists Leghaemoglobin (Pink coloured), Nitrogenase. The
bacterial cells in the nodule become spherical & called bacteroid.
Senior Inter Botany Important Questions - Mineral Nutrition - 4 Marks
Q: 'All elements that are present in a plant need not be essential for
its survival'. Justify.
A: Plants absorb 60 or even more mineral elements from the soil. All
60 are not present in one plant. In the same way all elements present
in a plant are useful to it. Only the useful elements are called
essential elements.
Q: Name at least five different deficiency symptoms in plants.
Describe them, and correlate them with concerned mineral deficiency.
A: Deficiency symptoms of
1. Zinc:
1) Little leaf disease
2) Leaf rosette
3) Mottled leaf
4) Interveinal Chlorosis - Necrosis
Zinc is a mobile, micro mineral essential element. It is an activator
for Carboxylase. It is needed for the synthesis of Auxins. It is
absorbed in the form of Zn2+.
2. Copper:
1) Die back disease of shoots in Citrus
2) Necrosis of young leaf tips
3) Exanthema
4) Reclamation disease of cereals and legumes
5) Blackening Potato tubers
3. Boron:
1) Heart rot in beets (Brown heart)
2) Water core in turnip
3) Heart rot in carrot
4) Fibres in apple fruit
5) Death of root tip and stem tip
4. Molybdenum:
1) Whiptail disease in Cauliflower
2) Interveinal Chlorosis
3) Inhibition of flowering
4) Mottled Chlorosis
5) Upper half leaf shows withering
5. Chlorine:
1) Bronzing in legumes
2) Flower abseision
3) Swollen root tips
Q: Some angiospermic plants adapted to absorb molecular nitrogen from
atmosphere. Explain, citing two examples.
A: Leguminaceae members and some plants like Myrica, Alnus, Casuarina
have adapted to absorb molecular nitrogen with the help of bacteria.
It occurs through symbiotic nitrogen fixation.
Rhizobium fixes molecular nitrogen to Legumes, and also to a
non-leguminous member called Parasponia.
Filamentous, Actinomycetus bacteria like Frankia fixes atmospheric
molecular nitrogen in Alnus, Casuarina and Myrica.
Nostoc fixes nitrogen in the stem glands of Gunnera.
Azospirillum, an associated symbiont fixes nitrogen in Maize, Sorghum,
Wheat, Barley and Finger millets.
its survival'. Justify.
A: Plants absorb 60 or even more mineral elements from the soil. All
60 are not present in one plant. In the same way all elements present
in a plant are useful to it. Only the useful elements are called
essential elements.
Q: Name at least five different deficiency symptoms in plants.
Describe them, and correlate them with concerned mineral deficiency.
A: Deficiency symptoms of
1. Zinc:
1) Little leaf disease
2) Leaf rosette
3) Mottled leaf
4) Interveinal Chlorosis - Necrosis
Zinc is a mobile, micro mineral essential element. It is an activator
for Carboxylase. It is needed for the synthesis of Auxins. It is
absorbed in the form of Zn2+.
2. Copper:
1) Die back disease of shoots in Citrus
2) Necrosis of young leaf tips
3) Exanthema
4) Reclamation disease of cereals and legumes
5) Blackening Potato tubers
3. Boron:
1) Heart rot in beets (Brown heart)
2) Water core in turnip
3) Heart rot in carrot
4) Fibres in apple fruit
5) Death of root tip and stem tip
4. Molybdenum:
1) Whiptail disease in Cauliflower
2) Interveinal Chlorosis
3) Inhibition of flowering
4) Mottled Chlorosis
5) Upper half leaf shows withering
5. Chlorine:
1) Bronzing in legumes
2) Flower abseision
3) Swollen root tips
Q: Some angiospermic plants adapted to absorb molecular nitrogen from
atmosphere. Explain, citing two examples.
A: Leguminaceae members and some plants like Myrica, Alnus, Casuarina
have adapted to absorb molecular nitrogen with the help of bacteria.
It occurs through symbiotic nitrogen fixation.
Rhizobium fixes molecular nitrogen to Legumes, and also to a
non-leguminous member called Parasponia.
Filamentous, Actinomycetus bacteria like Frankia fixes atmospheric
molecular nitrogen in Alnus, Casuarina and Myrica.
Nostoc fixes nitrogen in the stem glands of Gunnera.
Azospirillum, an associated symbiont fixes nitrogen in Maize, Sorghum,
Wheat, Barley and Finger millets.
Senior Inter Physics Important Questions - Wave Optics
Q: Explain Doppler effect in light. Distinguish between Red Shift and
Blue Shift. (4 marks)
A: Doppler effect in light:
To an observer on the earth light from a star moving towards him
appears with high frequency or less wavelength. Similarly the apparent
wavelength of light received by the observer is high in the case of
star moving away from him.
This change in apparent frequency or wavelength of light due to
relative motion between light source and observer is called Doppler
effect in light.
Red Shift: When light source is moving away from an observer, the
frequency of light seen by the observer is less than the frequency of
light emitted by the source (or) the apparent wavelength is more than
the wavelength of light emitted by the source i.e., apparent
wavelength shifts towards the red end of the visible spectrum.
Blue Shift: When a light source is approaching an observer the
apparent frequency of light seen by the observer is more than the
frequency of light emitted from the source (or) the apparent
wavelength decreases i.e. shifts towards the blue end of the visible
spectrum.
Q: Explain Brewster's law. (2 marks)
A: When unpolarised light is incident on transparent surface, at a
particular angle of incidence called Brewster angle (or) polarizing
angle (ip), the reflected light wave is totally polarised and is
perpendicular to the refracted
light wave. The tangent of the angle of polarization is numerically
equal to the refractive index (ì) of the refracting medium.
ì = tan (ip)
Q: What is the shape of wavefront is each of the following cases
(a) Light diverging from point source.
(b) Light emerging out of a convex lens when a point source is placed
at its focus.
(c) The portion of wavefront of light from a distance star intercepted
by the earth. (2 marks)
A: (a) Shape of wavefront is spherical
(b) Shape of wavefront is plane.
(c) Shape of wavefront is plane.
Blue Shift. (4 marks)
A: Doppler effect in light:
To an observer on the earth light from a star moving towards him
appears with high frequency or less wavelength. Similarly the apparent
wavelength of light received by the observer is high in the case of
star moving away from him.
This change in apparent frequency or wavelength of light due to
relative motion between light source and observer is called Doppler
effect in light.
Red Shift: When light source is moving away from an observer, the
frequency of light seen by the observer is less than the frequency of
light emitted by the source (or) the apparent wavelength is more than
the wavelength of light emitted by the source i.e., apparent
wavelength shifts towards the red end of the visible spectrum.
Blue Shift: When a light source is approaching an observer the
apparent frequency of light seen by the observer is more than the
frequency of light emitted from the source (or) the apparent
wavelength decreases i.e. shifts towards the blue end of the visible
spectrum.
Q: Explain Brewster's law. (2 marks)
A: When unpolarised light is incident on transparent surface, at a
particular angle of incidence called Brewster angle (or) polarizing
angle (ip), the reflected light wave is totally polarised and is
perpendicular to the refracted
light wave. The tangent of the angle of polarization is numerically
equal to the refractive index (ì) of the refracting medium.
ì = tan (ip)
Q: What is the shape of wavefront is each of the following cases
(a) Light diverging from point source.
(b) Light emerging out of a convex lens when a point source is placed
at its focus.
(c) The portion of wavefront of light from a distance star intercepted
by the earth. (2 marks)
A: (a) Shape of wavefront is spherical
(b) Shape of wavefront is plane.
(c) Shape of wavefront is plane.
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