Half of the male gametes (sperms) carry X chromosome and other half carry Y chromosomes. All the female gametes carry only X chromosomes. When a sperm fertilizes an egg, the following situations become possible. (i) When a sperm carrying X chromosome fertilises an egg that contains only X chromosomeRead more
Half of the male gametes (sperms) carry X chromosome and other half carry Y chromosomes. All the female gametes carry only X chromosomes. When a sperm fertilizes an egg, the following situations become possible.
(i) When a sperm carrying X chromosome fertilises an egg that contains only X chromosome), the resulting zygote develops into a female (XX condition).
(ii) When a sperm carrying Y chromosome fertilises an egg (that contains only X chromosome), the resulting zygote develops into a male (XY condition).
This information is not enough. This is because each individual is carrying two alleles. The recessive trait can occur only when who alleles are similar. It blood group A is dominant and O is recessive, then daughter can have blood group O only when both recessive alleles occur together in mother, aRead more
This information is not enough. This is because each individual is carrying two alleles. The recessive trait can occur only when who alleles are similar. It blood group A is dominant and O is recessive, then daughter can have blood group O only when both recessive alleles occur together in mother, and father has one allele of O and other of A.
Mendel took two pairs of alternate expression of two traits and carried out dihybrid crosses by crossing them. The traits appeared in first generation were termed as dominant. When he used these F1 progeny to generate F2 progeny by self-pollination plants of different types were produced. In some plRead more
Mendel took two pairs of alternate expression of two traits and carried out dihybrid crosses by crossing them. The traits appeared in first generation were termed as dominant. When he used these F1 progeny to generate F2 progeny by self-pollination plants of different types were produced. In some plants both the traits were dominant, while in some plants both were recessive and some plants exhibited mixed traits. This indicates that traits are inherited independently.
Mendel took pea plants with contrasting characteristics tall plant and dwarf (or short) plant. On cross pollination, he got all tall plants in first generation (F1). But by the self¬pollination of F1 tall plants, the plants of second generation consisted of tall and short pants in the ratio of 3 : 1Read more
Mendel took pea plants with contrasting characteristics tall plant and dwarf (or short) plant. On cross pollination, he got all tall plants in first generation (F1). But by the self¬pollination of F1 tall plants, the plants of second generation consisted of tall and short pants in the ratio of 3 : 1. On the basis of these experiments, the characteristics appeared in first generation were called dominant (i.e. tall plants) and the characteristics that did not appear were called recessive (dwarf i.e. plants).
Because the image is real, so magnification m must be negative. m = -v/u -3 = -v/-10 v = -30 Thus the image is located at a distance of 30 cm from the mirror on the object side of the mirror.
Because the image is real, so magnification m must be negative.
m = -v/u
-3 = -v/-10
v = -30
Thus the image is located at a distance of 30 cm from the mirror on the object side of the mirror.
(i) Wind mill farms are constructed to produce electricity. (ii) The traditional use of energy of flowing water has been modified by establishing hydro-power plants. At hydro-power plants, the energy of falling water or flowing water is tapped by using a water turbine and then made to drive generatoRead more
(i) Wind mill farms are constructed to produce electricity.
(ii) The traditional use of energy of flowing water has been modified by establishing hydro-power plants. At hydro-power plants, the energy of falling water or flowing water is tapped by using a water turbine and then made to drive generators.
We are looking at alternate sources of energy because the fossil fuels and nuclear fuels on the earth are limited which may not last for long and the undesirable effects of pollution, both from the burning of fossil fuels and from the radioactive nuclear wastes of nuclear power plants are creating tRead more
We are looking at alternate sources of energy because the fossil fuels and nuclear fuels on the earth are limited which may not last for long and the undesirable effects of pollution, both from the burning of fossil fuels and from the radioactive nuclear wastes of nuclear power plants are creating threat to our environment.
Disadvantages of fossil fuels are: (i) The burning of fossil fuels produces large amount of carbon dioxide that causes increased greenhouse effect. (ii) The burning of fossil fuels (such as coal) produces smoke which pollutes the air. (iii) The burning of fossil fuels produces acidic gases such as sRead more
Disadvantages of fossil fuels are:
(i) The burning of fossil fuels produces large amount of carbon dioxide that causes increased greenhouse effect.
(ii) The burning of fossil fuels (such as coal) produces smoke which pollutes the air.
(iii) The burning of fossil fuels produces acidic gases such as sulphur dioxide and nitrogen oxide. These acidic gases cause acid rain that affects our water and soil resources.
(iv) Fossil fuels cannot be replenished in short time because it takes millions of years to form them.
How is the sex of the child determined in human beings?
Half of the male gametes (sperms) carry X chromosome and other half carry Y chromosomes. All the female gametes carry only X chromosomes. When a sperm fertilizes an egg, the following situations become possible. (i) When a sperm carrying X chromosome fertilises an egg that contains only X chromosomeRead more
Half of the male gametes (sperms) carry X chromosome and other half carry Y chromosomes. All the female gametes carry only X chromosomes. When a sperm fertilizes an egg, the following situations become possible.
(i) When a sperm carrying X chromosome fertilises an egg that contains only X chromosome), the resulting zygote develops into a female (XX condition).
See less(ii) When a sperm carrying Y chromosome fertilises an egg (that contains only X chromosome), the resulting zygote develops into a male (XY condition).
A man with blood group A marries a woman with blood group O and their daughter has blood group O. Is this information enough to tell you which of the traits – blood group A or O – is dominant? Why or why not?
This information is not enough. This is because each individual is carrying two alleles. The recessive trait can occur only when who alleles are similar. It blood group A is dominant and O is recessive, then daughter can have blood group O only when both recessive alleles occur together in mother, aRead more
This information is not enough. This is because each individual is carrying two alleles. The recessive trait can occur only when who alleles are similar. It blood group A is dominant and O is recessive, then daughter can have blood group O only when both recessive alleles occur together in mother, and father has one allele of O and other of A.
See lessHow do Mendel’s experiments show that traits are inherited independently?
Mendel took two pairs of alternate expression of two traits and carried out dihybrid crosses by crossing them. The traits appeared in first generation were termed as dominant. When he used these F1 progeny to generate F2 progeny by self-pollination plants of different types were produced. In some plRead more
Mendel took two pairs of alternate expression of two traits and carried out dihybrid crosses by crossing them. The traits appeared in first generation were termed as dominant. When he used these F1 progeny to generate F2 progeny by self-pollination plants of different types were produced. In some plants both the traits were dominant, while in some plants both were recessive and some plants exhibited mixed traits. This indicates that traits are inherited independently.
See lessHow do Mendel’s experiments show that traits may be dominant or recessive?
Mendel took pea plants with contrasting characteristics tall plant and dwarf (or short) plant. On cross pollination, he got all tall plants in first generation (F1). But by the self¬pollination of F1 tall plants, the plants of second generation consisted of tall and short pants in the ratio of 3 : 1Read more
Mendel took pea plants with contrasting characteristics tall plant and dwarf (or short) plant. On cross pollination, he got all tall plants in first generation (F1). But by the self¬pollination of F1 tall plants, the plants of second generation consisted of tall and short pants in the ratio of 3 : 1. On the basis of these experiments, the characteristics appeared in first generation were called dominant (i.e. tall plants) and the characteristics that did not appear were called recessive (dwarf i.e. plants).
See lessA concave mirror produces three times magnified (enlarged) real image of an object placed at 10 cm in front of it. Where is the image located?
Because the image is real, so magnification m must be negative. m = -v/u -3 = -v/-10 v = -30 Thus the image is located at a distance of 30 cm from the mirror on the object side of the mirror.
Because the image is real, so magnification m must be negative.
See lessm = -v/u
-3 = -v/-10
v = -30
Thus the image is located at a distance of 30 cm from the mirror on the object side of the mirror.
Find the focal length of a convex mirror whose radius of curvature is 32 cm.
R = +32 cm f=R/2 =+32/2=+16cm The focal length of the given convex mirror is 16 cm.
R = +32 cm
See lessf=R/2
=+32/2=+16cm
The focal length of the given convex mirror is 16 cm.
How has the traditional use of wind and water energy been modified for our convenience?
(i) Wind mill farms are constructed to produce electricity. (ii) The traditional use of energy of flowing water has been modified by establishing hydro-power plants. At hydro-power plants, the energy of falling water or flowing water is tapped by using a water turbine and then made to drive generatoRead more
(i) Wind mill farms are constructed to produce electricity.
See less(ii) The traditional use of energy of flowing water has been modified by establishing hydro-power plants. At hydro-power plants, the energy of falling water or flowing water is tapped by using a water turbine and then made to drive generators.
Why are we looking at alternate sources of energy?
We are looking at alternate sources of energy because the fossil fuels and nuclear fuels on the earth are limited which may not last for long and the undesirable effects of pollution, both from the burning of fossil fuels and from the radioactive nuclear wastes of nuclear power plants are creating tRead more
We are looking at alternate sources of energy because the fossil fuels and nuclear fuels on the earth are limited which may not last for long and the undesirable effects of pollution, both from the burning of fossil fuels and from the radioactive nuclear wastes of nuclear power plants are creating threat to our environment.
See lessWhat are the disadvantages of fossil fuels?
Disadvantages of fossil fuels are: (i) The burning of fossil fuels produces large amount of carbon dioxide that causes increased greenhouse effect. (ii) The burning of fossil fuels (such as coal) produces smoke which pollutes the air. (iii) The burning of fossil fuels produces acidic gases such as sRead more
Disadvantages of fossil fuels are:
See less(i) The burning of fossil fuels produces large amount of carbon dioxide that causes increased greenhouse effect.
(ii) The burning of fossil fuels (such as coal) produces smoke which pollutes the air.
(iii) The burning of fossil fuels produces acidic gases such as sulphur dioxide and nitrogen oxide. These acidic gases cause acid rain that affects our water and soil resources.
(iv) Fossil fuels cannot be replenished in short time because it takes millions of years to form them.
Give any two ways in which non-biodegradable substances would affect the environment.
(i) They cause air, water and soil pollution. (ii) They may cause bio-magnification in the food chain and end up in humans.
(i) They cause air, water and soil pollution.
See less(ii) They may cause bio-magnification in the food chain and end up in humans.