Which one of the following statements is not correct with regard to genetically modified organisms?
- A.In this technique a gene from one organism is isolated and transferred to the cell of another organism.
- B.This technique has applications only in plants.
- C.Genes for insect resistance may spread from crop plants to wild plants.
- D.To produce a transgenic animal the novel genes are inserted at a very early stage of development.
Correct answer
Explanation
The correct answer is B, This technique has applications only in plants. Genetic modification is used in plants, animals and microbes alike, so this statement is false.
A genetically modified organism is one whose DNA has been changed, usually by taking a useful gene from one organism and putting it into another. Bt cotton carries a gene from the soil bacterium Bacillus thuringiensis that makes it resistant to the bollworm. Bacteria such as E. coli are modified to make human insulin, and transgenic animals, like the cow Rosie whose milk carried a human protein, are made for research and medicine.
A is wrong to choose: isolating a gene and transferring it to another organism's cell is exactly how a GMO is made, so the statement is correct.
C is wrong to choose: a real worry is that insect-resistance genes can pass to wild relatives through pollen, so the statement is correct.
D is wrong to choose: for a transgenic animal the gene is placed in the fertilised egg or early embryo so that every cell carries it, so the statement is correct.
Exam tip: Bt cotton is India's only approved GM crop for commercial farming; insulin from GM bacteria was the first such medicine.
Practice Questions
View allWhich one of the following plant tissues has dead cells ?
- A.Epidermis
- B.Parenchyma
- C.Collenchyma
- D.Sclerenchyma
Show answer
Sclerenchyma cells are dead at maturity, with thick walls hardened by lignin. Sclerenchyma is the tissue that makes plants hard and stiff.
Read the full explanation →Imagine a current-carrying straight conductor with magnetic field of lines in anti-clockwise direction. Then the direction of current is determined by
- A.the Right-Hand Thumb rule and it would be in the downward direction.
- B.the Left-Hand Thumb rule and it would be in the downward direction.
- C.the Right-Hand Thumb rule and it would be in the upward direction.
- D.the Left-Hand Thumb rule and it would be in the upward direction.
Show answer
For a straight wire, the right-hand thumb rule links the current to the circular field lines around it. Hold the wire in the right hand with the thumb along the current; the curled fingers then show the direction of the magnetic field lines, which form concentric circles around the wire.
Read the full explanation →Which one of the following statements is true for sound waves propagating in air?
- A.Sound is an electromagnetic wave and transverse in nature
- B.Sound is a mechanical wave and longitudinal in nature
- C.Sound is a mechanical wave and transverse in nature
- D.Sound is an electromagnetic wave and longitudinal in nature
Show answer
Sound needs a material medium to travel, and in air its particles vibrate back and forth along the direction the wave moves.
Read the full explanation →Which one of the following is primarily responsible for conduction of current in a metal?
- A.Bound electrons
- B.Free electrons
- C.Both bound and free electrons
- D.Ions
Show answer
In a metal, the outer electrons of the atoms are not tied to any one atom and drift through the lattice when a voltage is applied, carrying the current.
Read the full explanation →Which one of the following statements is correct about the magnification of an optical microscope?
- A.Magnification increases with the increase in focal length of eyepiece
- B.Magnification increases with the increase in focal length of objective
- C.Magnification does not depend upon the focal length of eyepiece
- D.Magnification decreases with the increase in focal length of eyepiece
Show answer
A compound microscope magnifies more when both its lenses have short focal lengths. In a compound microscope the objective forms a real, enlarged image, and the eyepiece magnifies it further like a simple magnifier.
Read the full explanation →