Which of the following statements about 'fission' is correct? 1. It is related with the creation of new individuals by means of cell division in unicellular organism. 2. It is related with the transformation of heavier nuclei into smaller nuclei. 3. It is related with the creation of a heavier nuclei by means of combining two higher nuclei. Select the correct answer using the code given below:
- A.1 only
- B.2 only
- C.1 and 2 only
- D.1 and 3 only
Correct answer
Explanation
The correct answer is C, 1 and 2 only. The word fission is used in two sciences: in biology for splitting of a single-celled organism, and in physics for splitting of a heavy nucleus. In biology, binary fission is a form of asexual reproduction in which one cell, such as an amoeba or a bacterium, divides into two new individuals; multiple fission, as in Plasmodium, gives many. In physics, nuclear fission is the splitting of a heavy nucleus such as uranium-235 into two lighter nuclei when it absorbs a neutron, releasing a great deal of energy and more neutrons; this is the process used in nuclear reactors and the first atomic bombs. Joining light nuclei to form a heavier one is a different process, nuclear fusion, which powers the Sun. Option A is wrong because it leaves out the nuclear meaning in statement 2. Option B is wrong because it leaves out the biological meaning in statement 1. Option D is wrong because statement 3 describes fusion, not fission. Exam tip: fission splits (amoeba, uranium-235); fusion joins (hydrogen into helium in the Sun).
Practice Questions
View allThe instrument used for detecting the presence of electric current in a circuit is
- A.Refractometer
- B.Galvanometer
- C.Viscometer
- D.Diffractometer
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A galvanometer detects whether a small electric current is flowing in a circuit and shows its direction. A moving-coil galvanometer has a coil placed between the poles of a magnet.
Read the full explanation →Reverberation is a phenomenon associated with a
- A.multiple refraction of sound.
- B.multiple reflection of sound.
- C.single refraction of sound.
- D.single reflection of sound.
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Reverberation is the persistence of sound in a hall after the source has stopped, caused by repeated reflections from the walls, ceiling and floor.
Read the full explanation →Which one of the following is NOT a basic property of electric charge ?
- A.Charges can be added
- B.Charge is conserved
- C.Charge on a body is always an integral multiple of an electron or a proton charge
- D.Charges can be created and destroyed in an isolated system
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This goes against the conservation of charge: the total charge of an isolated system always stays the same. Electric charge has three basic properties.
Read the full explanation →Which of the following organelles have their own DNA and ribosomes?
- A.Endoplasmic reticulum and Golgi bodies
- B.Mitochondria and Chloroplast
- C.Endoplasmic reticulum and cytoskeleton
- D.Cell wall and nucleolus
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These two organelles carry their own circular DNA and their own small (70S) ribosomes, so they can make some of their own proteins.
Read the full explanation →Which one of the following statements is NOT correct ?
- A.All proteins are enzymes
- B.Mostly enzymes are proteins
- C.All fats are energy rich compounds
- D.Glucose is a common carbohydrate
Show answer
This statement is false: enzymes are mostly proteins, but most proteins are not enzymes. Proteins do many jobs in the body.
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