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Science MCQ Questions with answers

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Learn Science MCQs [Page 1 of Department 12]

1) Decibel is the unit used for:

(A) Speed of light
(B) Intensity of heat
(C) Intensity of sound
(D) Radio wave frequency
Correct Answer - Option (C)

No Explanation found. Add Explanation and get +2 points.

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2) If a healthy freshwater fish is placed in salt water, what will be the expected consequence 

(A) The fish becomes bloated & dies
(B) There is no observable effect on the fish provided there is sufficient food
(C) The fish suffers from fungal or bacterial disease & dies
(D) The fish becomes dehydrated & dies
Correct Answer - Option (D)

Explanation:
The fish becomes dehydrated & dies.When freshwater fish is placed in salt water, the water molecules contained in the fish's body would pass through the cell membranes of the fish, causing the fish to lose water by diffusion. This sudden change in the molecular makeup of the fish wouldcause the fish to die.

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3) Outside the nucleus DNA is found in

(A) Golgi bodies
(B) Ribosome
(C) Mitochondria
(D) Endoplasmic reticulum
Correct Answer - Option (C)

Explanation:
Mitochondria.In eukaryotic (with nucleus) cells, the vast majority of DNA is found in the nucleus as discrete bodies called chromosomes. In human cells, more than 99% of the total DNA is nuclear genomic DNA & the remainder mitochondrial. The exception to this being the small amount of DNA found in organdies outside the nucleus (mitochondria & chloroplasts).

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4) Coupling & repulsion are the two states of:

(A) crossing over
(B) linkage
(C) chiasma
(D) mutation
Correct Answer - Option (B)

Explanation:
linkage.Genetic linkage is the tendency of genes that are situated proximal to each other on a chromosome to be inherited together during meiosis. The figure below depicts the gamete composition for linked genes from coupling & repulsion crosses

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5) DNA shows hyperchromicity on

(A) cooling
(B) replication
(C) heating
(D) crystallizing
Correct Answer - Option (C)

Explanation:
When a DNA solution is heated enough, the doublestranded DNA unwinds, & the Hydrogen bonds that hold the two strands together weaken & finally break. The hyperchromicity of DNA occurs when the DNA duplex is denatured. The process of breaking a double-stranded DNA into single strands is known as DNA denaturation, or DNA melting.

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6) Where does the cabbage store food 

(A) Root
(B) Stem
(C) Fruit
(D) Leaves
Correct Answer - Option (D)

Explanation:
Cabbages have no need to store food as they are seasonal plants & die after about 4 to 6 months. They do however produce food in the leaves of the plants & would utilize short-term storage (in the leaves) forsimple metabolic processes.

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7) Which of the following enzyme converts proteins

(A) Erepsin
(B) Enterokinase
(C) Pepsin
(D) Trypsin
Correct Answer - Option (D)

Explanation:
Trypsin is a serine protease found in the digestive system of many vertebrates, where it hydrolyses proteins. These peptides may then be further hydrolyzed into amino acids by other proteases before they enter theblood stream. Trypsin in the duodenum catalyses the hydrolysis of peptide bonds so that proteins can be broken down into smaller peptides.

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8) Sea sickness is due to the effect of the motion of ship, on

(A) internal ear
(B) stomach
(C) eyes
(D) heart
Correct Answer - Option (B)

Explanation:
Motion sickness or kinetosis, also known as travel sickness, is a condition in which a disagreement exists between visually perceived movement & the vestibular system's sense of movement. If the motion causing nausea is not resolved, the sufferer will usually vomit. Depending on the cause it can also be referred to as seasickness, car sickness, simulation sickness or airsickness. Ginger is reported to calm the pyloric valve situated at the base of the stomach. This relaxation of the valve allows the stomach to operate normally whereby the contents will enter the small intestine instead of being retained within the stomach. It is this undesirable effect of retention in the stomach that eventually results in vomiting.

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9) What is the approximate time required for a heart-beat -

(A) 0.8 2nd
(B) 1.0 minute
(C) 0.5 minute
(D) 0.5 2nd
Correct Answer - Option (A)

No Explanation found. Add Explanation and get +2 points.

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