Closely related people would have very similar DNA profiles. Select ere: a. True

Question

Closely related people would have very similar DNA profiles. Select ere: a. True b. False If a sac, selectively permeable to water, containing a 30% sucrose solution is placed in a beaker containing 5% sucrose, which of the following statements is/are true? MARK ALL ANSWERS THAT ARE TRUE. Select ore or mere: a. water will move out of the sac into the solution in the beaker b. water will move into the sac from the solution in the beaker c. the sac s hypertonic to the beaker solution d. the beaker solution is hypertonic to the sac e. Water will move from the side with a higher concentration of water molecules to the side with a lower concentration of water molecules In 1994, the first genetically engineered crop was approved, grown and sold to consumers. Which of the following was it? Select ore: a. Corn b. Cotton c. Tomato d. Soybeans e. Beets In the enzyme lab, why did the rate of reaction decease at higher temperatures? Select ore: a. The molecules were moving too quickly to react b. The concentration of the enzyme was limiting the rate of reaction c. The active site of the enzyme was altered by the higher temperature c. The concentration of the substrate was liming the rate of reaction e. This was not the result we observed In a demonstration, a paste rod rubbed with fur was able to 'bend' a stream of water as t flowed into a flowed into a beaker. What characteristic of water explains this bending of the water stream? Select ere: a. Polar nature b. Adhesion c. Density d. Temperature stability e. Oxygen ho ding capacity

Explanation / Answer

Ans. #1. A. True.

More closely related are individuals have greater degree of similarity in their DNA.

For example, (hypothetical) –

Say, you and you brother would have 99.99 % similarity in DNA

            You and your immediate cousin will have 99.80 % similarity in DNA.

#2. Correct options- B, C, E

30% sucrose is a more concentrated solution and has relatively lower water content.

5% sucrose is a less concentrated solution and have relatively higher water content.

When two solutions are speared by a semipermeable membrane, water moves from its (= water’s) higher concentration to lower concentration. So, water moves from 5 % sucrose (lower sucrose but higher water content) to 30% sucrose (higher sucrose but lower water content).

Or,

Water moves from hypotonic solution (5 % sucrose in beaker, relatively less concentrated solution) to hypertonic solution (30 % sucrose in sac, relatively more concentrated solution).

Therefore-

Water will move from beaker INTO the sac. [hence, option a incorrect; option b correct].

Option c- correct. [see above].

Option D - incorrect- the solution in beaker is hypotonic.

Option E. Correct.

#3. Correct option. C. Tomato

The first genetically engineered crop commercially available to consumers in 1994 in US was tomato (FlavrSavr tomato).

The tomato variety has prolonged self-life.

#4. Correct option- C.

Note the following points about effect of temperature on rate of enzyme activity-

I. Rate of enzyme activity increases with temperature upto optimum temperature (40.00C or so on). That is, if you increase the temperature from 10.00C to 40.00C, you will notice increase in rate of enzyme catalysis because substrate and enzymes molecules collide with each much frequently- it leads higher chances of substrate binding to enzyme and further catalysis.

II. Further increase in temperature, say from optimum temperature 42.00C to 90.00C, decrease the rate of enzyme catalysis. Higher temperature denatures enzyme by disrupting the non-covalent interactions (H-bond, van der Waal’s forces, hydrophobic interactions, etc.). So, denaturation, including alteration of enzyme’s active site, leads to loss of function and lowering rate of catalysis.

Option a. Incorrect. Increase in molecules’ kinetic energy increase rate of reaction. So, if molecules move very quickly, higher rate would be observed.

Option b. Incorrect. Enzyme concertation remains constant in particular tube or experiment.

Option d. Incorrect. [S] has nothing to do with temperature. If [S] is low, then rate of catalysis would be lower even at optimum temperature.

Option e. Incorrect. Lowering of rate of enzyme catalysis is observed when temperature is increased above 40.00C or so on.

#5. Correct option. A. Polar nature.

Rubbing plastic rod with fur generates negative charge on the plastic rod.

Water is polar molecule- each molecule has a positive and negative pole.

A stream of water flowing in close vicinity of negatively charge plastic rod is attracted (bent) towards the rod because orientation of positive pole of water molecules towards negatively charged rod causes attraction between both the substances.

Option b. Incorrect. Adhesion keeps two substances held together without letting them move against each other. Here, water flow is NOT glued (stuck, withhold) onto the rod, so, it’s not adhesion.

Option c. Incorrect. Density has nothing to do with the force of attraction between two substances. Flowing a neutral organic solvent (low density) in a steam similar to water against the negatively charged plate rod would NOT cause bending.  

Option e. Incorrect. The bending occurs solely due to fluid nature of water and force of attraction acting between the two substances. Oxygen binding capacity is not irrelevant.

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