Find the 12th Class Fsc Part 2 Short Questions Online Preparation Biology

Question # 1

Differentiate between continuous and discontinuous variations.

Ans 1: Continuous variations: In Continuous variations many intermediate forms of a trait are present and organism show very small difference for a trait.For example skin color,eye color.
Ans 2: Discontinuous variations: In discontinuous variations very sharp difference is present and no intermediate forms are present for a trait.For example tongue rolling,attached or free pinna.

Question # 2

How is newly synthesized mRNA protected after transcription?

Ans 1: A cap and tail is added so that molecule may remain stable during its travelling to cytoplasm. The cap is in the form of 7-methyl GTP where as tail is in the form of poly A tail linked to 3 end of the RNA.These cap and tail protects RNA from action of enzymes.

Question # 3

Differentitae between reflex arc and reflex action.

Ans 1: Reflex arc The path followed by the nerve impulse during the reflex action is called reflex arc.
Ans 2: Reflex Action Involuntary actions are called reflex action.This action is performed without the involvement of brain.

Question # 4

Name different bones of Hind Limb.

Ans 1: Bones of hind limb are femur, tibia, fibula, tarsals, metatarsals, phalanges.

Question # 5

What are mutagens? Give one example.

Ans 1: In genetics,a mutagen is a physical or chemical agent that changes the genetic material,usually DNA of an organism and thus increases the frequency of mutations.
For Example: X-ray,ultraviolet radiations etc.

Question # 6

Give briefly the application of PCR amplification and analysis.

Ans 1: Application of PCR amplification and analysis are
Ans 2: i. To diagnose viral infections,genetic disorders and cancer
ii. In forensic labs to identify criminals
iii. To determine evolutionary history of human

Question # 7

Define linkage and give its one disadvantage.

Ans 1: Phenomenon of staying together of all the genes of a chromosomes is called linkage.
Its disadvantage is that,alleles cannot be assorted independently and no new recombinations are formed.

Question # 8

State two methods of asexual reproduction in animals.

Ans 1: Binary fission is a method of asexual reproduction in which animals like amoeba. During binary fission nucleus elongates and then divides into two nuclei, at the same time cytoplasm divides and two daughter cells are formed.
Ans 2: Regeneration is another method of asexual reproduction in which missing part of the body which is separated from the main body part develops into a complete organism.

Question # 9

Explain the importance of gene sequencing.

Ans 1: i.Human pathogens can be sequenced
ii.Disputed parentage can be settled
iii.Suspected culprits can be identified

Question # 10

Give the chemical composition of RNA.

Ans 1: RNA is composed of nitrogen bases (adenine.guanine,cytosine and uracil),pentose sugar(ribose) and phosphate group.

Question # 11

Write symptoms of Turner's syndrome.

Ans 1: Individuals with this condition do not survive pregnancy and aborted.Those who survive have female appearance with short stature webbed neck,without ovaries and complete absence of germ cells.

Question # 12

Differentiate between kineses and taxes.

Ans 1: Kineses: kineses is a behavior in which an organism changes the speed of random movement which helps them to survive in the environment.
Ans 2: Taxes: in contrast to kineses a taxis is a directed movement either towards or away from a stimulus.

Question # 13

Differentiate between genome and probe.

Ans 1: Genome:A complete set of chromosomes which is haploid in number is called genome or a full set of genes of an individual is called genome
Ans 2: Probe:A probe is a single stranded nucleotide sequence that will hybridize into a certain piece of DNA.

Question # 14

Described the structure of a flame cell.

Ans 1: It is a complete eukaryotic cell.It has a unucles, other cell organelles and a cavity where the waste products are collected.Each flame cell has a tuft of cilia, whose beating propel interstitial fluid into the tubular system

Question # 15

What is monochromacy?

Ans 1: Monochromacy means only one colour can be perceived by the colour blind person.Monochromacy is true colour blindness.

Question # 16

Give role of temperature in plant growth.

Ans 1: Temperature influences the growth within a certain range (0-35^oC). Normally rate of growth increase with rise of temperature and decrease with decrease in temperature. For maximum growth the optimum temperature is 25-35^oC and it is least at 5-10^oC. But at very high temperature 35 to 40^oC the rate of growth stops and plant may dies.

Question # 17

What is meant by resting membrane potential?

Ans 1: A typical neuron at rest is more positive outside than inside the cell membrane.This net difference in charge between the inner and outer surface of a non-conducting neuron is called resting membrane potential.

Question # 18

Distinguish between karyokinesis and cytokinesis.

Ans 1: Karyokinesis: Division of nucleus is called karyokinesis.
Cytokinesis: Division of cytoplasm is called cytokinesis.

Question # 19

Define food web,give its significance.

Ans 1: Food Web: All the food chains interconnected or linked together to form food web.
Ans 2: Significance: The variety of pathways helps to maintain the stability of the ecosystem.Many alternate source of food are available to an organism,if one is not available the other can be used as food source.

Question # 20