Scientific reasons of biology ( Co-ordination and control)


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Scientific reasons of biology ( Co-ordination and control)

  1. 1. Chapter 3 Co-ordination and control(Exams are not the obstacles of our coursethey are like myelin sheath for the rapidconduction of impulses, the rapid progress)Biological Reasons: 1 Dr. Sajid Ali Talpur
  2. 2. Q 1: Do plants feel pain?Ans. No, because they do not have nervous system.Q 2: Which phytohormone is known as growthpromoter and why?Ans. Most of the hormones act as growth promoterbut Gibberelin serves for the purposes by windingup dwarfism.Q 3: Why certain plants get delayed age and livelong?Ans. It happens so because of the high quantity ofcytokinins and low quantity of abscisic acid.. sincecytokinin promotes the production of chlorophyll.Q 4: Why the emerge of abscission layer causes fallof the fruit?Ans. Because it serves as the separating agentbetween the fruit and stalk, also it breaks orweakens the other connecting cells.Q5: Why certain plants undergo parthenocarpy?Ans. Certain plants undergo production of fruitswithout fertilization, known as parthenocarpy whichis caused by several factors but mostly due to highconcentration of auxins.Q6: How ethen works as fruit ripening agent?Ans: It affects permeability of cell membrane whichactivates the enzymes to destroy chloroplastsubsequently red and yellow colors appear and thefruit assumes the ripened color.Biological Reasons: 2 Dr. Sajid Ali Talpur
  3. 3. Q 7: How plants response to herbivory?Ans. they overcome herbivory by developing thornsand producing distasteful or toxic compounds.Q 8: How plants response to heat stress?Ans. They overcome over heating by transpirationas a cooling effect and by producing heat shockproteins when temperature is above 40oC, whichprevent enzymes and other metabolic proteins fromgetting denatured.Q 9: What is the role of hormones in droughtconditions?Ans. Abscisic acid is release from mesophyll cellsin leaf, which keeps stomata close and supportswater conservation by reducing transpiration.Q10. Why biorhythms are called endogenous?Ans. Because they do not depend upon externalfactors like light and temperature but on internalsystem.Q11: Which of the three types of neurons is slowimpulse conducting and why?Ans. Inter neuron because it is unmylinated. Since itis in CNS and covers a small distance so the slowconduction is sufficient.Q12. How do you differentiate between sensationand perception?Ans. The awareness of stimulus is called sensationand the recognition of the stimulus is calledperception.Biological Reasons: 3 Dr. Sajid Ali Talpur
  4. 4. Q13: What is the effect on nervous system of nottaking salt at all?Ans. there will be nerve impulse and conductionproblems. Because Na (mainly obtained from salt)along with potassium maintains RMP, also the entryof Na ions into the neuron is the primaryrequirement of action potential.Q14: Why synapse requires neurotransmitters forthe transmission of impulse?Ans. because there is a gap between the twoneurons and the impulse can not be transmitteddirectly. Therefore neurotransmitters carry signalsfrom one presynaptic membrane through synapticcleft to the postsynaptic membrane and causedepolarization in it. In this way the nerve impulse istransmitted from one neuron to another neuron withthe help of neurotransmitters.Q15: What is the significance of reflex action?Ans. Reflex Actions are automatic, involuntaryresponses due to either internal or external stimuli,which protect us from deep damages like handwithdrawal on a painful stimulus, blinking of eyesprotecting entry of insects etc.Q16: Can a chick consider duck his mother insteadof hen?Ans. Yes, provided, the chick finds duck as itsmother when it hatches and it will follow the duckas its mother no matter its real mother i.e. hen ispresent. This is called imprinting.Biological Reasons: 4 Dr. Sajid Ali Talpur
  5. 5. Q17: What do you think learned behavior is morecommon in humans or other animals?Ans. In humans. Because they are born totallyignorant while the animals are highly educatedabout their requirements by birth.Q18: Lion is not as aggressive in zoo as in jungle.How do you explain this statement?Ans. This is a learned behavior called habituation inwhich the lion has adapted to remain calm in thezoo.Biological Reasons: 5 Dr. Sajid Ali Talpur