Question

41) Osmosis is the driving force for all the following except:

      a)water return to blood in venous capillaries       b) water reabsorption in the nephron collecting ducts

      c) neuronal propogation of an action potential    d) ovulation

42) The chemical that transmits an action potential across a synapse is called a(n):

     a)ion pump b) electron transporter c) neurotransmitter d)hormone

43) The type of enzyme that can cut double-stranded DNA is called

      a)a restriction enzyme b)a transposon c)a ligase d)a DNA polymerase

44) A genetic disorder caused by a chromosomal mutation is

      a) color blindness b)hemophilia c)Down’s syndrome d)cystic fibrosis

45) Meiosis occurs in a)all reproductive organs b) all tissues, to some extent   c)gonads only   d) ovaries only

46) The following type(s) of muscle is (are) nerve-dependent: a)striated b)smooth c)cardiac d)all the above                             

47) All of the following are adrenal steroids except a)aldosterone b)cortisol c)ACTH d)DHEA

Answer 1

1)neuronal propagation of action potential

action potentials are propagated along the axons through local currents.It is based on the change in membrane potential in response to signal from pre synaptic neuron.Sodium and Potassium gated ion channels are involved.

2)Neurotransmitter

These are chemical messengers that are secreted by neurons and are involved in propagation of electrical impulses from one cell to another.These are released into the synaptic cleft and synthesised by the neurons.

3)restriction enzymes

These are special classes of enzymes which recognizes specific nucleotide sequences and cleaves between nucleotides.They can be endonucleases or exonucleases depending upon their activity.

4) Down's syndrome

This genetic disorder is caused by the trisomy of 21st chromosome.The affected individual has some common features like flattened face,small head,low intelligence protruding tongue.

5)All reproductive organs

Meiosis is the reductional division which is especially involved in the formation of gametes in both male and female.

6)All of the above

7)ACTH

It is a poypeptide tropic hormone which is secreted by Pituitary.It causes adrenal gland to function properly in resonse to stress.