added, the team
The mean height of 20 boys of a class is 150 cm. When a boy leaves the class, the mean
height comes down by 0.5 cm. Find the height of the boy.
H. The mean monthly income of three members of a family is 8000. Another member of the
family gets a job, and his monthly salary is 10000. What is the mean monthly income of
the four earning members of the family?
12. The mean age of 6 persons is 14.5 years. The mean age of four of them is 13.25 years. If the
age of the nigh person is 16 years, find the age of the sixth.
13. The mean weight of 16 students of a school is 40 kg. If a student weighing 25 kg leaves the
school. find the mean weight of the remaining students.
14. A class has 26 boys and 14 girls. The mean weight of boys of the class is 40 kg and the
mean weight of the girls of the class is 35 kg. Find the mean weight of the students of the
class.
Answers
AMP-PNP is the abbreviation for a structural analogue of ATP in which the second and third phosphate groups are linked by an NH group (instead of an oxygen atom). AMP- PNP can bind to the ATP-binding site of most ATPases. It differs from ATP in that the terminal phosphate cannot be removed by hydrolysis (so you cannot create ADP, therefore, you cannot get energy from AMP-PNP). Based on this information, explain the following
a. When isolated myofibrils are placed in a flask containing Ca2+ and AMP-PNP, contraction is quickly arrested. Where in the contraction cycle will contraction stop? Be specific.
b. What affects would you predict for cilia on a paramecium to which AMP-PNP is added? Be specific as to the proteins / molecules whose function would be inhibited and what would be the overall affect?
c. When researchers incubated purified vesicles, axoplasm (containing motor proteins), and MT from the giant squid axon and added AMP-PNP, the vesicles did not move along the MT. Explain this observation using specific proteins / processes affected.
Explanation:
a.
Actin and myosin, two contractile proteins, make up myofibrils. ATPase activity is present in the myosin head. Troponin tropomyosin complex is displaced by calcium ions, exposing myosin’s entire surrounding binding site on actin. Myosin heads execute the power stroke, and detachment of the head is needed for the second cycle. Myosin head detachment is aided by ATP binding & hydrolysis. Since the solution contains AMP-PNP instead of ATP, myosin heads are unable to hydrolyze and detach from myosin-binding sites on actin, thereby preventing contraction.
b.
The active ATPase correlated with both the dynein arms is found in cilia and flagella. Dynein is a motion motor protein family that walks around microtubules. The core of cilia is made up of microtubule bundles linked to the motor protein dynein. In the presence of AMP-PNP, the net reaction will be to stop the ciliary movement by inhibiting dynein motor proteins.
c.
Kinesins and Dyneins, two groups of motion motor proteins with ATPase activity, are involved in axonal transportation. All the motion motor proteins use energy from ATP hydrolysis to transfer secretory vesicles through microtubules. Since the inclusion of AMP-PNP does not supply electricity, vesicular transport does not occur.