Question

The difference between benign and malignant tumors is

A) malignant tumors are adherent

B) benign tumors have not lost growth control

C) benign tumors have not spread to other sites

D) benign tumors do not stimulate angiogenesis

E) benign tumors are cancers, malignant tumors are not

In order for growth to occur at both ends of a microtubule..

A.The concentration of subunits must be higher than the critical concentration for the plus end

B.The concentration of subunits must be higher than the critical concentration for both the plus and minus ends

C. The concentration of subunits must be higher than the critical concentration for the plus end but less than the critical concentration for the minus end

In cilia, side arms are attached to

A) central pairs

B) a tubules

C) b tubules

D. interdoublet nexins

E. radical spokes

Answer 1

Answer-1: Correct answer is option-C

Explaination- Benign tumors are those which remain confined to one area only and they shows their growth in that confined region only. Whereas, maligant tumors are those which loses their contact from the tissue and it reaches to some other place by entering into the circulatory system or into lymphatic system. Malignant tumors usually are the lethal ones because they tend to spread to other tissues. This happens because they have lost their anchorange dependency property. Both benign and malignant tumors are cancerous, but the only difference between the two is that benign does not spread to other tissues but malignant tumors can.

Answer-2: Correct answer is option-A

Explaination- In the polymerization process of microtubules, addition occurs at +ve side and depolymerization occurs at -ve side. Polymerization occurs by the hydrolysis of a GTP molecule. However, depolymerization might not always occur simultaneous to polymerization. So, concentration of subunits must be higher than the critical concentration for the +ve end so that no limiting subunit concentration condition could occur, that can stop the overall growth of the microtubules.

Answer-3: Correct answer is option- D

Explaination- Side arms means an outer arm and an inner arm. Since, there are nine doublets in the structure of cilia. These two doublets are composed of Microtubule-A and Microtubule-B, from where these arms originates. These arms are attached to a protein called Nexin, which is sometimes also known to form Nexin-Dynein Regulatory Complex.