First things first, please dont go by the online answer keys, more often then not, they are wrong.
okay the first question; yeah its really easy to get tripped up on it, i did as well. Go to page 102 in FA2013; cyanide/CO inhibits complex IV, which is formed by cytochrome C. the process to complex V is actually what is inhibited, so the answer is E.
2. IL-1 is the answer. Apparently IL-1 is also known as osteoclastic activating factor, which is involved in osteoporosis. If you read the thread about NBME13 on StudentDoctor.net, they talk about this.
3. Aspirin induced Asthma, so excessive production of leukotrienes. Go look at your arachadonic acid metabolism pathway in FA.
4. Answer is B, loss of heterozygosity. The tumor cell shows the presence of M allele only, you have lost the n allele that is present in the normal cell gene.
5. Gait Ataxia is the answer- the man was an alcoholic, so alcoholism causes Cerebellar Ataxia- which causes Gait Ataxia
6. Biofilms. These organisms produce biofilms, thats how they keep causing infections. Its pseduomonas that produces pyocyanin.
in this q the pt have PSEDOMONAS Infec ? and is the biofilms also by psedumonas , what i know that only staph epider cz biofilms.
7. Answer is A, its the first graph. The Calcium concentration in the SR will be high because the SR is what stores and pumps Ca ions: From wikipedia:
"The sarcoplasmic reticulum (SR), from the Greek sarx, ("flesh"), is smooth ER found in smooth and striated muscle. The only structural difference between this organelle and the smooth endoplasmic reticulum is the medley of proteins they have, both bound to their membranes and drifting within the confines of their lumens. This fundamental difference is indicative of their functions: The endoplasmic reticulum synthesizes molecules, while the sarcoplasmic reticulum stores and pumps calcium ions. The sarcoplasmic reticulum contains large stores of calcium, which it sequesters and then releases when the muscle cell is stimulated.[11][12] It plays a major role in excitation-contraction coupling.[citation needed]"
8. Answer is D, above the 9th rib. The other choices are either too far down or too far up. You want to get into the pleura, not the lung tissue itself. If you go below the rib you have a chance of damaging the vascular bundle as it sits just below the rib. If you go above the rib completely, you should be fine.
