Answer:
Option A
Explanation:
Xeroderma pigmentosum arises as a result of the cell being unable to correct lesions induced by UV. This can be as a result of mutations in the enzymes which include XP A-E needed for correction of the lesions. Failure to correct these lesions leads to their accumulation and then damage to the cell.
Answer:
The correct answer is "5-1-3-2-4".
Explanation:
Internalization of LDL particles into cells, is needed to form the intracellular vesicles known as endosomes. The order of events that allow for this process are:
5) LDL receptors migrate to the cell surface and cluster in clathrin-coated pits. Clathrin acts directing the receptors to the cell membrane region where endosomes are formed.
1) A combination of cholesterol and apolipoprotein binds to LDL receptors and becomes internalized as endocytotic vesicles. Once the receptors are in the proper cell membrane region, cholesterol and apolipoprotein are bound and internalized.
3) Several endocytotic vesicles fuse to form an endosome.
2) The environment of the endosome becomes acidic, which causes the LDL to dissociate from its receptor; additionally, the endosome fuses with a lysosome. LDL should be dissociated from its receptor since it is going to be degraded in the following step.
4) The LDL particle is degraded by the lysosome. This takes place after endocytosis, when LDL particles are transported into lysosomes once they are fused, cleaving the cholesterol esters into cholesterol and fatty acids.
A. Photosynthesis converts light energy into glucose, whose bonds have to be broken down in order to access the energy.
Answer:
E. Erwin Chargaff >> Discovered that there were equal amounts of the nitrogen bases A T and C G in a human body cell; concluded that A paired with T and C paired with G
B. Hershey and Chase>> Did experiments with viruses to determine that DNA, not protein, is the genetic material of a cell
A. Frederick Griffith>> Did experiments with S and R strain pneumonia bacteria to determine that DNA is the genetic material of a cell
C. Rosalind Franklin >> Took x-ray crystallography images of a DNA molecule.
Explanation:
Chargaff rules helped to determine the double helix structure of the Deoxyribonucleic acid (DNA), i.e., the genetic material of prokaryotic and eukaryotic organisms. Chargaff indicated that DNA from any species contains a 1:1 ratio of purine bases (Adenine and Guanine) and pyrimidine bases (Cytosine and Thymine). Hershey and Chase provided evidence that the DNA, instead of protein, is the hereditary material. Hershey and Chase used radioactive phosphorus-32 in order to label the DNA of specific bacteriophages (T2), and they discovered that the DNA was responsible to generate progeny inside infected bacteria (i.e., DNA was hereditary material). Frederick Griffith observed that DNA molecule was the transforming factor that could be transferred to innocuous <em>Streptococcus pneumoniae</em> bacteria in order to convert them into deadly bacteria. Finally, Rosalind Franklin obtained the first X-ray image that showed the diffraction pattern of a crystallized DNA molecule, which was used by Watson and Crick to propose that DNA had a double helix structure.
Answer: CO alarms have a life expectancy of around seven years. The CO alarm will beep every 30 seconds or display ERR or END. If a CO alarm is at its end-of-life, replacing the battery will not stop the beep. Most detectors will beep 4 or 5 times in a row about every 4 seconds. Do not mistake dangerous levels of poisonous gas for a detector with low battery.
Explanation: (credits to the internet) Hope this helped! :D
