There is strong DNA sequence evidence that human chromosome resulted from the fu

Question

There is strong DNA sequence evidence that human chromosome resulted from the fusion of two primate chromosomes as evidenced by the alignment of centromere and telomere markers. a. True b. False Translocation is a chromosome abnormality caused by rearrangement of parts between nonhomologous chromosomes. a. True b. False The Philadelphia translocation a is a chromosome abnormality caused by rearrangement between nonhomologous chromosomes: t(9;22) (q34;q11) b. is a chromosome abnormality caused by rearrangement between homologous chromosomes: t(4;20) (q33;q12) c. is the result of an unequal crossing aver event d. was mast likely the result of 8 Mu phage infection causing a transposition e. is mediated by eEF-2 (a translocase) (Pick the best selection) In humans, there are several genetic isotypes for antibodies and collagen. What genetic mechanism explains the appearance of multiple gene copies in the human genome? a. Polyploidization b. Translocation c. Unequal exchange between non-sister chromatids d. Cross-overs with equal exchange e. Chromosome fusion The globin gene cluster (myoglobin & hemoglobin) contains stretches of DNA that are homologous to the sequences of functional globin genes but contain severe accumulated mutations that render them nonfunctional. Most of these noncoding regions have no know function. They are considered to be evolutionary relics and are called: a. promoters b. enymes c. pseudogenes d. proteins e. introns Which technique is best for locating a specific gene to a specific chromosome? a. C_0t analysis b. DNA fingerprinting c. Fluorescence in situ hybridization, FISH d. X-ray crystallography e. Metagenomics Which does NOT describe The National Academy of Sciences (NAS)? a. A private, non-profit society of scholars b Founded in 1660 and granted a Royal Charter by King Charles II of England. It's the oldest scientific society c. Nearly 500 members of the NAS have won Nobel Prizes d. Provides independent, objective advice to the nation on matters related to science and technology e. Publishes a scientific journal called Proceedings of the National Academy of Sciences (PNAS)

Explanation / Answer

49. the technique for locating specific gene is : (option c) fluorescence in situ hybridization, FISH

here the fluorescent or radio active markers are used to label segments of DNA with known sequences, then the probes are hybridized with single strands of segments of the unknown DNA.

successful hybridization occur when the bases from the probe match with their complementary bases on the DNA strand, by this the location of a particular gene on a chromosome is identified by using the information of the fragments on DNA.

in FISH, the probes are introduced to the chromosomes on a microscope slide,after washing away unmatched probes we can detect the areas where hybridization has occured by using a fluorescence microscope.

50. the national academy of sciences (option B) does not describe it

NAS was founded on march 3, 1863 at the height of the civil war.

it is a private non-profit society of scholars which is established by an act of congress signed by president abraham lincoln. scientists are elected by their peers to membership in the NAS for outstanding contributions to research. the 3 academics that work together in NAS are sciences, engineering and medicine.

48. the evolutionary relics which are non functional are: option c - pseudogenes

they are the segments of DNA related to real genes, they result from accumulation of multiple mutations within a gene.

they may be functional similar to other noncoding DNA, which are in regulatory functions. they are different from normal genes due to lack of protein coding ability resulting from variety of disabling mutations.

45. the statement is true

translocation is the chromosome abnormality caused by the rearrangement of parts between non homologous chromosomes.

translocations can be balanced or unbalanced or can be reciprocal or non reciprocal and can be detected on the cytogenetics or a karyotype of the affected cells. A balanced translocation results in no gain or loss of material while the unbalanced may result in trisomy or monosomy of a particular chromosome segment.

here the rearrangement of DNA within a chromosome or the transfer of a segment of one chromosome to a nonhomologous one occur. they may be inherited or acquired,in most cases they show no effect on the body as all the normal chromosomal material is present.

46. philadelphia translocation: option A

chronic myeloid leukemia is a myeloproliferative disorder characterized by the presence of philadelphia chromosome which cause reciprocal translocation.

various translocations of this type invoves chromosomes 9 and 22, where the translocation of genetic material between the 2 chromosomes occur and contains a fusion gene called BCR-ABL1, this is the gene coding for a hybrid protein tyrosine kinase signalling protein which causes the cell to divide uncontrollably. here, the chromosome changes are sub microscopic so these translocations are revealed by fluorescence in situ hybridization or molecular analysis.

the presence of this translocation is a highly sensitive test fo chronic myelogenous leukemia cells.

44. the given statement is true

chromosome 2 is the second largest human chromosome having more than 242 million base pairs, present about 8% of total DNA.

it is identical DNA sequence as that of the human but has a centromere and telomere sequences are also found. it contains 1300-1400 genes that provide instructions for making proteins which perform different roles in the body.

changes in chromosome 2 have been leading to several forms of cancer, and the mRNA transcript from a gene on chromosome 2 may produce a protein unique to humans and chimps.

47. the genetic mechanism explaining the presence of multiple genes in human genome is option A - ployploidization.

it refers to the organism containing more than two basic sets of chromosomes, it can occur because of cell fusion or abnormal cell division.

it occurs mostly due to cellular stress or with increasing age. it is regulated during liver growth and its consequence on liver function as it occurs mainly during the liver development.

polyploid occurs in highly differentiated human tissues and also in somatic cells of some animals, it is a mechanism of sympatric speciation because polypliods are unable to interbreed with their diploid ancestors.

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