Question

Multiple Choice Please answer all 3 no need to go in Depth

Instead of developing a head and a tail, an abnormal Drosophila embryo develops two tails. This is most likely due to _____.

		apoptosis
		a mutation in an operon
		a failure involving post-transcriptional modification of mRNA
		a mutation in a maternal effect gene
		destruction of the RNA polymerase molecules responsible for the transcription of genes that encode head-related proteins

Specific cells that appear undifferentiated under the microscope but are already fated to become muscle cells are called _____.

		meristematic cells
		bicoids
		myoblasts
		muscle cells
		myocytes

All your cells contain proto-oncogenes, which can change into cancer-causing genes. Why do cells possess such potential time bombs?

		Cells produce proto-oncogenes as a by-product of mitosis.
		Proto-oncogenes are necessary for the normal control of cell growth and division.
		Proto-oncogenes protect cells from infection by cancer-causing viruses.
		Proto-oncogenes are unavoidable environmental carcinogens.
		Proto-oncogenes are genetic junk that has not yet been eliminated by natural selection.

Answer 1

1. Instead of developing a head and a tail, an abnormal Drosophila embryo develops two tails. This is most likely due to _____.

Answer:- a mutation in a maternal effect gene ( maternal effect gene codes for transcription factors and proteins which determine anterior- posterior axis of drosophila embryo. e.g. Hunchback and Bicoid determine head and thorax while Nanos and Caudal protein determines tail of Drosophila . Mutation in bicoid  causes development of an abnormal Drosophila embryo with two tails).

2.Specific cells that appear undifferentiated under the microscope but are already fated to become muscle cells are called _____.

Answer- myoblasts ( Myoblasts are embryonic precursors of muscle cells . They are undifferentiated but gives rise to cell which get differentiated into muscle cells).

3.All your cells contain proto-oncogenes, which can change into cancer-causing genes. Why do cells possess such potential time bombs?

Answer- Proto-oncogenes are necessary for the normal control of cell growth and division. ( Cancer involves the uncontrolled cell division which leads to abnormal cell growth. This happens due to mutation in proto-oncogenes as these genes are involved in regulation of cell growth and division).