Developmental Genetics 1) How do bicoid and hunchback determine the anterior-pos

Question

Developmental Genetics 1) How do bicoid and hunchback determine the anterior-posteriors axis?
Cancer Genetics 2) Why is a tumor defined as a clonal line of cells?
Organelle DNA 3) Is mitochondrial DNA like Eukaryotic DNA or Prokaryotic DNA? Explain. (I believe mtDNA is like Eukaryotic DNA? need an explanation)
4) Why can we say that the mitochondrial genome is one big operon? Developmental Genetics 1) How do bicoid and hunchback determine the anterior-posteriors axis?
Cancer Genetics 2) Why is a tumor defined as a clonal line of cells?
Organelle DNA 3) Is mitochondrial DNA like Eukaryotic DNA or Prokaryotic DNA? Explain. (I believe mtDNA is like Eukaryotic DNA? need an explanation)
4) Why can we say that the mitochondrial genome is one big operon? Developmental Genetics 1) How do bicoid and hunchback determine the anterior-posteriors axis?
Cancer Genetics 2) Why is a tumor defined as a clonal line of cells?
Organelle DNA 3) Is mitochondrial DNA like Eukaryotic DNA or Prokaryotic DNA? Explain. (I believe mtDNA is like Eukaryotic DNA? need an explanation)
4) Why can we say that the mitochondrial genome is one big operon? 1) How do bicoid and hunchback determine the anterior-posteriors axis?
Cancer Genetics 2) Why is a tumor defined as a clonal line of cells?
Organelle DNA 3) Is mitochondrial DNA like Eukaryotic DNA or Prokaryotic DNA? Explain. (I believe mtDNA is like Eukaryotic DNA? need an explanation)
4) Why can we say that the mitochondrial genome is one big operon?

Explanation / Answer

1)

Maternal effect genes establish anterior-posterior, and dorsal-ventral axes of the embryo. The anterior-posterior axis of Drosophila arises from the activity of morphogens produced by the material effect genes such as Bicoid and nanos.

Unfertilized eggs store mRNAs. Before fertilization, mRNA for Bicoid protein is localized at the end, which is destined to become the anterior end of the Drosophila. After fertilization, nuclear divisions begin. At this point, bicoid mRNA is translated, forming a bicoid protein. This bicoid protein diffuses away from the anterior end, thus establishing a protein concentration gradient. At the posterior end, the Nanos protein also forms a similar gradient, but from the posterior direction. Thus, each nucleus in the developing embryo is exposed to different gradients of Bicoid and Nanos.

These two proteins regulate the expression of the gap genes. The Bicoid proteins regulate their transcription, while the Nanos regulates their translation. The high concentration of Bicoid protein in the anterior portion turns on a gap gene called hunchback, while turning off another gap gene called Kruppel. This is how two genes determine the anterior-posterior axis.

2)

Because tumor cells are genetically identical to each other, so they are defined as a clonal line of cells.

3) Mitochondrial DNA is like prokaryotic DNA.

The protein coding regions of organelle genes of eukaryotes more closely resemble those of bacteria. Endosymbiotic theory gives a clear idea about this. For example, organelles like mitochondria and chloroplast very much similar in morphology and size to prokaryotic bacteria. Both types of organelle have their own DNA (deoxyribonucleic acid) that is very much similar to that of prokaryotes – circular, not linear. Further, the DNA of mitochondria and chloroplasts neither use introns nor histones for chromosomal packing. Antibiotics such as streptomycin block the synthesis of proteins in mitochondria, and chloroplasts, but cannot inhibit the protein synthesis in cytoplasm of eukaryotes.

4) Mitochondrial DNA is circular, so it can be said as one big operon.

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