Unit 6, Topic 6: Gene Expression and Cell Specialization

Question 1

Describe how it is possible for only one identical twin to express an inherited disease

Answer 1

Identical twins pick up genetic mutations in the womb as their cells weave new strands of DNA - one twin may pick up a mutation that the other did not

Question 2

After fertilization a zygote forms. The cells then go through mitosis. Explain how this bundle of cells eventually forms a human with specialized cells (i.e. liver cells, blood cells, neurons, etc.)

Answer 2

The zygote evolves into a blastocyst made up of an inner group of cells with an outer shell-the inner group of cells becomes the embryo

Question 3

Differentiate between histone acetylation and DNA methylation.

Answer 3

Histone acetylation: the addition of acetyl groups to the lysine residues of the histone molecule.
DNA methylation: the addition of a methyl group to the cytosine residue of the DNA molecule.

Question 4

Do microRNAs and siRNAs block transcription or translation.

Answer 4

transcription

Question 5

What role do cytoplasmic determinants play in early embryonic development?

Answer 5

Major role in the development of the embryo’s organs- keep embryo organs operating well

Question 6

True or false: morphogenesis is the process that gives an organism its shape

Answer 6

true

Question 7

When some people hear of apoptosis, they think that this is a bad thing that cells go through. Provide one example that illustrates the importance of apoptosis (in reference to embryonic development).

Answer 7

Contributes to the appropriate formation of various organs and structures.