Week 1

Question 1

Histone Methylation

Answer 1

The specific amino acid in histone tail that gets methylated is important as to whether the chromatin structure is loosened or tightened.

Can’t use histone methylation as predictor for euchromatin or heterochromatin.

Question 2

Epigenetics

Answer 2

Chemical tags on DNA that can turn gene on or off. Environmental aspects of a person’s lifestyle can influence these tags and impact how our genes express themselves.

A persons diet and exposure to pollutants, stress can impact the epigenome.

Question 3

Human Genome

Answer 3

Encodes over 20,000 genes.

23 pairs of human chromosomes contain thousands of genes. DNA in nucleus is wound and compacted into chromosomes so it will fit in nuclear membrane.

Question 4

Nucleosome Complexes

Answer 4

Histones package and order DNA into structural units. Histone protein wound w DNA strands -called nucleosome. They can move along DNA and change structure of the molecule.

Question 5

Euchromatin

Answer 5

Transcriptionally active open regions of chromatin.

Allows for RNA polymerase and other proteins (transcription factors) to bind to promoter region and initiate transcription.

Question 6

Heterochromatin

Answer 6

Tightly wound regions of chromatin that are silenced and transcriptionally inactive.

Question 7

DNA methylation

Answer 7

Attaching small molecules (methyl groups-one carbon and 3 hydrogen atoms) to DNA nucleotides or amino acids that make up histone proteins.

When DNA is methylated the methyl group is typically added to cytosine nucleotides. Gene is turned off and no protein is produced.

Question 8

Histone Acetylation

Answer 8

Histone tails are loosened from around the DNA allowing chromatin to loosen.

Acetyl group (such as acetyl-CoA) is 2-carbon molecule.

Question 9

2 Other modifications to histone proteins

Answer 9

Histone phosphorylation (DNA repair)

Histone ubiquitinated (transcriptional activation/inactivation)