Lecture 02

Question 1

Epigenetics

Answer 1

Inheritance that is superimposed on genetic inheritance based on DNA (ex: methylation chromatin structure, histone modification)

Question 2

Heterochromatin

Answer 2

Densely packed, silences packaged genes, directly inherited by daughter cells; dark staining

Question 3

Euchromatin

Answer 3

Less condensed, usually involved in gene expression

Question 4

Acetylation of lysine on histones

Answer 4

Modification that loosens chromatin structure

Question 5

Position effect variegation

Answer 5

Breakage events that bring heterochromatin near active genes and tends to silence them

Question 6

Methylation of lysine on histones

Answer 6

Causes chromatin to be more compact, silences gene

Question 7

What is the purpose of variant histones?

Answer 7

Create more diversity in genes

Question 8

Code reader complex

Answer 8

Reads code by recognizing histone tail and covalent modifications (code is dynamic)

Question 9

Code reader-writer enzymes

Answer 9

Mark nucleosomes, create chain reaction marking more histones

Question 10

What halts the spread of chromatin modifications?

Answer 10

Barrier sequences - physical or enzymatic; HS4 region

Question 11

Role of CENP-A

Answer 11

Forms the kinetochore

Question 12

Condensins

Answer 12

Keep sister chromatids separate for cell division, protect fragile DNA molecule as separation occurs

Question 13

Homologues

Answer 13

Genes that are similar in both sequence and function due to common ancestry

Question 14

How do genomic changes occur?

Answer 14

Point mutations, duplications, deletions, inversions, translocations

Question 15

Purifying selection

Answer 15

elimination of mutations that interfere with important genetic functions