Cell Differentiation

Question 1

pattern formation

Answer 1

process by which cells in a developing embryo acquire identities that lead to the formation of distinct regions/functional entities

Question 2

specification

Answer 2

group of cells is specified if when isolated in cultures they develop according to their normal fate; reversible

Question 3

determination

Answer 3

implies stable change in the state of a cell such that the fate is now fixed; irreversible

Question 4

stuff Weismann postulated

Answer 4

chromosomes control development; chromosomes make nuclear determinants; different cell types inherit different determinants as the embryo divides

Question 5

Gurdon

Answer 5

demonstrated that nuclei of differentiated cells retain their full genomic content; laid foundation for animal cloning

Question 6

RNA Seq (shotgun sequencing)

Answer 6

extract RNAs from cell, select for mRNAs; convert mRNAs to cDNA

Question 7

histones

Answer 7

protein component of chromatin

Question 8

nucleosomes

Answer 8

basic unit of chromatin structure composed of an octamer of histone proteins wrapped with 2 loops of DNA

Question 9

methylated histone

Answer 9

closed DNA

Question 10

acetylated histone

Answer 10

open DNA

Question 11

DNA can be directly methylated on _______ residues

Answer 11

cytosine

Question 12

methylcytosines

Answer 12

facilitate binding of proteins that catalyze the methylation or deacetylation of histones; prevent TFs from binding to enhancers

Question 13

Chlp-Seq assay

Answer 13

1. chromatin isolated from cell
2. TFs are crosslinked to their DNA binding sites
3. antibodies bind to specific chromatin proteins
4. antibodies are precipitated out of solution
5. DNA frags associated with precip complexes are purified and sequenced
6. DNA sequences are compared with genome maps

Question 14

events of transcription

Answer 14

PIC must form on promoter plus RNA poly; mediator complex initiates a chromatin loop bridging the enhancers to the promoter region; cell specific TFs bind to enhancer

Question 15

domains of TFs

Answer 15

1. DNA binding domain
2. transcription activation domain
3. optional interaction domain for interacting with other TFs

Question 16

how are TFs asymmetrically distributed?

Answer 16

1. localized molecule tethering/stabilization of molecule transport
2. cytokinesis

Question 17

requirements for TFs to be asymmetrically distributed

Answer 17

mother cell must be polarized; mitotic spindle must be aligned with the axis of polarity

Question 18

changes in protein activity in cytoplasm from inductive signaling

Answer 18

electrical properties of cell; adhesive properties of cell; shape, migration, programmed cell death

Question 19

changes in gene expression in nucleus from inductive signaling

Answer 19

cell division, cell fate

Question 20

endocrine

Answer 20

uses bloodstream; physiological control

Question 21

juxtacrine

Answer 21

signal is bound to surface of sending cell and can only affect neighboring cells

Question 22

autocrine

Answer 22

when signalling cell and responding cell are of the same type

Question 23

paracrine

Answer 23

signals released into space between cells