Chapter21

Question 1

Stem Cells

Answer 1

Divide and produce 1 daughter stem, and another that differentiates into specialized cell

Question 2

meristems

Answer 2

stem cells in plants

Question 3

Signaling molecules

Answer 3

cells interact during development
present on surface
bound to extracellular matrix
receptors inside cell or on surface
in response, move expand, differentiate, die

Question 4

Differentiation Fate mechanisms

Answer 4

1.) cytomplasmic determinants
- regulatory molecules
2.) induction
- daughter recieves signal that the other doesn’t

Question 5

Programmed Cell Death

Answer 5

helps tissues organs take shape
Apsotosis is most common in animals
neurons die, immune cells (harmful ones) elimanted
without, risk of ALS and cancers

Question 6

Plant cells

Answer 6

genetically equivalent, can dedifferentiate into root cells, whole plant can grow from one adult cell

Question 7

Differential Gene expression

Answer 7

transcriptional control by regulartory transcription factors is most important

Question 8

Regulatory cascades

Answer 8

anterior to posterior
dorsal to ventral
left to right

Question 9

pattern formation

Answer 9

determines spatial organization in an embryo
includes molecules that signal head tail, dorsal ventral

Question 10

Morphogens

Answer 10

pattern forming molecules in a concentration gradient
obtain info from gradient
genes activated by morphogens provide more specific info about location

Question 11

Bicoid

Answer 11

mutagen
affects anterior posterior axis in fruit flies
anterior end lacked anterior structures
had posterior structures there instead
bicoid encodes a morphengen
highest concentraion at anterioir end
made from mother cells and transferrred into the egg
is a regulatory transcription factor
high bicoid tells cells to go to anterior
lower bicoid tells cells to go to posterior

Question 12

In situ hybridization

Answer 12

find where mRNA is located
label it with florescence
hybridize complementary sequence
shows where mRNA is

Question 13

Auxin

Answer 13

morphagen in plants
high concentration near top of stem
lower concentration near the roots

Question 14

Regulatory cascade

Answer 14

morphogens control formation of segments
Gap genes control large body regions
Hox genes speciffy identity
efffector genes lead to differentiation

Question 15

Homeotic Mutations

Answer 15

lead to wrong body part in the wrong place
involves homeotic or Hox genes

Question 16

Hox genes

Answer 16

involved in specifying which body parts to build
are homologous

Question 17

Determination

Answer 17

commitment of a cell to a specific fate
happens gradually
cant be undone, ignores signals after(in animals only, not plants)

Question 18

Master Regulators of differentiation

Answer 18

signals in the embryo induce transcription factors that alter patterns of chromatin

Question 19

myoblasts

Answer 19

cells that are determined to become muscle cells

Question 20

MyoD

Answer 20

protein, master regulator of muscle differentiation

Question 21

induced pluripotent stem cells (iPS cells)

Answer 21

fully differentiated cells that are reverted back to stem cells
can help with disease in medicine

Question 22

Sonic Hedgehog

Answer 22

tool-kit gene that causes extraordinary outcomes in very different animals