chapter 14: genes, develop, and evolution

Question 0

determination

Answer 0

-sets fate of cell, even before characteristics are observable

Question 1

4 developmental stages

Answer 1

1. ) determinism
2. ) differentiation
3. ) morphognesis
4. ) growth

Question 2

differentiation

Answer 2

• diff types of cells arise from less specialized cells

- leads to cells with specific structures/functions

Question 3

morphogenesis

Answer 3

• the organization/spacial distribution of differentiated cells
• can occur by cell division, cell expansion, cell movements, and apoptosis

Question 4

growth

Answer 4

• increase in size of body by cell division and expansion

- through increase in # of cells or enlargement of existing cells

Question 5

cell fate

Answer 5

-each of an enbryos undifferentiated cells are destined to become a part of a particular type of tissue

Question 6

totipotent

Answer 6

cell is able to form an entire organism with its differentiated cell
(this is usually just true of the zygote)

Question 7

dedifferentiate

Answer 7

• it is possible for a differentiated cell to become undetermined again
• lose differentiated characteristics

Question 8

genomic equivalence

Answer 8

• all plant cells contain the complete genome and therefore could become any cell in the plant
• for example, forestry companies regenerate trees by taking leaves from trees with desirable traits and cloning the tree

Question 9

nuclear totipotency in animals

Answer 9

• nuclear transfer experiments allow us to create cloned animals
• nucleus is removed (enucleated egg) and then a donor nucleus from a differentiated cell is introduced

Question 10

practical uses of cloning animals

Answer 10

• expansion of #s of valuable animals
• preservation of endangered species
• preservation of pets

Question 11

multipotent

Answer 11

stem cells in particular mammalian tissues that can only form a limited repertoire of diffentiated cells

Question 12

hematopoietic stem cell transplantation

Answer 12

• certain cancer treatments deplete bone marrow
• stem cells removed–>treatment–>cells are given signals to increase dividing in laboratory–>cells are restored after treatment

Question 13

embryonic stem cells (ESCs)

Answer 13

a group of cells in the blastocyst retain ability to form all the cells in the body (pluripotent)

Question 14

blastocyst

Answer 14

earliest embryotic stage before differentiation

Question 15

induced pluripotent stem cells (iPS cells)

Answer 15

• from skin cells
• still pluripotent
• means no immune response when used as treatment

Question 16

why cells transcribe differently

Answer 16

1. asymmetrical distribution of cytoplasmic factor

2. differential exposure to an external inducer

Question 17

polarity

Answer 17

developing organisms develop distict tops and bottoms that will eventually become opp ends of the mature organism

Question 18

cytoplasmic segregation model

Answer 18

cytoplasmic determinants are distributed unequally, which determines pattern of gene expression

Question 19

molecular switches

Answer 19

control much of development by allowing a cell to proceed down one of two alternative tracks

Question 20

pattern formation

Answer 20

develop process that results in spatial organization of a tissue or organism. cells must

1. know where they are in relation to rest of body
2. activate the pattern of gene expression that is appropriate for the location

Question 21

organ identity genes

Answer 21

a group of genes that encode proteins that act in combination

Question 22

loss of function mutation

Answer 22

mutation means the organ doesnt develop

results in homeotic mutation, where another organ replaces it

Question 23

homeosis

Answer 23

when organs dont develop properly so another takes its place

Question 24

gain of function mutations

Answer 24

???

Question 25

positional information

Answer 25

spatial sense

when the cell asks itself “where am i” which tells us “what will i be?”

Question 26

morphogen

Answer 26

an inducer that diffuses between groups of cells, setting up a concentration gradient.

1. it specifically affects target cells
2. different concentrations of the signal cause diff effects

Question 27

maternal effect genes

Answer 27

set up major axes of egg

Question 28

segmentation genes

Answer 28

determine boundaries and polarity of each segment

Question 29

hox genes

Answer 29

determine what organ will be made where

Question 30

evolutionary developmental biology (evo-devo)

Answer 30

field of study

1. all species share similar molecular mechanisms for morphogenesis and pattern formation
2. modularity: molecular pathways act independently from one another
3. changes in location and timing of expression are important for evolution
4. development produces morphology

Question 31

genetic toolkit

Answer 31

certain developmental mechanisms (controlled by specific dna sequences) have been conserved throughout evolution. they are modeled/reshuffled to create diversity

Question 32

genetic (molecular) switches

Answer 32

control genetic toolkit

Question 33

heterochrony

Answer 33

genes can be expressed at diff develop stages or for diff durations in diff species
(giraffe having longer cervical vertebrae–>longer neck)

Question 34

parallel phenotypic evolution

Answer 34

highly conserved developmental genes makes it likely that similar traits will evolve repeatedly