Chapter 21

Question 1

3 processes of cell development

Answer 1

cell division

morphogenesis

cell differentiation

Question 2

genomic equivalence

Answer 2

all cells have the same DNA, so they have the same genes

Question 3

how do we have different types of cells if all cells have genomic equivalence?

Answer 3

gene expression

differences arise during development by regulatory mechanisms

Question 4

what does it mean to express a gene?

Answer 4

gene is expressed through a physical trait

Question 5

differential gene expression

Answer 5

different cells have different genes that are active

heart cells and eye cells have same DNA, but different genes are expressed to give the cells different function

Question 6

totipotent cell

Answer 6

a cell that can generate a completely new organism

Question 7

cloning

Answer 7

using one or more somatic cells from a multicellular organism

makes a genetically identical individual

Question 8

nuclear transportation

Answer 8

nucleus of an unfertilized egg cell or zygote is replaced from a nucleus from a differentiated cell

Question 9

nuclear transportation creates fully developed creatures when…

Answer 9

nuclear transportation is from a nucleus of a less differentiated cell instead of a fully developed cell

Question 10

process of cloning mammals

Answer 10

1. mammary cell from donor taken, egg cell from donor taken
2. nucleus removed from egg cell, mammary cells are cultured to cause differentiation
3. cells fused
4. grown in culture
5. implanted in uterus of a different sheep
6. clone is identical to mammary cell donor

Question 11

x-inactivation

Answer 11

creates a random phenotype in offspring, even if a clone is genetically identical to the mother

Question 12

stem cell

Answer 12

relatively unspecialized cell that can reproduce itself indefinitely and differentiate into specialized cells of any type

Question 13

why are embryonic stem cells so controversial?

Answer 13

separated at the blastocyst stage

totipotent

taken from an unconsenting fetus

Question 14

why are adult stem cells not as useful as embryonic stem cells?

Answer 14

they are pluripotent

Question 15

transcriptional regulation of gene expression

Answer 15

cell determination- precedes differentiation

involves expression of genes for tissue-specific proteins

Question 16

outcome of transcriptional regulation

Answer 16

generic cell becomes a specialized cell

Question 17

cytoplasmic determinants

Answer 17

maternal substances in the cell influence early development

regulate expression of genes that affect cell’s developmental rate

Question 18

pattern formation

Answer 18

development of a spatial organization of tissues and organs

occurs continually in plants

Question 19

positional information

Answer 19

molecular cues that control pattern formation

tells a cell its location relative to the body

sent by chemicals

Question 20

egg-polarity genes

Answer 20

establish the axes of the body

control orientation of the egg and eventually the fly

Question 21

bicoid gene

Answer 21

affects front half of the body

Question 22

mutant bicoid gene

Answer 22

an individual will lack the front half of its body and has a duplicate posterior structure at both ends

Question 23

concentration of the mother’s bicoid gene is…

Answer 23

at the egg’s anterior

high to low concentration

Question 24

segmentation genes

Answer 24

produce proteins that produce the formation of segments after axes information

Question 25

positional information is provided by sequential activation of what genes?

Answer 25

gap genes

pair-rule genes

segment-polarity genes

Question 26

anatomical identity of drosophila segments

Answer 26

set by master regulatory genes called homeotic genes

Question 27

mutations to homeotic genes produce what kind of flies

Answer 27

flies with strange traits, such as legs growing from their head

Question 28

significance of nematode

Answer 28

model organism for investigating rolls of cell signaling, induction, and programmed cell death

Question 29

induction

Answer 29

process of cell signaling

directs daughter cells down the appropriate pathways

Question 30

apoptosis

Answer 30

cell shrinks and becomes lobed

nucleus condenses

DNA fragmented

cell dies