BIO 160 Chapter 11

Question 1

cellular differentation

Answer 1

cells must become specialized in structure and function

Question 2

gene regulation

Answer 2

the turning off and on of genes

Question 3

gene expression

Answer 3

process by which genetic information flows from genes to proteins

Question 4

lac operon

Answer 4

only in bacteria

Question 5

operon

Answer 5

a cluster of genes with related functions, along with the DNA control sequences

Question 6

promoter

Answer 6

site where the enzyme RNA polymerase attaches and initiates transcription

Question 7

operator

Answer 7

acts as an off and on switch

Question 8

repressor

Answer 8

binds to operator and blocks the attachment of RNA polymerase to the promoter

Question 9

X chromosome inactivation

Answer 9

one of the two X chromosomes is inactivated at randon and highly compact

Question 10

silencers

Answer 10

inhibit the start of transcription

Question 11

activatiors

Answer 11

proteins that turn genes on by binding to DNA

Question 12

enhancers

Answer 12

proteins acting in concert to bind to DNA sequences

Question 13

homeotic genes

Answer 13

master control genes that determine what body parts will develop in which locations

Question 14

DNA microarray

Answer 14

is a glass slide with thousands of different kinds of single-stranded DNA fragments attached to wells in a grid

Question 15

regeneration

Answer 15

regrowth of lost body parts

Question 16

nuclear transplantation

Answer 16

replacing the nucleus of an egg or a zygote with a lnucleuse removed from an adult body cell

Question 17

reproductive cloning

Answer 17

cloning that results in a new birth

Question 18

theraputic cloning

Answer 18

produces stem cells

Question 19

carcinogens

Answer 19

cancer causing agents

Question 20

how does the lac operon work?

Answer 20

needed to transport lactose, a sugar in bacteria

Question 21

what are the benefits of lac operon?

Answer 21

transport and use lactose in bacteria

Question 22

explain how DNA packing influences gene expression

Answer 22

Chromosomes are packed tightly, the more condense the chromosome is, the less likely the gene is to be expressed.. harder to get to.

Question 23

Prokaryote vs Eukaryote Transcription

Answer 23

prokaryote - lac operon
X-chromosome inactivation
Activator-enhancer complex is unique in eukaryotes because they normally have to be activated to begin protein synthesis, which requires the use of transcription factors and RNA polymerase. In general, the process of eukaryotic protein synthesis involves four steps:

Activators, a special type of transcription factor, bind to enhancers, which are discrete DNA units located at varying points along the chromosome.
The activator-enhancer complex bends the DNA molecule so that additional transcription factors have better access to bonding sites on the operator.
The bonding of additional transcription factors to the operator allows greater access by the RNA polymerase, which then begins the process of transcription.
Silencers are a type of repressor protein that blocks transcription at this point by bonding with particular DNA nucleotide sequences.

Question 24

explain how RNA is processed in ekaryotes before it leaves the nucleus

Answer 24

alternative RNA splicing, organism can produce more than one type of polypeptide from a single gene

Question 25

explain how homeotic genes help us understand animal evolution an development

Answer 25

homeotic genes regulate groups of other genes that determine what body parts will develop in which locations

Question 26

explain how DNA microarrays help scientists visualize gene expression

Answer 26

mRNA isolated, complementary DNA synthesized using nucleotides modified to glow, small amount of cDNA mixture is complemntarty to a DNA fragment at a particular location on the grid, unbound DNA rinses awayresearchers can lear which genes are active in different tissues, times and different states of health

Question 27

explain how plants are cloned, what this reveals about cell differentaiton, and why growers clone plants

Answer 27

plant cloning may bet the only commercially practical means of reproducing plants, ex:orchids and seedless grapes, mature plant cells can reverse their differentation and develop into all the specialized cells of an adult plant