BIO 160 Chapter 11 Flashcards
cellular differentation
cells must become specialized in structure and function
gene regulation
the turning off and on of genes
gene expression
process by which genetic information flows from genes to proteins
lac operon
only in bacteria
operon
a cluster of genes with related functions, along with the DNA control sequences
promoter
site where the enzyme RNA polymerase attaches and initiates transcription
operator
acts as an off and on switch
repressor
binds to operator and blocks the attachment of RNA polymerase to the promoter
X chromosome inactivation
one of the two X chromosomes is inactivated at randon and highly compact
silencers
inhibit the start of transcription
activatiors
proteins that turn genes on by binding to DNA
enhancers
proteins acting in concert to bind to DNA sequences
homeotic genes
master control genes that determine what body parts will develop in which locations
DNA microarray
is a glass slide with thousands of different kinds of single-stranded DNA fragments attached to wells in a grid
regeneration
regrowth of lost body parts
nuclear transplantation
replacing the nucleus of an egg or a zygote with a lnucleuse removed from an adult body cell
reproductive cloning
cloning that results in a new birth
theraputic cloning
produces stem cells
carcinogens
cancer causing agents
how does the lac operon work?
needed to transport lactose, a sugar in bacteria
what are the benefits of lac operon?
transport and use lactose in bacteria
explain how DNA packing influences gene expression
Chromosomes are packed tightly, the more condense the chromosome is, the less likely the gene is to be expressed.. harder to get to.
Prokaryote vs Eukaryote Transcription
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.
explain how RNA is processed in ekaryotes before it leaves the nucleus
alternative RNA splicing, organism can produce more than one type of polypeptide from a single gene
explain how homeotic genes help us understand animal evolution an development
homeotic genes regulate groups of other genes that determine what body parts will develop in which locations
explain how DNA microarrays help scientists visualize gene expression
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
explain how plants are cloned, what this reveals about cell differentaiton, and why growers clone plants
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
