2/11 Period 4 and 5 sit in new seats Short FRQ – read/outline together first, then 6 minute write...
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Transcript of 2/11 Period 4 and 5 sit in new seats Short FRQ – read/outline together first, then 6 minute write...
2/11
• Period 4 and 5 sit in new seats• Short FRQ – read/outline together first, then 6
minute write• Review what movie has covered so far – from
which chapters?• Continue What Darwin Never Knew (I check labs
during)Homework – Chapter 24 and 25 notes & concept checks due
Thurs. and online due next Tuesday..
Agenda 2/12
• Review what movie covered
• Continue What Darwin Never Knew (I check the rest of the labs)
Homework –
Chapter 24 and 25 notes & concept checks due Thursday and online due next Tuesday.
Agenda 2/13
• Finish What Darwin Never Knew
• Start Ch. 22-25 Highlights and practice questions
Homework -
Chapter 24 and 25 notes & concept checks due tomorrow and online due next Tuesday.
Agenda 2/14• Wrap up discussion of video – Sticklebacks and yesterday’s topics
(4 research studies about human evolution) and next slides about switches – 20 min
• Highlights Ch. 22-25 – 25 min• I check Ch. 24 and 25 notes while you do slides
Homework – Chapter 24 and 25 online due next Tuesday.Print Hardy-Weinberg lab packet from website for Tues.Ch. 22 Hardy Weinberg due next Thursday with quiz FridayChapter 26(parts 1,2,3,6) and 27.1-27.2 notes, concept checks due
next Friday 2/22 and online Monday 2/25 Test that Wed.
A “Switch” is an enhancer
• As the video explains, although two organisms may both possess the same gene linked to a particular trait, this trait may not be expressed unless the gene is turned on. This is done by an enhancer, a piece of noncoding DNA—previously thought of as "junk" DNA—that acts as a "switch." (NOVA, What Darwin Never Knew)
Organization of a Typical Eukaryotic Gene
• Associated with most eukaryotic genes are multiple control elements, segments of noncoding DNA that serve as binding sites for transcription factors that help regulate transcription
• Control elements and the transcription factors they bind are critical to the precise regulation of gene expression in different cell types
© 2011 Pearson Education, Inc.
Figure 18.8-1
Enhancer(distal control
elements)
DNA
UpstreamPromoter
Proximalcontrol
elementsTranscription
start site
Exon Intron Exon ExonIntron
Poly-Asignal
sequenceTranscriptiontermination
region
Downstream
• Proximal control elements are located close to the promoter
• Distal control elements, groupings of which are called enhancers, may be far away from a gene or even located in an intron
Enhancers and Specific Transcription Factors
© 2011 Pearson Education, Inc.
• An activator is a protein that binds to an enhancer and stimulates transcription of a gene
• Activators have two domains, one that binds DNA and a second that activates transcription
• Bound activators facilitate a sequence of protein-protein interactions that result in transcription of a given gene
© 2011 Pearson Education, Inc.
© 2011 Pearson Education, Inc.
Animation: Initiation of Transcription
Right-click slide / select “Play”
ActivatorsDNA
EnhancerDistal controlelement
PromoterGene
TATA box
Generaltranscriptionfactors
DNA-bendingprotein
Group of mediator proteins
RNApolymerase II
RNApolymerase II
RNA synthesisTranscriptioninitiation complex
Figure 18.10-3
Figure 18.9
DNA
Activationdomain
DNA-bindingdomain
• Some transcription factors function as repressors, inhibiting expression of a particular gene by a variety of methods
• Some activators and repressors act indirectly by influencing chromatin structure to promote or silence transcription
© 2011 Pearson Education, Inc.
Figure 18.11
Controlelements
Enhancer Promoter
Albumin gene
Crystallingene
LIVER CELLNUCLEUS
Availableactivators
Albumin geneexpressed
Crystallin genenot expressed
(a) Liver cell
LENS CELLNUCLEUS
Availableactivators
Albumin genenot expressed
Crystallin geneexpressed
(b) Lens cell
Coordinately Controlled Genes in Eukaryotes
• Unlike the genes of a prokaryotic operon, each of the co-expressed eukaryotic genes has a promoter and control elements
• These genes can be scattered over different chromosomes, but each has the same combination of control elements
• Copies of the activators recognize specific control elements and promote simultaneous transcription of the genes
© 2011 Pearson Education, Inc.
Figure 18.12
Chromosometerritory
Chromosomes in theinterphase nucleus
Chromatinloop
Transcriptionfactory
10 m
Hox genes code for transcription factors that create body axis
Found in all animals,Hox genes act to "regionalize" the body along the embryo's anterior-to-posterior (head-to-tail) axis.
Hox vs. later epigenetic mechanisms
• Hox genes make the initial decisions of which genes to turn on or off in different body regions and cell types.
• Later in an animal's development, epigenetic switches take over, controlling the "on" and "off" state of genes within each cell.
• Remember some of these epigenetic mechanisms of gene expression?
Figure 18.6 Signal
NUCLEUSChromatin
Chromatin modification:DNA unpacking involvinghistone acetylation and
DNA demethylationDNA
Gene
Gene availablefor transcription
RNA ExonPrimary transcript
Transcription
Intron
RNA processing
Cap
Tail
mRNA in nucleus
Transport to cytoplasm
CYTOPLASM
mRNA in cytoplasm
TranslationDegradationof mRNA
Polypeptide
Protein processing, suchas cleavage and
chemical modification
Active proteinDegradation
of proteinTransport to cellular
destination
Cellular function (suchas enzymatic activity,structural support)
Organize the following terms into a flowchart
• Adaptation, Environmental Change, Natural Selection, Species Changes, Variation exists
Can Individuals Evolve?
List as many categories of Evidence of Evolution as you can
What are the 2 main causes of genetic variation?
• Microevolution =
• Population =
Natural Selection = only mechanism that gives consistent Adaptive Evolution
• Relative fitness?
• 3 ways that it can affect phenotype distribution – name and draw
Genetic variation preserved how?
• Why not perfection?
Speciation – when does evolution result in a new species?
• Species defined =
• Macroevolution =
• What are 2 main types of reproductive isolation?
Prezygotic vs. Postzygotic
• Describe various methods of prezygotic: isolation: habitat, behavioral, temporal, mechanical, gametic
• Describe various methods of postzygotic:
Reduced hybrid viability, Reduced hybrid fertility, Hybrid breakdown
Allopatric vs. Sympatric speciation – has to do with geographic
isolation• Allopatric:
• Sympatric:
Speed of Speciation
• Gradualism
• Punctuated Equilibrium & Adaptive radiation
5 conditions of Hardy-Weinberg Equilibrium? Is it realistic?
What is genetic drift? Give 2 examples
Match up the person with the theory
• Carolus Linnaeus
• Aristotle
• Old Testament
• Lamarck
• Cuvier
• Lyell
• Darwin
• Uniformitarianism• Use and Disuse• Natural Selection• Catastrophism• Taxonomy• Scala naturae• Binomial Nomenclature• God designed perfect
species• Inheritance of Acquired
Characteristics
Classification terms
• Phylogeny = – Inferred from homologous structures and molecular
data• Systematics =
• Taxonomy = – Binomial nomenclature– DKPCOFGS – look at table of 3 domains– Taxon
• Phlyogenetic Tree• Cladogram and clades
Molecular systematics
• DNA that codes for rRNA
• DNA that codes for mitochondrial DNA
• Molecular clocks