Biology 102 lecture 11 & 12 notes
Biology 102 lecture 11 & 12 notes BIO102
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This 3 page Class Notes was uploaded by Danielle Kelly on Friday February 13, 2015. The Class Notes belongs to BIO102 at Washington State University taught by Dr. Strofer in Spring2015. Since its upload, it has received 51 views. For similar materials see Biology 102 in Biology at Washington State University.
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Date Created: 02/13/15
Lecture 11 February 11th and 13 2015 Speciation 2 types Allopatric speciation most common 0 Geographic separation among two populations 0 Time goes by local adaptation 0 Can no long interbreed Sympatric speciation less common 0 Speciation in the same area Common in plants 0 Animal example Chinook salmon reproductive isolation spawning different times in same streams rivers How fast is Speciation Gradualism versus punctuated equilibrium 0 Darwin generally though gradualist o Fossil records Mass extinctions follow by rapid in geological time radiations New species often appear more abruptly than predict under gradualist When might species NOT evolve o In a very stable environment natural selection might not change drastically through time EX coelacanth sh in Madagascar Biodiversity about 2 million species described may be as many as 520 million total Why so many species a Increases in atmospheric oxygen allowed aerobic and anaerobic respiration b Plate tectonics created geographic isolation among species which led to allopatric speciation aThese plates are sitting on molten lava which is the center of earth LEX species in India are similar to some in Africa because they used to be connected ccase study Australia basically an island separated by 65 MY iLots of endemic species there cClimate change regular glacial advances and recessions aConstantly changing geographic ranges of species and environment conditions d Mass extinctions loss of many species led to many open niches for speciation to occur e Adaptive radiation evolution of ecological and phenotypic diversity within a rapidly multiplying lineage a Speciation and phenotypic adaptation of an array of species exhibiting different morphological and physiological traits i Starts from single ancestor ii Can exploit a range of divergent environments Animal Diversity Cambrian explosion formation of hard outer body shells 0 Radiation of most modern animal phyla 0 Well marked in fossil records 0 Why Complex predator prey relationships Evolution of common body plans genes at control form Februarv 13 2015 Outline 0 Introduction to cells 0 HIV life cycle 0 Cell membrane functions 0 Basic Cell structure HIV Life cycle 1 Virus binds receptors on cell membrane and enters ceII Enzymes remove proteins of viral capsid 2 RT reverse transcriptase catalyzes formation of DNA complementary to viral RNA 3 New DNA strand serves as a template for complementary DNA strand 4 Double stranded DNA is incorporated into host ceII39s genome 5 Viral genes transcribed into mRNA Some viral DNA copied as the RNA genome for virions 6 mRNA messenger RNA translated into HIV proteins in cytoplasm 7 Capsids protein coats surround new viral RNA genomes 8 New viruses bud from host cell Questions 0 How does HIV get into a cell 0 Why aren39t cells permeable to other things 0 Why are cells quotalivequot and viruses not 0 How is virus structure different from cell structure 0 How does virus make copies of itself what ceII parts does it manipulate How does HIV get into a cell FirstHIV enters through the cell membrane 0 Cell membrane 0 quotSelectiver permeablequot o Viruses and other diseases have to quottrickquot it to get in 0 Structure Cell membrane structure remarkably similar among cell types Phospholipid bilayer a Hydrophobic quotwater hatingquot tail 0 Interact with aqueous medium Hydrophilic quotwater lovingquot head 0 quot0in corequot Why aren t cell permeable to other things 0 Cells are quotselectively permeablequot o Cant just let anything pass in or would get destroyed o Permeability depends on proteins embedded in phospholipid bilayer 0 Cell needs to communicate with other cells Different cell types need different materials 0 Cells also need to rid themselves of wastes Mechanisms of cell entry diffusion o Particles move from area of high concentration to area of low concentration 0 Small particles can just pass through cell membrane 0 Passive Mechanism of cell entry osmosis o Diffusion of water 0 From high concentration to low concentration 0 Passive 0 When medium has high concentration of water than cell cell is hypotonic o More water in cell less solutes than medium cell is hypertonic Mechanisms of cell entry facilitated diffusion o Substances enter protein carrier in membrane and change shape 0 After solute moved across membrane protein returns to original shape 0 Bigger molecules scan pass through 0 Required no energy Mechanisms of cell entry active transport 0 Carrier protein binds to substance being transported and carried it to other side of membrane 0 Most often required energy 0 Move substance against concentration gradient Mechanism of cell entry endocytosisexocytosis o Endocytosis substance engulfed by cell in vesicle o Exocytosis substance packed up by cell and quotsent offquot HIV cell entry 0 HIV binds to 2 cell receptor proteins in tcells Cells think it is necessary protein and quotlet it inquot Why are cells alive and viruses not Viruses do not have means of replicating themselves 0 Protein coat enzymes DNA or RNA 0 Cells quotfundamental unit of lifequot 0 Membrane o Organelles nucleus eukaryotic and ways to make proteins and replicate themselves