Lab Safety• Never stopper a test tube when heating it• Tie hair and sleeves back• No eating; no books or papers on the lab desk• Read directions; listen to teacher• Be aware of fire blanket, eye wash, fire extinguisher, etc.
Microscopes• Can be used to identify and compare cells and cell parts• Proper technique for: – Preparing wet-mount slides – Staining
Diffusion through a Membrane• Students had created a “cell” filled with glucose and starch. The cell is placed in an iodine-water bath. – Glucose moved out because it was small enough – Starch stayed in because it was too big• Evidence starch stayed in – inside of cell turned purple/black indicating the presence of starch
Diffusion through a Membrane• Must know: – Osmosis is the movement of water from high water concentration to low water concentration Ex: Onion cells treated with salt water – Diffusion is the movement of a solute from a high to low concentration Ex: Glucose moving out of the dialysis tubing, iodine going in
Diffusion through a Membrane• Let’s draw our “cell” and what happens after we allow diffusion to occur
Pulse Rate• Pulse – Representation of heart beat; blood pressure pushes out on artery walls with every heart beat• Pulse Rate increases with an increase in activity – The heart is meeting the body’s need for increased oxygen – Muscle fatigue occurs when waste builds up and oxygen is not replenished fast enough to keep up with activity
Similarities between Organisms• Molecular and genetic similarities are more meaningful than structural similarities – Organisms with similar DNA and proteins are closer related than organisms that show only structural similarities Hint: Look for similar DNA, RNA, Proteins, Enzymes when looking for closest related species
DNA Gel Electrophoresis• DNA Gel Electrophoresis: used to study DNA and separate it’s fragments according to size• Steps of DNA Gel Electrophoresis 1. Obtain DNA sample from DONOR 2. Cut DNA into fragments using DNA RESTRICTION ENZYME 3. Inject DNA fragments into WELLS IN THE GEL 4. ELECTRIC CURRENT is needed to pull fragments from the wells down the gel 5. SMALLEST DNA PIECES travel furthest from the wells 6. Compare bands for number of matches (closest relationship = DNA patterns with the most number of bands in common)
mRNA and Amino Acid Chart• The genetic code is read in triplets!• 3 DNA bases 3 RNA bases One Amino AcidLet’s try it for a pieceof DNA “A T A”
Using the mRNA codon chartDNA: GTA AACTGCRNA: _____ _____ _____AMINO ACIDS: _____ _____ _____
Paper Chromatography• Used to separate pigments• Organisms with similar chromatography patterns will be closer related
Dichotomous Key• For every organism being classified always start at one – simply follow the directions according to chart and the organism’s structures – The organisms scientific name will be written using their genus and speciesDichotomous Key to Represent Aliens____________________________________________1. a. The alien has two heads…….Martian Alieus b. The alien has one head……..Go to 22. a. The alien has two legs………Earthling Alieus b. The alien has three legs……Venetian Alieus
The Beaks of Finches• Organisms are able to coexist because – They do not compete – There is enough resources for both organisms• If organisms compete for same resources, it will be those with the best variations and adaptations that have success
The Beaks of Finches
The function of the coded instructions contained inthe body cells of an organism is to1. form a variety of gametes that will pass on hereditary information2. direct the synthesis of proteins necessary for proper cell function3. synthesize different kinds of amino acids in a specific sequence4. produce the inorganic molecules needed for normal cell growth
In members of a bird species living on a remoteisland, the greatest number of beak variations inthe population would most likely be found when1. there is a high level of competition for limited resources2. homeostasis is limited by a severe climate3. they have a large and varied food supply4. they are prey for a large number of predators
The sequence of amino acids in a Kinase molecule,an enzyme found in the body cells, is identical inhumans and chimpanzees. This fact best supportsthe concept that1. simpler organisms synthesized cytochrome c2. humans and chimpanzees have similar nutritional requirements3. simpler organisms evolved into more complex organisms4. human and chimpanzees have a common ancestor
Darwin’s studies of finches on the GalapagosIslands suggest that the finches’ differences inbeak structure were most directly due to1. acquired characteristics in the parent finches2. the size of the island where the finches live3. mating behaviors of the different finch species4. adaptations of the finches to different environments
A student set up a beaker with glucose andstarch inside a “cell” and iodine in the solutionoutside the “cell”. What would the set up looklike after about 30 minutes?
What would a cell look like after it was placed ina salt water solution? In distilled water?