4 Interest GrabberSection 11-2Tossing CoinsIf you toss a coin, what is the probability of getting heads? Tails? If you toss a coin 10 times, how many heads and how many tails would you expect to get? Working with a partner, have one person toss a cointen times while the other person tallies the results on a sheet of paper. Then, switch tasks to produce a separate tally of the second set of 10 tosses.
5 Interest Grabber Answers Assuming that you expect 5 heads and 5 tails in 10 tosses, how do the results of your tosses compare? How about the results of your partner’s tosses? How close was each set of results to what was expected?Add your results to those of your partner to produce a total of 20 tosses. Assuming that you expect 10 heads and 10 tails in 20 tosses, how close are these results to what was expected?If you compiled the results for the whole class, what results would you expect?How do the expected results differ from the observed results?Results will vary, but should be close to 5 heads and 5 tails.The results for 20 tosses may be closer to the predicted 10 heads and 10 tails.The results for the entire class should be even closer to the number predicted by the rules of probability.The observed results are usually slightly different from the expected results.
6 PROBABILITY____________________ is the __________ that a particular _________________likelihoodevent will occurIt can be written as a:Fraction ____Percent ____Ratio ____1/425%1:3
7 COIN FLIP 1/2 50% 1:1 There are 2 possible outcomes: HEADS TAILS COIN FLIPThere are 2 possible outcomes:HEADS TAILSThe chance the coin will land on either one is:____ ____ ____Alleles segregate randomly just like a coin flip. . . So can use probability to predict outcomes of genetic crosses.1/250%1:1
8 PROBABILITIES _____ outcomes ______ affect _________ones _____________works ______ in ___________ a ________ number of events.PASTDON’TFUTUREIf last coin flip was heads… there is still a 50/50 chance the next flip will be heads too.ProbabilitypredictingbestlargeThe more flips. . . The closer results will be tothe expected 50:50 average.
9 DOMINANT/RECESSIVE T t capital Dominant Recessive lower-case _____________ allele is represented by a ____________ letter. (usually the first letter of the trait)____________ allele is represented by the SAME_________________ letter.EX: Tall = ______Short =______capitalRecessivelower-caseTtNOT S for short
10 HOMOZYGOUS HETEROZYGOUS When both alleles in the pair are the _______, the organism is _______________ or __________EX: ____ or ___When both alleles in the pair are _____________, the organism is_________________ or _____________Ex: ____SAMEHOMOZYGOUS PURETT ttDIFFERENTHETEROZYGOUS HYBRIDTt
11 PHENOTYPE/GENOTYPEThe ________________ of an organism is its _____________The ____________of an organism isits _____________genetic makeupGENOTYPEappearancePHENOTYPE
12 MAKING A CROSS for only a __________ trait = ____________________ ONE GENEMONOHYBRID CROSSA Punnett square for a MONOHYBRID CROSS looks like this:
13 PUNNETT SQUARESare used to show possible offspring from a cross between 2 parents_______________ go attop and on left sideBoxes show ____________ ___________________Parent allelesT TTtpossible offspring combinations
14 STEPS FOR MAKING CROSSES Figure out parent allelesChoose Punnett sizePut in parent gametesFill in offspring combinationsprobabilities phenotypes genotypes1. ___________ what _________________ are2. ________correct__________ square __________3. ______ possible_______________________4. ______ boxes with _____________________5. Determine ____________of_____________& ____________
15 T t TALL = ____ SHORT = ____ IN PEA PLANTS Tall is dominant over short LET’S MAKE A CROSS!PURE TALL PURE SHORTX
16 PURE TALL parent What are the parent alleles? T T _________HOMOZYGOUSWhat gametescan it make?TT
17 PURE SHORT parent What are the parent alleles? t t _________HOMOZYGOUSWhat gametescan it make?tt
18 T t T t T t T t T t ALL _____ of the offspring ____ % ___/4 will be 1004T tT tTtTALLGENOTYPE _____ PHENOTYPE _______
19 HYBRID TALL parent What are the parent alleles? T t _________HETEROZYGOUSWhat gametescan it make?Tt
20 T t T t T t T T T t t t GENOTYPES ¼ = _____ ½ = _____ TT Tt tt 3/4 75 TALLPHENOTYPES ____ or ____% _____________ or ____% _________1/425SHORT
21 PRACTICE MAKING GAMETES for a MONOHYBRID CROSS Tall = ____ Round seeds = ___Short = ____ Wrinkled seeds = ___Ttr
22 What are the possible gametes? Homozygous Tall parent =What gametes can it produce?T TTT
23 What are the possible gametes? PURE wrinkled parent =What gametes can it produce?rrrr
24 What are the possible gametes? Heterozygous Round parent =What gametes can it produce?R rRr
25 What are the possible gametes? Hybrid Tall parent =What gametes can it produce?TtTt