# O T T F F S S E __ What comes next?.

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O T T F F S S E __ What comes next?

It’s EASY if you know the PATTERN! (Just like Punnett Squares)
9 NINE O T T F F S S E __ I V E X EVEN IGHT N E W O H R E O U R

PROBABILITY & PUNNETT SQUARES 11-2

Interest Grabber Section 11-2 Tossing Coins If 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 coin ten 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.

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.

PROBABILITY ____________________ is the __________ that a particular _________________ likelihood event will occur It can be written as a: Fraction ____ Percent ____ Ratio ____ 1/4 25% 1:3

COIN FLIP 1/2 50% 1:1 There are 2 possible outcomes: HEADS TAILS
COIN FLIP There are 2 possible outcomes: HEADS TAILS The 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. 1/2 50% 1:1

PROBABILITIES _____ outcomes ______ affect _________ones
_____________works ______ in ___________ a ________ number of events. PAST DON’T FUTURE If last coin flip was heads… there is still a 50/50 chance the next flip will be heads too. Probability predicting best large The more flips. . . The closer results will be to the expected 50:50 average.

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 =______ capital Recessive lower-case T t NOT S for short

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: ____ SAME HOMOZYGOUS PURE TT tt DIFFERENT HETEROZYGOUS HYBRID Tt

PHENOTYPE/GENOTYPE The ________________ of an organism is its _____________ The ____________of an organism is its _____________ genetic makeup GENOTYPE appearance PHENOTYPE

MAKING A CROSS for only a __________ trait = ____________________
ONE GENE MONOHYBRID CROSS A Punnett square for a MONOHYBRID CROSS looks like this:

PUNNETT SQUARES are used to show possible offspring from a cross between 2 parents _______________ go at top and on left side Boxes show ____________ ___________________ Parent alleles T T T t possible offspring combinations

STEPS FOR MAKING CROSSES
Figure out parent alleles Choose Punnett size Put in parent gametes Fill in offspring combinations probabilities phenotypes genotypes 1. ___________ what _________________ are 2. ________correct__________ square __________ 3. ______ possible_______________________ 4. ______ boxes with _____________________ 5. Determine ____________of_____________& ____________

T t TALL = ____ SHORT = ____ IN PEA PLANTS Tall is dominant over short
LET’S MAKE A CROSS! PURE TALL PURE SHORT X

PURE TALL parent What are the parent alleles?
T T _________ HOMOZYGOUS What gametes can it make? T T

PURE SHORT parent What are the parent alleles?
t t _________ HOMOZYGOUS What gametes can it make? t t

T t T t T t T t T t ALL _____ of the offspring ____ % ___/4 will be
100 4 T t T t Tt TALL GENOTYPE _____ PHENOTYPE _______

HYBRID TALL parent What are the parent alleles?
T t _________ HETEROZYGOUS What gametes can it make? T t

T t T t T t T T T t t t GENOTYPES ¼ = _____ ½ = _____ TT Tt tt 3/4 75
TALL PHENOTYPES ____ or ____% _________ ____ or ____% _________ 1/4 25 SHORT

PRACTICE MAKING GAMETES for a MONOHYBRID CROSS
Tall = ____ Round seeds = ___ Short = ____ Wrinkled seeds = ___ T t r

What are the possible gametes?
Homozygous Tall parent = What gametes can it produce? T T T T

What are the possible gametes?
PURE wrinkled parent = What gametes can it produce? rr r r

What are the possible gametes?
Heterozygous Round parent = What gametes can it produce? R r R r

What are the possible gametes?
Hybrid Tall parent = What gametes can it produce? Tt T t

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