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The Work of Gregor Mendel
Introduction to Genetics Chapter 6 The Work of Gregor Mendel
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Transmission of characteristics from _______________________is called ___________________.
The _________ that studies _____ those characteristics are _________ from one generation to the next is called___________________. parents to offspring heredity science how passed on genetics
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The __________________ is _________________, a monk whose _________ of genetic traits was the beginning of our_______________ about _____________________. Father of Genetics Gregor Mendel study understanding how genes work
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Gregor Mendel - Untamed Science
Mendel’s Experiments Gregor Mendel - Untamed Science
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_______ part of flower makes ___________ (sperm)
Mendel designed ____________ using __________ in the monastery garden _______ part of flower makes ___________ (sperm) __________ part of flower makes _______ cells experiments Pea plants MALE Pollen FEMALE egg
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In pea plants, the pollen normally joins with an egg from the
_______ plant (=_______________ ) so seeds have “_________________” same Self pollinating ONE parent
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MENDEL’S PEA EXPERIMENTS
Mendel started his experiments with peas that were _________________ = if allowed to _________________ they would produce ____________________ to themselves. true breeding self pollinate offspring identical
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MENDEL’S PEA EXPERIMENTS
Mendel ____________________ making parts and ____________ from _______ plant. This allowed him to _____________ plants with ______________ characteristics and ________ the results removed pollen added pollen another cross-breed different study
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A _____________________ is called a ____________
Mendel ______________ in peas. specific characteristic trait studied 7 traits Pearson Education Inc,; Publishing as Pearson Prentice Hall
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MENDEL’S EXPERIMENTS ____ generation (_________) ____ generation
(______= offspring) ___ generation parental F1 filial F2
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Principles of Dominance
Section 11-1 P Generation F1 Generation F2 Generation Tall Short Tall Tall Tall Tall Tall Short
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Principles of Dominance
Section 11-1 P Generation F1 Generation F2 Generation Tall Short Tall Tall Tall Tall Tall Short
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He always found same pattern: 1. ONLY ______ trait ____________
When Mendel ______________ PLANTS with 2 ______________ traits: (EX: Tall crossed with short) He always found same pattern: 1. ONLY ______ trait ____________ in the ____ generation BUT . . . 2. ___________ trait ____________ in the ____ generation in a _________ ratio crossed PURE contrasting ONE showed F1 Missing returned F2 3:1
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PATTERNS ARE THE KEY Image modified from:
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Mendel decided that there must be a __________________ that ________each trait and that
__________ must be able to _______ the other. pair of FACTORS control one factor HIDE
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We now know that Mendel’s ________________ carried on
the pair of________________ _________________ factors are genes homologous chromosomes
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trait are called ___________.
________ gene _______ for a trait are called ___________. DIFFERENT CHOICES ALLELES
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__________________ = An allele that ________ the presence of another allele
DOMINANT HIDES RECESSIVE is hidden by
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The F1 plants ALL ___________ but are ___________ an
____ offspring __________ an allele for tallness from their _______ parent and an allele for shortness from their ________ parent. The F1 plants ALL ___________ but are ___________ an allele for _____________ F received TALL SHORT LOOK TALL carrying shortness Images from: BIOLOGY by Miller & Levine; Prentice Hall Publishing ©2006
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LAW OF ___________________
EXPLAINING the F1 CROSS LAW OF ___________________ SEGREGATION alleles are separated when the F1 plants ______________ When these gametes recombined to make the F2 generation, the _____________ trait _______________ in ¼ of the offspring made gametes recessive reappears
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Law of Segregation Organisms inherit two copies of each gene, one from each parent Organisms donate only one copy of each gene in their gametes. Thus, the two copies of each gene segregate, or separate, during gamete formation
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Mendel’s Experiments/History
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Ticket Out the Door What is heredity? What is genetics?
Who is the Father of Genetics? What type of plant is this person most famous for studying? What is a trait? What are alleles? What is dominant? What is recessive? What is the law of segregation?
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Punnett squares and probability
Introduction to Genetics Chapter 6 Punnett squares and probability
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____________________ is the __________ that a particular _________________
PROBABILITY likelihood event will occur It can be written as a: Fraction ____ Percent ____ Ratio ____ 1/4 25% 3:1
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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 you can use probability to predict outcomes of genetic crosses. 1/2 50% 1:1
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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 best predicting large The more flips. . . The closer results will be to the expected 50:50 average.
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DOMINANT/RECESSIVE Dominant _____________ 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
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HOMOZYGOUS/HETEROZYGOUS
When both alleles in the pair are the _______, the organism is _______________ or __________ EX: ____ or ___ Ex: TT - _____________________ Ex: tt - ______________________ When both alleles in the pair are _____________, the organism is _________________ or _____________ Ex: ____ SAME HOMOZYGOUS PURE TT tt Homozygous dominant Homozygous recessive DIFFERENT HETEROZYGOUS HYBRID Tt
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PHENOTYPE/GENOTYPE genetic makeup The ________________ of an organism is its _____________ Example: TT or tt The ____________of an organism is its _____________. It is what you see in a photograph. Example: round or smooth GENOTYPE appearance PHENOTYPE
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MAKING A CROSS for only a __________ trait = ____________________
ONE GENE MONOHYBRID CROSS A Punnett square for a MONOHYBRID CROSS looks like this:
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are used to show possible offspring from a cross between 2 parents
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
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Steps for Making Punnett Squares
Figure out ___________________ what _________________ are. ___________________ correct ________ square ____________. ___________________ possible _____________________________. ___________________ boxes with ___________________. Determine ________________ of ____________________ & ___________________________. parent alleles Choose size Punnett Put in parent gametes Fill in offspring combinations probabilities genotypes phenotypes
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IN PEA PLANTS LET’S MAKE A CROSS! PURE TALL PURE SHORT
Tall is dominant over short TALL = ____ SHORT = ____ T t LET’S MAKE A CROSS! PURE TALL PURE SHORT X
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PURE TALL parent What are the parent alleles?
T T _________ HOMOZYGOUS DOMINANT What gametes can it make? T T
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PURE SHORT parent What are the parent alleles?
t t _________ HOMOZYGOUS RECESSIVE What gametes can it make? t t
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T t T t T t T t T t _____ of the offspring ____ % ___/4 will be ALL
100 4 T t T t Tt TALL GENOTYPE _____ PHENOTYPE _______
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HYBRID TALL parent What are the parent alleles?
T t _________ HETEROZYGOUS What gametes can it make? T t
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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 ____% _________ SHORT 1/4 25
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PRACTICE MAKING GAMETES for a MONOHYBRID CROSS
Tall = ____ Round seeds = ___ Short = ____ Wrinkled seeds = ___ t r
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What are the possible gametes?
Homozygous Tall parent = What gametes can it produce? T T T T
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What are the possible gametes?
Heterozygous Round parent = What gametes can it produce? R r R r
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What are the possible gametes?
Hybrid Tall parent = What gametes can it produce? Tt T t
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Punnett Square Animation
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Ticket out the Door Make Punnett Squares for the following (List the genotypes and phenotypes for each Punnett, that means letter combinations and physical appearance): A green pea plant (Gg) is crossed with a yellow pea plant (gg). A tall plant (TT) is crossed with a tall plant (Tt). A tall plant (Tt) is crossed with a short plant (tt). A red flower (Rr) is crossed with a white flower (rr).
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