The Work of Gregor Mendel

Transmission of characteristics from _______________________is called ___________________. The _________ that studies _____ those characteristics are _________ from one generation to the next is called ___________________ heredity Genetics parents to offspring SCIENCE how passed on

The __________________ is _________________, a monk whose _________ of genetic traits was the beginning of our _________________ about _____________________. Gregor Mendel Father of Genetics study understanding how genes work

Mendel designed ____________ using __________ in the monastery garden _______ part of flower makes ___________ (sperm) __________ part of flower makes _______ cells Pea plants Pollen experiments MALE FEMALE egg

In pea plants, the pollen normally joins with an egg from the _______ plant (=_______________ ) so seeds have “_________________” Self pollinating same ONE parent

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

MENDEL’S PEA EXPERIMENTS Mendel ____________________ making parts and ____________ from _______ plant. This allowed him to _____________ plants with ______________ characteristics and ________ the results different removed pollen added pollen another cross-breed study

A _____________________ is called a ____________ Mendel ______________ in peas. specific characteristic trait Pearson Education Inc,; Publishing as Pearson Prentice Hall studied 7 traits

MENDEL’S EXPERIMENTS ____ generation (_________) ____ generation (______= offspring) ___ generation P1P1 F1F1 F2F2 parental filial

Go to Section: P Generation F 1 Generation F 2 Generation TallShortTall Short Section 11-1 Principles of Dominance

Go to Section: P Generation F 1 Generation F 2 Generation TallShortTall Short Section 11-1 Principles of Dominance

Go to Section: P Generation F 1 Generation F 2 Generation TallShortTall Short Section 11-1 Principles of Dominance

When Mendel ______________ PLANTS with 2 ______________ traits: (EX: Tall crossed with short) He always found same pattern: 1. ONLY ______ trait ____________ in the ____generation BUT ___________ trait ____________ in the ____ generation in a _________ ratio ONE showed F1F1 F2F2 3:1 crossed PURE contrasting Missing returned

PATTERNS ARE THE KEY Image modified from:

Mendel decided that there must be a __________________ that ________each trait and that __________ must be able to _______ the other. pair of FACTORS one factor control HIDE

We now know that Mendel’s ________________ carried on the pair of________________ _________________ factors are genes homologous chromosomes

________ gene _______ for a trait are called ___________. ALLELES DIFFERENT CHOICES

__________________ = An allele that ________ the presence of another allele __________________ = An allele that __________________ the presence of another allele DOMINANT RECESSIVE HIDES is hidden by

DOMINANT/RECESSIVE _____________ allele is represented by a ____________ letter. (usually the first letter of the trait) ____________ allele is represented by the SAME _________________ letter. EX: Tall = ______ Short =______ capital lower-case T t NOT S for short Dominant Recessive

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: ____ HETEROZYGOUS HYBRID HOMOZYGOUS PURE SAME TT tt DIFFERENT Tt

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

Why did the recessive trait disappear in the F 1 generation and reappear in the F 2 ? Image modified from: The pattern corresponds to the ____________ of ______________ during ____________________ MEIOSIS movement chromosomes

REMEMBER _____________ chromosomes ________________ during ANAPHASE I = _________________ SEGREGATION Image modified from: HOMOLOGOUS SEPARATE

____ offspring __________ an allele for tallness from their _______ parent and an allele for shortness from their ________ parent. The F 1 plants ALL ___________ but are ___________ an allele for _____________ TALL Images from: BIOLOGY by Miller & Levine; Prentice Hall Publishing ©2006 SHORT LOOK TALL F 1 received carrying shortness

alleles are separated when the F 1 plants ______________ When these gametes recombined to make the F 2 generation, the _____________ trait _______________ in ¼ of the offspring EXPLAINING the F 1 CROSS LAW OF ___________________ SEGREGATION Image from: BIOLOGY by Miller & Levine; Prentice Hall Publishing ©2006 recessive made gametes reappears

MAKING A CROSS for only a __________ trait = ____________________ MONOHYBRID CROSS ONE GENE

DIHYBRID CROSSES ( 2 traits)

MAKING A CROSS with ___________________= ____________________ DIHYBRID CROSS TWO gene traits

LAW OF __________________________ the factors are distributed to gametes independently of other factors INDEPENDENT ASSORTMENT Image modified from: