section 10.1 - mendel’s law of...

Ch 10: Mendel and Meiosis

Section 10.1 - Mendel’s Law of Heredity

Section 10.1

Who is Gregor Mendel

Mendel’s Crosses

Phenotypes and Genotypes

Probability in Genetics

Inside This Section...

Known as the father of _________ _________

Developed the principles of heredity by studying the variation and heredity of seven pairs of inherited characteristics in ______________.

The significance of his work was not recognized during his lifetime.

Who is Gregor Mendel?

Section 10.1

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Genetics is the branch of biology that studies _________

Heredity is the passing of __________________ from parents to offspring

_______ are inherited characteristics

Genetics

Section 10.1

_________ are the sex cells that allow an organism to reproduce

A _______ is the offspring of parents who have different traits

More Definitions

Section 10.1

Both male and female parts on the same flower

Male gamete is in the _______ ______

Female gamete is in the ______ (located in the pistil)

Reproduction in Peas

Section 10.1

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Pollination is the transfer of male pollen grains to the _____

______________ happens when the male and female gametes unite

Reproduction in Peas

Section 10.1

The Generations

Parental (P) Generation

F2 Generation

F1 Generation

Section 10.1

Each organism has _____ factors that control each trait

These factors are called genes and are found on the chromosomes and have ___________ forms

The different gene forms that control one trait are called ________

The Rule of Factors

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Alleles and Genes

Section 10.1

__________: The trait that is more expressive in alleles than other traits (represented by a capital letter)

___________: The trait that is submissive in the alleles to the other traits. (Represented by a lowercase letter)

If an organism contains a dominant and a recessive allele, the __________ trait will be expressed

The Rule of Dominance

TT or Tt tt

Section 10.1

____________ is the physical expression of an organism genes

___________ is the genetic makeup of an organism

The Rule of Dominance

TT or Tt tt

Section 10.1

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Alleles separate during ________

Each new cell gets one allele for each ______

The Law of Segregation

TT or Tt tt

Section 10.1

All traits are inherited ________________ from each other

The Law of Independent assortment

Section 10.1

______________ Cross: A cross in which ALL traits are identical except one

_________ Cross: A cross in which two traits differ between organisms

Two types of Crosses

Section 10.1

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Mendel’s Monohybrid Cross

P: Parental GenerationF1- All TallF2 - 3 tall : 1 short

When Mendel crossed tall pea plants with short ones, the first generation (F1) consisted of all _____ plants

When he crossed the F1 generation, ____ of the F2 generation were tall and _____ were short

Section 10.1

The Punnett Square

Named after Reginald Punnett

Useful for making offspring ______________

Alleles for 1 parent placed at the top and for the other at the left

Each box is filled with the _______ to the top and to the left

T

T t

t

TT

tt

TT tt

Section 10.1

Mendel’s Dihybrid CrossWhen Mendel crossed Round Yellow peas with wrinkled green peas, all of the F1 generation were _______________ Peas

In the F2 generation, the following ratios were found:

__ Round Yellow

__ Round Green

__ Wrinkled Yellow

__ Wrinkled Green

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Mendel’s Dihybrid CrossRrYy * RrYy

rryyrrYyRryyRrYy

rrYyrrYYRrYyRrYY

RryyRrYyRRyyRRYy

RrYyRrYYRRYyRRYY

RY Ry rY ry

RY

Ry

rY

ry

Probability & Genetics

Section 10.1

Who is Gregor Mendel

Mendel’s Crosses

Phenotypes and Genotypes

Probability in Genetics

In Review...

Section 10.1

Ch 9: Energy in a Cell

Section 10.2 - Meiosis

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The Two Types of Cells

Chromosomes and Genes

What is Meiosis?

Genetic Recombination

Inside This Section...

Section 10.2Section 10.2

Section 10.2

________: A cell with two of each kind of Chromosomes (both alleles for each gene)

We signify this by writing ”___”

All cells in the body except sex cells are diploid

Two Types of Cells_________: A cell with one of each kind of Chromosome (only one allele for each gene)

We signify this by writing ”__”

Sex cells are Haploid

Section 10.2

Chromosomes usually have about a thousand or more ______

Chromosomes occur in ________ (______________ chromosomes)

Each chromosome has one allele for a particular gene

Each species contains a characteristic number of _______________

Chromosomes and Genes

Section 10.2

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Number of Chromosomes

Chromosome Numbers of Some Common OrganismsChromosome Numbers of Some Common OrganismsChromosome Numbers of Some Common Organisms

Organism Body Cell (2n) Gamete (n)

Fruit fly 8 4

Garden pea 14 7

Corn 20 10

Tomato 24 12

Leopard frog 26 13

Apple 34 17

Human 46 23

Chimpanzee 48 24

Dog 78 39

Adder’s tongue fern 2360 630

Section 10.2

A Process of cell division that results in the production of sex cells (_________)

Consists of

_____________: Cell replicates chromosomes

___________: Results in 2 haploid cells

___________ (similar to mitosis): Results in 4 haploid cells

What is Meiosis?

Section 10.2

Meiosis

Section 10.2

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Prophase I

Homologous chromosomes come together and form a _______ (four-part structure)

Sometimes chromosomes exchange genetic material in a process called ___________ ________

Meiosis I

Section 10.2

Section 10.2

Crossing Over

Section 10.2

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Metaphase I

Spindle fibers cause Homologous Chromosomes to line up side by side at the equator (___________________)

Meiosis I

Section 10.2

Section 10.2

Anaphase I

Homologous chromosomes separate making each new cell _________

Meiosis I

Section 10.2

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Section 10.2

Telophase I

Reversal of Prophase I

Spindle breaks down, chromosomes uncoil, ____________ divides

Meiosis I

Section 10.2

Section 10.2

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Identical to Mitosis

Results in ___________ cells

Meiosis II

Section 10.2

Section 10.2

Genetic recombination is the source of variation. This is caused by the re-assortment or crossing over during meiosis

7 pairs of chromosomes = 27 = 128 combinations

Any egg can be fertilized by any sperm, so 128 x 128 = 16,384 possibilities

N=23, 223 = 8,388,608 possibilities

8,388,608 x 8,388,608 = 7 Trillion possibilities

Crossing over is the exchange of genetic material during prophase I, which results in new combinations of Alleles

Genetic Recombination

Section 10.2

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The Two Types of Cells

Chromosomes and Genes

What is Meiosis?

Genetic Recombination

In Review...

Section 10.2

Ch 9: Energy in a Cell

Section 10-3: Mistakes in meiosis

Section 10.3

Nondisjunction

Triploidy and Polyploidy

Inside This Section...

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When chromosomes fail to __________ during meiosis.

_________: When one gamete gets an extra chromosome, causing the other gamete to be short by one (e.g. Down’s syndrome - trisomy 21)

__________: When one gamete lacks one chromosome

Nondisjunction

Section 10.3

Triploid is a total lack of ______________ of homologous chromosomes.

Polyploids are organisms that have more than the normal amount of chromosomes

Rare in _________ usually causing death

Frequently occurs in _______ causing fruit and flowers to be larger

Triploidy and Polyploidy

Section 10.3

In Review...

Section 10.3

Nondisjunction

Triploidy and Polyploidy

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