Chapter 10 Mendel and Meiosis - PowerPoint PPT Presentation

1 / 33
About This Presentation
Title:

Chapter 10 Mendel and Meiosis

Description:

They have both male and female sex cells called gametes. ... and female gametes come together. This is when the pollen grain bonds with the female gamete in the ... – PowerPoint PPT presentation

Number of Views:484
Avg rating:5.0/5.0
Slides: 34
Provided by: barbaram68
Category:

less

Transcript and Presenter's Notes

Title: Chapter 10 Mendel and Meiosis


1
Chapter 10 Mendel and Meiosis
  • Genetics
  • The branch of biology that studies genetics
  • Heredity
  • Passing on of traits from parents to children.
  • Gregor Mendel
  • Carried out the first important studies about
    heredity.

2
  • Traits
  • characteristics that are inherited.
  • Mendel was the 1st person to predict how traits
    would be passed down from 1 generation to the
    next.

3
  • Mendel studied pea plants because they reproduce
    sexually
  • They have both male and female sex cells called
    gametes.

4
  • In pea plants, the male and female gametes are in
    the same flower.
  • The male gamete is in the pollen grain produced
    by the anther and the female gamete is in the
    ovule located in the pistil.
  • The transfer of male pollen grains to the pistil
    is called pollination.

5
  • Fertilization
  • Male and female gametes come together.
  • This is when the pollen grain bonds with the
    female gamete in the ovule.
  • When the ovule is fertilized, it turns into a
    seed.

6
  • Self pollination
  • Male and female gametes come from the same plant,
    the plant can reproduce by its self
  • In pea plants, the parts of the flower are
    tightly enclosed in the petals.
  • This prevents other plant pollen from entering.

7
  • Cross pollination
  • Breeding plants or crossing one plant with
    another.
  • Turn to page 260
  • Figure 10.1
  • This is what Mendel did to cross pollinate his
    pea plants

8
  • When Mendel started he studied only 1 trait at a
    time.
  • Height short and tall pea plants
  • Mendel crossed the short and tall plants to
    produce new plants called hybrids.
  • Hybrids are the children of parents who have
    different forms of 1 trait.(short and tall)

9
  • Mendel called his crosses monohybrid crosses.
  • Mono means 1
  • His first experiments focused on 1 trait.
  • Turn to page 261
  • Bold section The First Generation

10
  • The parents are known as the P¹ generation
  • Pparent
  • The children are known as the F¹ generation
  • Ffilial son or daughter

11
  • When two F¹ plants reproduce, their children are
    called F².
  • F²second filial generation

12
Rule of Unit Factors
  • There are 2 factors that control our traits.
  • These factors are genes, genes have different
    forms called Alleles.
  • We saw in Mendels pea plants that a plant could
    have 2 alleles for shortness, 2 alleles for
    tallness or 1 for short and 1 for tall.

13
  • Alleles are located on different copies of a
    chromosome.
  • 1 we get from our mother and 1 we get from our
    father.

14
The Rule of Dominance
  • Dominant traits
  • Are the ones we can see.
  • Recessive traits
  • Are the ones that disappear.

15
  • Turn back to page 261
  • First and second generation
  • Which trait do you think was dominant and which
    was recessive?
  • In pea plants the tall allele is dominant and the
    short allele is recessive.

16
  • When we write this we use the same letter for
    different alleles of the same gene.
  • Tdominant
  • trecessive
  • Allele for tallnessT
  • Allele for shortnesst

17
Law of Segregation
  • 2 alleles for each trait separate when gametes
    are formed.
  • This lets them pass only 1 allele at random for
    each trait to its children.
  • You get 1 from each parent.

18
Assignment
  • Turn to page 261
  • Use figure 10.2 to show in pictures Mendels
    breeding of short and tall pea plants.
  • YOU MUST DRAW AND LABEL EACH STEP.
  • What does P¹, F¹ and F² stand for?
  • What is happening in each step?

19
Law of Independent Assortment
  • Genes for different traits are inherited
    independently from each other.
  • This means that a plant with RrYy alleles will
    separate from each other and recombine randomly
    at fertilization.

20
Section Assessment
  • Turn to page 268
  • Answer question 1-4 at the bottom of the page.
  • Be able to share your findings with the rest of
    the class.

21
Genotypes and Phenotypes
  • Phenotype
  • The way an organism looks and behaves.
  • The phenotype of a tall pea plant is tall. It
    does not matter whether it is TT or Tt.

22
  • Genotype
  • The gene combination an organism contains.
  • The genotype of a tall pea plant that has 2
    alleles for tallness is TT.
  • The genotype of a tall pea plant that has 1
    allele for tallness and 1 allele for shortness is
    Tt.

23
  • Homozygous
  • The 2 alleles for a trait are the same, TT or tt.
  • We would call TT homozygous dominant and tt
    homozygous recessive.

24
  • Heterozygous
  • The 2 alleles for a trait are different form each
    other.
  • Tt is heterozygous for the trait of height.

25
  • Punnet Square
  • Used to predict what the children will look like.

26
Dihybrid Crosses
  • Mendels second experiments involved pea plants
    that differed from each other in 2 traits.
  • We call this dihybrid crosses because di means 2.

27
Get Your Books!
  • Turn to page 265
  • We are going to read about Mendels dihybrid
    cross experiment.

28
Meiosis
  • Chromosomes occur in pairs, one from the father
    and one from the mother.
  • A cell with 2 of each kind of chromosomes are
    called diploid cells.

29
  • Oraganisms produce gametes that have 1 of each
    kind of chromosome.
  • A cell with 1 of each kind of chromosome is
    called a haploid cell.

30
  • Homologous chromosomes
  • The paired chromosomes in a diploid cell.
  • These help determine what an organism looks like.

31
Meiosis
  • A type of cell division which produces gametes
    that have half the number of chromosomes as a
    parents body cell.
  • Meiosis happens in 2 phases
  • Meiosis 1 and meiosis 2

32
  • Meiosis 1 begins with 1 diploid cell.
  • By the end of meiosis 2 there are 4 haploid cells
  • These are called sex cells or gametes.
  • Male gametes are sperm and female gametes are
    eggs.
  • When the sperm fertilizes the egg the resulting
    cell is called a zygote.

33
(No Transcript)
Write a Comment
User Comments (0)
About PowerShow.com