1. In the first generation of each experiment, how do the characteristics of the offspring compare to the parents - PowerPoint PPT Presentation

1 / 65
About This Presentation
Title:

1. In the first generation of each experiment, how do the characteristics of the offspring compare to the parents

Description:

Section 11-1 Parents Long stems short stems Red flowers white flowers Green pods yellow pods Round seeds wrinkled seeds Yellow seeds green seeds – PowerPoint PPT presentation

Number of Views:123
Avg rating:3.0/5.0
Slides: 66
Provided by: McDoug167
Category:

less

Transcript and Presenter's Notes

Title: 1. In the first generation of each experiment, how do the characteristics of the offspring compare to the parents


1
Section 11-1
  • 1. In the first generation of each experiment,
    how do the characteristics of the offspring
    compare to the parents characteristics?
  • 2. How do the characteristics of the second
    generation compare to the characteristics of the
    first generation?

Go to Section
2
  • Heredity The transmission of traits from parents
    to offspring.
  • Who was Gregor ____________?
  • Austrian monk and high school teacher born in
    ___________.
  • Father of _______________(1800s) study
    of_______________
  • Modern genetics is a core theme___________.

3
Mendels data revealed patterns of inheritance.
  • Mendel made ____________________in his
    experiments.
  • use of ________plants
  • control over __________observation of
    seveneither-or traits

4
  • 4 stock plants
  • Tall/Short Green/Yellow seeds
  • The peas were self pollinating and producing an
    exact copy of the parent plant. (True Breeding)
  • Mendel cross bred the seeds and got hybrid pea
    plants.
  • How ? He took pollen from the male structures
    (anthers) of a tall plant and placed it on the
    female structures (pistil) of a short plant.
  • All of the offspring were hybrid tall (F1).

5
A. Mendels Peas
  • Chose garden peas to test.
  • Why?
  • Grow ___________________in very little space.
  • True-breeding peas - all offspring show the same
    ______________after generation (homozygous).
  • Variety of _______________to study (tall v short,
    white v purple, etc.)
  • Easy to ____________because closed flower doesnt
    let random sperm/pollen in!

6
  • 4. Easy to control breeding
  • male female parts are in a closed flower
    other plant pollen cant get in.
  • a) self-pollinate fertilization in a single
    plant using ________(sperm) and ____to make a
    zygote (seed!)

7
  • Mendel wanted to study the results of breeding 2
    different plants, so he had to prevent
    self-pollination.
  • b) cross-pollination breeding ___________plants

8
B.Mendels experiments
  • Mendel studied__________________.
  • What is a trait?
  • A specific________________________.
  • P Generation are the parent plants.
  • F1 Generation are the 1st generation plants.
  • F2 Generation are the 2nd generation plants.
  • __________________and studied the results using
    math.
  • Cant study them all at once
  • Mendel studied _______________(1 variable) good
    science!

9
  • Bred true breeding plants.
  • True tall to true short.
  • P ______________parents (homozygous)
  • Tall x short
  • b) F1 ____________(offspring of P,
    heterozygous)
  • all tall

F2 second filial
P - parent
F1 first filial
10
2. Bred F1 x F1
  • F2 ______________(offspring of F1)
  • 3 tall1 short

F2 second filial
F1 first filial
P - parent
11
  • Mendels work led to 2 laws.
  • _________________ Members of each pair of
    alleles separate when the gametes are formed.
    (Homologous Chromosomes separate)
  • ___________________ Pairs of alleles separate
    independently of one another during gamete
    formation.

12
What do the results mean?
  • _______________are passed unchanged as a unit

No blending! Genes DNA sequence on a
chromosome that codes for specific protein(s)
that determine traits (The ____________that
determine traits.) Alleles - different
expressions of same gene for same trait Ex one
allele codes for tall, one allele codes for short
but both the same ______________for height
13
What do the results mean?
  • _________________ during gamete formation,
    alleles separate so you only inherit one copy of
    each gene from each parent
  • F1 had to have both alleles to get a short plant
    in F2, so the allele for shortness had to be
    separated from the allele for tallness when
    passed to the F2.
  • homologous chromosomes must separate
  • When does this happen during sexual
    reproduction???

MEIOSIS! Anaphase I
14
What do the results mean?
  • 3. ____________of Dominance one allele can mask
    another allele.
  • Tall allele dominated short allele.
  • ____________ allele or trait that is seen when
    present, masks recessive allele. Capital letters
    A
  • _____________ allele or trait that is only seen
    if the dominant trait is NOT present. Lower case
    letters a

15
  • Mendel drew three important conclusions.
  • Traits are inherited as_________________.
  • Organisms inherit_________________, one from each
    parent.
  • The two copies_______during ________formation.
  • The last two conclusions arecalled the law of
    segregation.

16
Interest Grabber continued
Section 11-2
1. 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 partners
tosses? How close was each set of results to what
was expected? 2. 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? 3. If you compiled the results for
the whole class, what results would you
expect? 4. How do the expected results differ
from the observed results?
Go to Section
17
Genes and Physical Traits
  • __________ genetic makeup of alleles
  • Geno genes
  • Ex AA, Aa or aa dominant or recessive,
    heterozygous or homozygous
  • _____________ physical expression of traits or
    what organism looks like!
  • Pheno to show
  • Ex tall or short, green or yellow, blue eyes or
    brown eyes

18
  • What is homozygous?
  • Having two identical alleles for a trait.
  • Homozygous Dominant ________________ AA
  • Homozygous Recessive ________________ aa
  • What is heterozygous?
  • Having _____________alleles for a trait. Aa

19
The same gene can have many versions.
  • A gene is a piece of DNA that directs a cell to
    make a certain protein.
  • Each gene has a______, aspecific position on a
    pair of___________chromosomes.

20
  • An allele is any _____________________occurring
    at a specific locus on a chromosome.
  • Each parent donates one allele for every gene.
  • Homozygous describes two alleles that are the
    same at a specific locus.
  • Heterozygous describes two alleles that are
    different at a specific locus.

21
  • Alleles can be represented using letters.
  • A dominant allele is expressed as a phenotype
    when at least one allele is dominant.
  • A recessive allele is expressed as a phenotype
    only when two copies are present.
  • Dominant alleles are represented by _________
    letters recessive alleles by _______________
    letters.

22
  • Both ________________________________ genotypes
    yield a dominant phenotype.
  • Most traits occur in a range and do not follow
    simple dominant-recessive patterns.

23
Probability and Punnet Squares
  • Whenever Mendel crossed two hybrid plants (F1),
    he got 31 ratio or ¾ dominant and ¼ recessive.
  • Mendel realized that the
  • principles of probability
  • (MATH!!) could be used
  • to explain the_________
  • _____________________

24
Genetics and Probability
Probability - the likelihood that any particular
event(s) will occur
  • Ex coin flip probability of heads is 1 chance
    out of 2 possible outcomes 1/2, or 50.
  • Does heads on the first flip change the
    probability of heads on the next? What if heads
    10 times in a row will next flip be more likely
    tails?
  • _____________do not affect future ones

25
Genetics and Probability
  • What is the probability that we will flip heads
    three times in a row?
  • Because each event is independent
  • (probability of event)N number of events
  • or
  • ½ x ½x ½ (½)3 1/8
  • 1 in 8 chance that 3 heads flipped in a row

26
Genetics and Probability
  • How is this related to genetics?
  • Allele segregation is ______________and each
    event
  • ______________________
  • _____________________a given allele from a
    heterozygous parent 50 or 1/2
  • If parent, T or t you have a 50 chance of
    either, same as heads or tails

27
Probability and Gender
  • Females ________________
  • What is the probability that you will inherit an
    X from your mother?
  • Males __________________.
  • What is the probability that you will inherit an
    X from your dad? Probability of a Y?
  • What is the probability of having a boy? Having a
    girl?
  • Which parents genes determine your gender?
  • What is the probability that a family with three
    children will have all girls?
  • (probability of event)N number of events
  • ½ x ½x ½ (½)3 1/8

28
  • Why ________________squares?
  • Predicts the probability of a cross between two
    organisms.
  • Rules
  • Dominant allele represented by a Capital
    letter.______________
  • Recessive allele represented by a lower case
    letter _____________
  • The letters designate the two forms of one gene,
    the two alleles for a monohybrid cross.
  • Every cell in your body has at least two alleles
    for every trait, one from Mom and one from Dad)

29
Punnet Squares
  • Punnett square grid showing possible gene
    combinations for offspring from a given genetic
    cross.
  • predicts ______________and their probability
  • Shows phenotype __________________________

30
Setting up a Punnett Square
  • Determine _________genotype.
  • _______for dominant, lower case__________.
  • Top and left letters ____________________
  • Bring down from top and over from left to create
    possible ______________________for offspring.

Short plant x Tall heterozygote
Tt
Tt
tt
tt
31
Ratios and Punnett Squares
  • ________________ number of each type of
    offspring genotype predicted by punnett square
  • For a single trait (_________________)
  • homozygous dominant heterozygous homozygous
    recessive
  • TT Tt tt
  • ________________ number of each type of
    offspring phenotype predicted by a punnett square
  • ____________________traits
  • Tall short

32
  • Monohybrid Cross
  • Provided data for one pair of contrasting traits.
  • What are the possible genotypes that can result?
  • What are the possible phenotypes that can result?
  • What is the ratio of tall to short plants in a
    hybrid cross?
  • Does this ratio agree with Mendels result in the
    F2 generation?

33
A monohybrid cross involves one trait.
  • Monohybrid crosses examine ____________________
    specific trait.
  • homozygous dominant-homozygous recessive all
    heterozygous, all dominant

34
  • heterozygous-heterozygous___________________
    dominant heterozygoushomozygous recessive 31
    dominantrecessive

35
  • heterozygous-homozygous recessive11
    heterozygoushomozygous recessive 11
  • __________________________
  • A testcross is a cross between an organism with
    an unknown genotype and an organism with the
    recessive phenotype.

36
_____________________involves two traits.
  • Mendels dihybrid crosses with heterozygous
    plants yielded ________________phenotypic ratio.
  • Mendels dihybrid crosses led to his second
    law,the law of independent assortment.
  • The law of independent assortment states that
    allele pairs separate independently of each other
    during meiosis.

37
Law of Independent Assortment
  • genes for different traits can ___________________
    _during the formation of gametes.
  • Independent assortment ____________________
  • Mendel concluded that the inheritance of one
    trait does not influence the inheritance of a
    second trait

38
Independent Assortment occurs in
__________________
39
Heredity patterns can be calculated with
probability.
  • Probability is the likelihood that something will
    happen.
  • Probability predicts an average number of
    occurrences, not an exact number of occurrences.
  • Probability applies to random events such as
    meiosis and fertilization.

40
Probability and Punnett Square
  • Probabilities predict averages,
  • _____________
  • outcomes
  • Probability is more accurate when you have more
    chances

41
DIHYBRID CROSS
  • Crossing organisms with genes for two different
    traits _______________possible gametes.
  • If we cross RRYY with rryy what are the
    possible gametes?

42
  • DIHYBRID CROSS punnett square for true breeding
    or homozygous parents.

R round r wrinkled Y yellow y green
43
heterozygous
Offspring have combinations of alleles ________in
earlier generations ______________
independently
44
DIHYBRID CROSS
  • ___________________from dihybrid cross of
    heterzygotes 9331

45
Summary of Mendels Principles
  • Traits come from your__________________.
  • _____________________________allele and some are
    dominant.
  • Your two copies of each gene (one from each
    parent) are _________________when gametes form.
  • Alleles for different genes usually segregate
  • __________________________of one another.

46
Height in Humans
Section 11-3
Interest Grabber
  • Height in pea plants is controlled by one of two
    alleles the allele for a tall plant is the
    dominant allele, while the allele for a short
    plant is the ecessive one. What about people? Are
    the factors that determine height more
    complicated in humans?

Go to Section
47
KEY CONCEPT Phenotype is affected by many
different factors.
48
  • Genetics can be affected by 5 other different
    heredity patterns.
  • __________________Dominance
  • ___________________
  • _________ Traits (Multiple Genes)
  • _____________ Influences

49
Phenotype can depend on________________________.
  • In incomplete dominance, neither allele is
    completely dominant nor completely recessive.
  • Heterozygous phenotype is intermediate between
    the two homozygous phenotypes
  • Homozygous parental phenotypes not seen in F1
    offspring

50
1. Incomplete Dominance
neither allele is completely dominant
so _________________________
  • cross between red-flowered (RR) and
    white-flowered (WW) plants consists of
    pink-colored flowers (RW).
  • What happens if you breed the pink flowers?

51
  • Codominant alleles will both be___________________
    _.
  • Codominant alleles are neither dominant nor
    recessive.
  • The ABO blood types result from codominant
    alleles.
  • Many genes have more than______________________

52
2. Codominance
  • both alleles expressed in the phenotype
    ____________________.

53
  • What are ____________ alleles?
  • Genes that have more than two alleles for a
    trait. Example ____ type in humans
  • What are ______________ traits?
  • Traits that are controlled by two or more genes.
    Example _______in humans.

54
3. Multiple Alleles
  • Genes with more________________________
  • This does not mean that an individual can have
    more than two alleles. It only means that more
    than two possible alleles exist in a population.
  • One of the best-known examples is blood type in
    humans.

55
Human Blood Types
  • _______type alleles gene
  • A makes A surface protein
  • B makes B surface protein
  • O doesnt make either.
  • ____________alleles are codominant to each other
    both __________over recessive O allele.
  • Is your blood type a genotype or phenotype?

56
4. Polygenic Traits
  • Traits controlled by interaction of two or more
    genes
  • _____________many genes.
  • Ex Hair color, eye color, skin color all the
    result of several genes

57
  • Environmental Influence
  • Phenotype can depend on conditions in the
    environment.
  • Conditions can cause a gene to _______
  • __________________ in coat color.
  • This allows the animal to blend in with its
    background.

58
ENVIRONMENT INFLUENCES ____________TRAITS
Environment factors like diet, exercise, exposure
to toxic agents, or medications can all influence
our genes and traits.
59
Section 11-3
Concept Map
Gregor Mendel
concluded that
experimented with
which is called the
which is called the
Go to Section
60
Linked Genes
  • Mendel concluded that traits are assorted
    independently, but some traits are Linked
  • Linked genes Genes usually _________________becau
    se on same chromosome

61
Sex-Linked Genes
  • Genes on the sex chromosomes are linked.
  • i. _________ genes Y has few genes mostly
    gender determining (boy or girl).
  • Y only in males so these genes only affect males.
  • ii. _______________ Many genes on X chromosome
  • Affects mostly males because only________________
  • Male copy of _____________(Dad gave Y to son)
  • Females less affected because ______________
    have to inherit trait from both parents.
  • Heterozygous females are _____________________trai
    ts.
  • EX baldness, colorblindness

62
Crossing Over affects linked genes.
  • Crossing over exchanging DNA during prophase
  • Genes _______on the chromosome _______ likely to
    be separated by crossing over.

63
Chromosome Mapping
  • The farther apart genes are, the higher
    probability that they will be separated by
    crossing over.
  • Scientists conduct experiments to determine how
    frequently genes of a particular trait are
    separated from one another.
  • Chromosome map - _______________sequence of genes
    on a chromosome.
  • Two genes that are separated by crossing-over 1
    percent of the time are considered to be
    one________________.

64
Summary of Mendels Principles
  • Traits come from your__________________.
  • Genes may have ______________and some are
    dominant.
  • Your two copies of each gene (one from each
    parent) are ________________________when gametes
    form.
  • Alleles for different genes usually
    ______________
  • ________________ of one another.

65
Beyond Mendel Other Patterns of Inheritance
  1. Most genes have more than two alleles.
  2. Some alleles are neither dominant nor recessive
    (codominance incomplete dominance)
  3. many traits are controlled by multiple genes.
  4. Some genes are linked and do not segregate
    independently - on the same chromosome so
    inherited together.
Write a Comment
User Comments (0)
About PowerShow.com