Chapter 11 Section 1Notes
The Work of Gregor Mendel
Biology pgs. 262-266
Name:
Objectives
_______________how Mendel studied inheritance in peas.
_____________Mendel’s conclusion about inheritance.
_____________what happens during segregation.
Gregor Mendel’s Peas
____________________ is the scientific study of heredity.
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Mendel knew that
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the male part of each flower produces _____________, (containing sperm).
the female part of the flower produces egg cells.
During sexual reproduction, sperm and egg cells join in a process called fertilization, to produce a new cell.
Mendel had _____________pea plants that, if allowed to self-pollinate, would produce offspring identical
to themselves.
He cut away the pollen-bearing male parts of the plant and dusted the plant’s flower with pollen from
another plant.
This process is called _______________________.
A __________________ is a specific characteristic that varies from one individual to another.
Each original pair of plants is the ____________(parental) generation.
The offspring are called the ____________, or “first filial,” generation.
The offspring of crosses between parents with different traits are called ___________________.
Today, scientists call the factors that determine traits _____________.
The different forms of a gene are called _________________.
Mendel's first conclusion was that biological ___________________is determined by factors that are
passed from one generation to the next.
Mendel’s second conclusion is called the principle of dominance.
The _________________________________states that some alleles are dominant and others are recessive.
Mendel crossed the F1 generation with itself to produce the _______(second filial) generation.
Some cells will segregate and have different copies or alleles for specific traits these cells are the sex cells,
or ___________________.
Chapter 11 Section 2 Notes
Probability and Punnett Squares
Biology pgs. 267-269
Objectives
________________how geneticists use the principles of probability.
_________________how geneticists use Punnett squares.
The likelihood that a particular event will occur is called _________________.
The gene combinations that might result from a genetic cross can be determined by drawing a diagram
known as a ____________________.
A capital letter represents the ______________ allele for tall.
A lowercase letter represents the ________________ allele for short.
In this example,
T = tall
t = short
Organisms that have two identical alleles for a particular trait are said to be _____________________.
Organisms that have two different alleles for the same trait are ___________________.
Homozygous organisms are _______________________for a particular trait.
Heterozygous organisms are ___________________for a particular trait.
All of the tall plants have the same _____________, or physical characteristics.
The tall plants do not have the same ______________, or genetic makeup.
Chapter 11 Section 3 Notes
Exploring Mendelian Genetics
Biology Pgs. 270-274
Objectives
______________the principle of independent assortment.
____________the other inheritance patterns
_____________how Mendel’s principles apply to organisms.
The alleles for seed shape segregated independently of those for seed color. This principle is known
as________________________.
Genes that segregate independently do not influence each other's inheritance.
The principle of independent assortment states that genes for different traits can segregate
independently during the formation of____________________.
Independent assortment helps account for the many genetic variations observed in plants, animals, and
other organisms.
A Summary of Mendel's Principles
• Genes are passed from ________________________to their offspring.
• If two or more _______________________of the gene for a single trait exist, some forms of
the gene may be dominant and others may be recessive.
Some alleles are neither dominant nor recessive, and many traits are controlled by
________________________or multiple genes.
Incomplete Dominance
 When one allele is not completely dominant over another it is
called____________________________.
Codominance
 In______________________, both alleles contribute to the phenotype.
Multiple Alleles
 Genes that are controlled by more than two alleles are said to have_______________________
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Polygenic Traits
Traits controlled by two or more genes are said to be___________________________
________________________in humans is a polygenic trait controlled by more than four different
genes.
Chapter 11 Section 4 Notes
Meiosis
Biology Pgs. 275-278
Objectives
_________________the chromosome number of body cells and gametes
______________the events of meiosis
_______________meiosis and mitosis
Each organism must inherit a single copy of every gene from each of its parents.
_________________are formed by a process that segregates the two ____________________chromosomes so
that each gamete ends up with just one of each.
Mitosis produces __________(2N) cells with the same number of chromosomes as the parent. Meiosis reduces
the number by half producing __________(N) cells.
As in mitosis, DNA is copied during interphase
Prophase I- same as mitosis except every chromosome lines up next to its homologue forming a tetrad.
Genes may be exchanged by____________
Metaphase I - Homologous pairs line up at center.
Anaphase I - One chromosome of each pair is pulled to each side.
At the end of Meiosis I: Two daughter cells are produced, each with one member of each pair of homologous
chromosomes.
Meiosis II: The same phases are repeated, except this time the sister chromatids are separated resulting in four
haploid cells.
Genetic recombination occurs in meiosis so the gametes are all different. This variation makes a species
more_______________
Chapter 11 Section 5 Notes
Gene Maps
Biology Pgs. 279-280
Objectives
__________________the structures that actually assort independently
Each _______________________is actually a group of linked genes.
Chromosomes assort independently, not individual genes.
Gene Maps
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Crossing-over during meiosis sometimes separates genes that had been on the same chromosomes
onto homologous chromosomes.
Crossover events occasionally separate and exchange linked genes and produce
___________________________of alleles.
If two genes are close together, the recombination frequency between them should be_____________,
since crossovers are rare.
If they are far apart, recombination rates between them should be________________.