Download Gregor Mendel - BHMS

Chapter 3: Section 1: Mendel’s Work
Gregor Mendel

 A priest who studied the physical features of __________ ____________.
Traits –
Heredity –
Genetics –
Mendel’s Peas
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Pea plants have many traits that exist in only ________ forms.
o Example:
 Pea plants produce a large amount of __________ in one __________.
 For these reasons it is possible to collect large amounts of __________.
Mendel’s Experiment
 First he decided to cross plants with __________ __________.
 Each plant needed to be a __________.
 Purebred –

He called his purebred plants the __________ __________ or ______
__________.
 He called the 1st set of offspring from the P Generation the __________
__________ __________ or ______ __________.
 Filial means “________” in __________.
 P Generation - ___ Tall __________& ___ Short __________
 F1 Generation - _____% Tall
 F2 Generation - _____% Tall & _____% Short
Other Traits
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He studied ___ other __________.
o 1)
2)
o 3)
4)
o 5)
6)
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Dominant & Recessive Alleles
 Mendel reasoned that individuals carry ________ factors for each
__________, but only pass down _______.
 Mendel also concluded that ______ factor is __________ over the other.
 Genes –

Alleles –
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Some alleles are __________ while others are __________.
Dominant Allele –

Recessive Allele –

In pea plants, the allele for ______ plants is __________ & the allele for
______ plants is __________.
 This is why Mendel’s _____ __________ were all _____ plants.
Understanding Mendel’s Crosses
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All were _____ plants, but contained both a __________ & __________
__________.
 Hybrid –
Using Symbols in Genetics
 __________________ __________ are represented with capital letters.
o Example:
 __________________ __________ are represented with a lowercase

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version of the same letter.
o Example:
A ______, _____________ plant would have its two alleles represented
with the letters ________.
A ______, _____________ plant would have its two alleles represented
with the letters ________.
A ______, ____________ plant would have its two alleles represented
with the letters ________.
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Chapter 3: Section 2: Probability & Traits
Probability
 The __________ that a particular __________ will __________.
o Example: flipping a __________
o ______% chance it will land __________ ________.
o ______% chance it will land __________ ________.
Principles of Probability
 __________ what is likely to __________, not what will
__________.
 The more an event occurs, the __________ the __________ will be
to the __________.

The __________ of one __________ doesn’t affect the
__________ of the next __________.
 __________ remains the same for each new __________.
Mendel and Probability
 __________ was the first person to recognize the importance of
__________ to predict the results of __________ __________.
Punnett Squares
 A __________ that shows all the __________ __________ of
__________ that can result from a __________ __________.

_______________ use Punnett squares to show all the possible
outcomes of a genetic cross and determine the __________ of a
__________ __________.
Using Punnett Squares
 The allele passed on by a parent is passed on by __________.
 Each parent has ________ alleles and will only pass on ________.
 The result between ________ parents are ________ possible
combinations.
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Predicting Probability
 If a genetic combination has a _____ in 4 chance, its __________
of occurring is ______%.
Phenotypes & Genotypes
 Phenotype –

Genotype –
o Homozygous –
o Heterozygous –
Codominance - aka Incomplete dominance
 The alleles for a particular __________ are neither __________ nor
__________.
 As a result __________ __________ are __________ in the
__________.
Symbols

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When a ______________ situation occurs you express the trait
being affected with a __________ letter.
o Example:
Next, you express the trait’s _____________ with a ____________
_____________ letter.
o Example:
o Example:
Then you _____________ the two to express the trait.
o Example:
o Example:
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Chapter 3: Section 3: Meiosis
2 kinds of reproduction


Asexual Reproduction
 Only 1 _____________ cell is needed
 Parent divides by ________________
 Daughter cells are __________ __________ copies of parent cell
 Most cells in ___________________ and most single celled organisms
reproduce this way
Sexual Reproduction

2 parent cells join together to form ______________ that are different
from both parents
Parent cells are called _______ ____________
Chromosomes that are similar are _________________ chromosomes
Humans have _____ _________ of homologous chromosomes (______
total chromosomes)
Sex cells have only _______ of the homologous chromosomes
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Meiosis
 Sex cells are created during __________________
 Meiosis creates cells with ______ the total chromosomes for the
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Genes
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organism
For example, a human _____ cell has 23 chromosomes and a human
_________ cell has 23 chromosomes. Together they form a human
with 23 _________________ chromosomes (46 total chromosomes)
& Chromosomes
_____________ _____________ observed sperm cells in grasshoppers
He knew of Mendel’s work and ______ ratio in 2nd generation offspring
He knew eggs and sperm were different
He knew chromosomes were in the _________________
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Meiosis
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He proposed –
Steps – Part 1
Interphase –
Mitosis 1
o
Prophase 1 – nucleus ______________, homologous
chromosomes form ______ _________ structures & pair up
o
Metaphase 1 - homologous chromosome pairs line up along
__________
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o
Anaphase 1 – homologous chromosomes ______________
and move to ___________
o
Telophase 1 –
 Cytokinesis 1 – cell divides into _____ _______ cells
Meiosis Steps – Part 2
 Mitosis 2
o Prophase 2 – ________________ in both cells dissolves
o Metaphase 2 – __________________ line up along equator
o Anaphase 2 – chromatids pulled to __________
o Telophase 2 – nucleus ______________
 Cytokinesis 2 – both cells divide to form a total of _______ cells
Sex Chromosomes
 Sex chromosomes carry _______ that determines sex - male and female
 In humans, females have ______ _____ chromosomes, males have
____ ______ and ______ ______ chromosome
 During ___________ meiosis each ______ cell gets an X chromosome
 During male meiosis each sperm gets an ____ or a _____ chromosome
Sex Linked Disorders
 X and Y chromosomes do not have exactly the ______ ______ on them
 Some _________ ___________ are carried only on the ___ chromosome
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They are ___________________ (need 2 recessive alleles or genes)
Examples include colorblindness and hemophilia
____________ have a backup (or ___________ gene) for a recessive
gene in the 2nd X chromosome
 _______ only have 1 X chromosome, so they are more likely to have
_____ _____________ disorders
Genetic Counseling
 Genetic _______________ can be traced through family _________
 A ____________ is a diagram of a family tree that traces certain traits

Pedigrees can predict if a person is a ____________ (1 recessive gene)
or has the genetic disorder (_____ _____________ genes)
Selective Breeding
 Organisms with _______________ characteristics and traits are mated
 Occurs in both plants and animals
 _________ are extensively selectively bred for specific purposes
 Plants are selectively bred to withstand _____________, __________,
____________, produce fruit with few seeds, etc
 Animals are selectively bred for ______ or ____________ (milk or eggs)
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