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7th Grade Chapter 5 Notes

7th Grade Chapter 5 Notes

Assessment

Presentation

Science

7th Grade

Medium

NGSS
HS-LS3-1, HS-LS3-2, HS-LS3-3

Standards-aligned

Created by

Mac McDowell

Used 14+ times

FREE Resource

28 Slides • 28 Questions

1

7th Grade Chapter 5 Notes

by Mac McDowell

2

Open Ended

Question image

This albino deer had a mother with a normal coat.  Why do you think it looks so different?

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Mendel and H​is Peas

​Lesson 1

4

​Mendel's Experimental Methods

​1. During the 1850s Gregor Mendel studied genetics by doing controlled experiments with pea plants.

​2. peas were used because they reproduced quickly, easily observed traits and the ability to control which plants reproduced

​3. pollination is when pollen lands on the pistil of a flower

​4. this allows sperm from the pollen to fertilize the egg in the pistil.

5

​cont

  • peas con pollinate two ways

  • ​self pollination is when pollen from one plant, lands on the pistil of the same plant

  • cross-pollinations is when pollen from one plant, reaches the pistil of another.

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Multiple Choice

Pea plants can pollinate ___________ ways

1

one

2

two

3

three

4

four

7

Multiple Choice

_____________ occurs when pollen lands on the pistil of a flower.

1

fertilization

2

pollination

3

reproduction

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Multiple Choice

_______________________ is when pollen from one plant, lands on the pistil of another.

1

self pollination

2

cross pollination

3

fertilization

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​true breeding plants

​1. Mendel began his experiments with true breeding plants

​2. when a true breeding plant self pollinates, it always produces offspring with traits that match the parent.

​ex. a true breeding plant with wrinkles seeds self pollinates and produces only wrinkled seeds

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​Mendel's Cross Pollination

  • ​by controlling which plants pollinated other plants, Mendel knew which traits the parents had.

  • ​The picture shows this happening between a plant with white flowers and one with purple flowers

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Multiple Choice

A plant, that when self pollinated, only produces plants with the same traits as the parent.

1

pollination

2

hybrid

3

cross breeding

4

true breeding

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Multiple Choice

How did mendel control which plants pollinated other plants?

1

by removing the stamens from one plant and pollinating them with pollen from a different plant

2

by leaving the plants to grow in the garden naturally

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​Mendel's Results

​1. When he had enough true breeding plants, he cross-pollinated selected plants.

​2. a cross between true breeding purple plants only produced purple and between white, only produced white

​3. when true breeding purple plants crossed with white, the offspring had all purple flowers

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Multiple Choice

What are the results after Mendel crossed the parent generation of a true breeding white flower, with a true breeding purple flower, to create the first generation?

1

some purple flowers, some white

2

all purple flowers

3

all white flowers

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Open Ended

What is a question Mendel might have asked himself with his results from the first generation?

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​Second Generation

1. the first generation is called hybrid plants

​2. this means they came from true breeding plants with different forms of the same trait.

​3. Mendel took these hybrids and cross pollinated them

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​cont.

  • ​some off these offspring had white flowers, even though all parents had purple flowers

  • ​the trait that disappeared in the first generation, reappeared in the second

  • ​this happened with other plea plant traits too

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Multiple Choice

What do we call a cross between two plants with different forms of the same trait?

1

fertilization

2

pollination

3

hybrid

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Multiple Choice

What plants did Mendel use to create the second generation?

1

different plants

2

the same original parents

3

the plants produced from the first cross

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Multiple Choice

What were the results of the second generation?

1

100% purple flowers

2

25% purple flowers 75% white flowers

3

100% white flowers

4

75% purple flowers 25% white flowers

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​more hybrid crosses

  • ​Mendel repeated these steps crossing plants with different traits shown to the right

  • ​he found that the first generation, a trait was always hidden, but reappeared the next generation

  • ​The ratio between them was 3:1

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​Mendel's conclusions

​1. he concluded that two genetic factors control each inherited trait

​2. when organisms reproduce, each reproductive cell, contributes one factor for each trait.

​3. he hypothesized that hybrids have one factor for purple and one for white, but only showed the purple

​4. this explains how white reappears in the next generation

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​cont.

5. he hypothesized purple is the only one seen because it blocks the white

​6. a genetic factor that blocks another is called a dominant trait

​7. a genetic factor that is blocked by the presence fo a dominant factor is called a recessive trait

​8. a recessive trait is only observed when two recessive genetic factors are present

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Multiple Choice

A genetic factor that blocks another genetic factor

1

dominant trait

2

recessive trait

3

hybrid

4

mitosis

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Multiple Choice

A genetic factor that is blocked by the presence of a dominant factor

1

dominant trait

2

recessive trait

3

hybrid

4

offspring

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​Understanding Inheritance

Lesson 2​

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​What controls traits?

​1. Mendel concluded that two factors- one from each parent - control each trait.

​2. chromosomes contain genetic information that controls traits

​3. Mendel's factors are part of chromosomes, chromosomes are inherited, one from each parent

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Multiple Choice

How many chromosomes are inherited from each parent?

1

1

2

2

3

3

4

4

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Multiple Choice

In Mendel's peas, how many factors control a trait?

1

1

2

2

3

3

4

4

30

Multiple Choice

Where are the factors that control traits located?

1

brain

2

chromosomes

3

mitochondria

4

hybrid

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​Genes and alleles

​1. each chromosome can have information about hundreds or even thousands of traits.

​2. a gene is a section on a chromosome that has genetic information for one trait.

​3. offspring inherit two genes for each trait, one from each parent.

​4. The different forms of a gene are called alleles.

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Multiple Choice

For the traits that Mendel studied, the offspring peas inherited one factor that control's a trait from each parent, as there is one factor per chromosome, one chromosome from each parent, and those chromosomes combine during fertilization to form the offspring pea.

1

true

2

false

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Multiple Choice

The different forms of a trait are called

1

meiosis

2

hybrid

3

peas

4

alleles

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​Genotype and Phenotype

​1. For flower color, they could have two alleles for purple, two for white, or one for white, one for purple.

​2. How a trait appears or is expressed is the trait's PHenotype or PHysical characteristic.

​3. the two alleles that control the phenotype of a trait are called the trait's genotype.

​4. the genotype is what the two alleles are

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Multiple Choice

the two alleles on the chromosomes are called its

1

phenotype

2

genotype

3

allele

4

hybrid

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Multiple Choice

How a trait appears, how it is expressed, or its PHysical characteristic 

1

phenotype

2

genotype

3

allele

4

zygote

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​Symbols for genotypes

​1. scientists use symbols to represent the alleles in a genotype

​2. Uppercase letters represent dominant alleles

​3. lowercase letters represent recessive alleles

​4. The dominant allele is written first, if present

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Multiple Choice

uppercase letters represent _________________ alleles

1

dominant

2

recessive

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Multiple Choice

lowercase letters represent __________________ alleles

1

dominant

2

recessive

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​round vs. wrinkled

  • ​a round seed can have two genotypes RR or Rr

  • ​A Rr still produces a round seed because it is the dominant trait

  • ​a wrinkled seed has the recessive genotype rr

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Homozygous and Heterozygous

​1. When the two alleles of a gene are the same, its genotype is homozygous, both RR and rr are homozygous

​2. if two alleles of a gene are different, its genotype is heterozygous, Rr

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Multiple Choice

If two alleles for a gene are the same we call it

1

homozygous

2

heterozygous

3

hybrid

4

clone

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Multiple Choice

If two alleles for a gene are different, we call it

1

homozygous

2

heterozygous

3

inferior

4

inheretance

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​Modeling Inheritance

​1. Flipping a coin that has two sides gives you a 50% chance of heads and 50% chance of tails or a 1:1 ratio

​2. Plant and animal breeders use a method for predicting how often a trait will appear in offspring

​3. A punnett square is a model used to predict possible genotypes and phenotypes of offspring.

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​Punnett Squares

  • ​A cross between two plants that are heterozygous for height shows off spring can be TT,Tt, or tt

  • ​the ratio of genotypes is 1:2:1

  • ​The ratio of phenotypes is 3 tall:1 short

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​Using ratios to predict

​1. you cannot expect 4 of these offspring to always have a 3:1 ratio, but the larger the group, the overall ratio will be more predictable

​2. A pedigree is another model that can show inherited traits.

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​Pedigrees

  • a pedigree shows phenotypes of genetically related family members

  • ​it can also determine genotypes

  • ​If the parents don't show a trait, but have offspring that do, it is a recessive trait

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​incomplete dominance

  • ​when the offspring's phenotypes is a combination of the parents' phenotypes

  • ​ex. a white and red flower producing a pink flower

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​Codominance

  • ​when both alleles can be observed in a phenotype

  • ​ex a red coat and white coat producing a roan pattern

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50

Multiple Choice

when the offspring's phenotype is a combination of the parents' phenotypes, ex a red and white flower, producing a pink flower

1

incomplete dominance

2

complete dominance

3

inheritance

4

hybrid

51

Multiple Choice

when both alleles can be observed in a phenotype, ex a red cow and a white cow producing a roan coat color

1

incomplete dominance

2

codominance

3

inheretance

4

hybrid

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​multiple alleles

  • ​unlike pea plant traits, some genes have more than two alleles, like human ABO blood type (Ia Ib and i)

  • ​results in four blood types, A, B, AB, or O

  • ​A and B are codominant, but dominant to the O

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​Polygenic Inheritance

  • ​occurs when multiple genes determine the phenotype of a trait

  • ​many possible phenotypes

  • ​ex eye and skin color

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Multiple Choice

genes that have more than two alleles inheritance patterns

1

multiple alleles

2

polygenic inheritance

3

codominance

4

incomplete dominance

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Multiple Choice

occurs when multiple genes determine the phenotype of a trait

1

multiple alleles

2

polygenic inheritance

3

codominance

4

incomplete dominance

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​Genes and the environment

​1. genotype determines phenotype

​2. environment can also affect phenotype

​3. ex. hydrangeas can be different colored flowers depending on how acidic the soil is.

​4. your health decisions can have an impact on what diseases you are likely to get due to genetics actually occur

7th Grade Chapter 5 Notes

by Mac McDowell

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