Genetics Unit Notes http://jeanapettus.webs.com/

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Learning Goals

1. I can accurately compare & contrast the processes of asexual & sexual reproduction.

2. I can accurately describe the functions of the key cell parts that effect heredity.

3. I can use tools to accurately predict the outcomes of mating and to analyze patterns of inheritance.

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Key Vocabulary for the Genetics Unit

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Chromosome – A long strand of DNA that has sections on the strand called genes

that have the “code” (or plans) for different proteins.

Gene – A section of DNA that has the “codes” (or plans) to make a protein.

Allele – A different “brand” of the code for a protein. (Ex: protein for Blue or Brown eye color)

Protein – Molecules that are built from DNA plans or “codes” that do important tasks in the

body. (muscle fiber, hair, collagen, enzymes, antibodies… etc.

Dominant Trait – Trait that overrides a recessive trait. (Brown, Green or Hazel Eyes vs Blue Eyes)

Recessive Trait – A trait that doesn’t show when paired with a dominant trait.

(Ex: The Blue Eye trait is recessive to the Brown Eye trait)

Characteristics – A genetic trait that is show or “expressed”…. like eye color, hair curliness,

widow’s peak, double jointedness, thumb crossing.

Mutation – A mistake in the code for a protein (on a gene)

Pedigree – A map used to study the inheritance of genetic traits.

Genotype - The code on the DNA for a specific trait. (BB = homozygous dominant genotype)

Phenotype – The way the genetic code is expressed, or shown. (Curly or Straight hair)

Key Vocabulary for the Genetics Unit

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Homozygous - when offspring inherit the same alleles of a particular gene from both parents

Heterozygous - when offspring inherit different alleles of a particular gene from their parents

Nucleus – A organelle in a cell that contains the genetic code (DNA /Chromosomes) for

that individual.

DNA – A molecule that holds the code with the genetic instructions for a person.

Punnett Square – A tool used to predict the result of a breeding experiment.

Offspring – The product of reproduction between two individuals.

Incomplete Dominance – When two different alleles pair up & neither is dominant.

(Ex: White flower X Red flower = Pink Flower)

Trade Off – When one has to chose between 2 (or more) competing “Goods”

(Ex: Going to a friend’s birthday party vs. Playing soccer in the championship

game)

Asexual Reproduction – When offspring are created by one parent. Each has identical traits

Sexual Reproduction – The offspring of two parents. Each offspring has a mix of traits.

Genetic Information – Family genetic history, often used to track probability of disease.

Bacteria Dividing

Asexual Reproduction

3. I am able to identify both sexually & asexually reproducing plants and animals.

Hydra Budding

Walking Stick

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Dolly (1st clone) & lamb

Sexual Reproduction - Animals

3. I am able to identify both sexually & asexually reproducing plants and animals.jschmied©2015

Sexual Reproduction - Plants

MalePollen

FemaleStigmaleads to

Ovary

Pines

All Flowering Plants sexually reproduce (some also asexually reproduce). Trees sexually reproduce many ways. Ferns sexually reproduce w/spores .

Big Leaf MapleCatkins

FernsHave spores

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Example: Both Sexual & Asexual Reproduction

A = The same Strawberry reproducing asexually w/stolens

B = Strawberry reproducing sexually w/Flowers…. And….

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Seeds eaten by birds & animals

spread new plants far from the parent plant.

Reproducing with stolens keep the new plants

near the parent plant.

Data Table Two – Sexual vs. Asexual Reproduction

Name DNA Process Advantages Disadvantages

Sexual

Asexual

DNA from two

Parents

ALLDNA from one

Parent

- Offspring are genetically diverse.

- Can adapt better in changing conditions & give better survival.

Ex: climate change, competition, predation

- Each mategives 1/2 the chromosomes to offspring.

- Female gives all other parts to mating.

- Everything duplicates.

- Divides into two identical organisms.

- “Clones”

- Reproduce without a partner.

- Lots of offspring- Helpful in disaster to ensure species survival. - Ex: volcano destroying

all but one plant..- Earthquake, Forest fire

- Need two partners.

- Offspring requires lots of time, energy & resources.

- Often fewer Offspring produced

- Offspring has no diversity. “Clones”

- Not able to adapt quickly in changing conditions.

- Susceptible to disease, sub lethal mutations.

I can accurately compare & contrast the processes of asexual & sexual reproduction.

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Comparing Sexual to Asexual Reproduction

5. I am able to explain why offspring from sexual reproduction have more diverse characteristics compared to offspring from asexual reproduction.

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One parent Offspring get ALL DNA

from one parent Offspring are identical to

parent unless mutation One-celled organisms

and some multi-celled organisms reproduce asexually

Offspring’s genes are the same as the parent’s

Cloning is a form of asexual reproduction

Two parents Gets ½ the DNA from

each parent. Offspring not identical Offspring inherit traits

from two parents Offspring inherits a

unique set of genes Generally only multi-

celled organisms reproduce sexually

Single-celled organisms do not reproduce sexually

Produce offspring Has at least one

parent Both pass DNA down

to offspring Offspring have a

complete set of DNA Can produce

mutations (not clear from reading)

Both Continuespecies

Sexual AsexualBoth

Organization: Human Body to DNA

1. I am able to explain that information on how cells are to grow and function is contained in the cell nucleus, on chromosomes, coded on genes.

x 2

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Data Table One – Types of Cell DivisionName Definition Where Done in body Purpose

Mitosis

Meiosis

Simple Cell Division

Also forAsexualReproduction

Sexual “Reproduction Cell Division”

a. All parts of body except in sex cells.

b. New cell has 2 of each chromosome. (A full set of chromosomes from the one parent.)

a. In sex organs (testes, ovaries.)

b. Sex cells have only 1 of each chromosome. - ½ of a complete set from each parent.

a. Growth

b. Replacement of injured or worn out cells

a. Reproduction of species.(Sperm & Egg unite to make a new organism w/ 2 of each chromosome)

jschmied©20134. I can describe how offspring from sexual reproduction differ from the parents because each receives ½ their genetic information from each parent.

c. Asexual Reproduction

Mitosis – Meiosis

4. I can describe how offspring from sexual reproduction differ from the parents because each receives ½ their genetic information from each parent.jschmied©2013

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Process of Human Sexual Reproduction

Helpful terms to learn: Gamete – cell with half the normal number of chromosomes, only in sexual reproduction Zygote – cell formed when two gametes combine Fertilization – term to describe the joining of two gametes Haploid – having half the normal number of chromosomes Diploid – having the normal number of chromosomes

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A Human Karyotype

4. I can describe how offspring from sexual reproduction differ from the parents because each receives ½ their genetic information from each parent.

Two Sets of

chromosomes!

One each

from

the Male,

One each

from the

Female

It’s a boy!

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The 23rd pair of chromosomes determine an offspring’s gender

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If the 23rd pairis XX, the baby is a Female.

If the 23rd pairis XY, the baby is a

Male

It’s a Boy!

Genes “Code” for proteins

1. I am able to explain that information on how cells are to grow and function is contained in the cell nucleus, on chromosomes, coded on genes.

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Correctly coded proteins make your body

function properly!

What do proteins do? Examples of protein functions

Function Description Example

Antibody Antibodies bind to specific foreign particles, such as viruses and bacteria, to help protect the body

Immunoglobulin G (IgG) (illustration)

Enzyme Enzymes carry out almost all of the thousands of chemical reactions that take place in cells. They also assist with the formation of new molecules by reading the genetic information stored in DNA.

Phenylalanine hydroxylase (illustration)

Messenger Messenger proteins, such as some types of hormones, transmit signals to coordinate biological processes between different cells, tissues, and organs.

Growth hormone (illustration)

Structural component

These proteins provide structure and support for cells. On a larger scale, they also allow the body to move.

Actin (illustration)

Transport/storage These proteins bind and carry atoms and small molecules within cells and throughout the body.

Ferritin (illustration)

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Proteins and ShapeShape is everything! React properly if correct shape!

It’s sorta like a Key in a Lock! If the protein is right shapereaction proceeds.

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1. I am able to explain that information on how cells are to grow and function is contained in the cell nucleus, on chromosomes, coded on genes. Also that each gene has at least two variations called alleles.

If shape is slightly wrong the reaction may proceed slowly

If protein is wrong shape the reaction can not happen!

Genes “code” for Proteins AND the code must be

correct …

wnthinktank.wordpress.com

More like reality, two molecules “induce the enzyme to fit and react.

jschmied©20131. I am able to explain that information on how cells are to grow and function is contained in the cell nucleus, on chromosomes, coded on genes. Also that each gene has at least two variations called alleles.

Who was Gregor Mendel? (1822 – 1884)

Father of Modern Genetics• An Augustinian Monk• Lived in Brno Monastry• Used the 6 acre garden to experiment w/Pea plants• Ist created terms: “recessive & “dominant” • Called these “factors”• Identified many of the

rules of heredity.

Mendel used peas w/traits thatwere independent of Other traits. Like Purple Vs White FlowersYellow vs Green PeasRound vs Wrinkled PeasGreen vs Yellow Pea Pods

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Mendel’s PeasMendel used peas w/traits that were independent of other traits. Like:

Purple Vs White FlowersYellow vs Green PeasRound vs Wrinkled PeasGreen vs Yellow Pea Pods

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Phenotype vs GenotypePhenotype:The way the genetic code

is shown, or “expressed”.

(Smooth or Wrinkled pea)

Genotype The code on the DNA for a

specific trait.

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HomozygousDominant

Heterozygous HomozygousDominant

Where do your genes come from?You get ½ your genes from Mom, ½ from Dad.

The Alleles fora specificGene areat same location

on each ofthe two

homologouschromosomes

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Dominant AllelesA dominant allele will always show, even if an individual only has one copy of the allele.

For example:

The allele for a widow’s peak is dominant.

You can have either one or two copies of the allele & have a widow’s peak.

While a widow’s peak is a dominant trait, it is not

common!

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Recessive Alleles

A recessive allele only shows if the individual has two copies of the recessive allele.

The allele for albinism is recessive.

This child has two copies of the recessive allele for albinism.

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Alleles “brands of the same gene”

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M D M D M D

M = Chromosome from Mother D = Chromosome from Father Called “Homologous Chromosomes”

Each allele for a gene is at the same

location on chromosomes

of the same type.

Mom’sChromosome

15

Dad’sChromosome

15

Genes & Alleles AT CG

1. I am able to explain that information on how cells are to grow and function is contained in the cell nucleus, on chromosomes, coded on genes. Also that each gene has at least two variations called alleles.

“B” “b”

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Base Pairs

A = Adenine

T = Thymine

C = Cytosine

G = Guanine

A Pairs with TC Pairs with G

Father’s Allele of the gene

From Crick

Mother’s Allele of the gene

From Crick

“Gene”

Chromosome15

Chromosome15

Alleles “brands of the same gene”

Allele for Eye Color Codes for Brown, Hazel or

Green appearing eye

color protein

“B”

Allele for Eye Color Codes for Blue appearing eye color protein “b”

• Each gene has at least two variations called alleles.

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Example using the Eye Color Trait

Dominant & Recessive AllelesIf a baby has two “B” alleles for eye color BB = Brown, Green or Hazel eyes (BGH)Called “Homozygous Dominant”Genotype = BB Phenotype = BGH Eye color

IF a baby has two “b” alleles for eye color bb = Blue eyesCalled “Homozygous Recessive”Genotype = bb Phenotype = Blue Eye color

IF a baby has “B” & “b” alleles for eye color Bb = Brown Green or Hazel eyesCalled “Heterozygous”Genotype = Bb Phenotype = BGH color

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4. I can describe how offspring from sexual reproduction differ from the parents because each receives ½ their genetic information from each parent.

Mutations

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7. I can explain how biological evolution accounts for the diversity of species on

Earth today.

Many mutations are lethal, but we take advantage of gene mutations every day!

Selective Breeding

Mutation in nature

Click the cow to see cool genetic projects

Some types of Mutations

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Photo credit ©Lineworks

Trisomy 21 – “Down’s Syndrome” (causes about 90% of Down’s cases)

Individuals with Down’s have an extra 21st chromosome. This often leads to the child having mental impairments and can impair growth. In the US, Down’s syndrome occurs in about 1 of 700 infants. Nearly 6,000 Down’s children are born each year. There are more than 350,000 people living with Down syndrome in the United States.

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Huntington’s Disease (a fatal dominant gene mutation)

A fatal malfunction in the HTT gene on Chromosome 4 causes progressive breakdown of nerve cells in the brain. Deteriorates a person’s physical & mental abilities during their 30’s & 40’s. HD has no cure. Children of a parent with HD have a 50/50 chance of getting the faulty Dominant gene. There’s about 30,000 symptomatic Americans & more than 200,000 at-risk of inheriting the disease.

>40 CAG Repeats in Huntingtin (HTT) Gene

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Turner’s Syndrome (Absent or partial 23rd X chromosome!)

Turner syndrome (TS) is a chromosomal condition that affects development in females. TS is caused by a missing, or only a partial, second 23rd sex (X) chromosome. This condition is caused by a random mutation. TS occurs in approximately 1 of 2000 live female births & about 10% of all miscarriages.

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Tay – Sach’s Disease(a fatal recessive gene mutation)

• A defective recessive gene on chromosome 15 causes Tay-Sachs (T-S).

• The defective gene doesn’t make a protein called Hex-A.

• Without this protein, chemicals called “gangliosides” build up in nerve cells in the brain & destroy brain cells.

• Individuals with T-S have inherited one defective gene from each parent.

• Usually affects children, ending life from 3-5 years.

• Rarer forms have been found in juveniles 2-10 years old, and in older adults.

• The incidence varies. Certain ethnic populations have a very high incidence.

(1 in 50).

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Creating a Family Pedigree

2. I can explain that genes are passed from parent cells to offspring during both sexual & asexual reproduction.

1. Gather Information

2. Plot Data

Phenotype =Is what a trait

“looks” likeEx: Wavy hair

Blue Eyes

Genotype = the code for a

protein thatmakes a

characteristic.Ex: code for

Wavy hairor for

Blue Eyes

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3. Evidence a. Label Recessives

b. Work on one side offamily tree

c. Sort out Heterozygous

c. Rest are BB or Bb

Creating a Family Pedigree

2. I can explain that genes are passed from parent cells to offspring during both sexual & asexual reproduction.

1. Gather Information

2. Plot Data

3. Evidence a. Label Recessives

b. Work on one side offamily tree

c. Sort out Heterozygous

c. Rest are BB or Bb

Phenotype =Is what a trait

“looks” likeEx: Wavy hair

Blue Eyes

Genotype = the code for a

protein thatmakes a

characteristic.Ex: code for

Wavy hairor for

Blue Eyes

Blue

Blue

BlueBlue

Brown Brown

Brown

Green

Hazel Hazel

Green

Hazel

BrownGreenGreen

bb

bb bb

Bb Bb

BB Bb

BB Bb

BB Bb

BB Bb

BB Bb BB Bb

One parent must be Bb to give their offspring a “b”

BB Bb

BB Bb

BB Bb

These offspring could be either BB or Bb. There’s not enough information

These offspring could be either BB or Bb. There’s not enough information

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Punnet SquaresMike and Suzy are investigating inherited traits in two Beebop Terriers• Ally, the female, is a rare Albino white coat. She is homozygous recessive (rr) for

coat color.• Herman, the male, is a Hungarian blue coat. Herman is heterozygous (Rr)Complete the Punnett Square and show the results of Mike and Suzy’s experiment.

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rr

Rr

Punnet SquaresMike and Suzy investigate inherited traits in Beebop Terriers• Ally, the female, is a rare Albino white coat. She is homozygous recessive (rr) for

coat color.• Herman, the male, is a Hungarian blue coat. He is heterozygous (Rr)Complete the Punnett Square and show the results of Mike and Suzy’s experiment.

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rr

Rr

r r

R

r

r

r

r

r

R R

r r

0

2

2

0%

50%

50%

rr

Rr

Pedigree Problems – Gryffindor HouseAnna and Andrew are investigating the heredity of curly (CC) and straight hair (ss) inwizard families at the Hogwarts houses. Below is a pedigree showing three generations of a wizarding family who all were chosen for the Gryffindor house. Please analyze this pedigree, then write in the genotype of each family member.

http://gothlupin.tripod.com/gryffindor.html

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Pedigree Problems – Gryffindor HouseAnna and Andrew are investigating the heredity of curly (CC) and straight hair (cc) inwizard families at the Hogwart’s houses. They discovered this pedigree showing three generations of a wizarding family who were all members of Gryffindor. Please analyze this pedigree, then write in the genotype of each family member.

http://gothlupin.tripod.com/gryffindor.html

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cc cc

cc cc

CC, Cc CC,Cc

Cc CcCcCcCcCc

CcCC

CcCC

CcCC

Less likely, Why?

Pedigree Problems – Slytherin HouseAnna and Andrew continue their investigation into the heredity of rolling tongues (RR) and non rolling tongues (rr) in wizard families at the Hogwart’s houses. They discovered this pedigree showing three generations of a wizarding family from Syltherin House. Please analyze this pedigree, then write in the genotype of each family member.

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Pedigree Problems – Slytherin HouseAnna and Andrew continue their investigation into the heredity of rolling tongues (RR) and non rolling tongues (rr) in wizard families at the Hogwart’s houses. They discovered this pedigree showing three generations of a wizarding family from Syltherin House. Please analyze this pedigree, then write in the genotype of each family member.

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Rr Rr

Rr rr

Rr Rr

rr RR,RrRR,RrrrRrRR,Rr

Rr Rr Rr

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