Genetics unit notes

Genetics Unit Notes 2.2 http://jeanapettus.webs.com/
http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa_pre_2011/celldivision/celldivision1.shtml
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Performance Expectations
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Key Vocabulary for the Genetics Unit
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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.
Offspring – The product of reproduction between two individuals.
Sex Cell (Gamete) – A cell with only one set (1/2 of a pair) of chromosomes. (Ex: Egg, Sperm Cells)
• Egg – the gamete produced the female of the species – has only one set of chromosomes. (1N)
• Sperm - the gamete produced the male of the species - has only one set of chromosomes. (1N)
Zygote – A fertilized cell. A zygote has a complete set of chromosomes. (2N)
Nucleus – A organelle in a cell that contains the genetic code (DNA /Chromosomes) for
that individual.
Chromosome – A long strand of DNA that has sections on the strand called genes
that have the “code” (or plans) for different proteins.
DNA – A molecule that holds the code with the genetic instructions for a person.
Gene – A certain location on a cell’s DNA that has the code (or plans) to make a specific protein
Genetic Information – Family genetic history, often used to track probability of disease.

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Allele – A different “brand” of the code for a protein. (Ex. Protein for Blue eye or Brown Eye color.)
Protein – Molecules that are built from a Gene “codes” or plans that do important tasks in the
body. (muscle fiber, hair, collagen, enzymes, antibodies… etc.
Phenotype – The way the genetic code is expressed, or shown. (Curly or Straight hair)
Genotype - The code on the DNA for a specific trait. (BB = homozygous dominant genotype)
Mutation – A mistake in the code for a protein (on a gene)
Characteristic – A genetic trait that is show or “expressed”…. like eye color, hair curliness,
widow’s peak, double jointedness, thumb crossing.
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)
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
Punnett Square – A tool used to predict the result of a breeding experiment.

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Pedigree – A map used to study the inheritance of genetic traits.
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)
(Genetic ex: Choosing to risk having genetically impaired offspring vs. Adopting offspring.)

Summarizing the two types of Reproduction
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There are advantages to each form of reproduction. Some organisms can do both forms.
Being able to do both can maximize species chances of survival.

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

Asexual Reproduction
Regeneration
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Starfish split in two pieces regenerating
into two different starfish!

Sexual Reproduction - Animals
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Sexual Reproduction - Plants
Male
Pollen
Female
Stigma
leads to
Ovary
Pines
All Flowering Plants sexually reproduce (some also asexually reproduce).
Trees sexually reproduce many ways. Ferns sexually reproduce w/spores .
Big Leaf Maple
Catkins
Ferns
Have spores
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Sexual Reproduction
Grass, Ferns & Fungi
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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
ALL
DNA
from
one
Parent
- Offspring are
genetically diverse.
- Can adapt better in
changing conditions
& give better survival.
Ex: climate change,
competition, predation
- Each mate
gives 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 Continue
species
Sexual Asexual
Both

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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www.daviddarling.info

Data Table One – Types of Cell Division
Name Definition Where Done in body Purpose
Mitosis
Meiosis
Simple Cell
Division
Also for
Asexual
Reproduction
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)
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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.
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
www.crackingthecode.ca

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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Where do your genes come from?
You get ½ your genes from Mom, ½ from Dad.
The Alleles for
a specific
Gene are
at same
location
on each of
the two
homologous
chromosomes
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Genes & Alleles AT CG
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 T
C Pairs with G
Father’s Allele of the gene
From Crick
Mother’s Allele of the gene
From Crick
“Gene”
Chromosome
15
Chromosome
15

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!

Proteins and Shape
Shape is everything! React properly if correct shape!
It’s sorta like a Key in a Lock! If the protein is right shape
reaction 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.
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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.

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 Alleles
If 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 eyes
Called “Homozygous Recessive”
Genotype = bb Phenotype = Blue Eye color
IF a baby has “B” & “b” alleles for eye color
Bb = Brown Green or Hazel eyes
Called “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.

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 pair
is XX, the
baby is a
Female.
If the 23rd pair
is XY, the
baby is a
Male
It’s a Boy!

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)
jschmied©2016 http://ghr.nlm.nih.gov/handbook/howgeneswork/protein

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

Three Key causes of Mutations
1. Environment
Chemical Exposure – Smoke, other hazardous chems
Radiation Exposure – Sunlight, Nuclear radiation
2. Errors in copying (see next page)
Inversion
Deletion
Duplication
3. Jumping (transposing) genes
DNA sequence changes position in DNA (genome)
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Some types of copying 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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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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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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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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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 Flowers
Yellow vs Green Peas
Round vs Wrinkled Peas
Green vs Yellow Pea Pods
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Mendel’s Peas
Mendel used peas w/traits that were
independent of other traits. Like:
Purple Vs White Flowers
Yellow vs Green Peas
Round vs Wrinkled Peas
Green vs Yellow Pea Pods
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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’s
Chromosome
15
Dad’s
Chromosome
15

Phenotype vs Genotype
Phenotype:
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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Homozygous
Dominant
Heterozygous Homozygous
Recessive

Dominant Alleles
A 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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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” like
Ex: Wavy hair
Blue Eyes
Genotype =
the code for a
protein that
makes a
characteristic.
Ex: code for
Wavy hair
or for
Blue Eyes
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3. Evidence
a. Label
Recessives
b. Work on
one side of
family 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 of
family tree
c. Sort out
Heterozygous
c. Rest are
BB or Bb
Phenotype =
Is what a trait
“looks” like
Ex: Wavy hair
Blue Eyes
Genotype =
the code for a
protein that
makes a
characteristic.
Ex: code for
Wavy hair
or 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 Squares Act One
Scientists investigate inherited traits by breeding Beebop Terriers.
• Alexa, the female, is Hungarian blue coat. She is heterozygous (Tt) for blue tail
color.
• Arnold, the male, is a Hungarian blue coat. He is also heterozygous (Tt) for blue tail
color.
Complete the Punnett Square, showing the results of this experiment.
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Tt
Tt
Phenotype Ratio
Blue ____ Orange ____

Punnet Squares – Act One
Scientists investigate inherited traits by breeding Beebop Terriers.
• Alexa, the female, is Hungarian blue coat. She is heterozygous (Tt) for blue tail color.
• Arnold, the male, is a Hungarian blue coat. He is also heterozygous (Tt) for blue tail
color.
Complete the Punnett Square, showing the results of this experiment.
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Tt
Tt
T t
T
t
T
T
t
t
T T
t t
1
2
1
25%
50%
25%
Tt
Tt
Phenotype Ratio
Blue ____ Orange ____75% 25%

Punnet Squares Act Two
The scientist continue their investigation of inherited traits in Beebop Terriers
• Ally the female, is a rare White coat. She is homozygous recessive (rr) for coat color.
• Herman, the male, is a Hungarian blue coat. He is heterozygous (Rr) for coat color
Complete the Punnett Square and show the results of Mike and Suzy’s experiment.
jschmied©2016
rr
Rr
Phenotype Ratio
Blue ____ White ____

Punnet Squares
The scientist continue their investigation of inherited traits in Beebop Terriers
• Ally the female, is a rare White coat. She is homozygous recessive (rr) for coat color.
• Herman, the male, is a Hungarian blue coat. He is heterozygous (Rr) for coat color
Complete the Punnett Square and show the results of Mike and Suzy’s experiment.
jschmied©2016
rr
Rr
r r
R
r
r
r
r
r
R R
r r
0
2
2
0%
50%
50%
rr
Rr
Phenotype Ratio
Blue ____ Albino ____50% 50%

Pedigree Problems – Gryffindor House
Anna and Andrew are investigating the heredity of curly (CC) and straight hair (cc) in
wizard 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 House
Anna and Andrew are investigating the heredity of curly (CC) and straight hair (cc) in
wizard families at the Hogwart’s houses. They discovered this pedigree showing three
generations of a wizarding family who were all members of Gryffindor.
http://gothlupin.tripod.com/gryffindor.html
jschmied©2013
cc cc
cc cc
CC, Cc CC,Cc
Cc CcCcCcCcCc
Cc
CC
Cc
CC
Cc
CC
Less likely, Why?

Pedigree Problems – Slytherin House
Anna 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.
jschmied©2013
harrypotter.wikia.com

Pedigree Problems – Slytherin House
Anna 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.
jschmied©2013
Rr Rr
Rr rr
Rr Rr
rr RR,RrRR,RrrrRrRR,Rr
Rr Rr Rr
harrypotter.wikia.com

Genetics unit notes

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Genetics unit notes