Download Name: Date: Period: GENETICS WHAT IS A CELL? A is the building

Name:
Date:
Period:
GENETICS
I. WHAT IS A CELL?
A __________________is the building block of all living things. Robert Hooke was the first to call them CELLS.
CELL THEORY



Important Dudes: Schleiden, Schwann, and Virchow
All living things are made of cells
Cells are the basic units of structure and function in living organisms
Living cells only come from other living cells
a) Some organisms are one cell big - _____________________________ (i.e. bacteria)
b) Some organisms have many cells - ____________________________ (i.e. animals, plants, etc.)
*All living organisms contain DNA – DeoxyriboNucleic Acid- in their cells. DNA is
the blueprint for making you, look like YOU!
In our cells, we have a NUCLEUS (The control center of the cell.) Inside this NUCLEUS, our DNA is stored in
organelles called CHROMOSOMES. The DNA is wrapped in tight coils, these coils make up the
CHROMOSOME. On each of these chromosomes, you have GENES (there could be hundreds of genes on one
chromosome). These GENES are what determine your TRAITS (i.e brown hair, blue eyes, height, length of
pinkie toe, etc).
How many CHROMOSOMES do you have in each of your cells in your body? _________________
What cells in your body have HALF of the CHROMOSOMES? __________________
What number pair are the sex cells (determine male or female)? _________
WHY DO SEX CELLS HAVE HALF THE NUMBER OF CHROMOSOMES? ______________________________
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II. GREGOR MENDEL AND THE PEA PLANTS
Genetics is the study of HEREDITY, or the passing of traits from parent to offspring.
*My name is
*I worked as a
________________.
_________
and I really love
_________
!
*I spent hours in my garden in the monastery planting pea plants, watching them
grow, and making observations.
*I discovered pea plants had observable
___________
.
*I discovered that after carefully crossing certain traits with other traits, some traits would
traits and cover them up.
*For example. When I crossed a
plant, I got all
__
__
pea plants!
pea plant with a
*I concluded that some traits are ____________ and some traits are
*Dominant traits always make recessive
(tall plant = dominant , short plant = recessive)
*I am still known as the
___
__________.
traits ______________ .
________
_________
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!
other
pea
III. HOW ARE GENETIC TRAITS DETERMINED?
You were created by a Sperm (from your dad) and an Egg (from your mom). We know that these two types of
cells contain half the genetic information (23 chromosomes), but together, they create an organism (you) that
has 46 chromosomes. So…for each trait, you receive one allele from Dad and one allele from Mom.
Let’s look at an example:
Straight Thumb allele
vs. Hitchhiker’s Thumb allele
Hitchhiker’s Thumb 
*We give each gene a letter (random).
*These letters represent the alleles your
parents gave you for each trait. You get
one from your mom and one from your
dad.
(H)
(h)
EXAMPLE: Gene controlling thumb shape = H
Straight Thumb allele =
H
Hitchhicker’s Thumb allele=
 We have
two
h
alleles for each gene. So for our thumb shape gene we could be any of these:
1 2
HH
1 2
1 2
Hh
hH
1 2
hh
These two are the same.
Always write the capitol letter first.
HOMOZYGOUS (PURE) means that the two alleles are IDENTICAL ( HH
HETEROZYGOUS (HYBRID) means the two alleles are DIFFERENT (Hh)
or hh)
What happens if you are Hh? Which trait will you have, hitchhiker or straight
thumb?
 DOMINANT alleles ALWAYS show through. If you have a capital H , this is the trait that will always
show. It masks or dominates the smaller letter or RECESSIVE allele (the lower case/ “weaker” trait)
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How do scientists figure out which traits we be inherited?

Punnett
!!
Introducing the Punnett square, a special chart used to show the
possible gene combinations in a cross between two organisms.
 The Punnet square helps us determine the genetic traits of offspring in
the next generation.
 How do you set it up? Let’s use an example of Momma Bear (CC) and Daddy Bear (cc)
Step one:
Place the parents’ alleles on the outside.
C
C
c
c
Step Two:
c
Go to the first box, and bring down Momma’s allele. Then go over and bring across Daddy’s
C
C
Cc
Cc
allele. (It works the same way as a multiplication table)
Step Three: Do the same for the second row of your Punnet
down Momma’s allele, then bring across Daddy’s
allele.
c
Final: The Punnet square is complete.
Each of the boxes represents a
square. Bring
C
C
c
Cc
Cc
c
Cc
Cc
possible allele of an offspring.
C
C
c
Cc
Cc
c
Rr
This Punnet square shows that there is only one allele combination for the
offspring…. Cc.
Cc
 This is the only allele combination that babies could
have from Mom and Dad.
Rr
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IV.
NON-MENDELIAN GENETICS:
Two main types of non-Mendelian Genetics:

Incomplete Dominance

Codominance
How does Incomplete Dominance work?


In the __________________ individual, the dominant allele is not completely dominant over the
other.
A ________________ ___________________ appears in the first generation of offspring.
RR
WW
RW
RW
First Generation
Second Generation
Third Generation
RR
RW
RW
WW
FIRST GENERATION
SECOND GENERATION
Genotype: __________
Phenotype: __________
Genotype: ___________
Phenotype: _________
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CODOMINANCE:


Most genes throughout populations involve more than _____ alleles, known as _______________.
The ____________ shows the phenotype of ________________ alleles.
Blood Type
(Phenotype)
Genotype
Can Receive blood
from
A
AA
AO
A or O
B
BB
BO
B or O
AB
AB
A, B, AB, O
O
OO
O
EXAMPLE: Mr. Brown is learning about blood typing in his college biology class.
 His research:
o DAD = Type A blood
o MOM = Type B blood

Mr. Brown is confused because he has TYPE 0 Blood.

How can Mr. Brown have TYPE O Blood? Show your work below.
Parent’s Possible Genotypes:
DAD: _________ and ______________
MOM: ______________ and ______________
Mr. Brown’s Genotype: ___________
Conclusions: Is it possible for Mr. Brown to have Type O blood? Explain.
_____________________________________________________________
_____________________________________________________________
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V. Pedigrees
 A ____________________________ is a “family tree” that tracks which family members have a trait.
= Female
= Female with trait
= Male
= Male with trait
Married with
two children
= Carrier of trait
Example. The Simpsons family consists of the father named Homer, the mother named Marge, and their three
children named Bart, Lisa, and Maggie. Their family pedigree would look like this…
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VI.
HOW DO I MAKE PROTEINS USING DNA/RNA?
BASIC STEPS TO MAKING PROTEINS
1) DNA is found inside the Nucleus of our cells.
2) DNA makes a single stranded copy of itself.
This is called RNA.
3) RNA is similar to DNA, containing 4 base
pairs, with one different letter (U instead of
T)
4) This RNA moves out of the nucleus (called
messenger RNA or mRNA)
5) mRNA travels to the RIBOSOMES (an
organelle in the cell that makes proteins)
6) The RIBOSOMES read the recipe that mRNA
is carrying.
7) The recipe has the information to bring in
specific AMINO ACIDS to build the needed
protein.
8) When the RIBOSOME reads “stop” on the
recipe (mRNA). The amino acids fold
together to make the protein. The protein
moves to the needed area in the body.
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VII. HOW DO CELLS, MAKE MORE CELLS?
MITOSIS
Cell division of BODY cells; Resulting in IDENTICAL cells.
(example: skin cells reproduce and make a new skin cells, just
as stomach cells make more stomach cells)
5 stages of Mitosis (IPMAT)
1) Interphase – resting phase of the cell
2) Prophase – DNA makes a copy of itself (now
forms the “X” shaped chromosome
3) Metaphase – Chromosomes line up in the center
4) Anaphase – Chromatids (half of the
chromosome) separate and move to opposite
ends of cell.
5) Telophase – Nucleus reappears and cell begins
to divide. Once division is complete cell enters
Interphase again.
HOW MANY CHROMOSOMES ARE FOUND IN EACH
NEW CELL? ______________________
MEIOSIS
Cell division of SEX cells; sperm and egg cells.
Similar steps as in Mitosis, however, the end result is each
cell has ______________ CHROMOSOMES.
Why do these cells (Sperm and Egg) have half the number
of chromosomes as BODY cells?
______________________________________________
______________________________________________
______________________________________________
What does the 23rd pair of Chromosomes determine?
____________________________________________
What letters do we use to determine
A boy: ________________ A girl: _____________
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VIII. DISEASES AND BIOTECHNOLOGY

Check your handouts for information on:
o Genetic Diseases
o Human Genome Project
o Cloning, Genetic Engineering, and Selective Breeding
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