Transcript Genetics SHOW

BUILDING BLOCKS….
A CELL is the building block of all living things!
/
CELL THEORY:
* All living things are made of cells
Hooke
* Cells are the basic units of structure and
function of an organisms
*Living cells come from other living cells
Schleiden
Schwann
Virchow
Some organisms are only 1 (one) cell big or UNICELLULAR!
Some organisms have many cells or are MULTICELLULAR!
•DNA is a long - Double helix
strand which stores our
genetic code
• There are 4 base pairs
•A – T
•C - G
DNA, DNA….where are you?
I’m inside the
NUCLEUS OF THE
CELL!
What is a Gene?
Genes are made up of
DNA
Genes are
instruction manuals
for our bodies.
Base pairs = Letters
Genes = Words
DNA = Book
Different organisms have different #’s of chromosomes
Humans
have
46
THESE CELLS ONLY HAVE 23 CHROMOSOMES.
SPERM
WHY? (Answer on your notes)
EGG
Karyotype
2 of those 46 chromosomes
determine whether you are a
male or a female.
They are called sex
chromosomes
(represented by X and Y).
XX
XY
= female
= male
The cell drawing
New terms to study
• New terms:
– Unicellular
– Multicellular
– Chromosomes
– Body cell – 46 chromosomes
– Sex cells – 23 chromosomes
– Cell membrane
– Nuclear membrane
– Nucleus
Gregor Mendel – Father of
Genetics
GREGOR MENDEL
FATHER OF GENETICS
•Worked as a MONK and loves Pea
plants
•Observable TRAITS
•Tall pea plant with a short pea plant I
got all TALL pea plants
Example:
We have two (1 from mom and 1 from dad) alleles for
each gene.
1 2
1 2
1 2
HH
Hh
hH
1 2
hh
1 2
1 2
1 2
HH
Hh
hH
Homozygous or “true” means two of the same alleles.
 HH
….. Straight
 hh
….. Hitchhikers
Heterozygous or “hybrid means two different alleles.
Ex.
Hh
1 2
hh
Heterozygous or
Homozygous?
B
b
aa
zZ
Zz
QQ
C
c
R
R
What will Hh look like?
There are dominant and recessive alleles
Dominant alleles
capitol
T
letter
= tall plant
Recessive alleles
lowercase
t
letter
= short plant
The “stronger” dominant allele masks the “weaker” recessive allele.
Results
HH =
(the dominant allele will be shown)
Hh =
(the dominant H allele masks the recessive h allele)
hh =
(the recessive alleles can come through
WRITE THESE DEFINITIONS ON THE
BOTTOM OF YOUR NOTE SHEET
The physical appearance of the organism is called the
Phenotype
.
The genetic makeup of an organism is called the
Genotype
Hh
.
The Claw gene (C)
Meet Mama and Papa Bear
Mama
Mama bear is
homozygous dominant
for the claw gene.
Genotype: CC
Phenotype: has claws
Papa bear is
homozygous recessive
for the claw gene.
Genotype: cc
Phenotype: no claws
Papa
CC
cc
Step
Two:
Step
Three:
CCc
c
C
c
C
c
C
C
c
c
C
c
Meet Baby
bear! : has
Phenotype
claws
Fur Color (B)
A male rat has a dominant gene for fur color,
which is brown. (We will show the homozygous
dominant gene as BB.) A female rat has the
homozygous recessive gene for fur color, which is
gray. (we will show this heterozygous recessive
gene by the letters bb.) What will the genotype of
the offspring look like?
Hitchhikers
Thumb(H)
Mom has
Straight Thumb
(Tt)
Dad has
Hitchhikers Thumb
(tt)
Pea Pod Color (Y)
Oh good.
Peas!
Green Pod color
(Yy)
Yellow Pod color
(Yy)
Earlobes (E)
Mom is
Heterozygous
with Free earlobes
Dad is
Homozygous
Recessive
with attached
earlobes
Pea Plant Height (T)
In pea plants, tall pea plants (T) are dominant
over short pea plants (t). Construct a Punnett
Square for a
heterozygous tall pea plant and a short pea plant.
T
t
t
Tt
tt
t
Tt
tt
What are the
percentage of
phenotypes?
50% tall
50% short
A _____Pedigree______ is a “family tree” that
tracks which family members have a trait.
We use the following symbols to represent
family members on pedigrees
Homer
Marge
Bart
Lisa
Maggie
Let’s
We fill
designed
in the family
a pedigree
members
for the
affected
Simpsons
with
investigating
the long
the trait
eyelash
of long
gene.
eyelashes.
Long eyelashes (E) are dominant to short
(E)- Long eyelashes
eyelashes(e)(e).short eyelashes
Marge has long
eyelashes
(EE)
Homer does not
(ee)
Marge
Bart
WhatifififMaggie
Maggie and
What
What
Maggie’s
first
herto
husband
had
were
child
got
getmarried?
three kids?
married?
Homer
Lisa
Maggie
Trait (R)
Mother is
_____________
Father is
_____________
Son is
_____________
Daughter is _____________
Trait (H)
Mother is
_____________
Father is
_____________
Son is
_____________
Daughter is _____________
1
10
12
14
DNA vs. RNA
DNA:
• Double helix
•Stays in/found in
Nucleus
•Genetic information to
make you
RNA:
• Single stranded
•Moves out of nucleus
•Carries the recipe
(information) to make
proteins
BOTH:
• Made up of 4 bases
•Contain genetic information
•Nucleic Acids
BASIC STEPS TO MAKING PROTEIN
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.
Mitosis – I P on a MAT
5 stages:
1) Interphase – resting phase
2) Prophase – DNA makes a copy
3) Metaphase – Chromosomes
line up in center
4) Anaphase – Chromatids
separate and move to opposite ends
of cell
5) Telophase – Nucleus
reappears and cell begins to divide.
How many chromosomes are found in each new cell?
MEIOSIS
– division of sperm and egg cells
Similar steps as in Mitosis,
however, the end result is
each cell has 23
Chromosomes.
•Why do these cells have half
the number of chromosomes as
body cells?
•23 +23 = 46
•What does the 23rd pair of
chromosomes determine?
•gender
•A boy – XY A girl - XX
An ALLELE is a version of a gene.
We give each gene a letter …
either lowercase or capitol
Example:
Gene controlling thumb shape = the letter H
Straight Thumb allele =
H
Hitchhicker’s Thumb allele=
.
h
.
1.
R
R
W
RW
RW
W
RW
RW
2.
A
O
B
AB
BO
O
AO
OO