do now complete the worksheet upfront “hardest multiple choice questions”
TRANSCRIPT
Do NowComplete the worksheet upfront “Hardest Multiple Choice Questions”
DNA__RNA___Protein_Synthesis_sc(3).pdf
Do Now - Genetics & HeredityWhat we know (page 5 at top)
Try and fill in the blanks to see how much you know
Do Now - Genetics & HeredityWhat we know:
DNA is in nucleus and codes for all proteins Each strand of DNA is condensed into a structure called a chromosome Each chromosome has many (thousands) of genes on them Each gene tells the ribosome how to make one specific protein (trait) The instructions for one gene are copied off the DNA strand and brought
to the ribosome by mRNA (mRNA codes for specific sequence of amino acids)
Genes are made differently because they have a different sequence of bases and different lengths
Bases for insulin = A T T A G T C G T A C G Bases for tallness = T A A G C G T G A G T C G G T A T G C
Every cell in your body has the same exact DNA, but uses different genes!! Different cells use different parts of the DNA!!
Genetics Traits – characteristics that can be passed from parents to their
offspring Examples:
FrecklesHaircolorEyecolor Height
Genes – small piece of DNA that holds the instructions to make proteins that make your haircolor, eyecolor, freckles and height.
What are Genes?Are all genes the same? .
Alleles – different forms of a gene that express a gene differently (green, blue, brown)
For example: Everyone has the gene for eye pigment
(color), but we all don’t have the same color eyes.
Therefore, everyone has the gene but they have different variations of the gene… (Blue, green and brown)
Does every eye color gene code for green eyes? ……
NO
NO
There are different forms of genes and therefore different traits (eye colors)!
What are Genes?Are all genes the same? .
Alleles – different forms of a gene that express a gene differently (green, blue, brown)
For example: Everyone has the gene for eye pigment
(color), but we all don’t have the same color eyes.
Therefore, everyone has the gene but they have different variations of the gene… (Blue, green and brown)
Does every eye color gene code for green eyes? ……
NO
NO
There are different forms of genes and therefore different traits (eye colors)!
Alleles Humans have 46 chromosomes (23 pairs) Chromosome 3 might have the gene that
codes for height– There are 2 single-stranded chromosomes– One comes from your mother and one from your
father – Each chromosome in a pair codes for the same
genes (homologous chromosomes), but the genes might be different.
– Variations in genes are called alleles
– So you have two genes inside you right now that code for the same protein!
T t
T t
So, which allele do we see?
Law of DominanceOne allele will be dominant and one allele will be recessive Dominant (uppercase letter)
Recessive (lowercase letter)
The allele that is physically expressed when there are two different alleles
The allele that is hidden when there are two different alleles.
This allele (version of a gene) is only carried, not expressed.
Example of Dominant & RecessiveSay you have an allele (r) that codes for red hair and an allele (R) that codes for black hair.
Your genotype would be Rr… Genotype – what your DNA codes for Phenotype – what trait is shown or expressed
1. What color hair would you have and why?
Rr
Can a recessive allele ever be physically expressed?
Yes, there are people with blue eyes, that are left-handed, have attached ear lobes that have red hair
When the genotype has two recessive red hair alleles, rr (genotype), then red hair is expressed (phenotype)
Homozygous –
Heterozygous –
When two different versions of a gene present
Example – R r
When both alleles are the SAME version Example – R R or r r
Where does our unique combination of alleles come from?
• They are inherited (come from our parents)
Do Now page 3 & 4
Questions #2, 7, 8, 9, 12, 13 ….packet from friday
Heridity___Genetic_Technology_sc.pdf
Where does our unique combination of alleles come from?
• They are inherited (come from our parents)
Most traits are determined by more than one gene, but there are a number of traits that are determined by only ONE gene. Such as:
1. Right (R) or left (r) handed
2. Free earlobes (F) or attached earlobes (f)
3. Left thumb on top (C) or right thumb on top (c)
4. Hitchhiker's thumb (h) or normal thumb (H)
Determining Possible GenotypesHitchhiker's thumb (h) or normal thumb (H)1. Using the key above, if you do not have a hitchhiker’s thumb,
what could your genotype be? Why?
2. Using the key above, if you have a hitchhiker's thumb, what MUST your genotype be? WHY?
h h • Lower-case letters are recessive
alleles• Recessive alleles are only expressed
when the genotype is homozygous recessive (hh)
H h or H H• Need one dominant allele to express a dominant trait!
Sex Chromosomes are also inherited Sex chromosomes – chromosomes that control sex characteristics • Females have two X chromosomes (XX)• Males have one X and one Y chromosome (XY)Autosomes - All non-sex chromosomes (the rest)
Label which set of DNA is a male and which is a females and circle the difference between the sets of DNA
Punnett squares: A Punnett square predicts the results of a
genetic cross between two individuals of a known genotype.
Cross a heterozygous brown eye male with a heterozygous brown eye female (Bb)
Cross a heterozygous brown eye male (Bb) with a Homozygous Blue eye female (bb)1. Chances of having a blue eyed
baby?
2. Chances of having a brown eyed baby?
1. Chances of having a blue eyed baby
2. Chances of having a brown eyed baby?
T t
T t
Do Now: Punnett Squares
The X and Y Punnett square has different letters? Why? They represent sex chromosomes! Males will always be XY
and females will always be XX.
T t
T t
Do Now 2: What are the chances
1. Jack and Jill want to make a baby. They want to know the chances of that baby being a male or female.
What are the chances of them making a:Female baby? _______Male baby? _______
Male’s alleles
Fem
ale’
s alle
les
What are the chances2. Bob and Mandy want to make a baby. They want to know the chances of that baby having attached ear lobes. Bob has attached ear lobs and Mandy does not. Mandy’s genotype is Ee and Bob’s genotype is ee.
What is the dominant trait?What are the chances of them making a:Attached ear baby? _______Detached ear baby? _______
Male’s alleles
Female’s alleles
E e
What are the chances3. Xavier and Mandy want to know if their baby will have sickle-cell anemia. Xavier has does not have sickle-cell anemia but Mandy has sickle-cell anemia. Mandy’s genotype is aa and Xavier’s genotype is Aa.
What is the dominant trait?What are the chances of them making an:Anemic baby? _______Non-anemic baby? _______
Male’s alleles
Female’s alleles
The transmission of traits from one generation to another in humans cannot be studied in the same way it is in plants and other organisms (ex: bacteria) due to:1. The long time between generations 2. The number of offspring produced is too small 3. No controlled experiments are possible
Pedigree Charts!! Shows the presence of absence of a particular trait in each
member of each generation
How are genetic traits traced through families
Pedigree ContinuedThis pedigree chart shows the inheritance of handedness in a family over 3 generations. The gene for right-handedness (R) is dominant over the gene for left-handedness (r).
1. For which individual is Rr the most probably genotype?
2. Give two individuals have identical genotypes for handedness?
What does this Pedigree show?
1. What are the genotypes of the male and female in row #1? Male __________ Female _________
2. In row 2, which person (W, X, Y, Z) is the only person carrying the sickle cell allele?
3. In row 3 there is an affected female! What must the genotypes
be for the parents (w and x)?
Gene Expression and Environment Environment factors can switch some genes on and off
Example: The Himalayan rabbit has white fur over its entire body, except in areas below 33oC the fur will turn black.
The white pigment gene is non-functional below 33⁰C. The black pigment gene will then be switched on.
Cell differentiationAll the cells in our body have the same DNA. Why are cells different from each other?
Cell differentiation – cells carry out different functions by using different genes in the DNA
Nerve cells might use the part of DNA that codes for neurotransmitters and muscle cells will use the part of DNA that codes for Myosin fibers for muscle growth
1. Take seats according to the seating chart
Dezmon R.
Brian E. Samanth
a Joshua S.
Chavonne T. Ariel C. Justin C. Anthony L .Jaylin J Ceniya N. Franlis P.
Rosa Hannah J James J. Alaiyo J Travis L OrianaMadelin
O.Roley
Kristie C.
Diego C. Melissa G.
Justin L. Misael S Shakeva J Braylin M.Elaine
Jordan D.
DOOR MR. B’s DESK WINDOWS
Where do our genes come from to make us??
• Sperm carry HALF the fathers DNA and the egg carries HALF the mothers DNA.
• Both come together to make one cell that contains both mom and dads’ DNA called a zygote
• That zygote will divide by mitosis creating genetically identical cells that carry out different functions!
• The DNA for EVERY cell in your body comes from your original 1 cell zygote (½ from mom and ½ from dad)
T tr R
Tr R
t
T t
Rr
Chromosomes Sex Determination– Scientists observed that chromosomes of males and
females were identical except for one pair. This pair of chromosomes are known as sex chromosomes
– All other chromosomes are called autosomes