Transcript Document

6 January 2015
Trait
Cross (two traits)
Purebred
Genes
Alleles
Genetics
Law of Segregation
Law of Independent Assortment
Punnett Square
Homozygous
Heterozygous
Dominant
Recessive
Genotype
Phenotype
Do study guide pages 57, 1 – 6.
7 January 2015
Trait
Cross (two traits)
Purebred
Genes
Alleles
Genetics
Law of Segregation
Law of Independent Assortment
Punnett Square
Homozygous
Heterozygous
Dominant
Recessive
Genotype
Phenotype
Do study guide pages 57, 1 – 6.
Mendel laid the groundwork for genetics.
Traits are distinguishing
characteristics that are
inherited.
Genetics is the study of
biological inheritance
patterns and variation.
Gregor Mendel showed that
traits are inherited as discrete
units.
Many in Mendel’s day
thought traits were blended.
Mendel’s data revealed patterns of inheritance.
 Mendel made three key decisions in his experiments.
 use of purebred plants
 control over breeding
 observation of seven
“either-or” traits
Seven traits were observed in Mendel’s peas.
• Mendel used pollen to fertilize selected pea plants.
– A cross is the mating of two organisms.
– P (parental) generation crossed to produce F1
generation (first generation of offspring)
– Interrupted the self-pollination process by removing male
flower parts
Mendel controlled the
fertilization of his pea plants
by removing the male parts,
or stamens.
He then fertilized the female
part, or pistil, with pollen from
a different pea plant.
• Mendel allowed the resulting plants to self-pollinate.
– Among the F1 generation, all plants had purple flowers
– F1 plants are all heterozygous
– Among the F2 generation (second generation of
offspring), some plants had purple flowers and some
had white
• Mendel observed patterns in the first and second
generations of his crosses.
• For all seven traits, Mendel found that ¾ of the F2 offspring
had one trait and ¼ had the other trait.
• Mendel drew three important conclusions.
– Traits are inherited as discrete units.
– The last two conclusions are
called the law of segregation.
– Organisms inherit two copies of each gene, one from
each parent.
– The two copies segregate
during gamete formation.
purple
white
Punnett squares illustrate genetic crosses.
 The Punnett square is a grid system for predicting all possible genotypes
resulting from a cross.
 The axes represent
the possible gametes
of each parent.
 The boxes show the
possible genotypes
of the offspring.
• The Punnett square
yields the ratio of
possible genotypes and
phenotypes.
If you cross a tall plant (TT) with a short plant (tt) what
will be the potential ratio of offspring?
If you cross a tall plant (T ?) with a short plant (tt) what
will be the potential ratio of offspring?
T
t
t
Tt
tt
t
Tt
tt
Sex linked trait
Hitchhiker's thumb (H) is dominant to no hitchhiker's thumb (h). A
woman who does not have hitchhiker's thumb marries a man who is
heterozygous for hitchhiker's thumb. What is the probable genotypic
ratio of their children?
A. 0% Hh: 100% hh
B. 50% Hh: 50% hh
C. 75% Hh: 25% hh
D. 100% Hh: 0% hh
H
h
h
Hh
hh
h
Hh
hh
Hitchhiker's thumb (H) is dominant to no hitchhiker's thumb (h). A
woman who does not have hitchhiker's thumb marries a man who is
heterozygous for hitchhiker's thumb. What is the probable genotypic
ratio of their children?
A. 0% Hh: 100% hh
B. 50% Hh: 50% hh
C. 75% Hh: 25% hh
D. 100% Hh: 0% hh
H
h
h
Hh
hh
h
Hh
hh
One of the parents of a child has phenylketonuria (PKU), which
is caused by recessive alleles. The other parent does not have the
PKU alleles. What is the chance that the couple will have a child
with phenylketonuria?
A. 0%
B. 50%
C. 75%
D. 100%
a
a
A
Aa
Aa
A
Aa
Aa
One of the parents of a child has phenylketonuria (PKU), which
is caused by recessive alleles. The other parent does not have the
PKU alleles. What is the chance that the couple will have a child
with phenylketonuria?
A. 0%
B. 50%
C. 75%
D. 100%
a
a
A
Aa
Aa
A
Aa
Aa
Work on pages 58 & 59 in
your Study Guide
Pg 58 – 8 & 9
Pg 59 – all
8 January 2015
Define what Pedigrees are – Chapter 7.4
https://www.youtube.com/watch?v=qY0ixUWJx0g
Hemophilia is a sex-linked, recessive trait. What is the chance
for a man and woman to have a child with hemophilia? The
man and woman do not have hemophilia, but the woman’s father
was a hemophiliac.
Hemophilia is a condition where males do not have a corresponding
allele on their Y chromosome.
H
X
h
X
XH XH XH XH Xh
Y
H
X Y
Xh Y
Pedigree
XH
Xh
X H Xh
XH
XH XH
Y
XH Y
XH Xh
Xh Y
Married
in 1840
Born
in 1889
XH Y
For Question 5 & 6:
A green-leafed plant is crossed with one with yellow-striped
leaves. The cross ONLY produces 185 green-leafed plants.
5) What are the genotypes of both parents?
6) Summarize the genotypes & phenotypes of the offspring
that would be produced by crossing green-leafed plants
obtained by the initial cross (F1 generation).
I will collect the paper for a grade tomorrow.
9 January
DNA
Nucleotide
Double Helix
Base Paring Rules
RNA
Messenger RNA (mRNA)
Ribosomal RNA (rRNA)
Transfer RNA (tRNA)
Replication
Transcription
Translation
Codon
Anticodon
Genotype
Phenotype
10 January
DNA
Nucleotide
Double Helix
Base Paring Rules
RNA
Messenger RNA (mRNA)
Ribosomal RNA (rRNA)
Transfer RNA (tRNA)
Replication
Transcription
Translation
Codon
Anticodon
Genotype
Phenotype
Reviewed board notes – Homework was a DNA package, due on 12 Jan.
12 January
Review of the steps of DNA replication:
1) DNA is unwound by an enzyme.
2) The unpaired strand has nucleotides exposed, which are
matched to “complementary” bases (A – T & C – G).
3) Enzymes attach the complementary nucleotides to each
other and to the other strand of DNA.
4) The entire DNA molecule is eventually replicated and
the two strands are separated from each other during
mitosis and meiosis.
http://www.pbs.org/wgbh/nova/body/cracking-the-codeof-life.html Cracking the Code of Life
13 January
Do you remember the steps of DNA replication discussed
yesterday?
Write down in your notebook what you remember.
Review of the steps of DNA replication:
1) DNA is unwound by an enzyme.
2) The unpaired strand has nucleotides exposed, which are
matched to “complementary” bases (A – T & C – G).
3) Enzymes attach the complementary nucleotides to each
other and to the other strand of DNA.
4) The entire DNA molecule is eventually replicated and
the two strands are separated from each other during
mitosis and meiosis.
13 January
Review of the steps of DNA replication:
1) DNA is unwound by an enzyme
called Helicase
2) A small piece of RNA is added to the DNA, then
3) The unpaired strand has nucleotides exposed. Nucleotide bases are matched to
by the enzyme called DNA
Polymerase which adds complementary nucleotides
“complementary” bases (A – T & C – G)
4) Enzymes attach (ligate) the complementary nucleotides to each other and to the other
strand of DNA and
is created in the 5’ to 3’ direction
5) The entire DNA molecule is eventually replicated and the two strands are separated from
each other during mitosis and meiosis.
This type of replication is called “Semi-Conservative”
Replication –
https://www.youtube.com/watch?v=7AnyWrHYBOE
DNA structure is the same in ALL organisms
15 January
Study Guide Questions:
Pg. 75, #s – all
Pg. 76, #s – all
Pg. 77, #s – all
Pg. 78, #s – 14, 15 & 17
Pg. 79, #s – all
Which of the following statements is exactly correct?
1) A DNA sequence is read by an RNA polymerase, which produces
another RNA strand that is complementary to the first strand.
2) Two exposed strands of DNA are base paired to create two antiparallel strands of RNA.
3) Messenger DNA molecules are build from complementary base
pairs after the helicase unwinds the DNA and DNA polymerase
attaches nucleotides to form two new messenger DNA strands.
4) DNA is unwound by topoisomerase and hydrogen bonds broken by
helicase, which allows complementary base pairs to attach to form two
new strands that are anti-parallel strands.
5) DNA is unwound by polymerase and the A, T, G, & Cs are attached
to their complementary molecule, forming two new parallel,
conservative strands of DNA.
DNA is composed of four types of nucleotides.
 DNA is made up of a long chain of nucleotides.
 Each nucleotide has three parts.
 a phosphate group
 a deoxyribose sugar
 a nitrogen-containing base
phosphate group
deoxyribose (sugar)
nitrogen-containing
base
• The nitrogen containing bases are the only difference in
the four nucleotides.
Watson and Crick determined the three-dimensional
structure of DNA by building models.
 They realized that DNA is a double
helix that is made up of a sugarphosphate backbone on the outside
with bases on the inside.
• Watson and Crick’s discovery built on the work of Rosalind
Franklin and Erwin Chargaff.
– Franklin’s x-ray images suggested that DNA was a
double helix of even width.
– Chargaff’s rules stated that A=T and C=G.
• The backbone is connected by covalent bonds.
• The bases are connected by hydrogen bonds.
hydrogen bond
covalent bond
Nucleotides always pair in the same way.
 The base-pairing rules show how nucleotides
always pair up in DNA.
– A pairs with T
– C pairs with G
• Because a single ring sugar
pairs with a double ring
sugar, the helix has a
uniform width.
Nucleotide bases
http://www.youtube.com/watch?v=NNASR
kIU5Fw
G
A
C
T
DNA is converted to a protein. Transcription (making mRNA) then
translation (making an amino acid chain which will become a protein)
https://www.youtube.com/watch?v=NJxobgkPEAo
 DNA serves only as a template.
 Enzymes and other proteins do the actual work of
replication.
Enzymes unzip the double helix.
Nucleotides pair with the exposed bases on the template
strand via hydrogen bonds.
nucleotide
The DNA molecule unzips
in both directions.
– DNA polymerase enzymes bond the new nucleotides
together to form the double helix.
– Polymerase enzymes form covalent bonds between
nucleotides in the new strand.
new strand
nucleotide
DNA polymerase
• Two new molecules of DNA are formed, each with an
original strand and a newly formed strand.
• DNA replication is semiconservative.
original strand
Two molecules of DNA
new strand
Replication –
http://www.youtube.com/watch?v=4jtmOZaIvS0&safe=active
Do page 77 & 78 in your Study Guide
16 January
Gene Expression: how the genes in DNA are turned into proteins.
Define the following terms:
RNA
Messenger RNA (mRNA)
Ribosomal RNA (rRNA)
Transfer RNA (tRNA)
Study Guide Questions:
Transcription
Translation
Codon
Anticodon
Pg. 75, #s – all
Pg. 76, #s – all
Pg. 77, #s – all
Pg. 78, #s – 14, 15 & 17
Pg. 79, #s – all
RNA carries DNA’s instructions.
 The central dogma states that
information flows in one
direction from DNA to RNA
to proteins.
DNA is converted to a protein. Transcription (making mRNA) then
translation (making an amino acid chain which will become a protein)
 DNA serves only as a template.
 Enzymes and other proteins do the actual work of
replication.
Enzymes unzip the double helix.
Nucleotides pair with the exposed bases on the template
strand via hydrogen bonds and the mRNA molecule
grows from the 5’ end, adding nucleotides to the 3’ end.
– RNA polymerase enzymes bond the new nucleotides
together to form the mRNA molecule.
– Polymerase enzymes form covalent bonds between
nucleotides in the new strand.
• RNA differs from DNA in three major ways.
– RNA has a ribose sugar.
– RNA has uracil instead of thymine.
– RNA is a single-stranded structure.
• Transcription is catalyzed by RNA polymerase.
– RNA polymerase and other proteins form a
transcription complex.
– The transcription complex recognizes the start of
a gene and unwinds a segment of it.
transcription complex
start site
nucleotides
– RNA polymerase reads one side of the DNA template
and strings together a complementary strand of RNA
nucleotides.
– The DNA helix winds again as the gene is transcribed.
DNA
RNA polymerase
moves along the DNA
– The RNA strand detaches from the DNA once the gene
is transcribed.
RNA
one
gene
growing RNA strands
DNA
Transcription –
https://www.youtube.com/watch?v=WsofH466lqk
Translation –
https://www.youtube.com/watch?v=5bLEDd-PSTQ
Codon – A sequence of three non-overlapping
nucleotides that code for a specific amino acid.
Anticodon – Nucleotides on the tRNA molecule that
help the molecule match up with the correct codon.
- complementary pairing.
21 January
Lab 9
DNA Extraction
1) Make an extraction buffer, 10 ml of soap, 2 g of
salt, and 50 ml of water in a 250 ml beaker
1) Place 40 ml of puree into the extraction buffer
and stir for 5 minutes
3) Use a paper towel to filter the solution into a
small beaker, you need at least 10 ml.
4) Place filtrate into a test tube and add 10 ml of
alcohol and look for the accumulation of DNA
22 January
Qualitative ranking for DNA extraction
Solution
Tomato
Milk
Raspberry
Blueberry
Banana
Yogurt
2nd
5
4
1
6
2
3
3rd
5
4
1
6
3
2
5th
4
3
1
6
5
2
6th
4
5
1
6
3
2
7th
2
4
5
6
1
3
27 January
Review Study Guide Questions: Pgs. 85 & 86 (8.7)
Define the following:
Reading Frame –
Mutation –
Amino acids are coded by mRNA base sequences.
First, let’s Review
 Translation converts mRNA messages into polypeptides.
 A codon is a sequence of three nucleotides that codes for an amino acid.
codon for
methionine (Met)
codon for
leucine (Leu)
• Reading frame: series of non-overlapping nucleotides
read in order.
• A change in the order in which codons are read changes
the resulting protein.
• Reading frame: series of non-overlapping nucleotides
read in order.
• A change in the order in which codons are read changes
the resulting protein.
• Regardless of the organism, codons code for the same
amino acid (common language).
Mutations are changes in DNA that may or may not
affect phenotype.
Some mutations affect a single gene, while others
affect an entire chromosome.
 A mutation is a change in an organism’s DNA.
 Many kinds of mutations can occur, especially during
replication.
 A point mutation substitutes one nucleotide for another.
Mutated base
• Many kinds of mutations can occur, especially during
replication.
– A FRAME SHIFT MUTATION inserts or deletes a
nucleotide in the DNA sequence.
In your textbook, answer questions
1 – 6 on page 261 and question 22 on
page 259 and question 23 on page 260
29 January
Define:
Law of Segregation
Independent Assortment
Law of Segregation (Mendel’s first law) . The principle
that states, during the production of gametes, the two
copies of each hereditary factor (allele) segregate so that
offspring acquire one factor from each parent.
One Trait
Law of Independent Assortment (Mendel’s Second Law) .
This states that separate genes, for separate traits, are passed
independently of one another from parents to offspring.
Two Traits
A pea plant is heterozygous for both seed shape and
seed color. R is the allele for the dominant, round shape
characteristic; r is the allele for the recessive, wrinkled
shape characteristic. Y is the allele for the dominant,
yellow color characteristic; y is the allele for the
recessive, green color characteristic.
What will be the probability distribution of these two
alleles in this plant's gametes if we cross the following?
Cross two round and yellow plants with the following
features: RrYy x RrYy
If you cross a BbDd female cat with a BbDd male
where the relationship between allele and phenotype is:
BB = black, Bb = Black, bb = brown
DD = pointy ears, Dd = pointy ears, dd = round ears,
What will the phenotypic ratio will be:
A) 3:3:1:3
B) 5:5:5:1
C) 7:4:3:2
D) 9:3:3:1
Do pages 67 & 68 in your study guide
(chapter 7.2)
Incomplete dominance (mixing traits)
Codominance (blood types)
30 January
•
Multiple Alleles & Codominance
•
Incomplete Dominance
Do pages 67 & 68 in your study guide (chapter 7.2)
Incomplete dominance (mixing traits)
Codominance (blood types)
Multiple Alleles & Codominance
This is when there are 4 or more possible phenotypes for
a particular trait in the population. This is called
"MULTIPLE ALLELES".
*** There may be multiple alleles within the population,
but individuals have only two of those alleles.
ALLELE
IA
IB
i
CODES FOR
Type "A" Blood
Type "B" Blood
Type "O" Blood
1) A woman with Type O blood and a man who is
Type AB have are expecting a child. What are the
possible blood types of the kid?
2) What are the possible blood types of a child who's
parents are both heterozygous for "B" blood type?
3) A test was done to determine the biological father
of a child. The child's blood Type is A and the
mother's is B. Boyfriend #1 has a blood type of O,
& boyfriend #2 has blood type AB. Which man is
the biological father of this child?
Incomplete dominance
A cross between a red bird (RR) & a white (WW) bird produces
offspring that are pink (RW). The color of the birds is determined by
just two alleles.
4) What are the genotypes of the parent birds in the original cross?
RR x WW
5) What is/are the genotype(s) of the parents offspring?
6) What would be the phenotypic ratios of offspring produced by two
pink birds?
3 February
Sex-linked baldness
Simple dominant/recessive
traits. Freckles FF, Ff, ff
XHXh
XhY
Ff
Ff
XhY
ff
Male
Mother
Father
F
f
F
FF
Ff
f
Ff
ff
Female
Male affected
Female affected
Writing prompt
DNA molecules can be tens of thousands of base pairs in
length. Mistakes in DNA replication lead to mutations,
which may or may not be harmful to an organism.
Considering the structure and enzymes present, how
does semi-conservative replication help prevent mutations
during DNA replication?
DNA
Replication
Protein synthesis
Using mRNA, tRNA, and rRNA
4 February
Replication, Transcription and Translation
a.k.a. The Central Dogma
Feature to limit mutation during DNA replication
•
Semi-conservative replication is where one side of the DNA
is used as a template for the construction new strand of DNA.
•
Complementary base paring. Due to one purine bonding
with one pyrimidine.
•
DNA polymerase attaches the correct bases one at a time
to the template ( old strand).
•
To further guard against mutations, DNA polymerase acts as
a proof reading enzyme to fix misplaced bases.
RNA carries DNA’s instructions.
 The central dogma states that
information flows in one
direction from DNA to RNA
to proteins.
Replication –
https://www.youtube.com/watch?v=7AnyWrHYBOE
• Transcription is catalyzed by RNA polymerase.
– RNA polymerase and other proteins form a
transcription complex.
– The transcription complex recognizes the start of
a gene and unwinds a segment of it.
transcription complex
start site
nucleotides
– RNA polymerase reads one side of the DNA template
and strings together a complementary strand of RNA
nucleotides.
– The DNA helix winds again as the gene is transcribed.
DNA
– The RNA strand detaches from the DNA once the gene
is transcribed.
RNA
• Translation is the event where mRNA joins with a ribosome (two
rRNA subuntis) that works with tRNA to place amino acids in the
correct order to form a specific protein, based on the nucleotide
sequence in the DNA.
• For translation to begin, tRNA binds to a start codon and signals
the ribosome to assemble.
– A complementary tRNA molecule binds to the exposed codon,
bringing its amino acid close to the first amino acid.
Amino acids are linked to become a protein.
 An anticodon is a set of three nucleotides that is complementary to an mRNA codon.
 An anticodon is carried by a tRNA.
Mutations may or may not affect phenotype.
 Chromosomal mutations tend to have a big effect.
 Some gene mutations change phenotype.
 A mutation may cause a premature stop codon.
 A mutation may change protein shape or the active site.
 A mutation may change gene regulation.
blockage
no blockage
• Reading frame: series of non-overlapping nucleotides
read in order.
• A change in the order in which codons are read changes
the resulting protein.
• Reading frame: series of non-overlapping nucleotides
read in order.
• A change in the order in which codons are read changes
the resulting protein.
• Regardless of the organism, codons code for the same
amino acid (common language).
Important
• Mutations in body cells do not affect offspring.
• Mutations in sex cells can be harmful or beneficial to
offspring.
• Natural selection often removes mutant alleles from a
population when they are less adaptive.
Mutations can be caused by several factors.
 Replication errors can cause
mutations.
 Mutagens, such as UV ray and
chemicals, can cause mutations.
 Some cancer drugs use mutagenic
properties to kill cancer cells.
Hemophilia is a condition where males do not have a corresponding
allele on their Y chromosome.
H
X
h
X
XH XH XH XH Xh
Y
H
X Y
Xh Y
XH
Xh
X H Xh
XH
XH XH
Y
XH Y
XH Xh
Xh Y
Married
in 1840
Born
in 1889
XH Y
Co-Dominance
Incomplete
Dominance
A dihybrid cross involves two traits.
Mendel’s dihybrid crosses with heterozygous plants
yielded a
9:3:3:1 phenotypic ratio.
• Mendel’s dihybrid crosses
led to his second law,
the law of independent
assortment.
• The law of independent
assortment states that
allele pairs separate
independently of each
other during meiosis.
Prokaryotic cells turn genes on and off by controlling
transcription.
 A promotor is a DNA segment that allows a gene to be transcribed.
 An operator is a part of DNA that turns a gene “on” or ”off.”
 An operon includes a promoter, an operator, and one or more structural genes that code
for all the proteins needed to do a job.
 Operons are most common in prokaryotes.
 The lac operon was one of the first examples of gene regulation to be discovered.
 The lac operon has three genes that code for enzymes that break down lactose.
Students will:
Chapter 8
• Explain why the genetic code is common to all organisms
• Explain why there are similarities in the genetic code of different animals
• Describe the basic process of replication
• Demonstrate the process of DNA replication given a strand of DNA
• Be able to predict changes in amino acid sequence due to the different types of mutations
• Explain how mutations in gametes may result in phenotypic changes in offspring
• Describe the basic processes of transcription and translation
Which of the following statements is true about DNA?
A. It is made up of twenty different nucleotides
B. It is a helix made up of two complementary strands
C. The sugar-phosphate backbone stores the genetic message
D. The nucleotides must fall apart for replication to occur
Genes are segments of DNA that code for polypeptides, or proteins. The order of amino
acids in the polypeptide chain is determined by…
A. The order of nucleotides in the ribosome
B. The relative abundance of different types of RNA
C. The order of nucleotides in the gene
D. The relative abundance of different types of amino acids
Which of the following statements is true of homologous chromosomes?
A. They are exact copies.
B. They contain the same genes.
C. They divide during meiosis II.
D. They connect to each other.
An investigator discovers that some mice have a mutation in a gene that
codes for a particular protein, yet the protein is identical to that found in
mice without the mutation. What is the mostly likely explanation for this
phenomenon?
A. The mutation occurred within a coding region of the gene
B. The mutation caused an intron not to be spliced out of the RNA
sequence
C. The mutation resulted in a codon that codes for the same amino acid
D. The mutation is not recognized by the cell’s translation machinery
What is the three nucleotide sequence that identifies an amino acid called
A karyotype is the made up of ?
Know how to make a complementary strand of DNA and RNA when
given a nucleotide sequence: AGCGCATAGCAA
What is apoptosis?
If an organism has 40 chromosomes, what is its haploid condition?
Your body cells are ________ and your gametes are ___________.
During which phase of the cell cycle does cell growth occur?
DNA is composed of how many different kinds of nucleotides?
What is the difference between transcription and translation?
Where does transcription and translation occur?
What is replication?
What is the central dogma of gene expression?
What is tRNA?
How do each of the three types of RNA differ?
Will the mRNA codon sequence UUA CCC GGG GGU AAU
produce a different polypeptide chain than CUG CCG GGC GGC AAA?
How many autosomes does a human have?
What are carcinogens?
What is the monomer of DNA called?
Test taking advice:
Relax – A calm demeanor and positive thoughts will
serve you better than stressing over the test.
Be happy when you study. Do anything that makes
you happy. If you are unhappy you won’t remember
much.
Think of tests as a challenge to show how great you are,
not as torture to show what you don’t know.
Define the following:
Sex Linked Trait –
Polygenic Inheritance –
the kind of inheritance in which the trait is produced from the
cumulative effects of many genes in contrast to monogenic inheritance
wherein the trait results from the expression of one gene (or one gene
pair). In humans, height, weight, and skin color are examples of
polygenic inheritance, which does not follow a Mendelian pattern of
inheritance.
Law of Independent Assortment –
Law of Segregation –
Mendel laid the groundwork for genetics.
 Traits are distinguishing characteristics that
are inherited.
 Genetics is the study of biological inheritance
patterns and variation.
 Gregor Mendel showed that traits are
inherited as discrete units.
 Many in Mendel’s day thought traits were
blended.
Mendel’s data revealed patterns of inheritance.
 Mendel made three key decisions in his experiments.
 use of purebred plants
 control over breeding
 observation of seven
“either-or” traits
• Mendel drew three important conclusions.
– Traits are inherited as discrete units.
– The last two conclusions are
called the law of segregation.
– Organisms inherit two copies of each gene, one from
each parent.
– The two copies segregate
during gamete formation.
purple
white
Punnett squares illustrate genetic crosses.
 The Punnett square is a grid system for predicting all possible genotypes resulting
from a cross.
 The axes represent
the possible gametes
of each parent.
 The boxes show the
possible genotypes
of the offspring.
• The Punnett square
yields the ratio of
possible genotypes and
phenotypes.
If you cross a tall plant (T ) with a short plant (tt) what
will be the potential ratio of offspring?
Hitchhiker's thumb (H) is dominant to no hitchhiker's thumb (h). A
woman who does not have hitchhiker's thumb marries a man who is
heterozygous for hitchhiker's thumb. What is the probable genotypic
ratio of their children?
A. 0% Hh: 100% hh
B. 50% Hh: 50% hh
C. 75% Hh: 25% hh
D. 100% Hh: 0% hh
H
h
h
Hh
hh
h
Hh
hh
Hitchhiker's thumb (H) is dominant to no hitchhiker's thumb (h). A
woman who does not have hitchhiker's thumb marries a man who is
heterozygous for hitchhiker's thumb. What is the probable genotypic
ratio of their children?
A. 0% Hh: 100% hh
B. 50% Hh: 50% hh
C. 75% Hh: 25% hh
D. 100% Hh: 0% hh
H
h
h
Hh
hh
h
Hh
hh
One of the parents of a child has phenylketonuria (PKU), which
is caused by recessive alleles. The other parent does not have the
PKU alleles. What is the chance that the couple will have a child
with phenylketonuria?
A. 0%
B. 50%
C. 75%
D. 100%
a
a
A
Aa
Aa
A
Aa
Aa
One of the parents of a child has phenylketonuria (PKU), which
is caused by recessive alleles. The other parent does not have the
PKU alleles. What is the chance that the couple will have a child
with phenylketonuria?
A. 0%
B. 50%
C. 75%
D. 100%
a
a
A
Aa
Aa
A
Aa
Aa
Pedigree
Female Male
XH
XH XHXH
Xh
XHXh
Y
Her father would have
been Xh Y
XH Y
XH Y
Xh Y
50%
XHX
h
50%
A. Each of their sons will have hemophilia.
B. None of their daughters will have hemophilia.
C. Their sons have a 25% chance of having hemophilia.
D. There is a 50% chance that their daughters will have hemophilia.
Which of the following describes the probability of hemophilia in
the offspring of a man who does not have hemophilia and a
woman whose father is a hemophiliac?
XH
XH XHXH
Xh
XHXh
Y
Her father would have
been Xh Y
XH Y
XH Y
Xh Y
50%
XHX
h
0%
A. Each of their sons will have hemophilia.
B. None of their daughters will have hemophilia.
C. Their sons have a 25% chance of having hemophilia.
D. There is a 50% chance that their daughters will have hemophilia.
Which of the following describes the probability of hemophilia in
the offspring of a man who does not have hemophilia and a
woman whose father is a hemophiliac?
Can we know the genotypes and
phenotypes of B and E?
1)
2)
3)
Alleles for the A and B blood cells are codominant. Which set of parents can most likely
produce a child with type O blood?
A. one parent with type AB blood, and the other parent with type A blood
B. one parent with type AB blood and the other parent with type O blood
C. one parent with heterozygous type A blood, and the other parent with type O blood
D. one parent with homozygous type A blood, and the other parent with homozygous type B
blood
4) What are enzymes that cut DNA molecules in specific locations are called?
a) Splicers
b) Gel electrophoresis
c) Introns
d) Restriction enzymes
5) The process by which fragments of DNA are separated by an electric current is called..
a) Splicers
b) Gel electrophoresis
c) Introns
d) Restriction enzymes
6) The process by which sections of DNA are copied is called …
a) Polymerase chain reaction
b) Gel electrophoresis
c) Exons
d) Reactions agents
7) A short segment of DNA that is used to identify the starting point during PCR is called a..
a) Splicers
b) Primer
c) Introns
d) Restriction enzymes
A
A
What are “A” and “B” called?
8) A are ___________________________
9) B are____________________________
B
10) What does Mendel’s ‘first’ law of segregation basically say?
11) Sex linked traits involved autosomal chromosomes. Yes or No
12) Incomplete dominance is where the heterozygous condition is a blending of two phenotypes
Yes or No
13) What percentage of phenotypes will a child have if the parents have AB and O blood?
14) When traits are produced by two or more genes it is called which of the following?
a) excitation
b) monohybrid trait
c) hybrid cross d) polygenic trait