8/31/20151 agenda for wednesday (january 27, 2011) journal questions: a. what are genes? b. what are...
TRANSCRIPT
04/21/23 1
Agenda for Wednesday (January 27, 2011)
Journal Questions: a. What are genes? b. What are some causes of genetic
mutations? c. What is RNA used for?
Agenda:*1. Lecture: Gene Mutations/DNA
Replication/Protein Synthesis. slide 492. DNA Lab (Handout): Color, Glue, Paste into
your composition book.3. Protein Synthesis Activity 3 in Packet3. Homework: Start studying for final: Chapters 1-12
04/21/23 2
Next Lecture: Protein Synthesis
04/21/23 3
What would happen if???
Created by:
Dr. Rick Woodward
04/21/23 4
Gene Mutations A. A gene mutation is a
chemical change that occurs within the DNA of a cell.
04/21/23 5
Mutagens A. A mutagen can change the
nucleotides within DNA molecules.
B. A nucleotide consists of three parts:
1. One nitrogen base (ATCG)
2. One sugar (deoxyribose)
3. One phosphate group
C. Hydrogen bonds join the two chains of nucleotides together.
04/21/23 6
The Structure of DNAA. Double Helix (Watson & Crick)
B. Four Nitrogen Bases
1. Adenine (A)
2. Thymine (T)
3. Cytosine (C)
4. Guanine (G)
04/21/23 7
The Structure of DNAC. Nitrogen Bases called Pyrimidines:
(Cytosine & Thymine)
04/21/23 8
The Structure of DNAD. Nitrogen Bases called Purines:
(Adenine & Guanine)
04/21/23 9
The Structure of DNAE. In what way do the nitrogen bases
bond? (Recall: The nitrogen base pairing rules)
1. A – T (Adenine bonds with Thymine)
2. C – G (Cytosine bonds with Guanine)
04/21/23 10
The Structure of DNAF. What is a gene?
(1) A gene is one sequence of nucleotides along a DNA molecule.
04/21/23 11
DNA ReplicationA. DNA replication results in
exact copies of genetic information that can be passed on to the offspring.
04/21/23 12
DNA Replication
B. Watson & Crick hypothesized that each original chain of nucleotides acts as a template, or mold, for making a new chain.
04/21/23 13
Mutagens
A. Some examples of mutagens:
(1) X-rays
(2) Ultraviolet Rays (from the sun)
(3) Chemicals (alcohol, drugs, etc.)
04/21/23 14
04/21/23 15
How X-Rays Damage DNA
04/21/23 16
Chromosome MutationsA. Chromosome mutations are
changes occurring within the structure of the chromosome.
04/21/23 17
Chromosome Mutations B. Some examples of
chromosome mutations:
(1) Deletion:
a. Involves the loss (deletion of a piece of chromosome.)
04/21/23 18
Chromosome Mutations(2) A duplication occurs
when an extra, but identical piece of chromosome is added to the normal chromosome.
04/21/23 19
Chromosome Mutations(3) Inversion occurs when
pieces of chromosome break apart and the pieces rejoin the same chromosome in a different order.
04/21/23 20
Chromosome Inversion
04/21/23 21
Recall: KaryotypeA. A picture of an individual’s chromosomes
04/21/23 22
Changes in the Number of Chromosomes: A. Monosomy is the loss of
a whole chromosome.
B. Trisomy is the addition of a chromosome.
04/21/23 23
Reviewing Terminology
04/21/23 24
Harmful Alleles A. Most of the harmful alleles in the
human population are recessive.
a. Why?
04/21/23 25
Harmful Alleles B. Most human genetic disorders
are caused by a homozygous recessive genotype.
04/21/23 26
Harmful Alleles
C. Examples:
(1) cc = homozygous recessive genotype for Cystic Fibrosis.
(2) ss = homozygous recessive genotype for Sickle Cell Anemia
04/21/23 27
Multiple GenesA. Multiple genes are involved in many
genetic disorders, including:
(1) Diabetes mellitus
(2) Heart disease
04/21/23 28
04/21/23 29
Diabetes Information:
Diabetes is a disease in which the body does not produce or properly use insulin. Insulin is a hormone that is needed to convert sugar, starches and other food into energy needed for daily life. The cause of diabetes continues to be a mystery, although both genetics and environmental factors such as obesity and lack of exercise appear to play roles.
04/21/23 30
04/21/23 31
Diabetes Information:There are 20.8 million children and adults in the United States, or 7% of the population, who have diabetes. While an estimated 14.6 million have been diagnosed with diabetes, unfortunately, 6.2 million people (or nearly one-third) are unaware that they have the disease.
04/21/23 32
DNA versus RNADNA RNA
1. Location: Nucleus Ribosome
2. Function: Directs activities Protein of the cell
Synthesis
3. Nitrogen Bases: ATCG AUCG
4. Structure: Double Helix Single
Strand
04/21/23 33
04/21/23 34
From Genes to ProteinsA. One chain of the DNA molecule acts
as a template for making RNA.
04/21/23 35
From Genes to ProteinsB. Transcription is the
process of making RNA from DNA.
04/21/23 36
From Genes to Proteins
C. RNA molecules are transcribed according to the information encoded in the base sequence of DNA. -C-G-A-G-C-G-A
04/21/23 37
From Genes to Proteinsd. RNA polymerase (enzyme) binds
to a DNA molecule and causes it to separate.
04/21/23 38
From Genes to Proteinse. Translation: The process of
converting the genetic code in RNA into the amino acid sequence that makes up a protein.
04/21/23 39
From Genes to Proteinsf. Three types of RNA:
(1) Messenger RNA (mRNA):
-Is transcribed from DNA and codes for polypeptides.
-Transmits information from DNA for use during protein synthesis.
04/21/23 40
From Genes to Proteinsf. Three types of RNA continued….
(2) Transfer RNA (tRNA): Allows complementary bases to pair.
-Exists in 20 or more varieties.
(Recall: 20 different amino acids)
04/21/23 41
From Genes to Proteinsf. Three types of RNA continued:
(3) Ribosomal RNA (rRNA)
04/21/23 42
From Genes to Proteinsg. Introns are intervening sets of
nucleotides that do not code for amino acids.
h. Exons are sets of nucleotides expressed by coding for amino acids.
04/21/23 43
From Genes to Proteinsi. What is mRNA processing? The
removing of introns from mRNA.
j. The mRNA molecule moves through pores in the nuclear membrane and travels to ribosomes.
04/21/23 44
From Genes to Proteins k. The assembly of amino acids into specific
proteins is called protein synthesis.
(The function of the ribosome)
04/21/23 45
From Genes to Proteins
l. A specific group of three sequential bases of mRNA is called a codon.
(1) Each codon codes for a specific amino acid.
04/21/23 46
Anticodonm. The anticodon is a region of tRNA
consisting of three bases complementary to the codon of mRNA.
04/21/23 47
The Big PictureA. DNA Transcription mRNA Translation tRNA
Amino Acid Proteins (Polypeptide Chains)
04/21/23 48
Today’s Lab Activity
1. Last two pages of your packet:Building a DNA Ladder1. Assign a color key for your
ladder.2. Color ladder according to your
color key.3. Cut out the pattern pieces.4. Construct your ladder.5. Glue your ladder into your
composition book
04/21/23 49
Agenda: Friday (January 29, 2010)
Journal Questions:
a. What is the function of tRNA and mRNA?
b. What is an anticodon?
*1. Lecture: Human Genetic Disorders -104
2. Finish DNA Ladder.
3. Protein Synthesis Activity 3
4. Finish Unit Packet
HW: Study guide for Final Exam is now available.
-All work is due on the day of the final.
Protein Synthesis
04/21/23 50
Activity 3 in Your Packet: Protein Synthesis
04/21/23 51
Activity 3 in Your Packet: Protein Synthesis
04/21/23 52
04/21/23 53
Human Genetic DisordersA. Cystic Fibrosis
1. How common is it?
Cystic fibrosis is the most commonly inherited genetic disorder among Caucasian people.
04/21/23 54
Cystic Fibrosis (CF)
04/21/23 55
Human Genetic DisordersA. Cystic Fibrosis
2. What happens? There is a malfunctioning in the mucous secreting glands of the body.
a. Thick mucous secretions build up in the air passages and lungs.
04/21/23 56
Human Genetic DisordersA. Cystic Fibrosis
b. Thick mucous secretions damage the pancreas and prevent or reduce the flow of digestive enzymes to the intestines.
04/21/23 57
Human Genetic DisordersA. Cystic Fibrosis
3. Symptoms: Wheezing, Coughing, Digestive Problems. (Max. Age = 27)
4. Etiology (the cause of the disease): Inheriting a recessive allele that codes for an abnormal protein.
04/21/23 58
Human Genetic DisordersB. Huntington’s Disease
1. Huntington’s disease is caused by a dominant gene.
2. The offspring of a parent having a trait expressed by a dominant gene have a 50% chance of also having that trait.
04/21/23 59
Risk of Huntington Disease (HD)
04/21/23 60
04/21/23 61
Human Genetic DisordersB. Huntington’s Disease
2. Symptoms of the disease usually appear by the time a person is about 40 years old.a. Brain cells begin to deteriorate.b. Death usually occurs within 20 years after the onset of symptoms.
04/21/23 62
04/21/23 63
Human Genetic DisordersB. Huntington’s Disease
c. Symptoms continued: Loss of muscle coordination, memory, and the ability to speak.
3. Location: Small segment on chromosome #4
04/21/23 64
Human Genetic Disorders
C. Sickle Cell Anemia
1. How common is it?
About one out of 500 Americans of African descent have this disorder.
a. Caused by inheriting a recessive allele
04/21/23 65
Recessive Allele: rr
04/21/23 66
Human Genetic Disordersb. Inheriting a mutant hemoglobin allele.
c. Hemoglobin is a protein found in red blood cells
-Hemoglobin binds with oxygen in the lungs and transports oxygen to body cells.
04/21/23 67
Human Genetic Disorders d. The slight difference in the
structure of the abnormal hemoglobin molecule makes them less soluble and causes them to form crystals with the red blood cells.
04/21/23 68
Human Genetic Disorderse. Crystals distort the red blood
cell shape causing it to become sickle-shaped. (Sickle = Crescent Shaped)
04/21/23 69
Human Genetic Disordersf. Sickle red blood cells are rigid
and cannot pass through capillaries as easily as normal (round) red blood cells.
(Capillaries become blocked causing symptoms….)
04/21/23 70
Human Genetic Disorders2. Symptoms: Severe Pain, Fever,
Weakness, and sometimes Strokes.
04/21/23 71
Human Genetic Disorders3. People who are homozygous for
sickle-cell hemoglobin resist malaria because the parasite that causes malaria does not thrive in cells with sickle hemoglobin.
04/21/23 72
Malaria (Not a Genetic Disorder) 1. Malaria is caused by a
unicellular organism (parasite) that invades red blood cells.
2. Mosquito (Anopheles) spreads the disease.
3. Malaria is prevalent in certain parts of Africa
04/21/23 73
04/21/23 74
Malaria Parasites among Normal Red Blood Cells
04/21/23 75
Malaria Statistics:
04/21/23 76
Film: The Coming Plaque Spotlight on
Malaria
04/21/23 77
04/21/23 78
Recall: Sex Chromosomes
1 Pair of Sex Chromosomes:
XX = Female
XY = Male
04/21/23 79
Sex-Linked Disorders1. Hemophilia (a protein
necessary for blood clotting is absent)
A. A small cut can cause significant loss of blood.
(life-threatening)
04/21/23 80
Hemophilia Continued… a. Hemophilia means that the fibrin
net does not get made properly.
b. Without the fibrin net, the platelet plug falls out and bleeding continues.
04/21/23 81
04/21/23 82
Sex-Linked Disorders
04/21/23 83
Sex-Linked Disorders1. Hemophilia continued….
B. Caused by a recessive allele on the X chromosome.
C. Quality of life can be improved by giving the patient the clotting factor and blood transfusions.
04/21/23 84
Sex-Linked Disorders
2. Color Blindness
A. Anything that is red or green appears brown to individuals with red-green color blindness.
04/21/23 85
Testing for Red-Green Color Blindness Normal Positive
Test
04/21/23 86
Sex-Linked Disorders2. Color Blindness
continued…
B. Caused by a recessive allele located on the X chromosome.
04/21/23 87
Sex-Linked Disorders
04/21/23 88
What is a Karyotype?A. The appearance of
chromosomes in an organism regarding number, size, and shape.
04/21/23 89
What is a Karyotype used for?
A. To detect certain chromosomal abnormalities.
04/21/23 90
Karyotypes are made by…
1. Taking a sample of blood.
2. The white blood cells are separated out of the blood sample.
a. Why?
b. Answer: Recall red blood cells have no nucleus (no genetic information to analyze.)
04/21/23 91
Karyotypes are made by….3. A chemical that stops the white
blood cells in metaphase of mitosis is added.
04/21/23 92
Karyotypes are made by….4. Water is added to the white
blood cells, causing the cells to swell and burst.
04/21/23 93
Karyotypes are made by ….
5. Chromosomes released by the white blood cells are stained and photographed.
04/21/23 94
Karyotypes are made by…
6. The photograph is enlarged and each individual chromosome is cut out and matched with its homologue.
04/21/23 95
Karyotypes are made by…
7. The chromosomes are arranged by size and then numbered.
-Visible chromosomal abnormalities can be easily identified by looking at the chromosomes.
04/21/23 96
Translocation…A. Translocation occurs when a
deleted portion of a chromosome attaches to another chromosome.
04/21/23 97
Down Syndrome A. Characteristics: Varying degrees of
mental retardation, from mild to severe:
(1) Short Stature: Shorter than normal.
(2) Many are born with heart, intestinal, or vision problems.
(3) Extremely susceptible to infection.
(4) May develop infections and/or blood cell cancer (leukemia).
04/21/23 98
Down Syndrome B. Causes of Down Syndrome:
(1) Nondisjunction: The failure of paired chromosomes to separate during meiosis.
04/21/23 99
Down SyndromeB. Causes continued…
(2) Translocation: The attaching of a deleted portion of one chromosome onto another chromosome.
04/21/23 100
Down Syndrome B. Causes continued…
(3) Trisomy of Chromosome #21
A. Trisomy = The presence of 3
chromosomes.
04/21/23 101
Down SyndromeB. Causes continued…
(4) Seen more often in children born to mothers over the age of 35.
04/21/23 102
Down Syndrome
C. Average Life Span: With better health care, the average life span has increased to 30 years of age.
04/21/23 103
Down Syndrome
D. Geneticists are currently studying the DNA of Chromosome #21:
(1) To learn which genes on chromosome 21 cause Down Syndrome.
(2) To discover which proteins are coded for by those genes.
(3) To discover why three chromosome cause this disorder.
04/21/23 104
Genetic Disorders versus Congenital Disabilities
1. Genetic disorders are inherited.
2. Congenital disabilities are acquired during development.
a. They are not inherited.
04/21/23 105
Genetic Disorders versus Congenital Disabilities
3. More than 200,000 babies are born in the United States each year with genetic disorders or congenital disabilities.
4. Some disorders may have little or no effect on people. Others cause severe health problems and may become fatal.
04/21/23 106
Genetic Counseling
A. Who does genetic counseling?
A person trained in genetics can give parents information about the chances of their newborn child having a genetic disorder.
04/21/23 107
Genetic CounselingB. Genetic counseling is
particularly valuable to parents with family histories of genetic disorders.
04/21/23 108
Genetic Counseling
C. Genetic counseling cannot tell if a specific individual will be afflicted.
-It can only determine probability.
04/21/23 109
Genetic Counseling
D. Genetic counselors:
1. Study family histories
2. Use diagnostic techniques
3. Utilize knowledge of basic patterns of heredity to determine the chances of a child having a genetic disorder.
04/21/23 110
Genetics
Journal Questions:
a. What are the symptoms of sickle cell anemia?
b. What does translocation mean?
c. Lecture: Diagnostic Techniques
Treating Genetic Disorders
Gene Therapy
(Science (2002) 295:1443)
Carbon Copy: The First Cloned Cat (2002)
04/21/23 111
Diagnosis in the UterusA. Amniocentesis
1. Used to examine the chromosomes in a developing fetus
04/21/23 112
Diagnosis in the UterusA. Amniocentesis continued..
2. Commonly used to identify
Down Syndrome (Trisomy 21).
a. Fluid can also be used to identify defective alleles.
(i.e. Hemophilia, Sickle Cell Anemia)
04/21/23 113
Diagnosis in the Uterus A. Amniocentesis continued…
3. Amniocentesis is not conducted until at least the 14th week of pregnancy because injury of the fetus could occur if this diagnostic technique were conducted earlier.
04/21/23 114
Diagnosis in the Uterus A. Amniocentesis continued….
4. Steps involved in amniocentesis:
(1) A sample of the fluid surrounding the fetus is withdrawn through a
long,
thin needle.
04/21/23 115
Diagnosis in the Uterus A. Amniocentesis continued…
4. Steps involved in amniocentesis:
(2) The fluid contains fetal cells that are then grown in lab.
a. Ten days are required to grow enough fetal cells for microscopic examination.
04/21/23 116
Diagnosis in the UterusA. Amniocentesis continued…
(4) Steps involved in amniocentesis:
(3) A karyotype of the chromosomes is then made from the fetal cells.
04/21/23 117
Diagnosis in the Uterus Amniocentesis &
Ultrasonography are often used together to diagnose genetic disorders.
04/21/23 118
Diagnosis in the Uterus
B. Ultrasonography
1. Used to determine the position and anatomy of the fetus.
04/21/23 119
Diagnosis in the Uterus 2. To perform an ultrasonography:
(1) An ultrasound probe is passed back and forth over the mother’s abdomen.
(2) Reflected sound waves are used to form an image of the fetus.
04/21/23 120
Diagnosis in the Uterus C. Chorionic Villus Biopsy
1. Cells from a tissue called the chorion, which is part of the structure by which the fetus is linked to the mother in the uterus, can be removed.
04/21/23 121
Diagnosis in the Uterus
C. Chorionic Villus Biopsy continued…
2. This procedure can be performed as early as the 9th week of pregnancy.
3. Cells can be karyotyped and analyzed as in an amniocentesis.
04/21/23 122
Diagnosis in the Uterus D. Fetoscopy:
1. An endoscope is inserted through a small incision in the mother’s abdomen.
04/21/23 123
Diagnosis in the Uterus D. Fetoscopy continued…
2. The fetus is viewed directly through the endoscope tube.
3. Samples of fetal skin or blood can be withdrawn and studied.
04/21/23 124
Treating Genetic DisordersKey Term: Recombination
Recombination is the formation of a new gene combination due to the crossing over by the homologous chromosomes.
Recall: Crossing Over from book questions.
04/21/23 125
Crossing OverThe exchange of genetic information:
04/21/23 126
04/21/23 127
Treating Genetic Disorders
A. Recombinant DNA technology has led to the development of techniques that allow geneticists to:
1. Locate the positions of some genes that cause genetic disorders.
04/21/23 128
04/21/23 129
Treating Genetic Disorders
2. Nucleotide sequences of normal alleles and harmful counterparts can be compared, as can the amino acid sequences of the proteins for which they code.
04/21/23 130
Treating Genetic Disorders
3. Scientists have made practical use of their knowledge of genetic transformation by learning how to transfer a gene artificially from a donor organism to a bacterium.
04/21/23 131
Treating Genetic Disorders
4. The DNA of the bacterium that has been altered by the insertion of a foreign gene is called recombinant DNA.
04/21/23 132
Treating Genetic Disorders
5. Using recombinant DNA techniques, E. Coli bacteria can be engineered to produce a desired protein, such as human insulin.
04/21/23 133
Treating Genetic Disorders
6. Plasmids in bacteria are the structures with which the foreign DNA is recombined.
a. Key Term: Plasmids
Plasmids = circular pieces
of DNA in bacteria.
04/21/23 134
04/21/23 135
Gene Therapy
A. Is the treatment of genetic diseases by introducing normal genes into body cells.
04/21/23 136
Gene Therapy
B. What is the number one cause of death in adults?
-Answer: Heart Disease
(Recall: Atherosclerosis)
04/21/23 137
Gene Therapy
C. Hope for the Heart
(1) Doctors have two main treatment options when the coronary arteries that supply blood to the heart muscle are blocked or get clogged.
04/21/23 138
Clogged Coronary Artery
04/21/23 139
Gene Therapy
C. Hope for the Heart
(2) Bypass Surgery: Re-routes blood through vessels taken from another part of the body
04/21/23 140
Gene Therapy
C. Hope for the Heart
(3) Angioplasty: Opens up obstructions in blood vessels with a tiny balloon or blasts through the cholesterol clogging obstructions with lasers and cutting tools.
-A third of these procedures do not work! (By-Pass & Angioplasty)
04/21/23 141
Angioplasty
04/21/23 142
Gene Therapy
C. Hope for the Heart
(4) Researchers are trying out genetic therapy to grow new blood vessels, a process called angiogenesis.
04/21/23 143
Gene Therapy
C. Hope for the Heart(5) Gene Therapy: A gene injected into the heart prompts the production of vascular endothelial growth factor, which tells the heart to make new blood vessels to re-vascularize the starved heart muscle.
04/21/23 144
Types of Cloning1. Therapeutic Cloning
2. Organism Cloning
Biotechnology
Dolly and surrogate Mom
Genetically modified rice.
Embryonic stem cells and gene therapy
04/21/23 146
Biotechnology
Biotechnology, defined broadly, is the engineering of organisms for useful purposes.
Often, biotechnology involves the creation of hybrid genes and their introduction into organisms in which some or all of the gene is not normally present.
Fourteen month-old genetically engineered (“biotech”) salmon (left) and standard salmon (right).
04/21/23 147
Biotechnology
We’ll examine:
Animal cloning
Gene cloning for pharmaceutical production
The promise and perhaps perils of embryonic stem cells
DNA fingerprinting
Genetically modified foods and the American-European opinion divide.
04/21/23 148
Animal Cloning
Dolly and her surrogate mother.
04/21/23 149
The Biotechnology of Reproductive Cloning
Even under the best of circumstances, the current technology of cloning is very inefficient.
Cloning provides the most direct demonstration that all cells of an individual share a common genetic blueprint.
04/21/23 150
Cloning
04/21/23 151
Genetic Testing Kits
With something as simple as a cotton swab touching the inside of your cheek, you can now have an extensive genetic profile (your genome) report given back to you. This report will highlight your genetic predispositions to a number of diseases, which you can then use to take corrective action in lifestyle, diet, and exercise decisions