Genetics Unit – Lesson 8: Genetic Disorders & Mutation

Genetics Unit – Lesson 8: Genetic Disorders & Mutation

Course: Monarch Park Grade IB Biology (SBI-4IB)

Teacher: Ms. FounkEmail: [email protected]

Human maladies

Melanoma

Monarch Park SBI-4IB – Genetics Unit – Lesson 8: Genetic Disorders & Mutants

Heart disease

Cold/Flu

HIV/AIDSKidney stones

Alzheimers

Parkinson’s disease

Huntington’s disease

Lou Gehrig’s Disease/ALS

Autism

Lung cancer

Crohn’s

Tuberculosis

Chicken poxMeasles

Cholera

Scurvy

STDs

Sickle cell anemia

Stroke

Malaria

Down syndrome

Do you make more errors than a cell?


Errors during meiosis: Non-disjunction

Meiosis is a process that uses cellular division to produce the sex cells or gametes that are used for reproduction. During meiosis, the cell identifies chromosome pairs and sorts them to opposite sides of the cell. Sometimes, errors occur during this sorting process resulting in extra or missing chromosomes.

INSTRUCTIONS

• Cut out chromosomes pairs• Mix the shapes in a pile on your desk. Imagine that this represents the nucleus of a cell• When instructed, sort the 23 chromosome pairs as fast as you can so that 1 copy of each chromosome is on either side of your desk.• You will have 1 minute to sort. • After 1 min, record the number of pairs you were able to successfully sort

Detecting chromosome abnormalities


Karyotyping

• Chromosome length• Chromosome structure

• Banding pattern• Position of centromere

Chromosomes are sorted according to several characteristics:

The X chromosome is much larger than the Y chromosome

• XX = female• XY = male

Karyotypes are used to assess the sex of a person



Karyotyping

TRIPLE X (XXX = female)

Varying numbers of sex chromosomes lead to a variety of different disorders

TURNER SYNDROME (XO = female)

KLINEFELTER SYNDROME (XXY = male)

Watch this talk:http://www.ted.com/talks/lang/en/alice_dreger_is_anatomy_destiny.html



Karyotyping

Look up

Varying numbers of autosomes lead to a variety of different disorders

DOWN SYNDROME (Trisomy 21) Look up



Errors during DNA replication: Point mutations

DNA replication occurs before mitosis and meiosis so that a new copy of DNA is created. The cell is very good at copying the 3 billion base pairs of DNA present in every human cell, but sometimes it makes mistakes.

Sequence: ATCCGACGTTTGCGATCGATCGATGGGGTCGATAAAAGCT Copy of Sequence: ____________________________________________ Number of mistakes: _______________________

Complementary Sequence: ____________________________________________ Number of mistakes: _______________________

Point mutations are single nucleotide changes in the DNA


Point mutations can have varying effects within the cell

Missense mutation

TTA TAT ATC GTA

Silent mutation

TTA TAT CTT GTA TTA TTA TCT CGT A

Frameshift mutation

TTA TAA CTC GTA

Nonsense mutation

e.g. Transcribe and translate the following sense strand: TTA TAT CTC GTAUUA UAU CUC GUALeu Met Leu Val

UUA UAU AUC GUALeu Met Ile Val

UUA UAU CUU GUALeu Met Leu Val

UUA UAA CUC GUALeu Stop

UUA UUA UCU CGU ALeu Leu Ser Ala

A Case Study: Sickle Cell Anemia

Transcribe and translate a section of the genome that encodes for hemoglobin (Hb)


Changing a single nucleotide changes the mRNA sequence which changes the codon which changes the amino acid. Glutamic acid and valine have very different chemical and physical properties which affects the ability of the hemoglobin to form proper quaternary structure resulting in sickle looking cells that have decreased ability to carry oxygen in the blood.

sense

CCU GAG GAG

Pro Glu Glu

CCU GUG GAG

Pro Val Glu

Glutamic acid Valine

sense

Sickle cell anemiaNormal blood cell

Repair pathways within the cell


SIDE NOTE: The cell has proteins that work to repair DNA

BRCA1 – gene linked to breast cancer-Repairs cell from double strand breaks

Repair proteins can be identified using DNA damage foci

BLAST tool from NCBI can be used to align sequences and detect sequence differences

Genetics Unit – Lesson 8: Genetic Disorders & Mutation

Course: Monarch Park Grade IB Biology (SBI-4IB)

Teacher: Ms. FounkEmail: [email protected]



Errors during meiosis: Non-disjunction

Meiosis is a process that uses cellular division to produce the sex cells or gametes that are used for reproduction. During meiosis, the cell identifies chromosome pairs and sorts them to opposite sides of the cell. Sometimes, errors occur during this sorting process resulting in extra or missing chromosomes.

INSTRUCTIONS

• Cut out chromosomes pairs• Mix the shapes in a pile on your desk. Imagine that this represents the nucleus of a cell• When instructed, sort the 23 chromosome pairs as fast as you can so that 1 copy of each chromosome is on either side of your desk.• You will have 1 minute to sort. • After 1 min, record the number of pairs you were able to successfully sort



Karyotyping

• Chromosome _________• Chromosome _________

• ________________• ________________

Chromosomes are sorted according to several characteristics:

The X chromosome is much _______than the Y chromosome

• XX = ____________• XY = ____________

Karyotypes are used to assess the sex of a person



KaryotypingVarying numbers of ________________ lead to a variety of different disorders

Watch this talk:http://www.ted.com/talks/lang/en/alice_dreger_is_anatomy_destiny.html



KaryotypingVarying numbers of _____________ lead to a variety of different disorders



Errors during DNA replication: Point mutations

DNA replication occurs before mitosis and meiosis so that a new copy of DNA is created. The cell is very good at copying the 3 billion base pairs of DNA present in every human cell, but sometimes it makes mistakes.

Sequence: ATCCGACGTTTGCGATCGATCGATGGGGTCGATAAAAGCT Copy of Sequence: ____________________________________________ Number of mistakes: _______________________

Complementary Sequence: ____________________________________________ Number of mistakes: _______________________

Point mutations are single nucleotide changes in the DNA


Point mutations can have varying effects within the cell

TTA TAT ATC GTA TTA TAT CTT GTA TTA TTA TCT CGT ATTA TAA CTC GTA

e.g. Transcribe and translate the following sense strand: TTA TAT CTC GTAUUA UAU CUC GUALeu Met Leu Val

UUA UAU AUC GUALeu Met Ile Val

UUA UAU CUU GUALeu Met Leu Val

UUA UAA CUC GUALeu Stop

UUA UUA UCU CGU ALeu Leu Ser Ala

A Case Study: Sickle Cell Anemia

Transcribe and translate a section of the genome that encodes for _______________


Changing a single nucleotide changes the mRNA sequence which changes the codon which changes the amino acid. Glutamic acid and valine have very different chemical and physical properties which affects the ability of the hemoglobin to form proper quaternary structure resulting in sickle looking cells that have decreased ability to carry oxygen in the blood.

sense

Glutamic acid Valine

sense

____________________________

Documents

Genetics Unit – Lesson 8: Genetic Disorders & Mutation