Download 8.7 Mutations - Perry Local Schools

8.7 Mutations
KEY CONCEPT
Mutations are changes in DNA that may or may not
affect phenotype.
8.7 Mutations
Mutations
Caused by errors in
• Replication, transcription, cell division, or by external
factors
Germ-cell mutation – occurs in a gamete
• Do not affect the individual but may be passed on to
offspring
Somatic mutation – occurs in a body cell
• Will affect the individual but are not passed on to
offspring
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Lethal Mutations
• Cause death, often before birth
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Some mutations affect a single gene
• A point mutation - substitutes one nucleotide for
another.
– Or adds or removes a single nucleotide
mutated
base
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Frame Shift Mutation
• Deletion & addition point mutation - causes the remaining
codons to be incorrectly grouped
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8.7 Mutations
Chromosome Mutations
• Deletion – loss of a piece of a chromosome due to
chromosomal breakage
• Inversion – chromosomal segment breaks off and then
reattaches in reverse order to the same chromosome
• Translocation – chromosome piece breaks off and
reattaches to another non-homologous chromosome
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8.7 Mutations
Nondisjunction – failure of homologous
chromosomes to separate properly during meiosis
One gamete would have an extra
chromosome
• when fertilized would have 3 copies of
chromosome
• trisomy.
One gamete would have one less
chromosome
• when fertilized would have 1 copy of
chromosome
• monosomy
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Mutations
7.4 Human
Genetics and Pedigrees
KEY CONCEPT
A combination of methods is used to study human
genetics.
13.1 Ecologists Study Relationships
Pedigree – family record that shows how a trait is inherited
over several generations
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Pedigrees
Carrier – individual with one copy of a recessive allele
• Usually do not express the trait but can pass it along to
offspring
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Mutations
7.4 Human
Genetics and Pedigrees
A pedigree is a chart for tracing genes in a family.
• Phenotypes are used to infer genotypes on a pedigree.
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Mutations
7.4 Human
Genetics and Pedigrees
• Karyotypes can show changes in chromosomes.
– deletion of part of a chromosome or loss of a
chromosome
– large changes in chromosomes
– extra chromosomes or duplication of part of a
chromosome
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Detecting Human Genetic Disorders
• Genetic screening – examination of a person’s genetic
makeup
• Genetic counseling – medical guidance that informs
about possible problems that could affect their offspring
Prenatal testing
• Amniocentesis – removes a small amount of amniotic
fluid between the 14th
and 16th week of pregnancy
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• Chorionic villi sampling – physician obtains a sample of
the chorionic villi – tissue that grows between the
mothers uterus and the placenta, between the 8th and
10th week of pregnancy
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5.3 Regulation
of Cell Cycle
KEY CONCEPT
Cell cycle regulation is necessary for healthy
growth.
8.7
Mutations
5.3 Regulation
of Cell Cycle
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.
13.1
Ecologists
5.3 Regulation
of CellStudy
Cycle Relationships
8.3 Cancer
Tumor – abnormal group of cells
that result from uncontrolled,
abnormal cell division
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Mutations
5.3 Regulation
of Cell Cycle
– Benign tumors remain clustered and can be removed.
– Malignant - uncontrolled dividing cells invade and
destroy healthy tissues elsewhere in the body
– Metastasize - spread of cancer cells beyond their
original site
normal cell
cancer cell
bloodstream
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Mutations
5.3 Regulation
of Cell Cycle
Kinds of Cancer – based on types of tissue that affect
• Carcinomas – grow in the skin and tissues that line
organs. Ex: lung cancer & breast cancer
• Sarcomas – grow in bone and muscle tissue
• Lymphomas – solid tumors that grow in the tissues that
form blood cells
– Leukemia – tumors that form in blood-forming tissue –
over production of white blood cells
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Mutations
5.3 Regulation
of Cell Cycle
Causes of Cancer
• Carcinogen – substance that increases the risk of
developing cancer Ex: tobacco, asbestos, X-rays, or UV
rays from sun
• Mutagen – cause mutations to occur within a cell that
leads to cancer
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Mutations
5.3 Regulation
of Cell Cycle
• Standard cancer treatments typically kill both cancerous
and healthy cells.
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Mutations
5.3 Regulation
of Cell Cycle
Oncogenes – gene that causes cancer
• Proto-oncogene – normal gene that control cell’s growth.
When mutated  oncogene
• Tumor-suppressor gene – code for proteins to prevent
uncontrolled cell division. When mutated  cancer
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5.3 Regulation
of Cell Cycle
Viruses & Cancer
• Viruses can stimulate uncontrolled cell division
• Cause mutations in proto-oncogenes & tumor suppressor
genes
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5.3 Regulation
of Cell Cycle
Cancer Prevention
• Diet high in fiber and low in fat
• Fruits & vegetables are high in fiber
• Vitamins & minerals: carotenoids, vitamins A, C, and E,
and calcium
• Daily exercise
• And lowering exposure to carcinogens (tobacco, UV
rays)
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Extra Credit:
• Millions of dollars are spent each year on cancer
research.
• Contact an oncologist in a cancer treatment center.
• Conduct an interview, prepare a paper, and create a
visual to show the new treatments that have been
developed in the past 10 years