Chromosomal Mutations

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2 Chromosomal Mutations A chromosome mutation is an unpredictable change that occurs in a chromosome. These changes are most often brought on by problems that occur during meiosis or by mutagens (chemicals, radiation, etc.) This can change # of chromosomes in a cell or the structure of the chromosome!

3 Chromosomal Mutations 4 Types: Deletion = loss of part or all of a chromosome Duplication = produce extra copies of parts of a chromosome Inversion = reverse the direction of parts of a chromosome

4 4. Translocation = part of a chromosome breaks off and reattaches to another

5 Down syndrome is a developmental disorder caused by an extra copy of chromosome 21 Cri-du-Chat Syndrome: A deletion is caused by a break in the DNA molecule that makes up a chromosome.

6 47, XXY (Klinefelter syndrome) 47, XXY (or XXY) is a genetic condition caused when someone has two X chromosomes and one Y chromosome. Males normally have an X chromosome and a Y chromosome (46, XY), and females normally have two X chromosomes (46, XX). Turner syndrome Turner syndrome is caused by a missing or incomplete X chromosome. People who have Turner syndrome develop as females.

7 What causes mutations? Many mutations are due to mistakes made in replication, or transcription. Mutagens are things that can cause a change in DNA sequences. All of these mutagens can damage your DNA: UV light radiation exposure to chemicals

8 The Pros and Cons of Mutations PRO: mutations are the source of genetic variability in a species! CON: mutations can disrupt normal biological activity, resulting in a genetic disorder or cancer.

9 Genetics: what is it? What is genetics? Genetics is the study of heredity, the process in which a parent passes certain genes onto their children. (http: // htm) What does that mean? Children inherit their biological parents genes that express specific traits, such as some physical characteristics, natural talents, and genetic disorders.

10 Match the genetic terms to their corresponding parts of the illustration. base pair cell chromosome DNA (Deoxyribonucleic Acid) double helix* genes nucleus Illustration Source: Talking Glossary of Genetic Terms gov/glossary.cfm?key=chromosome http: // gov/exhibition/harrypottersworld/education/lessonplans/science.html Review Activity

11 Word Match Activity base pair cell chromosome DNA (Deoxyribonucleic Acid) double helix* genes nucleus cell nucleus chromosome Illustration Source: Talking Glossary of Genetic Terms genome.gov/glossary.cfm? key=chromosome base pair (double helix) DNA genes

12 Genetic Concepts Heredity describes how some traits are passed from parents to their children. The traits are expressed by genes, which are small sections of DNA that are coded for specific traits. Genes are found on chromosomes. Humans have two sets of 23 chromosomes one set from each parent.

13 Genetic Terms Using your textbook define the following words and write their definitions using your own words. (You have 15 mins!) allele: genes: dominant : recessive: homozygous: heterozygous: genotype: phenotype: testcross: Mendelian Inheritance: