Genes: Answers & Questions 1.2

Why is DNA important? Genes code for proteins. Proteins have specific roles, and are involved in all structures & functions of an organism.

Genetic Screening Genetic disorders can be screened for using DNA screening. Amniocentesis is used to screen for conditions in a developing fetus.

Karyotype A micrograph of the chromosomes in a cell. Can be used to screen for Down syndrome in a fetus. Can you spot the abnormality in the karyotype?

Phenylketonuria (PKU) Causes problems with an enzyme that breaks down the amino acid phenylalanine. It can lead to brain damage. It can be detected in a blood test & can be managed with changes to diet.

Should you get tested? If you test positive for Huntington’s disease, you know you will develop it in your 40’s…what would you do with that knowledge? You can get tested for some forms of breast cancer, cystic fibrosis, spina bifida, etc.

Genetic Engineering Transgenic organisms have genes from other species inserted into them. For example, E. coli bacteria with human insulin genes.

Transgenic organisms Many plants are engineered to be resistant to pests, drought, or cold; to be more nutritious,, etc. Many animals are engineered to have a gene for growth hormone.

Cloning The process of creating identical genetic copies of a cell or organism. Cloning of plants through cuttings, cell culture, etc. “Dolly the sheep” cloned using nuclear transfer.

Gene Therapy Changes in DNA (mutations) can change the structure of the proteins it produces. Research into gene therapy is looking into methods to correct faulty genes.

Stem Cells 3.1

Stem Cells Unspecialized cells that can produce various specialized cells. Totipotent stem cells are found in embryos; adult stem cells are pluripotent.