January 11, Genetics with DNA.notebook. Genetics

Transcription

1 Genetics 1.DNA (deoxyribonucleic acid) is a chemical code that contains information for an organisms growth and function. It is found in the nucleus of all cells. 2. A gene is a section of DNA on a chromosome.the order of the nitrogen base pairs determine the traits of an organism. 3. Your characteristics are determined by the kinds of proteins the DNA (gene) tells the ribosomes to make. 4. Proteins are made of amino acids. Proteins build cells and enzymes. 5. Genes contain the instructions for making specific proteins. 6. Genes determine the order of amino acids in a protein. Changing the order of amino acids makes a different protein. 7. The codes for making proteins are carried from the genes to the ribosomes by RNA 8. RNA is like a ladder with rungs sawed in half. It has A, G, C, and U (uracil) instead of T. The sugar is ribose. 9. There are 3 types of RNA: a. messenger RNA (mrna) carries the code from the genes to the ribosomes. b. ribosomal RNA (rrna) makes up ribosomes c. transfer RNA (trna) brings the amino acids to the ribosomes. 1

2 10. In many celled organisms, each cell uses only some of the thousands of genes it has to make proteins. Each cell uses only the genes that direct the making of the protein it needs. 11. If DNA is not copied exactly the proteins may not be made correctly. These mistakes are called mutations any permanent change in the DNA sequence of a gene or chromosome of a cell. 12. Without correctly coded proteins, an organism can't grow, repair, or maintain itself. 13. If a mutation occurs in a body cell, it may or may not be life threatening. However, if a mutation occurs in a sex cell, all of the cells that are formed from that sex cell will have the mutation. and heredity/ 14. Heredity is the passing of traits from parent to offspring 15. Genetics is the study of how traits are inherited through the interactions of alleles. 16. Gregor Mendel is known as the "Father of Genetics." He worked with pea plants and kept very accurate and detailed records 17. Alleles are the different forms of a trait that a gene may have. 18. Hybrids (Heterozygous 2 different alleles) are organisms that receive different genetic information, or different alleles for a trait. 19. Purebreds (Homozygous 2 alleles are the same) are organisms that always produce the same traits generation after generation 20. Dominant alleles cover or mask another form of that trait. Represent with a capital letter. 21. Recessive alleles are hidden by a dominant allele for that trait. Represent with a lower case letter. 22. Probability is a branch of math that helps you predict the chance that something will occur. 23. A Punnett square is a tool used to predict results in genetics. 2

3 24. Genotype is the genetic make up of an organism(homozygous purebred or heterozygous hybrid). 25. Phenotype is the way an organism looks or behaves based on its genotype (brown hair/blue eyes) body/heredity.htm 26. Three Principles of Heredity: a. Traits are controlled by alleles on chromosomes. b. An allele's effect is dominant or recessive. c. When a pair of chromosomes separate during meiosis, the different alleles for a trait move into separate sex cells. Genetics Since Mendel 27. Incomplete dominance produces a phenotype that is intermediate between the two homozygous parents. They seem to be blended. 28. A trait controlled by more than two alleles is said to be controlled by multiple alleles. 29. Traits controlled by multiple alleles produce more than 3 phenotypes of that trait. Ex.: human blood groups the alleles for blood types are A, B, and O. Types A and B are dominant. Type O is recessive to both. 30. Chromosome disorders can occur if the incorrect number of chromosomes is inherited. This is called nondisjunction. Ex.: Down's Syndrome (Trisomy 21). 31. Most human genetic disorders are caused by recessive genes. 3

4 32. How the sex of an offspring is determined: a. Each egg (female) contains one X chromosome. b. Males produce sperm that have either X or Y chromosomes c. If a sperm with an X chromosome fertilizes an egg, the offspring will be female (XX). d. If a sperm with a Y chromosome fertilizes an egg, the offspring will be male (XY). 33. An allele inherited on a sex chromosome is called a sex linked gene. Ex.: colorblindness and hemophilia. Mothers pass the trait to their sons. Amoeba Sisters Sex Linked Traits 34. A pedigree is a visual tool for following a trait through generations of a family. 35. A pedigree can be used to predict the probability that a baby will be born with a specific trait and are important in breeding plants and animals. 4

5 Heredity Rock Anthem 1. How many children in the second generaon were affected? How many were boys and how many were girls? What is the total number of children from the first generaon? 2. How many children were affected in the third generaon? 3. Does the pedigree show any of the third generaon children married? 4. How many children married in the second generaon? 5. What condion do you think is affecng this family? Explain your answer. 5

6 Advances in Genetics 36. Genetic engineering is the use of biological and chemical methods to change the arrangement of a gene's DNA to improve crop production, produce large amounts of medicine, and change how cells perform their normal functions. 37. Recombinant DNA is made by inserting a useful segment of DNA from one organism into a bacterium. It is used to make insulin, HGH, and chemicals to treat cancer. 38. Gene therapy involves using a normal allele placed in a virus to infect (replace) an allele on a target cell (abnormal cell). It is used to treat cystic fibrosis and some types of cancer. 39. Selective breeding involves selecting plants and animals with the most desired traits to breed for the next generation. 40. Genetic engineering also involves finding the genes that produce desired traits in one organism and then inserting those genes into a different organism of the same species. 6

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