Genetics intro. 8th
- 1. GENETICS
- 3. What is Genetics? Genetics is the science that studies the process of heredity.
- 4. What is heredity? The passing on of traits from parent to offspring.
- 5. What is a trait? A unique characteristic. For example: hair color, eye color, height, tongue rolling, widows peak, etc
- 6. How are traits passed on? Traits are passed on from parent to offspring through DNA.
- 7. BrainPop DNA
- 8. What is DNA DNA is the chemical building block of life. Every human cell contains a nucleus with DNA. DNA is made up of 4 base pairs: Adenine, Thymine, Cytosine, and Guanine
- 9. Watson and Crick Are the two scientists who discovered the shape of DNA. They called the shape a double helix. Each chromosome is a long strand of DNA. Every cell has 23 homologous pairs of chromosomes
- 10. How does DNA make a human? The genetic code is spelled out with just four chemical letters, or bases: adenine (A), thymine (T), cytosine (C), guanine (G). These pair up, A with T and C with G. The human genome has between 2.8 and 3.5 billion base pairs!
- 11. DNA double helix The base pairs form the rungs of the ladder-like DNA double helix. Running up and down the ladder are the long sequences of bases which are the code for life. Each cell in the human body contains 2 meters (6 feet) of DNA!
- 12. DNA video
- 13. Genes As little as 3% of the total genome is made of genes - the rest is meaningless “junk”. Genes are special sequences of hundreds or thousands of base pairs that provide the templates for all the proteins which the body needs to produce.
- 14. Chromosomes The total number of genes is not known. The estimate ranges from 30,000 - 120,000! All genes are wrapped up into bundles called chromosomes. Every human has 23 pairs of chromosomes, one half of each pair from each parent!
- 15. Nucleus and the cell The 46 chromosomes are held in the nucleus found in most cells in the human body. Nearly every cell in the body contains the full DNA code for producing a human.
- 16. Heredity Heredity is the passing on of traits from parent to offspring.
- 18. Dominant Trait The stronger of two traits. Represented with a capital letter. R
- 19. Recessive Trait The weaker of two traits. Represented with a lower case letter. r
- 20. Genotype Every one has two genes for a trait. One gene from mom and one gene from dad. If mom gives you a dominant gene and dad gives you a recessive gene your genotype would be: Rr
- 21. What is a genotype? The genotype is the genetic make-up of a trait. The letters that represent the genes are the genotype. Rr
- 22. Phenotype The phenotype is the physical characteristic that you can see. For example: brown hair, brown eyes, widows peak, etc..
- 23. Homozygous genotype If both parents give you a dominant gene, your genotype would be homozygous dominant . RR Homozygous - means both genes are the same! If both parents give you a recessive gene, your genotype would be homozygous recessive . rr
- 24. Heterozygous genotype If one parent gives you a dominant gene, and the other parent gives you a recessive gene, you will have a heterozygous genotype Rr Heterozygous - means the two letters are different
- 25. Punnett squares Are tools used in genetics to predict the genotype and phenotype of offspring.
- 26. How to use a Punnett square