1. UNIT 6: H EREDITY & G ENETICS S7L3 Students will recognize how biological traits are passed on to successive generations.

2. U NPACKING THE S TANDARDS S7L3. Students will recognize how biological traits are passed on to successive generations. a. Explain the role of genes and chromosomes in the process of inheriting a specific trait. b. Compare and contrast that organisms reproduce asexually and sexually: (bacteria, protists, fungi, plants & animals). c. Recognize that selective breeding can produce plants or animals with desired traits.

3. W HAT WE WILL BE LEARNING Understanding of biological traits & heredity. Understanding the roles that genes and chromosomes have in how traits are passed through generations by sexual or asexual reproduction in organisms. Understanding the concept of selective breeding and how it can be used to produce desired traits in plants and animals.

4. C ELL D IVISION Stage 1: Interphase – the cell grows, makes a copy of its DNA, and prepares to divide into two cells. Stage 2: Mitosis – the stage where the nucleus divides into two new nuclei. One copy of the DNA is distributed into each of the two “daughter cells” Prophase Metaphase Anaphase Telophase Stage 3: Cytokinesis – Completes the process. The cytoplasm divides and organelles are distributed into each of the two new cells.

5. A SEXUAL & S EXUAL R EPRODUCTION One parent produces offspring. Offspring is genetically identical to the parent. Regeneration: lizards & starfish can grow back a body part that is lost. Budding: new growth on parent organism breaks off and is a new organism. Two parents produce offspring. Sex cells (sperm & egg) are produced. Sex cells contain half the number of chromosomes in body cells. Offspring are a combination of both parents genetics.

6. G REGOR M ENDEL

7. U NIT 6 V OCABULARY Heredity: the passing of physical characteristics from parents to offspring. Trait: a biological trait, a different form of a characteristic such as color Genetics: the scientific study of heredity Purebred: an organism that is the offspring of many generations that have the same trait. Gene: factors that control a trait Alleles: the different forms of a gene. Traits are controlled by alleles inherited from the parents. Some are dominant while others are recessive.

8. U NIT 6 V OCABULARY Dominant Allele: an allele whose trait always shows up in the organism when its present. Represented by a capital letter, tall stems = T Recessive Allele: an allele whose trait is hidden whenever the dominant allele is present. Represented by a lowercase letter, short stems = t Hybrid: an organism that has two different alleles for a trait. Two dominant alleles = TT Two recessive alleles = tt One allele for each = Tt

9. U NIT 6 V OCABULARY Genotypes: the combination of alleles (TT) Phenotype: the trait that is expressed (tall stem) Punnett Square: a diagram that shows all of the possible combinations of alleles that might result from a cross. Probability: describes the likelihood that a certain event will occur. Heterozygous: an organism that has 2 different alleles for a trait (Tt). Homozygous: an organism that has 2 identical alleles for a trait (TT) or (tt). Codominance: the alleles are neither dominant or recessive. Both alleles are expressed in offspring.

10. P UNNETT S QUARE

11. T HE C ELL & I NHERITANCE A sperm cell has 23 chromosomes An egg cell has 23 chromosomes During fertilization these chromosomes pair up. Humans have 23 PAIRS of chromosomes for a total of 46 chromosomes. Chromosome Theory of Inheritance = Genes are carried from parents to offspring on chromosomes. Chromosomes are made up of many genes joined together like beads on a string. You have 20,000+ genes!!

12. H UMAN I NHERITANCE Sex-Linked Genes – Genes on the X and Y chromosomes whose alleles are passed from parent to child. Color Blindness Hemophilia A carrier is a person who has one recessive allele for a trait and one dominant allele. They do not have the trait but can pass it on to their offspring.

13. H UMAN I NHERITANCE Sex-Linked Genes – Genes on the X and Y chromosomes whose alleles are passed from parent to child. Color Blindness

14. T HE DNA C ONNECTION Chromosomes are composed of DNA DNA is made of 4 Nitrogen bases: T - Thymine G - Guanine C - Cytosine A – Adenine Mutations – any change in a gene or chromosome. They can cause a cell to produce an incorrect protein during protein synthesis. As a result, the organism’s trait, or phenotype, may be different from what it normally would have been.

15. G ENETIC D ISORDERS A genetic disorder is an abnormal condition that a person inherits through genes or chromosomes. Some genetic disorders are caused by mutations in the DNA of genes. Others are caused by changes in the overall structure or number of chromosomes. Cystic Fibrosis: the body produces abnormally thick mucus in the lungs and intestines. Sickle-Cell Disease: when red blood cells have an unusual sickle shape and cannot carry as much oxygen. Hemophilia: when a person’s blood clots very slowly or not at all. Down Syndrome: when a person has an extra copy of chromosome 21. There is a degree of mental retardation.

16. S ELECTIVE B REEDING Selective Breeding - Humans use genetic patterns that occur naturally in plant and animals to pass desired traits on to the next generation. Inbreeding is selective breeding in order to maintain a certain characteristic in a line of organisms. Inbreeding increases the possibility of genetic defects Hybridization is selective breeding where you cross individuals with different traits in hopes of producing offspring with the best traits of each organism. Genetic engineering is the process of removing bits of genetic material from one organism and inserting it into another. Cloning uses the genetic information from a single cell of an organism to produce another organism with the same genetic information.