CMS Obj.10-14 State Correlation Obj. 2a-2d Heredity CMS Obj.10-14 State Correlation Obj. 2a-2d

DNA (Deoxyribonucleic acid) Chemical inside cell that contains hereditary information Controls how an organism will look & behave Shaped like a twisted ladder Rungs hold genetic information that is a pair of bases

DNA Video

Reproduction Organisms produce offspring through the process of reproduction. The purpose is to transfer DNA DNA passes from cell to cell in a process called Mitosis Two types of reproduction Asexual Sexual

Mitosis Process by which a cell divides to form two new identical cells Two main steps: DNA in the nucleus is copied Nucleus Divides into 2 identical nuclei Purpose is for growth, repair, or asexual reproduction

Asexual Reproduction New organisms produced with the same hereditary information as the parent using the process of Mitosis (one parent) Examples: One-celled organisms (bacteria) Regeneration: replacing lost body parts (lizard’s tail) Budding: new organism grows out of the old one (hydra) Cloning: make copies of an organism (grow new plant from part of another plant)

Asexual Reproduction Video

Sexual Reproduction New organisms is produced from the combined DNA of TWO different cells called sex cells. Male is called sperm & Female is called egg Fertilization occurs when an egg and sperm unite to form a new organism with half of each parent’s DNA Plants sexually reproduce from male and female parts of a flower Sex cells are formed by the process of Meiosis

Meiosis A double cell division process that produces 4 new cells called gametes with half the number of chromosomes as the original cell Human sex cells have 23 chromosomes

Mitosis & Meiosis

Group Time Transfer DNA Nucleus divides twice Nucleus divides once Two new cells New cells identical to original four new cells Haploid New cells have half the genetic information as original Starts with one cell Produces sex cells Reproductive process Diploid Use the following phrases to create a double-bubble map to compare and contrast Mitosis & Meiosis

MUTATIONS A mutation is a change in a gene or chromosome. Occurs because of an error during mitosis or meiosis or because of something in the environment. Some mutations are beneficial, some are harmful, and some are neutral. Examples: four-leaf clover, seedless grapes, & albino rabbit

LET’S REVIEW Complete the following thinking maps Mitosis as 2 cells divides once Use a tree map to classify organisms that use different types of reproduction

Group Time Use a double-bubble map to compare and contrast Asexual & Sexual Reproduction

Genetics: The study of Inheritance

The passing of traits from parent to offspring Heredity The passing of traits from parent to offspring Traits: physical characteristics of an organism Example: eye color, hair color, & height

Passing Traits to Offspring Sex cells have 23 chromosomes and the two sex cells combine to form body cells with 46 chromosomes. In fertilization, one sperm joins with one egg. The offspring receives half of its genetic information from its mother and the other half from its father.

Genetics The study of how traits are passed from parent to offspring by looking at genes Genes are small sections of DNA on a chromosomes that has information about a trait Each chromosome has a gene for the same trait (eye color from mom & eye color from dad) Traits are determined by alleles on the chromosomes Each gene of a gene pair is called an allele Inherited traits are determined by the alleles on the chromosome

Group Time Use a brace map to show parts of DNA using the following terms Chromosomes Gene allele

DOMINANT AND RECESSIVE Dominant Alleles describe a genetic factor that is always expressed. It prevents a recessive trait from showing up in offspring. Represented by capital letters (B) Recessive Alleles describe a genetic factor that is not always expressed. It only expresses itself when both of the recessive traits are inherited Represented by lowercase letters (b)

Group Time Use a double-bubble map to compare and contrast Dominant & Recessive Alleles

INHERITANCE & PASSING TRAITS

Examining & Studying Traits Two ways scientist study traits Phenotype: outside expression of a gene Blue Eyes Genotype: the two alleles a person has inherited that can only be seen on the DNA BB, Bb, or bb Two categories of genotypes Homozygous: inherited two identical alleles BB (pure dominant) or bb (pure recessive) Heterozygous: inherited two different alleles Bb (hybrid)

Use a double-bubble map to compare and contrast genotype & phenotype Group Time Use a double-bubble map to compare and contrast genotype & phenotype Use a tree map to classify the following genotypes: DD,Dd,dd,ee,LL,Ll,Hh,HH,Ss,tt,

B b BB Bb bb Punnett Squares Shows all possible combinations of alleles that children can inherit from parents Mom’s genotype for brown eyes (Bb) Dad’s genotype for brown eyes (Bb) Offspring’s Phenotype 75% brown, 25% blue Offspring’s Genotype 25% BB, 50% Bb, 25% bb B b BB Bb bb

DOMINANT & RECESSIVE

VARIATIONS Variations are the different ways that a certain trait appears. These variations would allow one offspring to have light brown hair & another to have darker brown hair

Genetic Advantages & Disadvantages Selective Breeding organisms for a certain trait Pure breeding Advantages: allows breeder to have desirable traits expressed in offspring Disadvantages: unfavorable traits can be passed & lack variety to survive diseases or climate changes Hybrid Advantages: has genetic variety to increase variations that allows species to adapt to climate changes or recover from diseases Disadvantages: traits are uncertain in predicting