Bell Work: 1/30/12 Draw the three pictures and explain why the third picture is correct.

Objectives Describe the relationship among genes, chromosomes, and inherited traits. (SPI )Describe the relationship among genes, chromosomes, and inherited traits. (SPI ) Sequence a series of diagrams that depict chromosome movement during plant cell division. (SPI )Sequence a series of diagrams that depict chromosome movement during plant cell division. (SPI ) Classify methods of reproduction as sexual or asexual. (SPI )Classify methods of reproduction as sexual or asexual. (SPI )

Mitosis Review 1.Interphase- DNA is copied 2.Prophase- Chromatin (DNA wrapped around protein) forms into chromatids (rods) 3.Metaphase- Chromatids line up in the middle of the cell 4.Anaphase- Chromatids separate 5.Telophase- two new nuclei form around the chromatin (separated chromatids) 6.Cytokinesis- two new cells form

Mitosis: process of a somatic (body) cell dividing to produce an exact copy of itself

MitosisInterphase DNA copies itself (chromosomes are copied) Centrioles copy

MitosisProphase DNA condenses into chromatids (rod-like structures), held together by centromeres Spindle fibers begin to form Centrioles move to opposite sides Nuclear membrane breaks apart

MitosisMetaphase Chromatids (chromosomes) line up across the center of the cell Spindle fibers attach to the centromere

MitosisAnaphase Spindle fibers pull the chromatids to opposite ends of the cell

MitosisTelophase Nucleus forms around the chromatids Chromosomes unwind

MitosisCytokinesis Division of the cytoplasm and the rest of the cell

FYI: Chromosomes  Human body cells have 46 chromosomes, or 23 pairs of chromosomes.  Each chromosome contains certain types of genes.  For example, chromosome 21 codes for Down Syndrome, or Trisomy 21.  A sex cell is produced with an extra copy of chromosome 21; the gamete thus has 24 chromosomes. When combined with a normal gamete from the other parent, the embryo now has 47 chromosomes, with three copies of chromosome 21.

Meiosis In sexual reproduction, two parent cells join together to form offspring that are different from both parents. These parent cells are called sex cells (sperm & egg). Sex cells are made during meiosis.

Meiosis process of a cell dividing to produce 4 cells with half the genetic material Why do the cells produced in meiosis only need half of the genetic material?

Meiosis Interphase I DNA copies itself (chromosomes are copied) Centrioles copy

Meiosis Prophase I DNA condenses into chromatids, held together by centromeres and attach to the membrane Spindle fibers begin to form Centrioles move to opposite sides Nuclear membrane breaks apart

Meiosis Metaphase I Chromatids line up on each side of the center of the cell Spindle fibers attach to the centromere Meiosis is a bit different because there something called crossing-over happens with the DNA. This crossing over is an exchange of genes. The genes are mixed up, not resulting in a perfect duplicate like mitosis.

Meiosis Anaphase I Spindle fibers pull the chromosome pairs apart to opposite ends of the cell

Meiosis Telophase I Nucleus forms around the chromosomes

MeiosisCytokinesis Division of the cytoplasm and the rest of the cell

Meiosis Interphase II Cell rests DNA DOES NOT duplicate Centrioles duplicate

Meiosis Prophase II DNA condenses into chromatids, held together by centromeres Spindle fibers begin to form Centrioles move to opposite sides Nuclear membrane breaks apart

Meiosis Metaphase II Chromosomes line up across the center of the cell Spindle fibers attach to the centromere

Meiosis Anaphase II Spindle fibers pull the chromatids to opposite ends of the cell

Meiosis Telophase II Nucleus forms around the chromatids Chromosomes unwind

MeiosisCytokinesis Division of the cytoplasm and the rest of the cell

Mitosis vs. Meiosis

MitosisMeiosis Both are processes of cell division Both reproduce new cells Both go through Interphase, Prophase, Metaphase, Anaphase, Telophase, & Cytokinesis Asexual cell reproduction (only one parent cell is needed) Produces an exact copy of itself with 46 chromosomes Reproduces two new cells Somatic cells: body cells (skin cells, blood cells, bone cells, muscle cells) Sexual cell reproduction (two parent cells are needed) Produces cells with half as many chromosomes (23) Reproduces four new cells Sex cells (sperm & egg)

Sex Chromosome: Chromosome 23 (XX or XY) xx

Determining the Sex or Gender of Offspring Sex chromosomes carry genes that determine the sex or gender of offspring. In humans, females have two X chromosomes and males have one X and one Y chromosome. During meiosis, one of each of the chromosome pairs ends up in a sex cell. Baby boy= XY Baby girl= XX Example:

Living Things Reproduce 2 Types of Reproduction: Asexual- a single parent produces an offspring identical to the parent Sexual- two parents produce an offspring with traits of both parents

Challenge Questions 1.When animals go through sexual reproduction, what type of cell division are they going through? –meiosis 2.When animals go through asexual reproduction, what type of cell division are they going through? –mitosis

Types of Asexual Reproduction In Animals Budding: happens when a part of the parent organism pinches off and forms a new organism.Budding: happens when a part of the parent organism pinches off and forms a new organism. The new organism separates from the parent and lives independently.The new organism separates from the parent and lives independently. –Jellyfish & hydra

Types of Asexual Reproduction In Animals Fragmentation: parts of the organism break off and a new organism grows identical to the parent.Fragmentation: parts of the organism break off and a new organism grows identical to the parent. –Worms & starfish

Types of Asexual Reproduction In Animals Regeneration: organism loses a body part and that part may develop into a new organism.Regeneration: organism loses a body part and that part may develop into a new organism. –Sea star

Asexual Reproduction in Other Organisms Binary fission is a method of asexual reproduction in which an organism splits into two.Binary fission is a method of asexual reproduction in which an organism splits into two. This occurs in bacteria and other single-celled organismsThis occurs in bacteria and other single-celled organisms

Asexual Reproduction in Plants Some plants can reproduce asexually when they are cut or damaged. These plants can sprout new growth from their roots, stems, and leaves.Some plants can reproduce asexually when they are cut or damaged. These plants can sprout new growth from their roots, stems, and leaves. In wild strawberry plants, stems are capable of arching downward and taking root in the ground, resulting in the formation of a new plant. This is an example of asexual reproduction.In wild strawberry plants, stems are capable of arching downward and taking root in the ground, resulting in the formation of a new plant. This is an example of asexual reproduction.

3-2-1 Reflection 3 differences between mitosis and meiosis 2 different types of asexual reproduction 1 way this relates to your life (real world)