5.4 Asexual Reproduction KEY CONCEPT Many organisms reproduce by cell division.

Binary fission is similar in function to mitosis. 5.4 Asexual Reproduction 5.4 Binary fission is similar in function to mitosis. Asexual reproduction is the creation of offspring from a single parent. Binary fission produces two daughter cells genetically identical to the parent cell. Binary fission occurs in prokaryotes. parent cell DNA duplicates cell begins to divide daughter cells

5.4 Asexual Reproduction 5.4 Environment determines what form of reproduction is most advantageous. Asexual reproduction is an advantage in consistently favorable conditions. Sexual reproduction is an advantage in changing conditions.

Some eukaryotes reproduce through mitosis. 5.4 Asexual Reproduction 5.4 Some eukaryotes reproduce through mitosis. Budding forms a new organism from a small projection growing on the surface of the parent. bud Hydra Yeast

5.4 Asexual Reproduction 5.4 Fragmentation is the splitting of the parent into pieces that each grow into a new organism. Vegetative reproduction forms a new plant from the modification of a stem or underground structure on the parent plant.

5.4 Asexual Reproduction KEY CONCEPT Gametes have half the number of chromosomes that body cells have.

KEY CONCEPT Cells divide during mitosis and cytokinesis.

Chromosomes condense at the start of mitosis. DNA wraps around proteins (histones) that condense it. DNA double helix DNA and histones Chromatin Supercoiled DNA

DNA plus proteins is called chromatin. chromatid telomere centromere One half of a duplicated chromosome is a chromatid. Sister chromatids are held together at the centromere. Telomeres protect DNA and do not include genes. Condensed, duplicated chromosome

Interphase prepares the cell to divide. Mitosis and cytokinesis produce two genetically identical daughter cells. Parent cell centrioles spindle fibers centrosome nucleus with DNA Interphase prepares the cell to divide. During interphase, the DNA is duplicated.

Mitosis divides the cell’s nucleus in four phases. During prophase, chromosomes condense and spindle fibers form.

Mitosis divides the cell’s nucleus in four phases. During metaphase, chromosomes line up in the middle of the cell.

Mitosis divides the cell’s nucleus in four phases. During anaphase, sister chromatids separate to opposite sides of the cell.

Mitosis divides the cell’s nucleus in four phases. During telophase, the new nuclei form and chromosomes begin to uncoil.

Cytokinesis differs in animal and plant cells. In animal cells, the membrane pinches closed. In plant cells, a cell plate forms.

You have body cells and gametes. 6.1 Chromosomes and Meiosis You have body cells and gametes. Body cells are also called somatic cells. Germ cells develop into gametes. Germ cells are located in the ovaries and testes. Gametes are sex cells: egg and sperm. Gametes have DNA that can be passed to offspring. body cells sex cells (sperm) sex cells (egg)

Your cells have autosomes and sex chromosomes. 6.1 Chromosomes and Meiosis Your cells have autosomes and sex chromosomes. Your body cells have 23 pairs of chromosomes. Homologous pairs of chromosomes have the same structure. For each homologous pair, one chromosome comes from each parent. Chromosome pairs 1-22 are autosomes. Sex chromosomes, X and Y, determine gender in mammals.

Body cells are diploid; gametes are haploid. 6.1 Chromosomes and Meiosis Body cells are diploid; gametes are haploid. Fertilization between egg and sperm occurs in sexual reproduction. Diploid (2n) cells have two copies of every chromosome. Body cells are diploid. Half the chromosomes come from each parent.

6.1 Chromosomes and Meiosis Haploid (n) cells have one copy of every chromosome. Gametes are haploid. Gametes have 22 autosomes and 1 sex chromosome.

6.1 Chromosomes and Meiosis Chromosome number must be maintained in animals. Many plants have more than two copies of each chromosome. Mitosis and meiosis are types of nuclear division that make different types of cells. Mitosis makes more diploid cells.

6.1 Chromosomes and Meiosis Meiosis makes haploid cells from diploid cells. Meiosis occurs in sex cells. Meiosis produces gametes.