Chapter 10 Cell Reproduction

10.1 Cell Division & Mitosis

A. The Cell Cycle 1. formation- growth & development- death 2. Individual cells have life cycles -cell cycle varies for different types of cells -may take seconds to hours -repair, growth, or replacement

B. Mitosis 1. Process in which the nucleus divides to form two identical nuclei 2. Chromosomes are found in the nucleus- they contain your hereditary information 3. Interphase- each chromosome duplicates, then tighten into thicker strands called chromatids

C. Steps of Mitosis 1. Prophase- chromatid pairs are now visible - spindle fibers are forming 2. Metaphase- chromatid pairs are lined up in the center of the cell 3. Anaphase- chromosomes have separated and pull toward the poles 4. Telophase- cytoplasm separates - two new cells form

ProphaseMetaphaseAnaphase Telophase

D. Results of Mitosis 1. Every cell in your body has 46 chromosomes (23 pairs) 2. Each cell has the same copy of DNA 3. All actors in a play have the same script, but each actor has it’s own lines 4. Each cell has a different job 5. Allows growth and replaces worn out or damaged cells

E. Asexual Reproduction 1. A new organism is produced from one organism 2. Each has the same DNA 3. Examples: -strawberry runners -bacteria (fission) -hydra (budding) -starfish (regeneration)

10.2 Meiosis

A. Sexual Reproduction fertilization MaleSex cell = sperm 23 chromo- somes haploid FemaleSex cell = egg 23 chromo- somes haploid 1 st cell = Zygote 23 pairs diploid Meiosis = division of sex cells -4 new sex cells are produced (4 eggs or 4 sperm) -Each new sex cell has 23 chromosomes (haploid)

B. Meiosis Meiosis 1 Prophase 1 Metaphase 1 Anaphase 1 Telophase 1 Produces 2 new cells similar to Mitosis These 2 new cells undergo division again Meiosis 2 Prophase 2 Metaphase 2 Anaphase 2 Telophase 2 Produces 4 new cells -4 egg or -4 sperm Each cell now has 23 chromosomes (haploid)

10.3 DNA

A. General Information DNA = deoxyribonucleic acid Blueprint of life (instructions) 1 st model made in 1953 by James Watson and Francis Crick Looks like a twisted ladder (“double helix”)  Duplicates during interphase  1 ladder becomes 2 identical ladders

Sides of ladder = sugar and phosphate Steps of ladder = nitrogen bases A = Adenine T = Thymine G= Guanine C = Cytosine Base-Pair Rule A bonds with T G bonds with C B. Parts of the Ladder

New strands unzips C. Making Copies

D. RNA 1. Ribonucleic Acid 2. DNA remains in the nucleus, but in order for it to get it’s instructions, it must send a message out to the ribosomes in the cytoplasm to make the correct proteins

3 types of RNA 1. Messenger RNA (mRNA) -Carries the code that directs the order in which amino acids bond (train) 2. Ribosomal RNA (rRNA) -protein factories 3. Transfer RNA (tRNA) -brings amino acids to protein factories (match-maker)

RNA is similar to DNA except for three things: 1. RNA has 1 strand instead of 2 2. RNA has Uracil (U) instead of Thymine (T) 3. RNA has ribose sugar instead of deoxyribose sugar

DNA mRNA Protein transcriptiontranslation (Draw picture from the board)

E. Genes Genes are sections of DNA on a chromosome Contain instructions for making specific proteins Cells use only the genes that direct the making of proteins needed by that particular cell

F. Mutations 1. Any permanent change in the DNA sequence of a chromosome 2. Caused by: a) Outside factors called Mutagens -X-rays, sunlight, chemicals, drugs b) Incorrect copying of DNA on the ladders