Cellular Basis of Life The Cell Cycle Growth, Repair, & Reproduce

1. All cells come from other cells 2. The division of cells allows living things to: Repair damage Grow Reproduce offspring Asexual Sexual Chromosomes

2. DNA usually exists in the nucleus as chromatin “string” Before cells divide, DNA duplicates & and condenses Chromosomes are DNA wound around proteins (histones) Sister chromatids joined at the centromere The Cell Cycle

3. Interphase (90%): cell does normal cell activities and: G1- increases proteins, organelles, and size S- duplicates DNA G2- increases supplies for cell division 2. Mitotic phase- division of cell * Mitosis (M)- nucleus divides (PMAT) Cytokinesis- cytoplasm divides The Mitotic Phase The Stages of Mitosis

4. Prophase- DNA condenses Nucleus disappears Spindle fibers appear and attach to kinetochores 2. Metaphase- DNA lines up in the middle 3. Anaphase- DNA separates

5. Telophase- Opposite of Prophase Cytokinesis

6. Animal cells pinch in the middle (cleavage furrow)

7. Plant cells from a cell plate in the middle

New cells are called daughter cells. Reproduction in Prokaryotes

1. Binary fission- 1 cell divides into 2 daughter cells Asexual reproduction Divide every 20 minutes Sexual Reproduction Homologous Chromosomes

2. Chromosomes can be examined by amniocentesis The display of the chromosomes is called karyotype 2. Each chromosome has a twin referred to as a homologous chromosome homologous pairs contain the same type of information The genes may have different versions of the same trait Ex: (eyes: blues/brown) Diploid and Haloid Cells

   1. Diploid cells (2n) have two sets of homologous chromosomes Human’s body cell (46) 23 homologous pairs (numbered 1-23) One set from each parent Pair #23 are the sex chromosomes Female- XX Male- XY All the other pairs calle autosomes

3. Haploid cells (n) have one set of chromosomes Human sex cells (23) 3. When two sex cells (gametes) are joined (fertilization) a zygote is formed Cancer

4. Benign tumor is a mass of normal cells

5. Malignant tumor is a mass of cancer cells Cancer is a disease caused when cells divide and grow out of control When cancer spreads, it is called metastasis Cancer is treated by: Radiation Chemotherapy Meiosis & Variations The Stages of Meiosis

6. Meiosis I: separation of homologous pairs Prophase I: Crossing over b/w homologous pairs Metaphase I: homologous pairs line up Anaphase I: homologous pairs separate Telophase I: homologous pairs sometimes relax (interkinesis)

7. Meiosis II (same as mitosis): separation of sister chromatids Causes of Genetic Variations

   1. Crossing over Synapsis occurs by forming tetrads Exchange of DNA between homologous pairs Different chromosomes are produced through genetic recombination

   2. Independent assortment Homologous pairs of chromosomes are separated randomly 2n possible combinations of 223 = 8 million Mitosis vs. Meiosis

   3. Mitosis produces: 2 cells Diploid (2n) genetically identical

   4. Meiosis produces: 4 cells Haploid genetically different

DNA: The Language of Life (Chapter 11 Lesson) The Structure of DNA History 4. DNA- Deoxyribonucleic Acid Hereditary material of the cell Makes up genes Determines the traits of all living things Located in the nucleus Nucleotides 1. DNA (polymer) is composed of long chains of four different nucleotides (monomers) 2. Each nucleotide has: phosphate group sugar (deoxyribose) nitrogenous base adenine A thymine T guanine G cytosine C 3. Adenine and Guanine are Purines (2 rings) 4. Thymine and Cytosine are Pyrimidines (1 ring) 5. DNA strands form when nucleotides join together Repeating sugar-phosphate “Backbone” nitrogenous bases are lined up 6. Two strands join together by hydrogen bonds The Double Helix 1. Franklin & Wilkins and Watson & Crick determine the structure 2. DNA resembles a twisted ladder Sugar-phosphate on the outside Complementary nitrogenous bases pair on the inside A - T C - G DNA Replication & Mutations DNA Replication 1. Replication is the process used to make a copy of DNA 2. During DNA replication: The two complementary strands separate to form templates Free nucleotides line up with complementary bases New strands are covalently bonded Enzymes control the process Replication is semi-conservative Protein Production From Gene to Protein

1. For every gene (recipe) there is a protein

2. Proteins determine the appearance and function of the cell/ organism

3. DNA → RNA → protein Transcription Translation 4. The genetic code consists of 3 letter codes (codon) Each condon stands for a particular amino acid “All” organisms share this code RNA

4. RNA (Ribonucleic Acid) differs from DNA: Sugar (ribose) Single Strand 2. Types of RNA mRNA (message) copy of the recipe rRNA (ribosome) stove tRNA (transfer) utensils Transcription

5. Transcription is the process of converting the information of DNA onto mRNA Similar to DNA replication except: Uses RNA nucleotides (U pairs with A) Only 1 gene is copied mRNA leaves the nucleus Translation

6. Translation is the process of converting information of mRNA into a protein tRNA acts as the translator b/w nucleic acids and proteins The ribsome is the meeting place for mRNA and tRNA

7. Steps in reading mRNA: AUG is the code for start As each code word is read, amino acids are added UAA, UAG, or UGA are the codes for stop 3. Protein is completed and released