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 form 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 called autosomes

  1. 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
  2. Benign tumor is a mass of normal cells
  3. 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
  4. 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)
  5. 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

Patterns of Inheritance The Language of Genetics History

  1. The blending hypothesis of the 1800s was discarded
  2. Gregor Mendel, the “father of genetics”    believed that distinct factors (genes) were responsible for inheritance    Conducted breeding experiments on pea plants    3. Genetics- the study of how traits are passed from parent to offspring    The Rules of Chance

       1. Gene- a portion of the chromosome that controls a trait (flower color)    2. Allele- Either one of the alternate versions of a gene (P or p)       Genotype- genetic composition (PP or Pp or pp)       Phenotype- physical appearance (purple or white)    3. True-breed- an organism that always passes on it characteristics       Homozygous- two of the same alleles for the same trait

  1. Hybrid- an organism that has two different alleles for the same trait    Heterozygous- two different alleles for the same trait    5. Dominant- in a hybrid, the allele that is expressed (P-purple)    6. Recessive- in hybrid, the allele that is not expressed (p- white)    7. P Generation- parents (PP x pp)    8. F1 Generation- Children (4/4 Pp)    9. F2 Generation- grandchildren (¼ PP, ½ Pp, ¼ pp)    Punnet Squares    Mendel’s Laws

       1. Individual units, called genes, determine biological characteristics    2. For each gene, an organism receives one allele from each parent       Alleles separate from each other (segregation)       Forming sex cells

  1. If an organism inherits different alleles for the same trait, one allele is dominant over the other.    4. Some genes separate, or segregate independently    Monohybrid Cross

       1. A monohybrid cross results from crossing two organisms that differ in one characteristic       Identify the dominant and recessive alleles       Determine the genotype of each parent and possible gametes       Set up a Punnet square and cross       List the genotypes and phenotypes of the offspring in each box       Determine the solution to the problem       Dihybrid Cross

  1. A dihybrid cross results from crossing organisms that differ in two characteristicsSeed color and shape    Seed color and shape    A cross between two hybrids results in a 9:3:3:1 ratio

Inheritance Patterns Incomplete Dominance 1. Incomplete dominance is when neither gene is totally dominant 2. Produces an intermediate phenotype Multiple Alleles 1. There are 4 blood types, A, B, AB, and O Type A Type AA Type Ao Type B Type BB Type Bo Type AB Type O 2. The gene for o is recessive to A and B 3. A and B are codominant 4. Mixing blood types can result in blood clotting Polygenic Inheritance 1. Polygenic inheritance is when more than one gene affects a single trait. Height and skin color 2. Produces a broad range of phenotypes

Environmental Influences 1. The environment can affect an individual's phenotype Height and weight, coloring, blood count

DNA: The Language of Life (Chapter 11 Lesson) The Structure of DNA History

 1. 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  2. Adenine and Guanine are Purines (2 rings)  3. Thymine and Cytosine are Pyrimidines (1 ring)  4. 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     3. Replication is the process used to make a copy of DNA     4. 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  5. For every gene (recipe) there is a protein  6. Proteins determine the appearance and function of the cell/ organism  7. 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  8. 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  9. 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

  1. Translation is the process of converting information of mRNA into a protein     tRNA acts as the translator b/w nucleic acids and proteins     The ribosome is the meeting place for mRNA and tRNA
  2. 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     Sex-linked Traits

         1. Sex chromosomes carry genes for traits        Some genes are located on the X chromosomes (females have 2 genes)        Males have only 1 gene for each of these traits     2. Thomas Hunt Morgan discovered sex-linked traits (eye color) in fruit flies

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