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All life has heredity in DNA A always bonds with T, and C always bonds with G. Hydrogen bonds connect the two strands of DNA. DNA and Proteins All life has heredity in DNA 1)DNA replication – the process of making an identical copy of DNA. Must occur before a cell divides. 3 All life has heredity in DNA 2)DNA transcription: to rewrite the DNA code in RNA as a messenger that will travel outside the nucleus to begin protein production.(Enzymes,hormones,tissue) RNA Single stranded; sugar is ribose. A—U DNA T — A RNA G—C C—G Messenger RNA 4 All life has heredity in DNA 3)DNA translation: the code in the messenger RNA is translated into protein within an organelle called a ribosome. Cytoplasm Nucleus Ribosome 5 Proteins Proteins are polypeptides, which are long chains of amino acids. The sequence of nucleotides in each gene contains information for assembling the string of amino acids that make up proteins. During translation, proteins are created from long chains of amino acids whose structure depends on the order of amino acid assembly. A mutation in DNA changes the protein. Biochemical Reactions All organisms contain DNA. DNA (deoxyribonucleic acid) carries the genetic code for all organisms. Four nucleotides: Nitrogenous bases A - adenine T – thymine G – guanine C - cytosine 8 Cells can undergo chemical reactions that release energy from carbon-containing compounds (organic) as food. There are 4 major classes of organic molecules in organisms: Carbohydrates Proteins Lipids Nucleic Acids Cells can undergo chemical reactions that release energy from carbon-containing compounds (organic) as food. There are 4 major classes of organic molecules in organisms: Carbohydrates Proteins Lipids Nucleic Acids Carbohydrates Include sugar – C6H12O6 Formed from photosynthesis Broken down in cellular respiration Equation: Photosynthesis 6CO2 + 6H2O → C6H12O6 + 6O2 Equation: Cellular Respiration P + ADP + C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP Carbohydrates Needed Deliver energy to the cell as glucose Structural strength in plants as cellulose Storage of energy in plants a starch Short term storage of energy in animal as glycogen Needed: Proteins to access energy stored in cells to build cell structures to regulate rate of chemical reactions as enzymes Video Lipids Commonly known as fats and oils Create membranes of cells that provide sites for essential energy conversions. Needed As Long term energy storage in animal As Insulating material in cold climate As Shock absorber Nucleic Acids Commonly known DNA and RNA Are made of nucleotides that contain, carbon , nitrogen and phosphorus. Needed To contain and transmit genetic code from generation to generation Asexual and Sexual Reproduction All organisms must reproduce For sexual reproduction Gametes For asexual reproduction video Asexual Reproduction One parent passes copies of all its chromosomes to each of its offspring. Organisms produce new cells by mitosis. Mitosis is the process of nuclear division in which 2 new daughter cells each receive a complete set of chromosomes. Offspring are genetically identical to each other and the parent. Examples: Refer to table 1 video Sexual Reproduction Involves two parents The offspring receives half of its chromosomes from the father and half from the mother. Gametes are sex cells (eggs – sperms) Meiosis produces gametes (1/2 # chromosomes) Upon fertilization, full number of chromosomes is restored with the formation of a zygote. Sexual Reproduction A zygote contains all the information necessary for growth, development, and reproduction. The zygote will be similar but not identical to its parents and different also from its siblings. Increased genetic variations and ,consequently, better adaptations to environmental changes Punnett Squares Genotype – genetic characteristics carried by an organism. Phenotype – the way an organism looks and behaves. Alleles – genes that exists in alternative forms. The allele combination determines its genotype. Dominant Recessive Punnet squares predict probabilities of outcomes. Gametes produced by each parent pea plant are shown along the top and left side. Remember: when the germ cell that produces the sperm or egg divides, the 2n (diploid) number of chromosomes is split in half: Tt becomes T and t. T = dominant t = recessive All life has heredity in DNA Punnet squares predict probabilities of outcomes. ¼ of offspring are TT. ½ of offspring are Tt. ¼ of offspring are tt. T = dominant t = recessive But ¾ of offspring are tall, and only ¼ are short (3:1 ratio). The dominant characteristic usually overpowers the recessive one. All life has heredity in DNA Pedigree charts relate to punnet squares Square = man Circle = woman Filled = disease Half filled = carrier Open = healthy An example of a sex-linked gene All life has heredity in DNA DNA The code of life Mutation in the DNA code in a sex cell chromosome creates a new inheritable alleles Two pink-flowering plants are crossed. The offspring flower are as follows: 25% red, 25% white; 50% pink. What pattern of inheritance does flower color in these flowers follow? A. dominance B. multiple alleles C. incomplete dominance D. recessiveness E. polygenic trait