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UNIT 1 – UNDERSTANDING LIFE ON EARTH. What qualifies something as living?. Organisms are made up of cells Organisms reproduce sexually or asexually and some can do both Organisms will have a genetic code, DNA Organisms will grow and develop Organisms will obtain and use energy
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What qualifies something as living? • Organisms are made up of cells • Organisms reproduce sexually or asexually and some can do both • Organisms will have a genetic code, DNA • Organisms will grow and develop • Organisms will obtain and use energy • Organisms will respond to their environment • Organisms will strive to maintain homeostasis • Organisms will change over time
Discussion • What kinds of cells? • What is an example of asexual reproduction? • What is an example of sexual reproduction? • If all organisms have DNA is that DNA identical? • What is the difference between grow and develop? • What are 2 ways organisms obtain energy? • What does homeostasis mean? • What if living things do not adapt to changes in their environment?
Answers: • Prokaryote-bacteria Eukaryote-plant , animals • Mitosis is asexual reproduction • Meiosis is sexual reproduction • No the DNA is not identical, except in identical offspring. There are similarities but variation in the species • Growth is to add more cells, Develop is to mature into and adult • Organisms can obtain energy by being either an autotroph or heterotroph • Homeostasis means same-state. Organisms need to maintain a stable internal environment in the body • If an organisms does not adapt to changes in the environment then they must change the environment or die
Evolution • Can be sudden or gradual • Sudden changes that interrupt the gradual progress is called Punctuated Equilibrium. • Explanation: • https://www.youtube.com/watch?v=6QiRoO8af7s
Levels Life is organized • Atoms • Molecules • Cells *life begins here • Tissue • Organ • Organ System • Organism • Species • Population • Community • Ecosystem • Biosphere
What elements from the periodic table support all life on Earth? Answer: • CARBON • HYDROGEN • OXYGEN • NITROGEN • PHOSPHORUS
Periodic Table of Elements • Highlight the following element on your Periodic Table. The table should be glued in on the Left. • Carbon • Hydrogen • Oxygen • Nitrogen • Phosphate • Sulfur
Carbon-based Molecules: Organic chemistry: study of carbon compounds Carbon has 4 electrons in an outer energy levelthat holds eight; Can form 4 covalent bonds with many other elements
Shape of Organic Molecules: shape=function The shape determines its function in an organism
Giant Molecules – Polymers: • Large molecules are called polymers • Monomerslink together to form larger molecules called polymers • Biologists call polymers macromolecules or biomolecules
Linking Monomers: Cells link monomers by removing a molecule of water this process is called dehydration synthesis. Remove H H2O Forms Remove OH
Breaking Down Polymers: • Cells break down macromolecules by adding a molecule of water • this process is called hydrolysis
Macromolecules in Organisms: There are four macromolecules: Carbohydrates (CHO) Lipids (CHO) Proteins (CHON) Nucleic Acids (CHONP)
Monosaccharides: • Monosaccharides are the monomers of carbohydrates; also called simple sugars • Examples: glucose, fructose, & galactose • Chemical Formula for monosaccharides is C6H12O6; this a ratio of 1:2:1 • Monosaccharides are the main fuel that cells use for cellular work; they are a source of quick energy • Disaccharides (2 Sugars bonded); example – sucrose (table sugar)
Polysaccharides: Large sugar molecules; take longer for body to break down • Starch is an example of a polysaccharide in plant cells • Glycogen is a polysaccharide found in animal cells • Starch and glycogen are extra amounts of sugar taken in by the cell and stored for later use • Cellulose is a polysaccharide found in plant cell walls; most abundant organic compound on earth
Lipids: • Lipids are hydrophobic –”water fearing”; they do not mix with water • Includes fats, waxes, steroids and oils • Functions – • store energy • Insulate body • Cushion and protect organs • Form cell membranes
Structure of Lipids: • Triglyceride - Monomer of lipids Composed of 1 glycerol molecule and 3 fatty acid chains Glycerol forms the “backbone” of the triglyceride • Triglycerides are composed mainly of carbon and hydrogen; oxygen is found only in the glycerol molecule
Lipids in Organisms: Most animal lipids exist as solids at room temperature (butter, lard, fat layer on steak/chicken, waxes) Most plant lipids tend to exist as liquids at room temperature (peanut, sunflower, canola oils)
Lipids & Cell Membranes: • Cell membranes are made of phospholipids • Phospholipids have a head that is polar; it attracts water (hydrophilic) • Phospholipids also have 2 tails that are nonpolar and do not attract water (hydrophobic)
Steroids: • Cholesterol is the “base steroid” from which your body produces other steroids • Estrogen and testosterone are examples of these other steroids
Proteins: • Proteins are large, folded polymers made of monomers called amino acids • Elements in proteins: C, H, O and N • Functions: • Build cells • Act as hormones • Act as enzymes • Cellular transport
Linking Amino Acids: • This process is done by the ribosomes in the cell by removing a water molecule from the amino acids • The process is called a condensation or dehydration reaction; forms peptide bonds
Enzymesare proteins • What do enzymes do? • Enzymes control the rate of chemical reactions • Enzymes are also referred to as biological catalysts • enzymes work by weakening bonds and lowering the amount of activation energyneeded for the reaction • Enzymes act on a substrate; they are specific to substrate
Nucleic Acids • Store hereditary information • Contain information for making all the body’s proteins • Elements in nucleic acids: C, H, O, N and P • Types of nucleic acids: DNA and RNA
Nucleic acids are polymers; Nucleotides are the monomers • Nucleotides are composed of: 5-carbon sugar phosphate group nitrogeneous base
Nitrogeneous Bases: • Each DNA nucleotide has one of the following bases: • Each RNA nucleotide has one of the following bases: • Adenine (A) • Guanine (G) • Uracil (u) • Cytosine (C) • Adenine (A) • Guanine (G) • Thymine (T) • Cytosine (C)
Shape of dna and rna: • One strand of RNA forms a single helix • Two strands of DNA join together to form a double helix
ATP • ATP is the energy currency of cells • Made of a nucleotide with 3 phosphate groups