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 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

INTRO TO BIOCHEMISTRY

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 level that 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 Monomers link together to form larger molecules called polymers Biologists call polymers macromolecules or biomolecules

Cells link monomers by removing a molecule of water 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)

carbohydrates

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: 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: 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

Enzymes are 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 energy needed for the reaction Enzymes act on a substrate; they are specific to substrate

Enzyme + Substrate = Product:

Nucleic acids

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