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MIDTERM REVIEW 2016-2017 Biology Chahda-Gonzalez Burton WHAT IS BIOLOGY? Biology is the study of all living things Living things are called organisms Organisms include bacteria, protists, fungi, plants, & animals CELL THEORY Cell theory: all living things are composed of cells, cells are the smallest unit (structure) of living things that can perform the processes (functions) necessary for life, living cells come only from other living cells. Prokaryote: single celled creature (EX: bacteria) Eukaryote: multi-celled creature (EX: cat) PLANT VS. ANIMAL CELL Animal Cell Plant Cell Cell wall Absent Present (formed of cellulose) Shape Round (irregular shape) Rectangular (fixed shape) Vacuole One or more small vacuole. One, large central vacuole Centrioles Present in all animal cells Chloroplast Animal cells don't have them Plant cells have chloroplasts Plasma Membrane Lysosomes Only present in lower plant forms. Only cell membrane Lysosomes occur in cytoplasm. Cell wall and a cell membrane Lysosomes usually not evident. CHARACTERISTICS OF LIFE 1. Basic Unit is the Cell 2. They Reproduce 3. All Based On Universal Genetic Code (DNA) 4. Grow & Develop 5. Obtain & Use Materials & Energy 6. Respond To Their Environment 7. Maintain A Stable Internal Environment (homeostasis) 8. Living Things Evolve, That Is They Change Over Time SCIENTIFIC METHOD Observation, Hypothesis, Experiment, Data Collection, Conclusion, Retest An experimenter changes one factor and observes or measures what happens. The experimenter makes a special effort to keep other factors constant so that they will not effect the outcome. Those factors are called control variables. An independent variable is the variable that is changed or controlled in a scientific experiment to test the effects on the dependent variable. A dependent variable is the variable being tested and measured in a scientific experiment. BIOCHEMISTRY Molecule: a group of atoms bonded together. The smallest unit of a chemical compound that can take part in a chemical reaction. Atom: the basic unit of a chemical element. Compound: a thing that is composed of two or more separate elements; a mixture. Proton: a subatomic particle with a positive charge. Located in the atomic nuclei. Neutron: a subatomic particle with no charge. Located in the atomic nuclei. Electron: a subatomic particle with a negitive charge. Located outside the atomic nuclei in the atomic shell. Element: pure substance that consists of only one type of atom. EX: Carbon, C Isotope: a radioactive element, which has a different amount of neutrons than protons CHEMICAL BONDS Covalent bonds: when atoms share electrons Ionic bonds: when atoms transfer electrons Polar bonds: A type of covalent bond between two atoms in which electrons are shared unequally, resulting in a bond in which one atom has a slightly negative charge and the other a slightly positive charge. Non-polar bonds: a type of chemical bond where two atoms share a pair of electrons with each other. Hydrogen bonds: A chemical bond in which a hydrogen atom of one molecule is attracted to an electronegative atom, especially a nitrogen, oxygen, or fluorine atom, usually of another molecule. PROPERTIES OF WATER 1. Cohesion: water molecules stick to each other. 2. Adhesion: water molecules stick to other surfaces. This causes water to move upward against gravity in plant stems and to be absorbed by paper towels. 3. Surface Tension: water has the ability to support small objects. The hydrogen bonds between neighboring molecules cause a “film” to develop at the surface. 4. Capillary Action: water has the ability to “climb” structures. Think about what happens when you stick the tip of a straw in a glass of water. 5. Ability to Dissolve: water is consider to be the universal solvent. More substances will dissolve in water than any other liquid. 6. Heat of vaporization: Water has a high boiling point. It takes a lot of energy to heat water to boiling. 7. Density qualities: Ex: ice floats on liquid water CARBON Having the atomic number 6, every carbon atom has a total of six electrons. Two are in a completed inner orbit, while the other four are valence electrons—outer electrons that are available for forming bonds with other atoms. The carbon atom's four valence electrons can be shared by other atoms that have electrons to share, thus forming covalent (shared-electron) bonds. They can even be shared by other carbon atoms, which in turn can share electrons with other carbon atoms and so on, forming long strings of carbon atoms, bonded to each other like links in a chain. PH (1-14) pH is a measure of the hydrogen ion concentration of a solution. Solutions with a high concentration of hydrogen ions have a low pH and solutions with a low concentrations of H+ ions have a high pH. MACROMOLECULES: MOLECULES OF LIFE Biological macromolecules are the large molecules necessary for life. Carbohydrates Lipids Proteins Nucleic acids Composed of CHONP HOW MACROMOLECULES JOIN TOGETHER Monomer: A single unit Polymer: A chain of similar single units In dehydration synthesis, OR creating bonds between molecules by REMOVING water, monomers combine with each other via covalent bonds to form polymers. In hydrolysis, OR breaking down molecules by ADDING water, polymers are broken down into smaller units or into monomers. CARBOHYDRATE Used for energy and structure Built from C, H, O Monosaccharide: simple sugars like glucose, galactose, and fructose. Disaccharide: double sugars like sucrose or lactose. Polysaccharide: long chains of monosaccharides like cellulose or glycogen. LIPID Large, non-polar molecules. Phospholipids are used in the cell membrane. They can make waxy covering in plants, pigments, and steroids. They can also be used for energy. They are made of C, H, O. They use more C and H than carbohydrates. Triglycerol: made of a glycerol (alcohol) and 3 fatty acid chains. Phospholipid: a lipid with a phosphate Saturated lipids: only single bonds between carbons Unsaturated lipids: contain at least one double bond PROTEIN Composed of amino acids, proteins are used to build cells and they do a lot of work inside an organism. They act as enzymes to control metabolic reactions. Two functional groups: Carboxyl (-COOH) and Amino (-NH2) They are made of C, H, O, N. Amino acids join together to form chains called polypeptides. Proteins have different structures: primary, secondary, and quaternary. NUCLEIC ACID Carry the genetic information in a cell. ATP is used for energy. It is made of subunits called Nucleotides. DNA: Deoxyribose Nucleic Acid RNA: Ribonucleic Acid ATP: Energy molecule for organisms ENZYMES Most enzymes are proteins. They can act as catalysts to speed up a reaction. Enzymes are not used up or changed in a reaction, they can be re-used. Their names end in –ase. The area where an enzyme attaches to a substrate is called an active site. Certain things called cofactors or coenzymes can help enzymes, inhibitors stop enzymes from working. The activation energy is the energy required to start a reaction. Enzymes can lower the energy required to make the reaction happen. PASSIVE TRANSPORT Concentration gradient: the process of particles, moving from an area with a higher number of particles (higher concentration) to an area with a lower number of particles (lower concentration). Diffusion: movement along a concentration gradient. Osmosis: movement of water along a concentration gradient. Facilitated diffusion: movement along a concentration gradient with the help of integral proteins. ACTIVE TRANSPORT Active transport: movement AGAINST the concentration gradient. Phagocytosis: the process by which a cell— often a phagocyte or a protist—engulfs a solid particle with the help of a vesicle. Pinocytosis: the ingestion of liquid into a cell with the help of small vesicles from the cell membrane TONICITY Hypotonic: the inside of the cell has LESS water than the outside, so the water will want to go into the cell. Hypertonic: the inside of the cell has MORE water than the outside, so the water will want to leave the cell. Isotonic: the water is balanced between the inside and the outside of the cell. PHOTOSYNTHESIS PHOTOSYTHESIS Photosynthesis is the process by which plants, some bacteria, and some protists use the energy from sunlight to produce sugar, which cellular respiration converts into ATP, the "fuel" used by all living things. It takes place in the chloroplast. THE CELL CYCLE The cell cycle or celldivision cycle is the serie s of events that take place in a cell leading to its division and duplication of its DNA (DNA replication) to produce two daughter cells. CELLULAR RESPIRATION Cellular respiration is what cells do to break up sugars into a form that the cell can use as energy. This happens in all forms of life. Cellular respiration takes in food and uses it to create ATP, a chemical which the cell uses for energy. It takes place in the mitochondria. Glycolosis: the breakdown of glucose by enzymes, releasing energy and pyruvic acid. Krebs Cycle: the sequence of reactions by which most living cells generate energy during the process of aerobic respiration Electron Transport Chain: a series of compounds that transfer electrons from electron donors to electron acceptors. Enzyme cofactors: NAD+ NADPH CHLOROPLASTS AND MITOCHONDRIA MITOSIS Interphase Prophase Metaphase Anaphase Telophase • Cytokinesis at the cleavage furrow Diploid diploid MEIOSIS Interphase Prophase I Crossing over Metaphase I Anaphase I Telophase I Prophase II Metaphase II Anaphase II Telophase II Diploid haploid REPRODUCTION Mitosis creates clones, exact copies. Meiosis is for sexual reproduction. Spermatogenesis: the creation of the male sexual reproduction cells by meiosis. Oogenesis: the creation of the female sexual reproduction cells by meiosis. Crossing-over: the exchange of genes between two chromosomes, resulting in non-identical chromatids that comprise the genetic material of gametes. Creates diversity. Nondisjunction: the failure of one or more pairs of homologous chromosomes or sister chromatids to separate normally during nuclear division, usually resulting in an abnormal distribution of chromosomes in the daughter nuclei. In meiosis, the parent is DIPLOID (2n), it has the regular amount of chromosomes. The daughter cells are HAPLOID (n), meaning they have HALF the amount of chromosomes. DNA AND RNA DNA: Double helix Deoxyribose sugar A:T, G:C RNA: Single strand Ribose sugar U:A, G:C DNA REPLICATION The process in which cells make proteins is called protein synthesis. Transcription takes place in the nucleus. It uses DNA as a template to make an RNA molecule. RNA then leaves the nucleus and goes to a ribosome in the cytoplasm, where translation occurs. Translation occurs outside of the nucleus reads the genetic code in mRNA and makes a protein. The protein is made on the ribosome.