Master - Hesi A2 Study Guide.docx Version 2.

MASTER - HESI A2 STUDY GUIDE.DOCX VERSION 2. Biology – Scientific study of life. Hierarchic organizational system for nomenclature: Kingdom, Phylum, Class, Order, Family, Genus, and Species. Kingdom is the largest and most inclusive while species is the most restrictive. The scientific method: 1. Observation: New observations made/ previous data collected and studied. 2. Hypothesis: Statement or explanation of certain events or happenings. 3. Experiment: Repeatable procedure of gathering data to support or refute the hypothesis 4. Conclusion: Where the date and its significance are fully explained. The most significant aspect of water is the polarity of its bonds that allow for hydrogen bonding between molecules. Several resulting benefits of hydrogen bonding (intermolecular bonding): 1. Waters high specific heat capacity. (specific heat – amount of temp needed to raise temp of 1 gram to 1 degree Celsius). Due to waters (H2O) high specific heat it’s able to resist changes in temperature and can stabilize environments. 2. Hydrogen bonding also results in strong cohesive (two molecules of likeness stick together) and adhesive (two molecules attract that are different) properties. Cohesion example – water tends to run together on newly waxed car. Adhesion example – When water is spread on the wall some sticks. - When water freezes it’s known as lattice crystal (only solid that floats on water). 3. The polarity of water also allows it to act as a versatile solvent. Biologic Molecules include: Carbohydrates, lipids, proteins, and nucleic acids. 1. Carbohydrates – generally long chains or polymers of sugar. The most important functions: storage, structure, and energy. Carbohydrates form the backbone of DNA and RNA. 2. Lipids (AKA Fats) – Saturated fats contain no double bonds hydrocarbon tail, as a result saturated fat are solid a room temp and related to cardiovascular problems. Unsaturated fats: have one or more double bond. o Phospholipids – two fatty acids varying in length bonded to a phosphate group. Phosphate group is charged and therefore polar and soluble in water which is important for cellular membranes which creates a barrier to protect the cell. o Steroids – lipids that are important because they are a precursor to most hormones and drugs. 3. Proteins – Most significant to cellular function and are polymers of 20 molecules called amino acids. Proteins are largest biologic molecule and are used to catalyze reactions with enzymes. Nearly all cellular function is catalyzed by some type of enzyme. 4. Nucleic acids – Important for a cells inheritance. DNA: Contains code necessary for replication. RNA is used to transfer info from DNA to protein level and as a messenger in most species of genetic code. Metabolism – is the sum of all chemical reactions that occur in an organism. In a cell, reactions take place in a series of steps known as metabolic pathways from high energy to low energy. The Cell – Is the fundamental unit of biology. There are two types of cells: Prokaryotic and Eukaryotic. o Prokaryotic cells: lack a defined nucleus and do not contain membrane bound organelles. o Eukaryotic Cells: Have a membrane bound enclosed nucleus and a series of membrane bound organelles that carry out the functions of the cell. The eukaryotic cell is more complex than prokaryotic. Several organelles functioning in a cell: 1. Nucleus – contains DNA of the cell organized in masses known as chromosomes. Chromosomes contain all genetic info for regeneration (replication and repair) of the cell and instructions for the function of cells. 2. Ribosomes – organelles that read RNA produced in the nucleus and translate genetic instructions to produce proteins. Cells with a high rate of protein synthesis tend to have large numbers of ribosomes. o Ribosomes found in two places: Bound ribosomes found attached to endoplasmic reticulum (ER) and free ribosomes are found in cytoplasm. o Rough ER: responsible for protein synthesis and membrane protection. o Smooth ER: lacks ribosomes and functions as detoxification and metabolism of multiple molecules. 3. Golgi Apparatus – Packaging, processing, and shipping organelle. Transports proteins from the ER throughout the cell. 4. Lysosomes – intracellular digestion takes place here. Lysosomes can hydrolyze (with hydrolytic enzymes) proteins, fats, sugars, and nucleic acids. Lysosomes normally have an acidic environment (around 4.5 PH) 5. Vacuoles – membrane enclosed structures, process of phagocytosis (eating of other cells) takes place here. Uptake of food through the cell membrane creating food vacuole. Plant cells have central vacuole that function as storage, waste, disposal, protection, and hydrolysis. 6. Mitochondria and chloroplast – Produce cell energy: o Mitochondria - are found in most eukaryotic cells and are the site of cellular respiration. o Chloroplast – are found in plants and are the site of photosynthesis. 7. Cellular membrane – most important component of a cell contribution protection, communication, and the passage of substances into and out off a cell. o Cell membrane is composed of a bilayer of phospholipid with protein, cholesterol, and glycoproteins peppered throughout. o Phospholipids are amphipathic molecules creating bilayers making it selectively permeable. 8. Cellular respiration: Two catabolic pathways that lead cellular energy production: cellular respiration and fermentation. Cellular respiration produces far more energy that it’s anaerobic counterpart, fermentation. o Respiration formula: C6H12O6 + 6O2  6CO2 + 6H2O o There complex steps to cellular respiration: ATP – energy currency of a cell, NADH – reducing agent and is a vehicle of stored energy (this molecule is a precursor to greater amounts of ATP being produced in final steps of respiration). 1. Glycolysis – conversion of glucose to pyruvate taking place in the cytosol of the cell and produces 2 ATP, 2 pyruvate, and 2 NADH molecules. 2. Citric Acid Cycle (Krebs Cycle) – takes place in the matrix of the mitochondria and for 1 single glucose molecule – 2 ATP, 6 CO2, and 6 NADH molecules are produced. 3. Electron transport Chain – Remarkable energy harvest here – 28 to 32 ATP molecules for every single glucose molecule. This conversion results in overall ATP production numbers of 32 to 36 ATP molecules for every glucose molecule consumed. o Photosynthesis – The reverse of cellular respiration: 6CO2 + 6H2O + Light Energy  C6H12O6 + 6O2 o The only noticeable difference is light energy. o Photosynthesis consists of two different stages: light reactions and Calvin Cycle. 1. Light reactions – cell accomplishes production of ATP by absorbing light and converting energy to split a water molecule and transfer the electron (which creates NADPH). 2. These molecules are then used in the Calvin Cycle to produce sugar. These sugars are consumed by the organisms or by the plant itself to produce energy by cellular respiration. Hesi Hint: The raw materials for cellular respiration are Glucose and Oxygen and the products are water, carbon dioxide, and ATP. The products of cell respiration is oxygen and glucose become the raw materials of cellular respiration. Three types of cellular reproduction: Asexual and sexual reproductions – 1. Binary fission 2. Mitosis 3. Meiosis