HESI A2 BIOLOGY QUESTIONS AND ANSWERS

HESI A2 BIOLOGY QUESTIONS AND ANSWERS kingdom largest and most inclusive category species most restrictive category hierarchic organizational system kingdom, phylum, class, order, family, genius, species steps to an experiment 1. observation 2. hypothesis 3. experiment 4. conclusion observation data is observed and recorded/ previous data is studied hypothesis a statement or explanation of certain events or happenings experiment repeatable procedure of gathering data to support or refute the hypothesis conclusion where the data and its significance are fully explained aqueous water based water molecule consists of two hydrogen atoms covalently bonded to one oxygen atom most significant aspect of water is the polarity of its bonds that allows for hydrogen bonding between molecules specific heat the amount of heat necessary to raise the temperature of 1 gram of that molecule 1 degree celsius water has high specific heat due to the extent of hydrogen bonding between water molecules, which allows waters to resist shifts in temperature (ability of oceans or large bodies of water to stabilize climates) cohesion the ability of a molecule to stay bonded or attracted to another molecule of the same substance (water running together on a newly waxed car) adhesion the ability of water to bond to or attract other molecules or substances (when water is sprayed onto the wall, some of it sticks to the wall) when water freezes it forms lattice crystals; causing the molecules to spread apart, resulting in the phenomenon of ice floating polarity of water allows it to act as an versatile solvent (used to dissolve a number of different solvents) carbohydrates longs chains, or polymers of sugar -used for storage, structure, and energy -the backbone of important molecules such as DNA and RNA lipids known as fats, but specifically they are fatty acids, phospholipids, and steroids fatty acids Vary greatly but simply are grouped into two categories: saturated and unsaturated saturated fats contain no double bonds in their hydrogen tail -solids at room temp -lead to cardiovascular problems associated with diets unsaturated fats have one or more double bonds -liquid at room temperature phospholipids -consist of two fatty acids of varying length bonded to a phosphate group -phosphate group is charged and therefore polar and soluble in water steroids -component of membranes -precursors to significant hormones and drugs proteins -most significant contributor to cellular function -polymeres of 20 molecules called amino acids -complex, consist of several structural types and are the largest biological molecule enzymes particular types of proteins that are used to catalyze different reactions or processes (physical factors such as temperature and pH can alter the activity because they have an effect on the shape) *enzymes speed up reactions Nucleic Acids -components of the molecules of inheritance -DNA and RNA DNA deoxyribonucleic acid unique molecule specific to a particular organism and contains the code necessary for replication RNA ribonucleic acid used in transfer of information from DNA to protein level and as a messenger in most species of the genetic code metabolic pathways progressing from a standpoint of high energy to low energy.