NURSING HESI A2 STUDY GUIDE WELL
ANALYSED
Biology – Scientific study of life.
Hierarchic organizational system for nomenclature: Kingdom,
... [Show More] 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.
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NURSING HESI A2 STUDY GUIDE WELL
ANALYSED
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.
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NURSING HESI A2 STUDY GUIDE WELL
ANALYSED
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. [Show Less]