HESI A2 BIOLOGY PRACTICE
QUESTIONS & STUDY GUIDE
2025 (100+ Q&A, PDF)
kingdom largest and most inclusive category
species most restrictive category
hierarchic organizational kingdom, phylum, class, order, family, genius, species
system
1. observation
2. hypothesis
steps to an experiment 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 the polarity of its bonds that allows for hydrogen
water is bonding between molecules
specific heat the amount of heat necessary to raise the
temperature of 1 gram of that molecule 1 degree
celsius
the extent of hydrogen bonding between
water has high specific water molecules, which allows waters to resist
heat due to
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 lattice crystals; causing the molecules to spread
forms apart, resulting in the phenomenon of ice
floating
polarity of water allows it versatile solvent (used to dissolve a number of different
to act as an solvents)
longs chains, or polymers of sugar
carbohydrates -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
contain no double bonds in their hydrogen tail
saturated fats -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
-most significant contributor to cellular function
proteins -polymeres of 20 molecules called amino acids
-complex, consist of several structural types and are the
largest biological molecule
particular types of proteins that are used to
catalyze different reactions or processes
enzymes
(physical factors such as temperature and pH
QUESTIONS & STUDY GUIDE
2025 (100+ Q&A, PDF)
kingdom largest and most inclusive category
species most restrictive category
hierarchic organizational kingdom, phylum, class, order, family, genius, species
system
1. observation
2. hypothesis
steps to an experiment 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 the polarity of its bonds that allows for hydrogen
water is bonding between molecules
specific heat the amount of heat necessary to raise the
temperature of 1 gram of that molecule 1 degree
celsius
the extent of hydrogen bonding between
water has high specific water molecules, which allows waters to resist
heat due to
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 lattice crystals; causing the molecules to spread
forms apart, resulting in the phenomenon of ice
floating
polarity of water allows it versatile solvent (used to dissolve a number of different
to act as an solvents)
longs chains, or polymers of sugar
carbohydrates -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
contain no double bonds in their hydrogen tail
saturated fats -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
-most significant contributor to cellular function
proteins -polymeres of 20 molecules called amino acids
-complex, consist of several structural types and are the
largest biological molecule
particular types of proteins that are used to
catalyze different reactions or processes
enzymes
(physical factors such as temperature and pH
