BIO 2301 Human Physiology - Exam 1 (CSCC - SU18) Exam Questions &
Answers Test QUESTIONS AND VERIFIED SOLUTIONS |2026|
ELABORATED &DETAILED ANSWERS!!
Homeostasis - (answer)The body's ability to maintain internal stability, even in the face of external
change
Components of a homeostatic mechanism - (answer)- Control center: usually found in the hypothalamus
of the brain, contains the "set point" for the variable, receives info from the receptors and sends
instructions to effectors
- Receptors: detect or sense the variable and send that info to the control center
- Effectors: receive instructions from the control center and carry them out to get the variable back to
normal
Examples of homeostatic mechanisms - (answer)- The maintenance of body temperature
- Blood glucose levels
- Blood sodium levels
- Blood pressure
Negative feedback - (answer)- When a change in the variable occurs, the body responds by causing a
change in the opposite direction
- The main way that homeostatic mechanisms work
Positive feedback - (answer)- When a change in the variable occurs, the body responds by causing more
of a change in the same direction
- Rarely used in the body
- Examples: blood clotting, oxytocin release during child birth, and milk release
Structure of the plasma membrane - (answer)- Semi-permeable, phospholipid bilayer
,BIO 2301 Human Physiology - Exam 1 (CSCC - SU18) Exam Questions &
Answers Test QUESTIONS AND VERIFIED SOLUTIONS |2026|
ELABORATED &DETAILED ANSWERS!!
- Regulates passage of substances into and out of the cell
- Principal components: lipids, proteins, carbohydrates
Phospholipids in the plasma membrane - (answer)- Hydrophilic head
- Hydrophobic tail
- Arranged in a double layer (bilayer) with the heads surrounded by fluid and the tails kept from the
water
Cholesterol in the cell membrane - (answer)- Hydrophobic so found in the tail
- Maintains the consistency of the cell membrane
- Strengthens it by preventing smell molecules from crossing
- Keeps the phospholipid tails from coming into contact and solidifying it to ensure the hydrophobic tail
stays fluid and flexible
Proteins in the cell membrane - (answer)- Function as enzymes to speed up chemical reactions
- Act as receptors for specific molecules or transport materials across the cell membrane
- Integral proteins are located within the lipid bilater
- Peripheral proteins are located outside the lipid bilayer
Carbohydrates in the cell membrane - (answer)- Sometime attached to proteins or lipids on the outside
of the cell membrane
- Form the glycocalyx which provides cushioning and protection for the membrane, important for cell
recognition and determining if cells should be there or not, and acts as a glue to attach cells together
,BIO 2301 Human Physiology - Exam 1 (CSCC - SU18) Exam Questions &
Answers Test QUESTIONS AND VERIFIED SOLUTIONS |2026|
ELABORATED &DETAILED ANSWERS!!
Polar substances - (answer)- Water soluble
- Water, sodium, potassium
Nonpolar substances - (answer)- Fat soluble
- Urea, carbon dioxide, oxygen, and alcohol
Solubility - (answer)- Like dissolves like
- Polar liquids dissolve polar substances
- Nonpolar liquids dissolve nonpolar substances
What substances can easily pass through the phospholipid bilayer of cell membranes? - (answer)-
Nonpolar substances will pass through easily
- Polar substances must go through a channel in the cell membrane
Disorder - (answer)- Disorder increases
- Molecules want to go where there is more room for them to spread out
Diffusion - (answer)- The movement of small molecules from an area of high concentration to an area of
low concentration
- Does not require ATP energy
- Consists of a solute (molecules being dissolved) and a solution (water)
- Nonpolar, small lipid-soluble molecules will easily pass through the lipid bilayer
Osmosis - (answer)- The unassisted diffusion of water across a selective permeable membrane
, BIO 2301 Human Physiology - Exam 1 (CSCC - SU18) Exam Questions &
Answers Test QUESTIONS AND VERIFIED SOLUTIONS |2026|
ELABORATED &DETAILED ANSWERS!!
- Water will go through an aquaporin (a pore) and will move from where there is more water to where
there is less water (high to low) OR movement of water from an area of low solute concentration to an
area of high solute concentration
- Happens when the membrane is not permeable to the solutes
Osmotic pressure - (answer)- The pressure needed to stop osmosis
- Water follows salt concept
- The more particles there are, the greater the osmotic pressure
Osmolarity - (answer)- The concentration of solute particles in a solution
- NaCl and NH4Cl= x2
- Glucose and Urea = x2
- Must be constantly maintained or neurons will be damaged - osmoreceptors in the hypothalmus
detect increased in osmolarity (due to dehydration) which triggers antidiuretic hormone release, thrist,
and decresed excretion of water in urine
Tonicity - (answer)- The ability of a solution to affect a cell - cell volume will increase and decrease
according to the concentration of the solute surrounding it
- It involves the number of nonpenetrating solutes in a solution and take into account the permeability
of the membrane to the solutes and water
- 3 solution types: isotonic, hypertonic, and hypotonic
Isotonic solutions - (answer)- Causes no changed in the cell
- Examples: 0.9% NaCl (normal saline), 5% dextrose (D5W), and lactated ringers solutions (LRS)
- These are the solutions you want to give people intravenously
Answers Test QUESTIONS AND VERIFIED SOLUTIONS |2026|
ELABORATED &DETAILED ANSWERS!!
Homeostasis - (answer)The body's ability to maintain internal stability, even in the face of external
change
Components of a homeostatic mechanism - (answer)- Control center: usually found in the hypothalamus
of the brain, contains the "set point" for the variable, receives info from the receptors and sends
instructions to effectors
- Receptors: detect or sense the variable and send that info to the control center
- Effectors: receive instructions from the control center and carry them out to get the variable back to
normal
Examples of homeostatic mechanisms - (answer)- The maintenance of body temperature
- Blood glucose levels
- Blood sodium levels
- Blood pressure
Negative feedback - (answer)- When a change in the variable occurs, the body responds by causing a
change in the opposite direction
- The main way that homeostatic mechanisms work
Positive feedback - (answer)- When a change in the variable occurs, the body responds by causing more
of a change in the same direction
- Rarely used in the body
- Examples: blood clotting, oxytocin release during child birth, and milk release
Structure of the plasma membrane - (answer)- Semi-permeable, phospholipid bilayer
,BIO 2301 Human Physiology - Exam 1 (CSCC - SU18) Exam Questions &
Answers Test QUESTIONS AND VERIFIED SOLUTIONS |2026|
ELABORATED &DETAILED ANSWERS!!
- Regulates passage of substances into and out of the cell
- Principal components: lipids, proteins, carbohydrates
Phospholipids in the plasma membrane - (answer)- Hydrophilic head
- Hydrophobic tail
- Arranged in a double layer (bilayer) with the heads surrounded by fluid and the tails kept from the
water
Cholesterol in the cell membrane - (answer)- Hydrophobic so found in the tail
- Maintains the consistency of the cell membrane
- Strengthens it by preventing smell molecules from crossing
- Keeps the phospholipid tails from coming into contact and solidifying it to ensure the hydrophobic tail
stays fluid and flexible
Proteins in the cell membrane - (answer)- Function as enzymes to speed up chemical reactions
- Act as receptors for specific molecules or transport materials across the cell membrane
- Integral proteins are located within the lipid bilater
- Peripheral proteins are located outside the lipid bilayer
Carbohydrates in the cell membrane - (answer)- Sometime attached to proteins or lipids on the outside
of the cell membrane
- Form the glycocalyx which provides cushioning and protection for the membrane, important for cell
recognition and determining if cells should be there or not, and acts as a glue to attach cells together
,BIO 2301 Human Physiology - Exam 1 (CSCC - SU18) Exam Questions &
Answers Test QUESTIONS AND VERIFIED SOLUTIONS |2026|
ELABORATED &DETAILED ANSWERS!!
Polar substances - (answer)- Water soluble
- Water, sodium, potassium
Nonpolar substances - (answer)- Fat soluble
- Urea, carbon dioxide, oxygen, and alcohol
Solubility - (answer)- Like dissolves like
- Polar liquids dissolve polar substances
- Nonpolar liquids dissolve nonpolar substances
What substances can easily pass through the phospholipid bilayer of cell membranes? - (answer)-
Nonpolar substances will pass through easily
- Polar substances must go through a channel in the cell membrane
Disorder - (answer)- Disorder increases
- Molecules want to go where there is more room for them to spread out
Diffusion - (answer)- The movement of small molecules from an area of high concentration to an area of
low concentration
- Does not require ATP energy
- Consists of a solute (molecules being dissolved) and a solution (water)
- Nonpolar, small lipid-soluble molecules will easily pass through the lipid bilayer
Osmosis - (answer)- The unassisted diffusion of water across a selective permeable membrane
, BIO 2301 Human Physiology - Exam 1 (CSCC - SU18) Exam Questions &
Answers Test QUESTIONS AND VERIFIED SOLUTIONS |2026|
ELABORATED &DETAILED ANSWERS!!
- Water will go through an aquaporin (a pore) and will move from where there is more water to where
there is less water (high to low) OR movement of water from an area of low solute concentration to an
area of high solute concentration
- Happens when the membrane is not permeable to the solutes
Osmotic pressure - (answer)- The pressure needed to stop osmosis
- Water follows salt concept
- The more particles there are, the greater the osmotic pressure
Osmolarity - (answer)- The concentration of solute particles in a solution
- NaCl and NH4Cl= x2
- Glucose and Urea = x2
- Must be constantly maintained or neurons will be damaged - osmoreceptors in the hypothalmus
detect increased in osmolarity (due to dehydration) which triggers antidiuretic hormone release, thrist,
and decresed excretion of water in urine
Tonicity - (answer)- The ability of a solution to affect a cell - cell volume will increase and decrease
according to the concentration of the solute surrounding it
- It involves the number of nonpenetrating solutes in a solution and take into account the permeability
of the membrane to the solutes and water
- 3 solution types: isotonic, hypertonic, and hypotonic
Isotonic solutions - (answer)- Causes no changed in the cell
- Examples: 0.9% NaCl (normal saline), 5% dextrose (D5W), and lactated ringers solutions (LRS)
- These are the solutions you want to give people intravenously
