BYU PDBIO 305 - HANSEN EXAM 1 2025 QUESTIONS AND ANSWERS
Describe the concept of homeostasis and how it relates to the regulation of physiological processes -
(answer)our external environment is always changing but in order to survive we must keep our internal
environment the same. Homeostasis is the maintaining of relatively constant conditions of the internal
environment. Our body adjusts based on the changing environment
Explain how negative feedback works its effect on homeostasis - (answer)negative feedback is what
happens when our sensor recognizes a change it notifies the control center (often the hypothalamus)
which then makes a change in the body to COUNTERACT the change in conditions.
Describe examples of negative feedback in the human body - (answer)ex: the weather is hot. your skin
sensors recognize your body temperature is increasing and notifies your hypothalamus which then tells
your sweat glands (effector) to start sweating to decrease body temperature
Describe the parts of a negative feedback system (sensor, control center, effector) - (answer)sensor:
picks up changes in environment
control center: receives information from the sensor and directs changes accordingly based on the set
point
effector: makes a response to produce a desired effect
Explain how positive feedback works and its effect on homeostasis - (answer)positive feedback is when
your sensor picks up a change in the environment and then lets the control center know which then
amplifies the initial change
Describe examples of positive feedback in the human body - (answer)ex: when a woman goes into labor
her bodies picks up on the contractions and the hypothalamus then amplifies the contractions and
makes them close together in order to help push the child out.
Describe feed-forward control and give examples - (answer)feed forward is a response that comes in
anticipation to a change. For example when your mouth waters before you eat lunch because your body
is expecting to be fed.
ICF/ECF Osmolarity - (answer)300 mOsm/L
,BYU PDBIO 305 - HANSEN EXAM 1 2025 QUESTIONS AND ANSWERS
what is a biomolecule? - (answer)molecules synthesized by living things
what do all biomolecules contain? - (answer)CARBON
what are the 4 basic types of biomolecules? - (answer)carbohydrates, lipids, amino acids and proteins,
nucleotides
what are carbohydrates composed of? - (answer)carbon, hydrogen, and oxygen
What is the major source of energy for the body? - (answer)carbs
what is the general formula for carbs? - (answer)(CH2O)n
what are the three types of carbs - (answer)monosaccharides
disaccharides
polysaccharides
what makes carbs polar? - (answer)the hydroxyl group
how are disaccharides bonded? - (answer)covalent bonds
what are polysaccharides used for? - (answer)storage of carbs
what is glycogen? - (answer)storage form of glucose in animals
what prevents cells from swelling due to osmotic forces? - (answer)glycogen
, BYU PDBIO 305 - HANSEN EXAM 1 2025 QUESTIONS AND ANSWERS
what is starch? - (answer)storage form of glucose in plants
what is cellulose? - (answer)plant cell walls; dietary fiber
what elements are lipids primarily composed of? - (answer)hydrogen and carbon atoms
what type of bonds do lipids have? - (answer)covalent
what are the 5 classes of lipids? - (answer)triglycerides, ketones, phospholipids, eicosanoids, steroids
what makes a triglyceride? - (answer)3 fatty acids + a glycerol
what is a glycerol? - (answer)a 3 carbon alcohol
when are ketones produced? - (answer)during fasting, low carb diets, or low blood insulin level (type 1
diabetes)
how are ketones produced - (answer)1. hydrolysis of triglyceride in fat tissue
2. free fatty acid released into blood
3. fatty acid converted to ketones by the liver (acetoacetic acid, acetone)
what is ketoacidosis? - (answer)diabetes, it is when their are too many ketones in the blood and can lead
to death.
what is a noticeable ketoacidosis symptom? - (answer)acetone breath (said to smell fruity but more like
nail polish remover)
how do phospholipids react to water? - (answer)react to create a surfactant and create a bilayer where
the phobic tails point inward and the philic head point out. to keep water out of the cell
Describe the concept of homeostasis and how it relates to the regulation of physiological processes -
(answer)our external environment is always changing but in order to survive we must keep our internal
environment the same. Homeostasis is the maintaining of relatively constant conditions of the internal
environment. Our body adjusts based on the changing environment
Explain how negative feedback works its effect on homeostasis - (answer)negative feedback is what
happens when our sensor recognizes a change it notifies the control center (often the hypothalamus)
which then makes a change in the body to COUNTERACT the change in conditions.
Describe examples of negative feedback in the human body - (answer)ex: the weather is hot. your skin
sensors recognize your body temperature is increasing and notifies your hypothalamus which then tells
your sweat glands (effector) to start sweating to decrease body temperature
Describe the parts of a negative feedback system (sensor, control center, effector) - (answer)sensor:
picks up changes in environment
control center: receives information from the sensor and directs changes accordingly based on the set
point
effector: makes a response to produce a desired effect
Explain how positive feedback works and its effect on homeostasis - (answer)positive feedback is when
your sensor picks up a change in the environment and then lets the control center know which then
amplifies the initial change
Describe examples of positive feedback in the human body - (answer)ex: when a woman goes into labor
her bodies picks up on the contractions and the hypothalamus then amplifies the contractions and
makes them close together in order to help push the child out.
Describe feed-forward control and give examples - (answer)feed forward is a response that comes in
anticipation to a change. For example when your mouth waters before you eat lunch because your body
is expecting to be fed.
ICF/ECF Osmolarity - (answer)300 mOsm/L
,BYU PDBIO 305 - HANSEN EXAM 1 2025 QUESTIONS AND ANSWERS
what is a biomolecule? - (answer)molecules synthesized by living things
what do all biomolecules contain? - (answer)CARBON
what are the 4 basic types of biomolecules? - (answer)carbohydrates, lipids, amino acids and proteins,
nucleotides
what are carbohydrates composed of? - (answer)carbon, hydrogen, and oxygen
What is the major source of energy for the body? - (answer)carbs
what is the general formula for carbs? - (answer)(CH2O)n
what are the three types of carbs - (answer)monosaccharides
disaccharides
polysaccharides
what makes carbs polar? - (answer)the hydroxyl group
how are disaccharides bonded? - (answer)covalent bonds
what are polysaccharides used for? - (answer)storage of carbs
what is glycogen? - (answer)storage form of glucose in animals
what prevents cells from swelling due to osmotic forces? - (answer)glycogen
, BYU PDBIO 305 - HANSEN EXAM 1 2025 QUESTIONS AND ANSWERS
what is starch? - (answer)storage form of glucose in plants
what is cellulose? - (answer)plant cell walls; dietary fiber
what elements are lipids primarily composed of? - (answer)hydrogen and carbon atoms
what type of bonds do lipids have? - (answer)covalent
what are the 5 classes of lipids? - (answer)triglycerides, ketones, phospholipids, eicosanoids, steroids
what makes a triglyceride? - (answer)3 fatty acids + a glycerol
what is a glycerol? - (answer)a 3 carbon alcohol
when are ketones produced? - (answer)during fasting, low carb diets, or low blood insulin level (type 1
diabetes)
how are ketones produced - (answer)1. hydrolysis of triglyceride in fat tissue
2. free fatty acid released into blood
3. fatty acid converted to ketones by the liver (acetoacetic acid, acetone)
what is ketoacidosis? - (answer)diabetes, it is when their are too many ketones in the blood and can lead
to death.
what is a noticeable ketoacidosis symptom? - (answer)acetone breath (said to smell fruity but more like
nail polish remover)
how do phospholipids react to water? - (answer)react to create a surfactant and create a bilayer where
the phobic tails point inward and the philic head point out. to keep water out of the cell
