NAS 2 CHALLENGE EXAMS SCRIPT QUESTIONS AND
ANSWERS GUARANTEE A+ 2025/2026
✔✔Describe the relationship between salts in the blood and blood volume - ✔✔this will
increase blood volume, which will increase blood pressure
✔✔Describe how the kidneys regulate blood volume - ✔✔the kidneys can decrease
blood volume by excreting potassium and can increase blood volume by reabsorbing
sodium
✔✔Differentiate between a strong acid and a weak acid - ✔✔-strong acids dissociate
completely
-weak acids partially dissociate (carbonic acid)
✔✔Describe how chemical buffers prevent dramatic changes in H+ concentration of
body fluids - ✔✔one or two molecules that act to prevent dramatic changes in hydrogen
ion concentration when acids or bases are added
✔✔Explain how the kidneys respond chemically when blood pH falls (becomes acidic) -
✔✔- bicarbonate ions are reabsorbed back into the blood capillaries in the kidneys
- hydrogen ions are secreted out of the blood into the kidney tubules
✔✔Explain how the kidneys respond chemically when blood pH rises (becomes
alkaline) - ✔✔- bicarbonate ions are excreted out of the blood and into the urine
- hydrogen ions are allowed to accumulate in the blood
✔✔State the main buffering system of the blood - ✔✔The Carbonic Acid-Bicarbonate
Buffer System OR Bicarbonate Buffer System
✔✔Describe how the breathing rate helps to regulate blood pH. - ✔✔
✔✔Define organic compounds and list the 4 major groups of organic compounds in the
body - ✔✔All organic compounds contain carbon and hydrogen.
1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic Acids
✔✔Define carbohydrates. Name the elements that make-up carbohydrates - ✔✔Sugars
(saccharide) and starches that are formed by a 1:2:1 ratio of carbon (C), Hydrogen (H),
and Oxygen (O)
✔✔State which monosaccharide the body prefers to use to make ATP - ✔✔glucose
, ✔✔Name the simplest building block of carbohydrates and lipids - ✔✔carbon
✔✔Define glycogen and its function - ✔✔A major source of fuel for the body, brain, and
cells. The cells convert glucose into a ATP that is used for energy and to carryout life
sustaining processes
✔✔Define lipids, name the main types of lipids and their functions. Name the elements
found in
lipids - ✔✔C, H, O, P & sometimes S
1. Triglycerides (fats):
Main functions:
a. Energy
b. Insulation
c. Protection
d. Structure
2. Phospholipids:
a. Main component of membranes
b. Phospholipid Bilayer!
c. Held together by hydrophilic/hydrophobic interactions and H bonding
3. Steriods: Functions:
a. Cell membranes
b. Hormones
c. Regulate metabolism and immune function
d. Contribute to homeostasis: Regulate excretion of electrolytes
e. In bacteria, contributor to cell wall of some species
✔✔Compare the amount of stored energy in fat to proteins and carbohydrates. - ✔✔Fat
provides twice as much energy per gram than carbohydrates or proteins.
✔✔Explain lipogenesis and lipolysis and state the physiological situation that triggers
each
process to occur. - ✔✔1. Lipogenesis: Excess fats are stored as triglycerides in
adipocytes (fat cells)
- Triglycerides synthesis
- A dehydration reaction
2. Lipolysis: Breakdown of stored triglycerides into fatty acids & glycerol
- A hydration reaction
- FA & glycerol used to make energy
- Preferred energy source for liver, heart, and muscles
ANSWERS GUARANTEE A+ 2025/2026
✔✔Describe the relationship between salts in the blood and blood volume - ✔✔this will
increase blood volume, which will increase blood pressure
✔✔Describe how the kidneys regulate blood volume - ✔✔the kidneys can decrease
blood volume by excreting potassium and can increase blood volume by reabsorbing
sodium
✔✔Differentiate between a strong acid and a weak acid - ✔✔-strong acids dissociate
completely
-weak acids partially dissociate (carbonic acid)
✔✔Describe how chemical buffers prevent dramatic changes in H+ concentration of
body fluids - ✔✔one or two molecules that act to prevent dramatic changes in hydrogen
ion concentration when acids or bases are added
✔✔Explain how the kidneys respond chemically when blood pH falls (becomes acidic) -
✔✔- bicarbonate ions are reabsorbed back into the blood capillaries in the kidneys
- hydrogen ions are secreted out of the blood into the kidney tubules
✔✔Explain how the kidneys respond chemically when blood pH rises (becomes
alkaline) - ✔✔- bicarbonate ions are excreted out of the blood and into the urine
- hydrogen ions are allowed to accumulate in the blood
✔✔State the main buffering system of the blood - ✔✔The Carbonic Acid-Bicarbonate
Buffer System OR Bicarbonate Buffer System
✔✔Describe how the breathing rate helps to regulate blood pH. - ✔✔
✔✔Define organic compounds and list the 4 major groups of organic compounds in the
body - ✔✔All organic compounds contain carbon and hydrogen.
1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic Acids
✔✔Define carbohydrates. Name the elements that make-up carbohydrates - ✔✔Sugars
(saccharide) and starches that are formed by a 1:2:1 ratio of carbon (C), Hydrogen (H),
and Oxygen (O)
✔✔State which monosaccharide the body prefers to use to make ATP - ✔✔glucose
, ✔✔Name the simplest building block of carbohydrates and lipids - ✔✔carbon
✔✔Define glycogen and its function - ✔✔A major source of fuel for the body, brain, and
cells. The cells convert glucose into a ATP that is used for energy and to carryout life
sustaining processes
✔✔Define lipids, name the main types of lipids and their functions. Name the elements
found in
lipids - ✔✔C, H, O, P & sometimes S
1. Triglycerides (fats):
Main functions:
a. Energy
b. Insulation
c. Protection
d. Structure
2. Phospholipids:
a. Main component of membranes
b. Phospholipid Bilayer!
c. Held together by hydrophilic/hydrophobic interactions and H bonding
3. Steriods: Functions:
a. Cell membranes
b. Hormones
c. Regulate metabolism and immune function
d. Contribute to homeostasis: Regulate excretion of electrolytes
e. In bacteria, contributor to cell wall of some species
✔✔Compare the amount of stored energy in fat to proteins and carbohydrates. - ✔✔Fat
provides twice as much energy per gram than carbohydrates or proteins.
✔✔Explain lipogenesis and lipolysis and state the physiological situation that triggers
each
process to occur. - ✔✔1. Lipogenesis: Excess fats are stored as triglycerides in
adipocytes (fat cells)
- Triglycerides synthesis
- A dehydration reaction
2. Lipolysis: Breakdown of stored triglycerides into fatty acids & glycerol
- A hydration reaction
- FA & glycerol used to make energy
- Preferred energy source for liver, heart, and muscles
