BIOL 204
Biol 204 Exam 4 Study Questions and
Answers Top Graded 2026
Nutrition definition
the process of providing or obtaining the food necessary for health and growth.
Digestion definition
It is the catabolic process that breaks down large food molecules to monomers (chemical
building blocks)
-carbohydrates—> monosaccharide
-proteins—> amino acids
-lipids—> fatty acid, Glycerol
-nucleic acids—> nucleotide
*the enzymatic breakdown of any food molecule is HYDROLYSIS bc it involves adding a
water molecule to each molecular bond to be broken (lysed)
Absorption definition
The process of moving substances from the lumen of the gut into the body
-small intestine
-capillaries(villi)—> hepatic portal system—> liver
Metabolism definition
The sum of all biochemical reactions in the body
-anabolism: all reactions that build larger molecules or structures from smaller ones
-catabolism: all processes that that break down complex structures to simpler ones
Nutrient definition
A substance in food the body uses to promote normal growth, maintenance, and repair
Essential nutrient definition
Those that are inadequately synthesized by body cells and must be ingested in the diet
What are the 6 major nutrient categories?
Macronutrients: must be consumed in relatively large quantities
(Supply energy and are used as building blocks)
1. Carbs
2. Protein
BIOL 204
,BIOL 204
3. Fats
4. Water
Micronutrients: only small quantities are required
5. Vitamins
6. Minerals
State the Acceptable Macronutrient Distribution Ranges for the 3 energy-yielding
macronutrient
(% of daily caloric intake)
-Proteins (10-35%)
-fats (20-35%)
-carbohydrates (45-65%)
* < or equal to 10% of fat intake should be saturated fat
Why is food considered "fuel"?
Food contains energy in the form of chemical bonds. The extracted energy is usually
used to make ATP.
calorie definition
1 calorie (c) is the amount of heat (energy) needed to raise the temperature of 1 gram of
water 1° C.
1000 calories= a Calorie (capital C) = a kilocalorie (kcal)
Calories are units representing the ability of food to be converted by the body into
energy
Indicate the number of calories produced when 1 gram of each of the 3 energy-yielding
macronutrients is fully oxidized in our body
-carbohydrates and proteins: 4 kcal/g
-fats: 9 kcal/g
Define empty calories + examples
-calories that contribute to your total caloric intake but supply little or no nutritional
value
-e.g. Alcohol (7.1 kcal/g) and sugary foods promote malnutrition by providing "empty
calories" — they (-) the appetite but fail to provide other nutrients
BIOL 204
,BIOL 204
Distinguish between fat- and water-soluble vitamins + list the vitamins in each group
Water soluble vitamins:
-absorbed with water by simple diffusion. —> water is absorbed by osmosis, following
the absorption of salts and organic nutrients that create an osmotic gradient.
-excreted in urine —> not stored in the body
Examples:
-Vitamin B: (coenzymes)
-vitamin B12 needs to bind the intrinsic factor secreted by the stomach's parietal cells-
specific receptor
-vitamin C: (antioxidant)
Fat soluble vitamins:
-absorbed with dietary lipids
-stored in the body(except for vit. k) —> can accumulate to toxic amounts
Examples:
-Vitamin A: visual pigments
-vitamin D: calcium absorption and bone mineralization
-vitamin E: (antioxidant)
-vitamin K: prothrombin synthesis and blood clotting (not stored in body)
Iron metabolism and regulation
Iron absorption and mobilization are regulated by hepcidin (liver hormone)
(From diagram):
-stomach acid reduces most Fe3+ to its absorbable form (Fe2+) by the intestinal
enterocytes
-ferroportin transports iron into the bloodstream
-Fe2+ is taken up by transferrin
-hemoglobin synthesis (erythropoiesis)
-myoglobin synthesis
-storage (excess) —ferritin
Describe the process of carbohydrates digestion
1. Oral Cavity
-salivary amylase breaks down the carbohydrate to a shorter polysaccharide
-low pH in stomach inactivates the amylase
2. Duodenum (small intestine)
-the intestine can absorb only monosaccharides
-break oligosaccharides and disaccharides into monosaccharides
BIOL 204
, BIOL 204
-(Dextrinase & glucoamylase: act on oligosaccharides composed of >3 simple sugars)
-(Disaccharides (maltase, sucrase, lactase): hydrolyze maltose, sucrose, and lactose
respectively into their constituent monosaccharides)
-absorbed monosaccharides other than glucose are converted to glucose by the liver.
-monosaccharides are used primarily for cellular fuel
-small amounts are used for nucleic acid synthesis and to add sugar residues to plasma
membrane proteins and lipids
Discuss the purpose of the aerobic respiration of glucose
-the primary function of cellular respiration is to generate ATP (energy-carrying molecule
that releases it to fuel cellular processes)
-the aerobic respiration of glucose can be represented in the summary equation:
-3 successive pathways: (reaction not in a single step, if not: intense burst of heat which
kills the cells)
1. Glycolysis
2. Citric acid cycle
3. Electron transport chain
C6H12O6 + 6 O2 ———> 6 CO2 + 6 H2O
(32 ADP + Pi —-> 32 ATP) : for each glucose molecule oxidized to carbon dioxide and
water, there is a net gain of 32 ATP
-the function of this reaction is to transfer energy from glucose to ATP
-ATP is not a storage molecule for chemical energy; that is the job of carbohydrates and
fats. When energy is needed by the cell, it is converted from storage molecules into ATP.
Important events in glucose oxidation
1. Glycolysis (breaks down glucose molecules)
2. Pyruvate processing (anaerobic fermentation)
3. Citric acid cycle (Krebs cycle) (oxidizes Acetyl CoA to CO2)
4. Electron Transport & Oxidative Phosphorylation
Differentiate among these glucose pathways
-the goal of carbohydrate metabolism is to make sure that just the right amount of
glucose is present in the blood
-glycolysis: converts glucose to pyruvic acid
-gluconeogenesis: forms glucose from non carbohydrate precursors (fat or protein)
-glycogenesis: polymerizes glucose to form glycogen (when cellular ATP reserves are
high, glucose is converted to glycogen (glycogenesis) or to fat (lipogenesis). Much more
BIOL 204
Biol 204 Exam 4 Study Questions and
Answers Top Graded 2026
Nutrition definition
the process of providing or obtaining the food necessary for health and growth.
Digestion definition
It is the catabolic process that breaks down large food molecules to monomers (chemical
building blocks)
-carbohydrates—> monosaccharide
-proteins—> amino acids
-lipids—> fatty acid, Glycerol
-nucleic acids—> nucleotide
*the enzymatic breakdown of any food molecule is HYDROLYSIS bc it involves adding a
water molecule to each molecular bond to be broken (lysed)
Absorption definition
The process of moving substances from the lumen of the gut into the body
-small intestine
-capillaries(villi)—> hepatic portal system—> liver
Metabolism definition
The sum of all biochemical reactions in the body
-anabolism: all reactions that build larger molecules or structures from smaller ones
-catabolism: all processes that that break down complex structures to simpler ones
Nutrient definition
A substance in food the body uses to promote normal growth, maintenance, and repair
Essential nutrient definition
Those that are inadequately synthesized by body cells and must be ingested in the diet
What are the 6 major nutrient categories?
Macronutrients: must be consumed in relatively large quantities
(Supply energy and are used as building blocks)
1. Carbs
2. Protein
BIOL 204
,BIOL 204
3. Fats
4. Water
Micronutrients: only small quantities are required
5. Vitamins
6. Minerals
State the Acceptable Macronutrient Distribution Ranges for the 3 energy-yielding
macronutrient
(% of daily caloric intake)
-Proteins (10-35%)
-fats (20-35%)
-carbohydrates (45-65%)
* < or equal to 10% of fat intake should be saturated fat
Why is food considered "fuel"?
Food contains energy in the form of chemical bonds. The extracted energy is usually
used to make ATP.
calorie definition
1 calorie (c) is the amount of heat (energy) needed to raise the temperature of 1 gram of
water 1° C.
1000 calories= a Calorie (capital C) = a kilocalorie (kcal)
Calories are units representing the ability of food to be converted by the body into
energy
Indicate the number of calories produced when 1 gram of each of the 3 energy-yielding
macronutrients is fully oxidized in our body
-carbohydrates and proteins: 4 kcal/g
-fats: 9 kcal/g
Define empty calories + examples
-calories that contribute to your total caloric intake but supply little or no nutritional
value
-e.g. Alcohol (7.1 kcal/g) and sugary foods promote malnutrition by providing "empty
calories" — they (-) the appetite but fail to provide other nutrients
BIOL 204
,BIOL 204
Distinguish between fat- and water-soluble vitamins + list the vitamins in each group
Water soluble vitamins:
-absorbed with water by simple diffusion. —> water is absorbed by osmosis, following
the absorption of salts and organic nutrients that create an osmotic gradient.
-excreted in urine —> not stored in the body
Examples:
-Vitamin B: (coenzymes)
-vitamin B12 needs to bind the intrinsic factor secreted by the stomach's parietal cells-
specific receptor
-vitamin C: (antioxidant)
Fat soluble vitamins:
-absorbed with dietary lipids
-stored in the body(except for vit. k) —> can accumulate to toxic amounts
Examples:
-Vitamin A: visual pigments
-vitamin D: calcium absorption and bone mineralization
-vitamin E: (antioxidant)
-vitamin K: prothrombin synthesis and blood clotting (not stored in body)
Iron metabolism and regulation
Iron absorption and mobilization are regulated by hepcidin (liver hormone)
(From diagram):
-stomach acid reduces most Fe3+ to its absorbable form (Fe2+) by the intestinal
enterocytes
-ferroportin transports iron into the bloodstream
-Fe2+ is taken up by transferrin
-hemoglobin synthesis (erythropoiesis)
-myoglobin synthesis
-storage (excess) —ferritin
Describe the process of carbohydrates digestion
1. Oral Cavity
-salivary amylase breaks down the carbohydrate to a shorter polysaccharide
-low pH in stomach inactivates the amylase
2. Duodenum (small intestine)
-the intestine can absorb only monosaccharides
-break oligosaccharides and disaccharides into monosaccharides
BIOL 204
, BIOL 204
-(Dextrinase & glucoamylase: act on oligosaccharides composed of >3 simple sugars)
-(Disaccharides (maltase, sucrase, lactase): hydrolyze maltose, sucrose, and lactose
respectively into their constituent monosaccharides)
-absorbed monosaccharides other than glucose are converted to glucose by the liver.
-monosaccharides are used primarily for cellular fuel
-small amounts are used for nucleic acid synthesis and to add sugar residues to plasma
membrane proteins and lipids
Discuss the purpose of the aerobic respiration of glucose
-the primary function of cellular respiration is to generate ATP (energy-carrying molecule
that releases it to fuel cellular processes)
-the aerobic respiration of glucose can be represented in the summary equation:
-3 successive pathways: (reaction not in a single step, if not: intense burst of heat which
kills the cells)
1. Glycolysis
2. Citric acid cycle
3. Electron transport chain
C6H12O6 + 6 O2 ———> 6 CO2 + 6 H2O
(32 ADP + Pi —-> 32 ATP) : for each glucose molecule oxidized to carbon dioxide and
water, there is a net gain of 32 ATP
-the function of this reaction is to transfer energy from glucose to ATP
-ATP is not a storage molecule for chemical energy; that is the job of carbohydrates and
fats. When energy is needed by the cell, it is converted from storage molecules into ATP.
Important events in glucose oxidation
1. Glycolysis (breaks down glucose molecules)
2. Pyruvate processing (anaerobic fermentation)
3. Citric acid cycle (Krebs cycle) (oxidizes Acetyl CoA to CO2)
4. Electron Transport & Oxidative Phosphorylation
Differentiate among these glucose pathways
-the goal of carbohydrate metabolism is to make sure that just the right amount of
glucose is present in the blood
-glycolysis: converts glucose to pyruvic acid
-gluconeogenesis: forms glucose from non carbohydrate precursors (fat or protein)
-glycogenesis: polymerizes glucose to form glycogen (when cellular ATP reserves are
high, glucose is converted to glycogen (glycogenesis) or to fat (lipogenesis). Much more
BIOL 204
