bio digestion multiple choice Flashcards
What is a tissue?
A) A group of cells that work together to perform a specific function
B) An individual cell with a unique function
C) A layer of skin in the body
D) A complete organ in the body
Answer: A) A group of cells that work together to perform a specific function
Which of the following is an organ in the human digestive system?
A) Mitochondria
B) Stomach
C) Muscles
D) Alveoli
B) Stomach
Which organ absorbs nutrients from digested food?
A) Stomach
B) Liver
C) Small intestine
D) Large intestine
Answer: C) Small intestine
What is the main role of the large intestine?
A) To absorb nutrients
B) To digest proteins
C) To store bile
D) To absorb water from undigested food
D) To absorb water from undigested food
What nutrient does the Biuret test identify in food?
A) Carbohydrates
B) Protein
C) Lipids
D) Starch
Answer: B) Protein
What color change occurs in a positive iodine test for starch?
A) Red to blue
B) Blue to purple
C) Brown to blue-black
D) Clear to white
C) Brown to blue-black
Which nutrient is primarily used for energy in the human body?
A) Carbohydrates
B) Proteins
C) Lipids
D) Vitamins
Answer: A) Carbohydrates
Which test would you use to detect lipids in a food sample?
A) Biuret test
B) Emulsion test
C) Benedict’s test
D) Iodine test
Answer: B) Emulsion test
What are enzymes?
A) Types of sugars
B) Proteins that act as biological catalysts
C) Structures within cells that provide energy
D) Hormones that regulate growth
Answer: B) Proteins that act as biological catalysts
Which enzyme breaks down starch?
A) Protease
B) Lipase
C) Amylase
D) Catalase
Answer: C) Amylase
The ‘lock and key’ model is used to describe:
A) How nutrients are absorbed in the stomach
B) The process of emulsification
C) The way enzymes interact with specific substrates
D) The formation of cell membranes
Answer: C) The way enzymes interact with specific substrates
What is the active site of an enzyme?
A) The part that binds to substrates
B) The cell in which the enzyme is found
C) The section that determines the enzyme’s color
D) The part that digests the enzyme itself
Answer: A) The part that binds to substrates
Which factor can denature an enzyme?
A) Low temperature
B) High pH or extreme temperatures
C) Neutral pH
D) Stable conditions
B) High pH or extreme temperatures
What is the optimal pH for pepsin, an enzyme in the stomach?
A) Neutral (pH 7)
B) Highly acidic (around pH 2)
C) Slightly basic (pH 8)
D) Neutral to slightly acidic (pH 6)
Answer: B) Highly acidic (around pH 2)
What happens to enzyme activity as temperature increases to its optimal point?
A) It decreases
B) It remains unchanged
C) It increases
D) It stops completely
Answer: C) It increases
Which factor will increase enzyme activity until all active sites are occupied?
A) Substrate concentration
B) Water availability
C) Light intensity
D) Size of substrate
A) Substrate concentration
What is the role of saliva in digestion?
A) To neutralize stomach acid
B) To moisten food and begin breaking down starch
C) To store bile
D) To digest proteins
B) To moisten food and begin breaking down starch
Which organ produces bile?
A) Stomach
B) Gallbladder
C) Liver
D) Pancreas
Answer: C) Liver
What is peristalsis?
A) The release of bile into the stomach
B) The breaking down of proteins into amino acids
C) Wave-like muscle contractions that move food through the digestive tract
D) The process of nutrients being absorbed in the large intestine
C) Wave-like muscle contractions that move food through the digestive tract
How does bile aid in the digestion of fats?
A) By breaking down proteins
B) By emulsifying fats for easier digestion
C) By neutralizing stomach acid
D) By storing nutrients
B) By emulsifying fats for easier digestion
What is the function of the pancreas in the digestive system?
A) To store bile
B) To produce digestive enzymes like amylase, lipase, and protease
C) To absorb nutrients
D) To remove waste from the blood
B) To produce digestive enzymes like amylase, lipase, and protease
What type of enzyme breaks down proteins into amino acids?
A) Amylase
B) Protease
C) Lipase
D) Catalase
Answer: B) Protease
Which nutrient provides the body with insulation and long-term energy storage?
A) Carbohydrates
B) Proteins
C) Lipids (fats)
D) Vitamins
Answer: C) Lipids (fats)
What is the primary function of villi in the small intestine?
A) To increase surface area for nutrient absorption
B) To secrete enzymes for digestion
C) To mix food with bile
D) To break down large food molecules
Answer: A) To increase surface area for nutrient absorption
What is the role of hydrochloric acid in the stomach?
A) To digest fats
B) To neutralize bile
C) To provide an acidic environment for enzymes to function
D) To absorb nutrients
C) To provide an acidic environment for enzymes to function
Which of the following is a reason why antibiotics do not work against viruses?
A) Viruses lack the cell structures antibiotics target
B) Viruses are resistant to all drugs
C) Viruses cannot be killed by any treatment
D) Antibiotics can only kill fungi
A) Viruses lack the cell structures antibiotics target
What is the process of emulsification in digestion?
A) Breaking down proteins
B) Mixing nutrients with blood
C) Breaking down large fat droplets into smaller ones
D) Filtering waste products from blood
C) Breaking down large fat droplets into smaller ones
What is the purpose of mucus in the digestive system?
A) To digest carbohydrates
B) To neutralize acids
C) To protect the lining of the digestive tract
D) To break down proteins
C) To protect the lining of the digestive tract
Where does most chemical digestion and nutrient absorption occur?
A) Mouth
B) Stomach
C) Small intestine
D) Large intestine
C) Small intestine
What does the Benedict’s test identify in a food sample?
A) Starch
B) Lipids
C) Sugars
D) Proteins
C) Sugars
Which part of the digestive system is primarily responsible for water absorption?
A) Small intestine
B) Large intestine
C) Stomach
D) Pancreas
B) Large intestine
Which enzyme is responsible for breaking down fats into fatty acids and glycerol?
A) Amylase
B) Protease
C) Lipase
D) Pepsin
Answer: C) Lipase
In which part of the digestive system does the absorption of most vitamins and minerals occur?
A) Mouth
B) Large intestine
C) Small intestine
D) Stomach
C) Small intestine
What is the role of the esophagus in digestion?
A) To produce bile
B) To absorb nutrients
C) To transport food from the mouth to the stomach
D) To break down proteins
C) To transport food from the mouth to the stomach
Which of the following increases the surface area in the small intestine for nutrient absorption?
A) Bile
B) Enzymes
C) Villi
D) Gastric acid
Answer: C) Villi
What does pepsin specifically break down?
A) Carbohydrates
B) Proteins
C) Fats
D) Fiber
B) Proteins
Where is bile stored before it is released into the small intestine?
A) Stomach
B) Gallbladder
C) Pancreas
D) Liver
B) Gallbladder
Which of the following is NOT a function of the liver?
A) Producing bile
B) Filtering toxins from the blood
C) Producing insulin
D) Storing glucose as glycogen
C) Producing insulin
What happens to enzymes when they are exposed to extremely high temperatures?
A) They work faster
B) They break down substrates more efficiently
C) They denature and lose their function
D) They increase in size
C) They denature and lose their function
Which component of food is broken down into glucose molecules for energy?
A) Proteins
B) Fats
C) Carbohydrates
D) Nucleic acids
C) Carbohydrates
How does the structure of villi in the small intestine maximize nutrient absorption?
A) Villi are large, finger-like projections that slow down food movement.
B) Villi have microvilli on their surface to increase surface area further.
C) Villi are smooth to allow quick passage of food through the intestine.
D) Villi contain digestive enzymes that actively transport nutrients.
B) Villi have microvilli on their surface to increase surface area further.
What is the effect of a high pH on pepsin, an enzyme active in the stomach?
A) Pepsin becomes more efficient at breaking down proteins.
B) Pepsin is denatured and loses its function.
C) Pepsin changes shape but remains effective.
D) Pepsin is unaffected by changes in pH.
Answer: B) Pepsin is denatured and loses its function.
Which of the following statements best explains why enzymes are specific to certain reactions?
A) Enzymes only function in the stomach.
B) Enzymes are designed to have multiple active sites for different substrates.
C) Each enzyme has an active site that only fits certain substrate molecules.
D) Enzymes function best in low temperatures and only interact with a few molecules.
C) Each enzyme has an active site that only fits certain substrate molecules.
Why is bile important in the digestion of fats, even though it is not an enzyme?
A) Bile breaks down fat molecules chemically.
B) Bile increases stomach acid to digest fat.
C) Bile emulsifies fats, increasing the surface area for enzyme action.
D) Bile transports fats to the liver for digestion.
C) Bile emulsifies fats, increasing the surface area for enzyme action
Which of the following best explains why enzymes have an optimum temperature?
A) Enzymes function better at high temperatures.
B) Too low a temperature denatures the enzyme.
C) Optimum temperature ensures the highest rate of reaction without denaturation.
D) The active site only forms at a specific temperature.
C) Optimum temperature ensures the highest rate of reaction without denaturation.
What is the primary reason why starch digestion begins in the mouth and not in the stomach?
A) Starch can only be digested by stomach acid.
B) The enzyme amylase, which breaks down starch, is present in saliva.
C) The stomach has no enzymes for breaking down carbohydrates.
D) Amylase only becomes active at acidic pH levels.
B) The enzyme amylase, which breaks down starch, is present in saliva.
Which of the following does NOT happen during the process of emulsification?
A) Large fat droplets are broken into smaller droplets.
B) Bile salts surround fat molecules to keep them separate.
C) Fat molecules are chemically broken down into fatty acids and glycerol.
D) Emulsified fats increase enzyme efficiency for digestion.
C) Fat molecules are chemically broken down into fatty acids and glycerol
What would likely happen to enzyme activity if the enzyme concentration were increased but substrate concentration remained constant?
A) The rate of reaction would continue to increase.
B) The rate of reaction would remain unchanged once all substrates are bound.
C) Enzyme activity would decrease as more enzymes compete for substrates.
D) Substrate concentration would increase to match enzyme activity.
B) The rate of reaction would remain unchanged once all substrates are bound.
Which statement best describes why proteins are not absorbed directly into the bloodstream in the digestive system?
A) Proteins are too small to be detected by blood vessels.
B) Proteins need to be digested into amino acids to pass through the intestinal wall.
C) Proteins are absorbed by the liver and then broken down.
D) Proteins dissolve in the stomach and are lost as waste.
B) Proteins need to be digested into amino acids to pass through the intestinal wall
How does temperature influence the shape of an enzyme’s active site?
A) Temperature does not affect the enzyme’s shape.
B) Lower temperatures cause the active site to expand.
C) Higher temperatures may denature the enzyme, altering the active site.
D) Enzyme shape only changes due to pH, not temperature.
C) Higher temperatures may denature the enzyme, altering the active site.
