4.2

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Questions and Answers

What is the primary function of enzymes in the digestive system?

To speed up chemical reactions in digestion (correct)

To produce hormones that regulate metabolism

To store nutrients for later use

To provide energy directly to cells

In cellular respiration, which of the following is produced as a waste product?

Glucose

Lactic Acid

Oxygen

Carbon Dioxide (correct)

Which statement best describes the process of energy metabolism?

It exclusively refers to the storage of energy in fat cells.

It consists of all physical and chemical processes related to energy within the body. (correct)

It involves only the breakdown of carbohydrates for energy.

It is limited to metabolic activities in the liver.

What role does insulin play in the body?

It regulates blood glucose levels by facilitating cellular uptake. Signup and view all the answers

Which nutrient absorption takes place primarily in the small intestine?

All types of carbohydrates Signup and view all the answers

What is the primary function of bile in the digestive process?

To emulsify fats for easier digestion Signup and view all the answers

Which enzyme is responsible for initiating the breakdown of proteins in the stomach?

Pepsin Signup and view all the answers

What nutrient is primarily absorbed in the small intestine through the villi?

Fatty acids Signup and view all the answers

What role does the pancreas play in digestion?

It secretes enzymes that assist in digesting fats, proteins, and carbohydrates Signup and view all the answers

What is the primary function of the large intestine?

To absorb water and minerals, and eliminate waste Signup and view all the answers

Which of the following enzymes is NOT produced by the pancreas?

Pepsin Signup and view all the answers

Which part of the digestive system is primarily responsible for the fermentation of fiber?

Cecum Signup and view all the answers

What triggers the peristaltic movement that moves food through the esophagus?

Swallowing Signup and view all the answers

What role do enzymes play in metabolic processes?

They act as biological catalysts to speed up reactions. Signup and view all the answers

What is the primary function of the digestive system?

To break down food into absorbable molecules. Signup and view all the answers

Which macronutrient is primarily disassembled into fatty acids during digestion?

Fats Signup and view all the answers

What percentage of energy expenditure is typically attributed to basal metabolism?

About 2/3 Signup and view all the answers

During metabolism, what happens to absorbed nutrients?

They are transformed into CO2 and H2O. Signup and view all the answers

Which organ primarily manufactures bile in the digestive system?

Liver Signup and view all the answers

What is the thermic effect of food?

Energy lost as heat during digestion and metabolism. Signup and view all the answers

Which enzyme is secreted by salivary glands during digestion?

Amylase Signup and view all the answers

What occurs during the absorption phase of digestion?

Molecular building blocks enter the bloodstream. Signup and view all the answers

At what point in life is basal metabolic rate generally highest?

In the first year of life Signup and view all the answers

Study Notes

Learning Objectives

Define the main parts of the human digestive system and describe digestion.
Explain the basics of human metabolism.
Explain the role of enzymes.
Explain the action of insulin and glucagon.
Define Type 1 and Type 2 diabetes.
Define the main parts of the urinary system.

Review

Metabolism is all physical and chemical processes inside an organism, involving a flow of matter and energy from food.
Metabolism is incredibly complex.

Food Energy

Energy exists in various forms (kinetic, thermal, chemical).
Living organisms extract chemical energy from food molecules through cellular respiration.
Cellular respiration produces ATP molecules and heat, releasing carbon dioxide and water.
The heat keeps the body warm.
ATP molecules provide energy for bodily functions and muscle movement.
The body stores unused energy as glycogen and fat.

What Food Is For

The body breaks down macronutrients into molecular building blocks (monosaccharides, amino acids, fatty acids, and glycerol).
These building blocks are used to assemble body molecules.
Molecules are disassembled into CO2 and H2O to release energy.

Food In The Body

Digestion, absorption, metabolism, and excretion are all processes that occur in the cells of a living organism.

The Body's Use Of Food Energy

Basal metabolism is the minimal energy expenditure to stay alive.
Basal metabolism accounts for about 2/3 of total energy needs, varying with age.
Physical activity contributes to energy expenditure (the thermic effect of food, ~10% of metabolizable energy).
Some energy is used to maintain bodily temperature.

Metabolic Processes

Metabolism involves chemical reactions that maintain basic life functions, build new molecules, keep warm, and enable physical activity.
Metabolic pathways are sequences of reactions leading to final products and energy, regulated by enzymes.

Enzymes

Enzymes are biological catalysts that enable or speed up metabolic reactions.
They lower the activation energy required for reactions.
Enzymes change shape slightly as they bind to substrates, forming an enzyme-substrate complex, which then becomes an enzyme-product complex before releasing the products.

The Human Digestive System

The digestive tract includes organs like the mouth, esophagus, stomach, small intestine, and large intestine.
Digestive system organs aiding digestion include salivary glands, liver, gallbladder, and pancreas.

Mouth and Stomach

Chewing mixes food with saliva, initiating starch breakdown.
Peristalsis moves food through the esophagus.
The stomach mixes food with gastric juices to create chyme.
Gastric acid and enzymes break down proteins.

Small and Large Intestine

Bile emulsifies fats, while pancreatic and intestinal enzymes digest nutrients.
Sugars, amino acids, fatty acids, vitamins, and minerals are absorbed into the bloodstream.
The large intestine absorbs water, minerals, and fermentation products.
Waste products are excreted as feces.

Test Practice (Organs and Functions)

Pancreas secretes insulin and glucagon.
Esophagus performs peristalsis.
Stomach transforms food into chyme.
Liver synthesizes glycogen and produces bile.

The Liver

The liver is the largest organ.
It converts simple sugars into glycogen, non-carbohydrates into glucose, synthesizes and stores iron and fat-soluble vitamins, converts amino acids into proteins for blood and other functions.
It removes waste products, toxins, and bacteria from the bloodstream.

Hormones and Nutrition

Blood glucose levels must remain within a narrow range (70-100mg/dL).
Pancreas secretes insulin and glucagon to regulate blood glucose.
Insulin increases nutrient uptake when blood glucose rises, and glucagon breaks down glycogen when blood glucose drops

The Urinary System

Kidneys filter waste products and toxins from the blood.
They regulate water and blood volume, influenced by hormones.
The bladder stores urine until expulsion.

Review (Page 21)

Review the functions of the liver.
Determine hormones regulating blood glucose.
Define Type 1 and 2 diabetes.
Identify main urinary system organs.
Analyze urinary system functions.

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Description

Test your knowledge on the human digestive and urinary systems, as well as metabolism and the role of enzymes. This quiz covers the main components of digestion, energy processes in the body, and the differences between Type 1 and Type 2 diabetes. Challenge yourself on these essential biology topics!

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