Nutrition & Cellular Respiration Review

60 question-and-answer flashcards reviewing key concepts from Chapter 27 on nutrition and the central role of cellular respiration.

What is the definition of nutrition?

The study of how the body takes in and uses nutrient molecules for growth, maintenance, and repair.

What are nutrients?

Substances in food that provide energy, serve as building blocks, or regulate body processes.

How do macronutrients differ from micronutrients?

Macronutrients are needed in large amounts for energy and structure, whereas micronutrients are required in much smaller quantities mainly for regulation and co-enzyme/co-factor roles.

Name the three macronutrients.

Carbohydrates, lipids, and proteins.

Give three examples of micronutrients.

Vitamins, minerals, and water.

What is the general function of macronutrients?

They supply energy and provide the raw materials for growth and repair.

What is the general function of micronutrients?

They enable enzymatic reactions and physiological regulation without providing significant calories.

Define a calorie in nutrition.

The amount of heat energy required to raise the temperature of 1 kilogram of water by 1 °C; used to quantify energy content in food.

List the three major nutrient biomolecules required in the diet.

Carbohydrates, lipids, and proteins.

Briefly describe carbohydrates.

Organic molecules composed mainly of carbon, hydrogen, and oxygen that serve as the primary energy source.

Briefly describe lipids.

Hydrophobic biomolecules such as triglycerides, phospholipids, and cholesterol used for energy storage, insulation, and membrane structure.

Briefly describe proteins.

Chains of amino acids that provide structural support, enzymes, hormones, and can be used for energy when necessary.

What is the main function of carbohydrates in the body?

To provide readily available energy, particularly for the brain and red blood cells.

What is the primary function of lipids?

Long-term energy storage, insulation, protection, and forming cell membranes.

What is the primary function of proteins?

Growth, repair, enzyme production, transport, and, when needed, energy supply.

In what form are excess carbohydrates stored?

Glycogen.

Where is most glycogen stored?

In liver and skeletal muscle cells.

In what form are excess lipids stored?

Triglycerides in adipose tissue.

Where in the body are triglycerides mainly stored?

Adipose (fat) tissue throughout the body.

How are excess amino acids handled when energy is needed?

They are deaminated and their carbon skeletons enter cellular respiration for ATP production.

Are amino acids stored long-term in a specialized depot?

No; amino acids are used immediately for protein synthesis or deaminated for energy.

What usually happens to excess dietary protein?

It is converted to fat or used for energy after deamination.

List the four stages of cellular respiration in order.

Glycolysis, intermediate (transition) stage, citric acid cycle, and electron transport system.

Where does glycolysis occur?

In the cytosol of the cell.

Where does the citric acid cycle occur?

In the mitochondrial matrix.

What are the main products of glycolysis?

Two pyruvate molecules, a net gain of 2 ATP, and 2 NADH.

What is the purpose of the intermediate (transition) stage?

To convert pyruvate into acetyl-CoA while producing NADH and releasing CO₂.

Which molecule enters the citric acid cycle?

Acetyl-CoA.

Who is the final electron acceptor in the electron transport chain?

Molecular oxygen (O₂).

What is the main energy currency generated by cellular respiration?

Adenosine triphosphate (ATP).

At which step does glucose enter cellular respiration?

It begins glycolysis directly as glucose is phosphorylated to glucose-6-phosphate.

Where does glycerol from triglycerides feed into cellular respiration?

It can be converted to an intermediate of glycolysis.

Where do fatty acid chains from triglycerides enter the pathway?

After β-oxidation, as acetyl-CoA entering the citric acid cycle.

Where do deaminated amino acid carbon skeletons most commonly enter respiration?

As pyruvate, acetyl-CoA, or citric acid cycle intermediates, depending on the amino acid.

Which two stages receive products from triglyceride breakdown?

Glycolysis (via glycerol) and the citric acid cycle (via acetyl-CoA from fatty acids).

What is one physiologic advantage of interconverting nutrient biomolecules?

It allows the body to meet energy demands and maintain blood glucose during varying dietary intake or fasting.

Which biomolecule can be synthesized when carbohydrates are consumed in excess?

Lipids (fat) through lipogenesis.

During starvation, which macronutrient can be converted to glucose?

Proteins (via gluconeogenesis using amino acid carbon skeletons).

What is glycogenesis?

The formation of glycogen from excess glucose.

What is β-oxidation?

The sequential removal of two-carbon units from fatty acids to form acetyl-CoA.

What happens to excess carbohydrates beyond glycogen storage capacity?

They are converted to fatty acids and stored as triglycerides.

What happens to excess dietary lipids?

They are stored directly as triglycerides in adipose tissue.

In which tissues does most lipogenesis occur?

Liver and adipose tissue.

What is a vitamin?

An organic micronutrient required in small amounts to serve as a co-enzyme or regulator of metabolism.

What is a mineral?

An inorganic micronutrient that serves as a structural component or enzymatic co-factor.

Give one example of a water-soluble vitamin.

Vitamin C (ascorbic acid).

Give one example of a fat-soluble vitamin.

Vitamin A (retinol).

Provide one example of a major mineral.

Calcium.

Provide one example of a trace mineral.

Iron.

Approximately what percentage of daily energy intake is often recommended to come from carbohydrates?

About 45–65 % of total calories (general guideline).

What is gluconeogenesis?

The formation of glucose from non-carbohydrate precursors such as lactate, glycerol, or amino acids.

What is glycogenolysis?

The breakdown of glycogen to release glucose.

Define the term glyconeogenesis as sometimes used in metabolism discussions.

Another name for gluconeogenesis—the creation of new glucose molecules from non-carbohydrate sources.

Which macronutrient yields the most ATP per gram?

Lipids (approximately 9 kcal per gram).

Which macronutrient is the primary structural component of enzymes and tissue?

Proteins.

Which macronutrient class includes cholesterol as an example?

Lipids.

What do we call amino acids that cannot be synthesized by the body and must be obtained from food?

Essential amino acids.

How many kilocalories are supplied by 1 g of carbohydrate?

Approximately 4 kcal.

How many kilocalories are supplied by 1 g of fat?

Approximately 9 kcal.