How is the small intestine adapted to absorb food?

Answer explanation

The small intestine has a large surface area due to villi and microvilli, which increase absorption efficiency. It also has a rich blood supply and is lined with specialized cells that facilitate nutrient uptake.

How is food processed after absorption?

Answer explanation

After absorption, food is processed in the liver where nutrients are metabolized, stored, or distributed to cells for energy, growth, and repair. Waste products are then prepared for excretion.

What is the difference between “digestion” and “absorption”?

Answer explanation

Digestion refers to the process of breaking down food into smaller components, while absorption is the process of taking those components into the bloodstream for use by the body. They are distinct but interconnected stages of nutrient processing.

Can we absorb nutrients from food as whole proteins and carbohydrates?

Answer explanation

No, nutrients are not absorbed as whole proteins and carbohydrates. They must be broken down into amino acids and simple sugars during digestion before absorption into the bloodstream.

Explain the role of saliva, stomach secretions, pancreatic juice, and bile in digestion.

Answer explanation

Saliva begins digestion with enzymes like amylase. Stomach secretions, including hydrochloric acid, break down food and kill pathogens. Pancreatic juice contains enzymes for further digestion, while bile emulsifies fats for absorption.

Why are enzymes specific according to the 'Lock and Key' model?

Answer explanation

Enzymes are specific due to the 'Lock and Key' model, where the enzyme's active site (the 'lock') perfectly fits a specific substrate (the 'key'). This precise interaction ensures that only the correct substrate can bind and undergo a reaction.

Explain how temperature and pH affect enzyme activity.

Answer explanation

Temperature and pH affect enzyme activity by altering the enzyme's shape and function. Optimal conditions enhance activity, while extreme changes can denature enzymes, reducing their effectiveness.

Describe peristalsis.

Answer explanation

Peristalsis is a series of wave-like muscle contractions that move food through the digestive tract. It occurs in the esophagus, stomach, and intestines, facilitating digestion and absorption.

How is the gut microbiome important for health?

Answer explanation

The gut microbiome plays a crucial role in digestion, immune function, and mental health. It helps break down food, synthesize vitamins, and protect against pathogens, contributing significantly to overall health and well-being.

What is the liver's role in processing absorbed sugars and amino acids?

Answer explanation

The liver processes absorbed sugars by converting excess glucose into glycogen for storage and regulating blood sugar levels. It also metabolizes amino acids, synthesizing proteins and converting excess into glucose or fat.