Biology digestion Flashcards

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1
Q

What is a tissue, and give an example of one in the human body.

A

A tissue is a group of similar cells that work together to perform a specific function. For example, muscle tissue in the stomach helps with the mechanical digestion of food.muscular tissue brings about movement. .Glandular tissuecontain secretory cells that can produce and release substances such as hormones or enzymes

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2
Q

Define an organ and give an example in the digestive system.

A

An organ is a structure made up of different types of tissues that work together to perform a specific function. The stomach is an organ that helps in digesting food.

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3
Q

List the main organs in the human digestive system in the order food passes through.

A

Mouth, esophagus, stomach, small intestine, large intestine, rectum, and anus

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4
Q

What is the function of the small intestine?

A

The small intestine absorbs nutrients from digested food into the bloodstream.

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5
Q

Describe the role of the stomach in digestion.

A

The stomach uses muscular contractions to mix food with gastric juice, which contains acid and enzymes to break down proteins.

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6
Q

What are the main nutrients in food, and why are they important?

A

The main nutrients are carbohydrates, proteins, and lipids (fats). Carbohydrates provide energy, proteins are needed for growth and repair, and lipids store energy and insulate the body.

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7
Q

What is a simple test for the presence of starch in food?

A

Iodine test: Add iodine solution to the food. If starch is present, it turns blue-black.

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8
Q

How do you test for protein in food?

A

Biuret test: Add Biuret solution to the food. If protein is present, it turns purple.

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9
Q

Describe how to test for lipids (fats) in a food sample.

A

Emulsion test: Mix the food with ethanol and water. If lipids are present, a milky-white emulsion forms.

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10
Q

What are enzymes, and why are they essential for digestion?

A

Enzymes are biological catalysts that speed up the breakdown of large food molecules into smaller, absorbable ones.

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11
Q

What is an enzyme?

A

An enzyme is a protein that acts as a biological catalyst, speeding up chemical reactions in the body.

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12
Q

What is the “lock and key” model in enzyme action?

A

The lock and key model suggests that each enzyme’s active site fits only specific substrates, like a key fits a specific lock.

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13
Q

What is the active site of an enzyme?

A

The active site is the part of the enzyme where the substrate binds and the reaction takes place.

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14
Q

Why are enzymes important in the digestive system?

A

Enzymes help break down complex food molecules into simpler ones that can be absorbed by the body.

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15
Q

What are the three main types of digestive enzymes, and what do they break down?

A

Amylase: breaks down starch into sugars.
Protease: breaks down proteins into amino acids.
Lipase: breaks down fats into fatty acids and glycerol.

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16
Q

Q: How does temperature affect enzyme activity?

A

Enzyme activity increases with temperature up to an optimal point, but high temperatures can denature enzymes, reducing their effectiveness.

17
Q

What is meant by “enzyme denaturation”?

A

Denaturation is when the enzyme’s structure is altered, usually due to high temperature or extreme pH, causing it to lose its function.

18
Q

How does pH affect enzyme activity?

A

Each enzyme has an optimal pH. Deviations from this pH can change the shape of the enzyme’s active site, reducing its activity.

19
Q

Why is the pH of the stomach acidic?

A

The acidic pH in the stomach helps activate pepsin, a protease enzyme that digests proteins.

20
Q

What is the effect of substrate concentration on enzyme activity?

A

As substrate concentration increases, enzyme activity rises until all enzyme active sites are occupied, after which activity plateaus.

21
Q

Describe the role of saliva in digestion.

A

Saliva contains amylase, which begins breaking down starch into sugars, and it also moistens food, making it easier to swallow.

22
Q

What happens to food in the large intestine?

A

In the large intestine, water is absorbed from undigested food, and waste is formed for excretion.

23
Q

How does bile aid in digestion?

A

Bile emulsifies fats, breaking them into small droplets that increase the surface area for lipase action.

24
Q

What is peristalsis, and why is it important?

A

Peristalsis is the wave-like muscle contractions that move food along the digestive tract, ensuring it continues through the system.

25
Q

How does the pancreas contribute to digestion?

A

The pancreas produces enzymes like amylase, protease, and lipase, which are released into the small intestine to help digest carbohydrates, proteins, and fats.