Biology Chapter 4 - Carbohydrates
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Biology Chapter 4 - Carbohydrates

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Questions and Answers

What are carbohydrates?

An important source of energy for all cells, composed of Carbon, Hydrogen, and Oxygen. Good sources are found in fruits, vegetables, and grains.

What is glucose?

The most abundant carbohydrate produced by plants through photosynthesis.

What are simple carbohydrates?

Carbohydrates that contain one or two molecules, commonly referred to as sugars.

What are monosaccharides?

<p>Carbohydrates that contain ONE molecule, examples include glucose, fructose, and galactose.</p> Signup and view all the answers

What are disaccharides?

<p>Carbohydrates that contain TWO molecules, examples include lactose, maltose, and sucrose.</p> Signup and view all the answers

What are oligosaccharides?

<p>Carbohydrates that contain 3 to 10 monosaccharides.</p> Signup and view all the answers

What are polysaccharides?

<p>Carbohydrates that consist of hundreds to thousands of glucose molecules, examples include starch, glycogen, and fibers.</p> Signup and view all the answers

What is starch?

<p>A complex carbohydrate that plants use to store carbohydrates, made up of amylose and amylopectin.</p> Signup and view all the answers

What is glycogen?

<p>A complex carbohydrate that serves as the storage form of glucose in animals, not found in food.</p> Signup and view all the answers

What is fiber?

<p>A complex carbohydrate made of long polysaccharide chains that aids in digestion.</p> Signup and view all the answers

What are soluble fibers?

<p>Fibers that dissolve in water, are viscous, and gel-forming, associated with health benefits.</p> Signup and view all the answers

What are insoluble fibers?

<p>Fibers that do not dissolve in water, promote regular bowel movements and alleviate constipation.</p> Signup and view all the answers

Where does carbohydrate digestion occur?

<p>In the small intestine, not in the stomach.</p> Signup and view all the answers

What happens to monosaccharides during digestion?

<p>Enzymes digest disaccharides to monosaccharides, which are then absorbed into the bloodstream.</p> Signup and view all the answers

What causes lactose intolerance?

<p>Insufficient enzyme lactase to digest lactose-containing foods.</p> Signup and view all the answers

What does the liver do with monosaccharides?

<p>It converts them to glucose, which is the primary energy source circulating in the blood.</p> Signup and view all the answers

How does the body digest fiber?

<p>The body does not have enzymes to digest fiber, but some can be broken down by bacteria in the large intestine.</p> Signup and view all the answers

What hormones control blood glucose?

<p>Insulin, glucagon, epinephrine, norepinephrine, cortisol, and growth hormone.</p> Signup and view all the answers

What does insulin do?

<p>Stimulates glucose transporters to help take glucose from the blood across the cell membrane.</p> Signup and view all the answers

What does glucagon do?

<p>Stimulates the liver to convert glycogen to glucose and promotes gluconeogenesis.</p> Signup and view all the answers

What do epinephrine and norepinephrine do?

<p>Increase glycogen breakdown in the liver, releasing glucose into the blood.</p> Signup and view all the answers

What are the effects of cortisol and growth hormone?

<p>Cortisol increases gluconeogenesis and decreases muscle glucose use while growth hormone increases fatty acid mobilization.</p> Signup and view all the answers

What is the glycemic index?

<p>A food's potential to raise blood glucose.</p> Signup and view all the answers

What is a high glycemic index?

<p>It causes a sudden surge in blood glucose.</p> Signup and view all the answers

What is a low glycemic index?

<p>It leads to low to moderate fluctuations in blood glucose.</p> Signup and view all the answers

What is glycemic load?

<p>It determines the effect of a food on a person's glucose response.</p> Signup and view all the answers

How do carbohydrates provide energy?

<p>Red blood cells use only glucose for energy, and both carbohydrates and fats supply energy for daily activities.</p> Signup and view all the answers

What is ketosis?

<p>A state where fats break down during fasting to form ketones.</p> Signup and view all the answers

What is gluconeogenesis?

<p>The body's process of making glucose from protein when carbohydrates are deficient.</p> Signup and view all the answers

The RDA for carbohydrates is ____ grams/day.

<p>130</p> Signup and view all the answers

The AMDR for carbohydrates is ____% to ____% of daily calories.

<p>45, 65</p> Signup and view all the answers

What are the effects of simple carbohydrates in diets?

<p>They lead to tooth decay, may increase 'bad cholesterol', decrease 'good cholesterol', and contribute to obesity.</p> Signup and view all the answers

What are enrichment foods?

<p>Foods where nutrients lost during processing have been added back to meet a specified standard.</p> Signup and view all the answers

What are fortified foods?

<p>Foods that have had nutrients added that did not originally exist in them.</p> Signup and view all the answers

The adequate intake for fiber is ____ g/day for women and ____ g/day for men.

<p>25, 38</p> Signup and view all the answers

What are nutritive sweeteners?

<p>Sweeteners like sucrose and fructose that contain 4 kcal energy per gram.</p> Signup and view all the answers

What are non-nutritive sweeteners?

<p>Sweeteners that provide little or no energy and are safe for various populations.</p> Signup and view all the answers

What is diabetes?

<p>The inability to regulate blood glucose levels.</p> Signup and view all the answers

What characterizes Type 1 diabetes?

<p>The body does not produce enough insulin, leading to hyperglycemia.</p> Signup and view all the answers

What characterizes Type 2 diabetes?

<p>Insulin sensitivity where cells become less responsive to insulin, often associated with obesity and inactivity.</p> Signup and view all the answers

What is hypoglycemia?

<p>A condition of low blood glucose characterized by symptoms such as shakiness and weakness.</p> Signup and view all the answers

What is reactive hypoglycemia?

<p>A condition where the pancreas secretes too much insulin after a high-carbohydrate meal.</p> Signup and view all the answers

What is fasting hypoglycemia?

<p>A condition where the pancreas produces too much insulin even when someone has not eaten.</p> Signup and view all the answers

Study Notes

Carbohydrates Overview

  • Carbohydrates are essential energy sources for all cells, composed of carbon, hydrogen, and oxygen.
  • Rich dietary sources include fruits, vegetables, and grains.

Types of Carbohydrates

  • Glucose: The most abundant carbohydrate, produced by plants via photosynthesis.
  • Simple Carbohydrates: Comprise one or two sugar molecules, commonly known as sugars.
  • Monosaccharides: Single-molecule carbohydrates like glucose, fructose, and galactose.
  • Disaccharides: Formed from two monosaccharides, examples include lactose, maltose, and sucrose.
  • Oligosaccharides: Contain 3 to 10 monosaccharides.
  • Polysaccharides: Composed of hundreds to thousands of glucose molecules; include starch, glycogen, and fiber.

Specific Carbohydrates

  • Starch: A complex carbohydrate, primarily stored in plants. Exists as:
    • Amylose: Straight-chain glucose.
    • Amylopectin: Branched-chain glucose.
    • Resistant Starch: Indigestible fiber linked by beta bonds, found in grains, legumes, fruits, and vegetables.
  • Glycogen: Animal storage form of glucose, found in liver and muscles, but not in the diet.
  • Fiber: Long polysaccharide chains with two types:
    • Dietary Fiber: Non-digestible parts of plants.
    • Functional Fiber: Extracted carbohydrates with known health benefits.

Fiber Types

  • Soluble Fiber: Dissolves in water; contributes to fullness, heart health, and glycemic control. Found in citrus, berries, oats, and beans.
  • Insoluble Fiber: Does not dissolve in water; promotes digestive health and regularity. Found in whole grains, seeds, and vegetables.

Digestion

  • Carbohydrate digestion occurs in the small intestine, not the stomach.
  • Enzymes like maltase, sucrase, and lactase convert disaccharides to monosaccharides, which are absorbed into the bloodstream.
  • The liver converts all absorbed monosaccharides to glucose.

Blood Glucose Regulation

  • Regulated by hormones: insulin, glucagon, epinephrine, norepinephrine, cortisol, and growth hormone.
    • Insulin: Promotes glucose uptake and glycogen storage.
    • Glucagon: Stimulates glucose release from glycogen.
    • Epinephrine/Norepinephrine: Increase blood glucose during stress ("fight or flight").
    • Cortisol/Growth Hormone: Influence glucose production and utilization.

Glycemic Index (GI)

  • Measures a food's potential to raise blood glucose.
    • High GI: Causes sudden blood glucose spikes.
    • Low GI: Ensures stable glucose levels; benefits include reduced risks for heart disease and colon cancer.
  • Glycemic Load: Assesses the overall impact of foods on blood glucose, calculated from carbohydrate content multiplied by its GI.

Energy and Ketosis

  • Red blood cells rely solely on glucose for energy.
  • Carbohydrates and fats supply energy; glucose is crucial during exercise.
  • In fasting states, fats produce ketones, which can lead to ketoacidosis if excessive.
  • RDA: 130 grams/day for adequate brain glucose.
  • AMDR: 45% to 65% of daily caloric intake.

Fiber and Sweeteners

  • Adequate Fiber Intake: 25 g/day for women, 38 g/day for men.
  • Nutritive Sweeteners: Include sugars like sucrose and provide 4 kcal/g.
  • Non-Nutritive Sweeteners: Provide little to no energy, safe for various populations.

Diabetes

  • Refers to inability to regulate blood glucose levels:
    • Type 1 Diabetes: Autoimmune, results in little insulin production.
    • Type 2 Diabetes: Characterized by insulin resistance; linked to obesity and lifestyle factors.

Hypoglycemia

  • Reactive Hypoglycemia: Excessive insulin release post-high carbohydrate meals.
  • Fasting Hypoglycemia: Overproduction of insulin despite fasting.

Conclusion

  • Understanding carbohydrates, their types, digestion, regulation, and health implications is vital for proper nutrition and management of conditions like diabetes.

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Description

Test your knowledge of carbohydrates with this quiz based on Chapter 4. Explore the definition, types, and functions of carbohydrates as important energy sources. Perfect for biology students looking to solidify their understanding of plant-derived energy nutrients.

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