Carbohydrates Final Flashcards

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Questions and Answers

Carbohydrates are made of?

C, O, S

C, H, N

H, O, N

C, H, and O (correct)

Which of the following are monosaccharides? (Select all that apply)

Galactose (correct)

Glucose (correct)

Fructose (correct)

Sucrose

What are the components of maltose?

Glucose + Glucose

What are the components of lactose?

Glucose + Galactose Signup and view all the answers

What are the components of sucrose?

Glucose + Fructose Signup and view all the answers

Which of the following are examples of polysaccharides? (Select all that apply)

Starch Signup and view all the answers

What is the role of starch in plants?

Storing glucose created by photosynthesis Signup and view all the answers

Give examples of food containing starch.

Potatoes and root vegetables Signup and view all the answers

The Benedict's test detects sucrose.

False Signup and view all the answers

What are the indicators of a positive Benedict's test?

Colored precipitate (yellow, green, orange, or red) Signup and view all the answers

What does a positive iodine test indicate?

Presence of starch Signup and view all the answers

The Seliwanoff test can only detect reducing sugars.

False Signup and view all the answers

What is a chemical reaction used to break down polymers?

Hydrolysis Signup and view all the answers

Which carbohydrates are reducing sugars based on part A results?

Glucose, fructose, lactose Signup and view all the answers

Which carbohydrates are ketoses according to part B results?

Fructose, sucrose Signup and view all the answers

Which carbohydrate gives a blue-black color in the iodine test?

Starch Signup and view all the answers

What carbohydrate produces a reddish-orange solid with Benedict's reagent?

Fructose Signup and view all the answers

What carbohydrate produces no bubbles during fermentation?

Lactose Signup and view all the answers

What carbohydrate turns blue-black with iodine reagent?

Amylose Signup and view all the answers

How do the results of the iodine test indicate that hydrolysis of starch occurred?

Polysaccharide traps iodine molecules Signup and view all the answers

Study Notes

Carbohydrates Overview

Composed of Carbon (C), Hydrogen (H), and Oxygen (O).
Essential organic compounds that provide energy and structural functions.

Types of Carbohydrates

Monosaccharides: Simple sugars like glucose, fructose, galactose, and ribose.
Disaccharides: Formed by two monosaccharides:
- Maltose: Glucose + Glucose
- Lactose: Glucose + Galactose
- Sucrose: Glucose + Fructose
Polysaccharides: Complex carbohydrates for storage and structure:
- Starch: Energy storage in plants
- Cellulose: Structural component of plant cell walls
- Glycogen: Energy storage in animals

Starch

Primary function is to store glucose produced through photosynthesis.
Found in foods such as potatoes and root vegetables.

Carbohydrate Tests

Benedict's Test:
- Detects monosaccharides and disaccharides (not sucrose).
- Positive result: colored precipitate (yellow, green, orange, or red).
- Must be mixed with sample and heated; limitations include being qualitative.
Seliwanoff Test:
- Identifies complex carbohydrates with fructose.
- Aldohexoses react but more slowly than ketoses like fructose.
Iodine Test:
- Detects starch by mixing with iodine solution; positive: dark blue, negative: yellow.
Fermentation Test:
- Detects monosaccharides and disaccharides (not lactose and galactose).
- Produces CO2 bubbles during fermentation.

Hydrolysis

A reaction to break down polymers using water (H2O).
Sucrose hydrolyzes faster than starch due to its simpler structure.

Reducing Sugars

Reducing sugars include glucose, fructose, and lactose, identifiable by their reaction to specific tests.

Ketoses

Fructose and sucrose are classified as ketoses based on test results.

Iodine Test Results

Starch gives a blue-black color indicating its presence after hydrolysis.

Test Result Interpretations

Fructose: Produces reddish-orange solid with Benedict's reagent, reacts quickly with Seliwanoff's reagent.
Lactose: Shows color change with Benedict's reagent, slower with Seliwanoff's, produces no bubbles in fermentation.
Amylose: No reaction with Benedict's or Seliwanoff's but turns blue-black with iodine.

Importance of Iodine Test in Hydrolysis

Polysaccharides trap iodine, confirming the completion of starch hydrolysis.

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Description

Test your knowledge on carbohydrates with these flashcards covering key concepts, structures, and types of carbohydrates. Dive into monosaccharides, disaccharides, and polysaccharides to enhance your understanding of these essential biomolecules.