Photosynthesis and Carbohydrates Quiz

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Questions and Answers

What is the main product of photosynthesis?

Glucose and carbon dioxide

Glucose and oxygen (correct)

Water and glucose

Oxygen and carbon dioxide

Which of the following is a disaccharide?

Fructose

Lactose (correct)

Glucose

Glycogen

How many sugar units are contained in a monosaccharide?

Three

One (correct)

Four

Two

What type of carbohydrates are pectin and cellulose classified as?

Non-starch polysaccharides Signup and view all the answers

What process forms disaccharides from monosaccharides?

Condensation Signup and view all the answers

What is the primary role of cellulose in the digestive system?

It absorbs water and stimulates peristalsis. Signup and view all the answers

Where in the digestive system does salivary amylase act on carbohydrates?

In the mouth. Signup and view all the answers

Excess carbohydrates are primarily converted to which substance for long-term energy storage?

Glycogen. Signup and view all the answers

Which enzyme is responsible for breaking down sucrose into glucose and fructose in the small intestine?

Sucrase. Signup and view all the answers

What happens to fructose and galactose in the liver after absorption?

They are converted to glucose. Signup and view all the answers

Which of the following processes does NOT involve the action of amylase?

Converting glucose to glycogen. Signup and view all the answers

What is the role of the hepatic portal vein in carbohydrate absorption?

It carries monosaccharides to the liver. Signup and view all the answers

What is a consequence of consuming excess carbohydrates over time?

Storage as adipose tissue. Signup and view all the answers

What is the primary role of non-starch polysaccharides (NSPs) in the body?

To absorb water and aid waste removal Signup and view all the answers

Which sugar undergoes hydrolysis to produce glucose and fructose?

Sucrose Signup and view all the answers

What is the result of gelatinization of starch?

Thickening of the liquid occurs Signup and view all the answers

What happens during the Maillard reaction?

Browning of foods occurs Signup and view all the answers

Which of the following statements about cellulose is NOT true?

It is soluble in water Signup and view all the answers

Which type of carbohydrates is mainly used for energy storage in the body?

Glycogen Signup and view all the answers

What is the effect of dry heat on carbohydrates?

Dextrins form, causing browning Signup and view all the answers

What is one of the main properties of fructose?

It has a relative sweetness of 170 Signup and view all the answers

Which of the following is a culinary use of pectin?

To set jams and jellies Signup and view all the answers

What is a key characteristic of starch in cold water?

Insoluble Signup and view all the answers

Which process describes the breakdown of complex carbohydrates into simpler sugars?

Hydrolysis Signup and view all the answers

During the caramelisation process, what temperature range does sugar begin to melt and change?

104°C to 177°C Signup and view all the answers

Which option is an effect of moist heat on carbohydrates?

Absorption of liquid by starch grains Signup and view all the answers

Which of the following is NOT a property of sugar?

Absence of flavor Signup and view all the answers

How does the presence of sugar affect the process of aeration in baking?

It denatures egg proteins Signup and view all the answers

Study Notes

Photosynthesis

Green plants use sunlight to convert carbon dioxide and water into glucose and oxygen.

Carbohydrates

Three main types: monosaccharides, disaccharides, polysaccharides.

Monosaccharides

Single sugar unit.
Chemical formula: C₆H₁₂O₆.
Examples: glucose, fructose, galactose.

Disaccharides

Formed by joining two monosaccharides through a condensation reaction (water loss).
Chemical formula: C₁₂H₂₂O₁₁.
Examples: maltose, sucrose, lactose.

Polysaccharides

Formed by joining three or more monosaccharides through repeated condensation reactions.
Can be straight or branched chains.
Examples: starch, pectin, cellulose, gums, glycogen.
Non-starch polysaccharides (NSPs) are also known as dietary fibre or roughage.

Starch

Composed of:
- Amylose (straight chains).
- Amylopectin (branched chains).

Non-starch Polysaccharides (NSPs/Dietary Fibre)

Cannot be digested by the body.
Absorbs large amounts of water.
Aids waste removal through peristalsis (muscular gut movements).
Sources: wholemeal bread, brown rice, wholemeal pasta.

Properties of Sugars

Solubility: Soluble in water; solubility increases with heating.
Aeration: Denatures egg proteins for aeration (e.g., sponge cakes).
Crystallization: Forms when more sugar is added than the liquid can absorb; crystals form on cooling.
Caramelization: Heating produces brown caramel through gradual chemical changes (104°C to 177°C).
Maillard Reaction: Sugar + amino acid + dry heat = browning.
Sweetness: Fructose is significantly sweeter than lactose.
Hydrolysis: Chemical breakdown by adding water to form smaller molecules (reverse of condensation).
Inversion: Hydrolysis of sucrose into glucose and fructose (invert sugar); used in jam production.

Properties of Starch

Flavour: Not sweet.
Solubility: Insoluble in cold water.
Hygroscopic: Absorbs moisture from the air (e.g., biscuits).
Dextrinization: Heating forms shorter dextrin chains, and then brown pyrodextrins (e.g., toasting bread).
Gelatinization: Heating in water causes swelling, bursting, and liquid absorption, thickening the mixture. Forming a sol that turns into a gel upon cooling.

Properties of Non-starch Polysaccharides (NSPs)

Solubility: Insoluble in water.
Bulk: Adds bulk to diet for feeling of fullness.
Pectin: Found in fruit and vegetables; used in setting jams and jellies.
Pectin Extraction: Rich fruits like blackcurrants and apples are heated, and an acid like lemon juice is added to change protopectin to pectin.
Gel Formation: When heated with acid and sugar, pectin forms a gel by trapping water.

Effects of Heat on Carbohydrates

Dry Heat: Browning from dextrins, caramelisation of sugar, and Maillard reactions.
Moist Heat: Softening of cellulose, gelatinization of starch (thickening), pectin extraction (e.g., jam).

Culinary Uses of Carbohydrates

Sugar: Sweetener, preservative, caramelisation, fermentation (bread), gel formation (jam), colour prevention, thickener, hygroscopic, dextrinization.
NSPs: Gel formation (jam), bulkiness (texture), absorption of moisture.

Biological Functions of Carbohydrates

Energy Source: Provides heat and energy for body functions.
Protein Sparing: Allows proteins to be used for growth and repair instead of energy production.
Energy Storage: Excess carbohydrate is stored as glycogen in the liver and muscles, or as fat.
Cellulose: Speeds up waste removal; prevents bowel disorders like constipation.

Digestion of Carbohydrates

Mouth: Chewing and salivary amylase breaks down starch to maltose.
Pancreas: Amylase continues breaking down starch to maltose.
Small Intestine: Maltase, sucrase, and lactase break down disaccharides into monosaccharides (glucose, fructose, galactose).

Absorption and Utilisation of Carbohydrates

Monosaccharides are absorbed by the small intestine.
Hepatic portal vein transports to the liver.
Liver converts fructose and galactose to glucose.
Glucose is used for energy, stored as glycogen, or converted to fat.

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Description

Test your knowledge on photosynthesis and the different types of carbohydrates, including monosaccharides, disaccharides, and polysaccharides. This quiz covers their definitions, structures, and examples, providing a comprehensive overview of vital concepts in plant biology and nutrition.