biomolecules

Carbohydrates

Types include starch, glycogen, cellulose, and various sugars.
Starch is primarily found in plants and serves as an energy reserve.
Glycogen, the animal counterpart of starch, functions similarly in energy storage.
Glucose is the key sugar, dissolving in blood plasma for transport to cells.
Common sugars include glucose, fructose, maltose, and sucrose; glucose is found in both plants and animals.
Glucose has a hexagonal shape and can be linked to form different structures:
- Starch: coiled, spiral chains for energy storage in plants.
- Cellulose: straight-lined chains forming cell walls.
- Glycogen: branched chains serving as energy reserve in animals.

Mono- and Polysaccharides

Monosaccharides are the simplest carbohydrates and dissolve easily in water, tasting sweet.
Polysaccharides are formed when monosaccharides link together and are often insoluble and complex to break down.
Examples of polysaccharides include starch, glycogen, and cellulose.

Lipids

Comprise fats and oils and are insoluble in water.
Lipids provide significant energy, with 1 g yielding 39 kJ.
The body first utilizes carbohydrates for energy, then relies on fats.
Adipose tissue, made from lipids, offers protection and insulation.
Lipids are composed of glycerol and three fatty acids.

Proteins

Essential for muscle building and overall bodily structure.
Composed of nitrogen, sulfur, carbon, hydrogen, and oxygen.
Proteins function in growth, repair, and regeneration, as well as creating antibodies and hormones.
Formed from chains of amino acids, with 20 known amino acids contributing to different proteins.
Protein detection: mix with copper sulfate and dilute potassium hydroxide—purple indicates protein presence.

Testing for Biomolecules

Carbohydrates: Starch tested with iodine solution, changing from orange-brown to blue-black.
Reducing sugars tested with Benedict’s solution, transitioning from blue to orange-red.
Lipids tested using the ethanol emulsion test; a milky-white layer indicates presence.
Proteins tested with Biuret reagent, changing from blue to violet.
Vitamin C tested with DCPIP, losing its color.

DNA Structure

DNA stands for deoxyribonucleic acid and is the genetic material in cells.
Contains 23 chromosomes inherited from each parent, totaling 46.
Alleles can be dominant or recessive and determine traits.
DNA consists of nucleotides that form a double helix structure.
Nitrogenous bases include adenine, thymine, guanine, and cytosine, following A-T and G-C pairing rules for proper base pairing.
Base pairing is crucial for protein synthesis, with the type of protein depending on the sequence of bases.

Carbohydrates

Types include starch, glycogen, cellulose, and various sugars.
Starch serves as the primary energy reserve in plants.
Glycogen functions as the energy storage for animals.
Glucose is transported in blood plasma, providing energy to cells.
Sugars encompass glucose, fructose, maltose, and sucrose; glucose is present in both plants and animals.
Glucose has a hexagonal structure.
Starch is formed by long, coiled chains of glucose; it is utilized as an energy reserve in plants.
Cellulose consists of straight-lined chains of glucose, forming the structure of plant cell walls.
Glycogen is a branched glucose chain, acting as an energy reserve in animals.

Monosaccharides vs. Polysaccharides

Monosaccharides are the simplest form of carbohydrates, dissolve easily in water, and taste sweet.
Polysaccharides are complex carbohydrates formed from linked monosaccharides, are generally insoluble, and require conversion to glucose before breakdown.
Examples of polysaccharides include starch, glycogen, and cellulose.

Lipids

Comprise fats and oils that do not dissolve in water.
Fats are energy-dense, providing 39 kJ of energy per gram.
The body uses carbohydrates first, followed by fats for energy.
Adipose tissue, composed of fat layers, provides insulation and protection.
Lipids are structured from glycerol and three fatty acids.

Proteins

Essential for muscle building and regeneration.
Consist primarily of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur.
Hemoglobin is a crucial protein that transports oxygen in the blood.
Keratin is a structural protein found in hair and nails.
Proteins also include antibodies and hormones, involved in various body functions.
Composed of 20 known amino acids; different combinations yield diverse proteins.
A protein test involves using copper sulfate and potassium hydroxide, resulting in a color change to purple if protein is present.

Testing for Biomolecules

Carbohydrates:
- Starch tested with iodine solution: color changes from orange-brown to blue-black.
- Reducing sugars using Benedict’s solution: turns from blue to orange-red.
Lipids:
- Ethanol emulsion test involves shaking food with ethanol, leading to a milky-white layer upon mixing with distilled water if lipids are present.
Proteins:
- Biuret reagent turns from blue to violet in the presence of protein.
Vitamin C:
- DCPIP test reflects a color loss.

Structure of DNA

DNA (deoxyribonucleic acid) is the genetic material within cells.
Humans carry 23 chromosomes from each parent, totaling 46 chromosomes.
Alleles can be dominant or recessive.
DNA is composed of nucleotides, which are the building blocks of genetic material.
Its structure forms a double helix.
Nitrogenous bases include adenine, thymine, guanine, and cytosine, adhering to specific pairing rules (A-T and G-C only).
Base pairing is essential for protein synthesis; the type of protein is determined by the sequence of these bases.
The DNA structure resembles a ribbon, highlighting its twisted formation.

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Questions and Answers

What is the primary function of glycogen in animals?

Which of the following is a characteristic of monosaccharides?

What type of test is used to detect the presence of starch?

What element is commonly found in proteins that is not found in carbohydrates and lipids?

Which of the following statements about glucose is accurate?

What happens to reducing sugars when they are tested with Benedict's solution?

Which type of fatty acids are lipids primarily made of?

What is the main role of DNA?

Which of the following polysaccharides serves as an energy reserve for plants?

Lipids dissolve easily in water.

What is the structural shape of glucose?

The test for lipids involves shaking the food with ______ and observing for a milky-white layer.

Match the following biomolecules with their functions:

Which amino acid is NOT part of the 20 known amino acids used to build proteins?

DNA consists of a single strand of nucleotides.

List one nitrogenous base that pairs with thymine in DNA.

Study Notes

Carbohydrates

Mono- and Polysaccharides

Lipids

Proteins

Testing for Biomolecules

DNA Structure

Carbohydrates

Monosaccharides vs. Polysaccharides

Lipids

Proteins

Testing for Biomolecules

Structure of DNA

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