which of the following is not a macromolecules? A) protein B) Nucletide C) Starch D) DNA E) Lipid Organic compounds that are composed of carbon of carbon, hydrogen, and oxygen in a 1:2:1 ratio are called: A) proteins B) Nucleotides C) sugars D) fatty acids E) nuclei acids in a lipid bilayer __ tails point inward and form a region that exclude water A) acidic B) basic C) hydrophobic D) hydrophilic E) none of these Amino acids are the building blocks for A) proteins B) Steroids C) lipids D) nucleic acids E) Carbohydrates
The correct answer and explanation is:
Answers:
- Which of the following is NOT a macromolecule?
B) Nucleotide - Organic compounds composed of carbon, hydrogen, and oxygen in a 1:2:1 ratio are called:
C) Sugars - In a lipid bilayer, _________ tails point inward and form a region that excludes water:
C) Hydrophobic - Amino acids are the building blocks for:
A) Proteins
Explanation:
- Macromolecules and Nucleotides:
Macromolecules are large, complex molecules that play crucial roles in biological systems. Examples include proteins, nucleic acids (DNA and RNA), polysaccharides (like starch), and lipids. Nucleotides, on the other hand, are not macromolecules themselves but are the building blocks (monomers) of nucleic acids like DNA and RNA. While nucleotides are essential in forming macromolecules, they are smaller and do not qualify as macromolecules on their own. - Sugars and the 1:2:1 Ratio:
Sugars, also known as carbohydrates, are organic compounds with the general formula Cn(H2O)n\text{C}_n(\text{H}_2\text{O})_n, where carbon, hydrogen, and oxygen are present in a 1:2:1 ratio. Examples include glucose (C6H12O6\text{C}_6\text{H}_{12}\text{O}_6) and fructose. This ratio is unique to carbohydrates, which serve as an energy source and structural components in organisms. Other organic molecules, such as proteins or nucleotides, do not follow this specific ratio. - Hydrophobic Tails in Lipid Bilayers:
A lipid bilayer forms the foundation of cellular membranes. It consists of phospholipids, each with a hydrophilic (water-attracting) head and hydrophobic (water-repelling) tails. The hydrophobic tails face inward, avoiding water, while the hydrophilic heads face outward toward the aqueous environment. This arrangement creates a selective barrier essential for cellular function. - Amino Acids and Proteins:
Amino acids are organic compounds that combine to form proteins through peptide bonds. Proteins perform a vast array of functions in organisms, including enzymatic activity, structural support, transport, and cell signaling. Unlike steroids, lipids, or carbohydrates, which have different building blocks, proteins are exclusively made from chains of amino acids.