Biology: Functional Groups and Molecules

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Questions and Answers

What is the primary function of polysaccharides in plants?

Energy storage (correct)

Cell wall structure

Protein synthesis

Nutrient transport

What distinguishes the structure of cellulose from starch?

Cellulose is soluble in water.

Cellulose contains galactose monomers.

Cellulose is composed of fructose units.

Cellulose has a 1–4 linkage of beta glucose monomers. (correct)

Why are humans unable to digest cellulose effectively?

Humans lack the enzyme to break down beta linkages. (correct)

Cellulose is toxic to the human digestive system.

Cellulose forms complex structures that humans cannot process.

Cellulose is fully oxidized in humans.

What is a characteristic of lipids compared to carbohydrates?

Lipids have more calories per gram than carbohydrates. Signup and view all the answers

Which type of lipid is composed of three fatty acids bonded to glycerol?

Triglycerides Signup and view all the answers

What type of bond characterizes saturated fatty acids?

No double bonds Signup and view all the answers

Which of the following is a major structural component of plant cell walls?

Cellulose Signup and view all the answers

Phospholipids differ from triglycerides in that they contain:

A phosphate group Signup and view all the answers

What process breaks polymers into monomers?

Hydrolysis Signup and view all the answers

What type of bond is formed when two monosaccharides join together?

Glycosidic linkage Signup and view all the answers

Which of these is a characteristic of monosaccharides?

They are the simplest form of carbohydrates. Signup and view all the answers

What happens during dehydration synthesis?

A water molecule is removed to form a bond. Signup and view all the answers

Which carbohydrate is formed from glucose and fructose?

Sucrose Signup and view all the answers

What are polysaccharides primarily composed of?

Hundreds to thousands of monosaccharides Signup and view all the answers

Which of the following is NOT a function of carbohydrates?

Storing genetic information Signup and view all the answers

What does hydrolysis do to a polymer?

Adds a water molecule to break a bond. Signup and view all the answers

What is the primary role of functional groups in biological molecules?

They affect the molecule's shape and function. Signup and view all the answers

Which of the following is NOT one of the four major types of biological molecules?

Vitamins Signup and view all the answers

What process is involved in the joining of monomers to form polymers?

Dehydration synthesis Signup and view all the answers

Why are phospholipids important for cell membranes?

They possess amphipathic properties. Signup and view all the answers

Which type of biological macromolecule is made up of amino acids?

Proteins Signup and view all the answers

What happens during a condensation reaction?

Water molecules are produced. Signup and view all the answers

Which of the following statements is true regarding carbohydrates?

They are made of monomers called sugars. Signup and view all the answers

Which functional group is characterized by the presence of a nitrogen atom?

Amino group Signup and view all the answers

What characterizes saturated fatty acids?

They are solid at room temperature. Signup and view all the answers

What is the main structural difference between phospholipids and traditional fats?

Phospholipids have a hydrophilic head and hydrophobic tails, while traditional fats do not. Signup and view all the answers

What is the primary structure of a protein?

The sequence of amino acids in the polypeptide chain. Signup and view all the answers

What happens during the process of denaturation?

Proteins unravel and lose their biological activity. Signup and view all the answers

What is the primary role of chaperonins in protein synthesis?

To facilitate protein folding Signup and view all the answers

Which of the following correctly describes unsaturated fats?

They have kinks in their structure due to double bonds. Signup and view all the answers

Which part of a nucleotide varies between DNA and RNA?

Sugar component Signup and view all the answers

What defines quaternary structure in proteins?

The interactions between multiple polypeptide chains. Signup and view all the answers

What role do eicosanoids play in the body?

They act as hormone-like signals between cells. Signup and view all the answers

Which nitrogenous base is found in RNA but not in DNA?

Uracil Signup and view all the answers

How are peptide bonds formed?

By a dehydration reaction between the carboxyl group of one amino acid and the amino group of another. Signup and view all the answers

What is the structure of DNA primarily characterized by?

Double helix with antiparallel strands Signup and view all the answers

How do the complementary bases in DNA pair with one another?

A pairs with T, G pairs with C Signup and view all the answers

What is a key function of nucleic acids in cells?

Hereditary information control Signup and view all the answers

What type of bond connects the nitrogenous bases in the DNA double helix?

Hydrogen bonds Signup and view all the answers

What describes the orientation of the sugar-phosphate backbones in DNA?

Both run in opposite directions Signup and view all the answers

Study Notes

Functional Groups

Functional groups are chemical groups that affect molecular function, either by influencing shape or directly participating in chemical reactions.
The seven most important functional groups in biology are: hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, phosphate, and methyl.

Chemical Building Blocks of Life

There are four major types of biological molecules: lipids, nucleic acids, proteins, and carbohydrates.
Lipids, particularly phospholipids, are essential for cell membranes due to their amphipathic nature.
Nucleic acids are polymers of nucleotides that exist as either DNA or RNA.
Carbohydrates are polymers of sugars and serve as both structural components and energy sources.
Proteins are polymers of amino acids and play vital roles in structure and enzymatic activity.

Polymers

Polymers are large molecules composed of repeating units called monomers.
Polymerization occurs through dehydration synthesis (condensation), where monomers are linked together with the loss of a water molecule.
The process is facilitated by enzymes.
Polymers are broken down into monomers through hydrolysis, the addition of a water molecule to break the bond.

Carbohydrates

Carbohydrates include sugars and polymers of sugars.
Monosaccharides are simple sugars, disaccharides are formed by two monosaccharides joined by a glycosidic linkage, and polysaccharides consist of many sugar units.
The general formula for carbohydrates is (CH2O)n.
Examples of monosaccharides include glucose, galactose, and fructose.
Examples of disaccharides include sucrose, lactose, and maltose.

Polysaccharides

Polysaccharides are macromolecules comprised of hundreds to thousands of monosaccharides linked by glycosidic linkages.
Their function depends on the type of sugar monomers and the position of the glycosidic linkages.
Storage polysaccharides include starch (plants) and glycogen (animals), both polymers of glucose.
Structural polysaccharides like cellulose provide strong building material in plants.
Humans lack enzymes to break down cellulose, making it a source of insoluble fiber.

Lipids

Lipids are hydrophobic organic molecules composed primarily of carbon, hydrogen, and oxygen.
They are less oxidized than carbohydrates, leading to higher caloric content per gram.
The five main types of lipids in humans are: fatty acids, triglycerides, phospholipids, eicosanoids, and steroids.
Fatty acids can be saturated (no double bonds) or unsaturated (one or more double bonds).
Triglycerides consist of three fatty acids bound to a glycerol molecule.
Phospholipids are similar to triglycerides but with a phosphate group replacing one fatty acid, giving them amphipathic properties.
Eicosanoids are hormone-like signaling molecules between cells.

Proteins

Proteins are composed of polypeptides, which are chains of amino acids linked together.
Each amino acid has an amine group, a carboxyl group, and a unique side chain.
Amino acids are linked together by peptide bonds formed via dehydration reactions.
The structure of a protein can be categorized into four levels:
- Primary: The linear sequence of amino acids.
- Secondary: Local twists and turns in the polypeptide chain, such as alpha helices and beta pleated sheets.
- Tertiary: The overall three-dimensional shape of a polypeptide, determined by interactions between side chains.
- Quaternary: The arrangement of multiple polypeptide chains in a protein complex.
Denaturation refers to the unfolding of a protein, often due to unfavorable environmental conditions, leading to loss of function.
Chaperonins are proteins that assist in proper protein folding.

Nucleic Acids: DNA & RNA

DNA is the genetic material passed from parents to offspring, organized into genes located on chromosomes.
Genes contain the instructions for all cellular activities.
RNA is synthesized from DNA and carries genetic information to ribosomes for protein synthesis.
The process of DNA to RNA to protein is known as gene expression.

Nucleic Acid Structure

Nucleic acids are polymers of nucleotides.
Each nucleotide consists of a sugar (ribose or deoxyribose), a phosphate group, and a nitrogenous base.
The nitrogenous bases include adenine (A), guanine (G), cytosine (C), thymine (T) (in DNA), and uracil (U) (in RNA).
RNA is single-stranded, while DNA is double-stranded.
The two DNA strands are antiparallel, running in opposite 5' to 3' directions, and held together by hydrogen bonds between complementary bases (A with T, G with C).
The structure of DNA is a double helix, with sugar-phosphate backbones on the outside and bases towards the interior.

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Description

Explore the essential functional groups and biological molecules that make up life. This quiz covers important concepts such as the role of functional groups, the four major types of biological molecules, and polymerization processes. Test your understanding of these fundamental topics in biology.