Biology Chapter on Macromolecules and Lipids

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Questions and Answers

What are the primary components that form phospholipids?

Glycerol, fatty acids, and charged groups (correct)

Cholesterol, triglycerides, and amino acids

Triglycerides, steroids, and polysaccharides

Fatty acids, amino acids, and glucose

Which type of fatty acid has all carbon atoms linked by single covalent bonds?

Hydrophobic fatty acids

Polyunsaturated fatty acids

Unsaturated fatty acids

Saturated fatty acids (correct)

Which of the following is NOT a function of lipids?

Insulation

Hormone production

Energy source

Carbon storage (correct)

What is the structural feature of phospholipids that allows them to interact with water?

Charged groups Signup and view all the answers

Which macromolecule is primarily based on amino acid monomers?

Proteins Signup and view all the answers

Which group of bonds holds together the complementary bases in the DNA double helix?

Hydrogen bonds Signup and view all the answers

What is the primary function of nucleotides in nucleic acids?

Energy transfer and storage Signup and view all the answers

What distinguishes RNA from DNA in terms of chain structure?

RNA has a single chain Signup and view all the answers

Which of the following correctly describes a difference between the sugars found in DNA and RNA?

DNA contains deoxyribose and RNA contains ribose Signup and view all the answers

Which statement about amino acids is true?

Amino acids contain an amino group, a carboxyl group, and a varying side chain Signup and view all the answers

What mass of glucose is required to prepare 1 liter of a 1 M glucose solution?

180 g Signup and view all the answers

Which of the following correctly describes polar compounds?

They have opposite charges at each end of the bond. Signup and view all the answers

What type of compound does NaCl represent in relation to water?

Hydrophilic compound Signup and view all the answers

What defines an ion?

An electrically charged atom due to a mismatch in protons and electrons Signup and view all the answers

Which of the following organic molecules is NOT one of the four main types?

Vitamins Signup and view all the answers

What is the primary function of carbohydrates in biological systems?

Energy storage and production Signup and view all the answers

Which type of bond involves the sharing of electrons?

Covalent bond Signup and view all the answers

What structural difference exists between glucose and galactose?

Location of hydroxyl (OH) group Signup and view all the answers

Which strength classification accurately refers to ionic bonds?

Strong Signup and view all the answers

What is the result of sharing electrons more favorably with a larger atom?

Polar covalent bonding Signup and view all the answers

What type of bond primarily links monosaccharides to form disaccharides?

Covalent bonds Signup and view all the answers

Which statement about molecular weight (MW) is correct?

It represents the grams needed to create a 1-molar solution in one liter Signup and view all the answers

What is glycogen primarily used for in living organisms?

High-energy storage Signup and view all the answers

In a chemical solution, what does the term 'chemical concentration' refer to?

The amount of solute present in a specific volume of solvent Signup and view all the answers

Which of the following correctly represents a chlorine ion that has gained an electron?

Cl- Signup and view all the answers

What type of molecular interaction is represented by the attraction between hydrogen and oxygen or nitrogen?

Hydrogen bonds Signup and view all the answers

Study Notes

Chemical Composition of the Body

Humans are complex systems composed of tissues and organ systems.
Organ systems contain extracellular matrices and cells.
Cells are composed of organelles and molecules.
Molecules are collections of atoms held together by chemical bonds.
Atoms are made up of subatomic particles: a nucleus with protons and neutrons, and surrounding electrons.

Ions

An ion results when an atom gains or loses one or more electrons, leading to an electrical charge.
The charge is indicated using plus and minus signs.
The number of plus or minus signs indicates the number of electrons gained or lost.
Examples: Cl⁻ represents a chlorine atom that gained an electron, Ca²⁺ represents a calcium atom that lost two electrons.

Molecular Structure

Several ways exist to represent molecular structure which helps understand function.
Two-dimensional representations show the connectivity of atoms.
Three-dimensional models provide a better visualization of the molecule's shape.
Space-filling models illustrate the relative sizes of atoms in a molecule.
Examples given for two-dimensional and three-dimensional representations include methane (CH₄) and ammonia (NH₃).

Chemical Bonds and Interactions

Strong Bonds:
- Covalent bonds: atoms share electrons, seen in methane (CH₄)
- Ionic bonds: opposite charges attract (e.g., sodium chloride, Na⁺Cl⁻).
Weak Interactions:
- Hydrogen bonds: attraction between a hydrogen atom and an electronegative atom (e.g., oxygen or nitrogen). This is shown in water molecules.
- Van der Waals forces: weak, short-range attractive forces between molecules.

Solvent + Solute(s) = A Chemical Solution

A solution consists of a solvent and one or more solutes.
Chemical concentration measures the amount of solute dissolved in the solvent.
Molecular weight (MW) is the mass in grams of one mole of a solute.
One molar (1M) solution contains one mole of solute per liter of solvent.
Example: glucose (C₆H₁₂O₆) has a MW of 180 g/mol, so a 1 M solution requires 180 grams of glucose dissolved in 1 liter of water.

Polar and Non-polar Bonds

Polar compounds have atoms with opposite charges at each end (e.g., water). They readily associate with each other.
Nonpolar compounds have atoms with similar charges at each end (e.g., some hydrocarbons). They readily associate with each other.
Hydrophilic molecules dissolve readily in water.
Hydrophobic molecules do not dissolve readily in water but often dissolve in nonpolar solvents.

NaCl Dissolves in Water

Sodium chloride (NaCl) consists of Na⁺ and Cl⁻ ions.
Water, due to its polarity, dissolves Na⁺ and Cl⁻ ions, forming a solution.
Water molecules surround and dissolve Na⁺ and Cl⁻.
Na⁺ and Cl⁻ are solutes, and water is the solvent.

Non-polar and Polar regions

Non-polar regions associate with each other.
Polar regions form hydrogen bonds with polar water molecules.

Organic Molecules

Organic molecules contain carbon (C) and hydrogen (H)
Four main types: carbohydrates, lipids, proteins, and nucleic acids.

Carbohydrates

Structure: sugars and starches; contain C, H, O (often with hydroxyl OH groups linked to carbons.) They are characterized as covalent bonded chains.
Function: energy storage and production.
Examples: glucose, fructose, sucrose, glycogen.

Lipids

Structure: based on fatty acid monomers; long hydrocarbon chains, can be saturated (single bonds) or unsaturated (double bonds).
Function: energy storage, cell membranes, hormones, insulation.
Examples: triglycerides, phospholipids, steroids, cholesterol.

Proteins

Structure: based on amino acid monomers; diverse shapes with different levels of structures, contain C, H, O, N (often with sulfur), with covalent bonds between amino acids.
Function: many roles, including enzymes, cell attachment, cytoskeleton, locomotion, and hormones.
All amino acids share an amino group and a carboxyl group and vary with their differing "side chains." Side chains can be nonpolar, polar, or ionized.

Nucleic Acids (Nucleotides)

Structure: sugar + bases + phosphate; repeating units (nucleotides) in a chain.
Functions: information storage (DNA and RNA), energy storage and transfer (ATP), coenzymes.
DNA: deoxyribose sugar, contains four bases (adenine, guanine, cytosine, and thymine); double helix.
RNA: ribose sugar, contains four bases (adenine, guanine cytosine, and uracil); single strand.

DNA and RNA Comparison

Structure and function differ in the sugars, bases and chain quantities, and overall structure.

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Description

This quiz covers essential concepts related to biological macromolecules, including lipids, nucleic acids, and proteins. Test your understanding of the structures and functions of these critical components in living organisms. Answer questions on phospholipids, fatty acids, nucleotides, and amino acids.