Biology Chapter 3: The Molecules of Cells

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Questions and Answers

What is the primary characteristic of carbon that allows it to form a wide variety of complex molecules?

It can form single ionic bonds.

It has 6 valence electrons.

It has 4 valence electrons, allowing it to form four covalent bonds. (correct)

It is naturally hydrophilic.

Which of the following is NOT a functional group commonly found in biological molecules?

Triple bond (correct)

Methyl group

Carbonyl group

Hydroxyl group

What type of reaction is used to link monomers together to form polymers?

Dehydration reaction (correct)

Reduction

Hydrolysis

Oxidation

What is the name of a molecule consisting of only carbon and hydrogen atoms?

Hydrocarbon Signup and view all the answers

What makes functional groups likely to participate in chemical reactions?

They are polar and hydrophilic. Signup and view all the answers

What is the molecular formula for both glucose and fructose?

C6H12O6 Signup and view all the answers

What is a key difference between glucose and fructose?

They have the same molecular formula but differ in properties such as taste. Signup and view all the answers

What role do enzymes play in biological reactions?

They speed up chemical reactions in cells, like hydrolysis and dehydration. Signup and view all the answers

A disaccharide is formed by the joining of two monosaccharides through which process?

Dehydration reaction Signup and view all the answers

What is the primary factor contributing to the diversity of polymers?

The arrangement of monomers Signup and view all the answers

Which of the following is a disaccharide composed of one glucose monomer and one fructose monomer?

Sucrose Signup and view all the answers

What is the primary function of polysaccharides in biological systems?

To act as structural components or storage molecules Signup and view all the answers

Which structural polysaccharide is a major component of plant cell walls and is not digestible by most animals?

Cellulose Signup and view all the answers

What characteristic of lipids makes them hydrophobic?

The presence of non-polar covalent bonds in their structure Signup and view all the answers

Why are unsaturated fatty acids typically liquid at room temperature?

They contain one or more double bonded carbons, creating bends in the chain Signup and view all the answers

What is the result of the hydrogenation process on oils?

Convert unsaturated fats into saturated fats Signup and view all the answers

Which of the following is a storage polysaccharide found in plants?

Starch Signup and view all the answers

Which of these is NOT typically a function of lipids?

Structural support in plant cell walls Signup and view all the answers

What is a key difference between fats and carbohydrates?

Fats are made from different monomers and are generally smaller than carbohydrates Signup and view all the answers

What does a food label indicating 'partially hydrogenated oils' suggest?

The oil has some fat molecules with added hydrogen, and may contain trans fats Signup and view all the answers

Study Notes

Chapter 3: The Molecules of Cells

Life's diversity is based on the properties of carbon
- Organic molecules are carbon-based, often containing hydrogen
- Carbon forms four covalent bonds, allowing for complex structures
- Carbon chains are the backbone of most organic molecules
Key chemical groups in biological molecules
- Functional groups (hydroxyl, carbonyl, carboxyl, amino, phosphate, methyl)
- These groups affect molecular function by participating in chemical reactions
- Hydrophilic (water-loving) groups are often polar
- Hydrophobic groups, like hydrocarbons, are nonpolar and insoluble in water
Building large molecules from small ones
- Monomers are the building blocks of polymers
- Dehydration reactions join monomers by removing water molecules
- Hydrolysis reactions break polymers apart using water
Carbohydrates
- Monosaccharides are simple sugars; examples include glucose and fructose
- Disaccharides are two monosaccharides joined together
- Polysaccharides are complex carbohydrates; starch, glycogen, and cellulose are examples
  - Starch is a storage polysaccharide in plants
  - Glycogen stores glucose in animals
  - Cellulose forms plant cell walls
Lipids
- Fats are composed of glycerol and fatty acids
  - energy storage molecules
  - Fatty acids with double bonds are unsaturated; those with no double bonds are saturated.
  - Animals store mostly saturated fats, while plants often store unsaturated fats.
- Phospholipids have a hydrophilic (polar) head and two hydrophobic (nonpolar) tails.
- Steroids have a four-ring hydrocarbon structure
Proteins
- Proteins are polypeptides, chains of amino acids
- Amino acids are the monomers of proteins
- Proteins have four levels of structure: primary, secondary, tertiary, and quaternary
  - Primary structure: amino acid sequence
  - Secondary structure: alpha helix or beta pleated sheet
  - Tertiary structure: overall 3D shape
  - Quaternary structure: arrangement of multiple polypeptides
Nucleic acids
- Nucleic acids are polymers of nucleotides
- Nucleotides have a sugar, a phosphate group, and a nitrogenous base
- DNA (deoxyribonucleic acid) stores genetic information
- RNA (ribonucleic acid) plays a role in protein synthesis

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Description

Explore the fundamental concepts of cellular molecules in this quiz based on Chapter 3 of your biology textbook. Understand the role of carbon in organic molecules, key chemical groups, and the processes of building large molecules from smaller ones. Assess your knowledge of carbohydrates and their structure.