Textbook Question
What do some photosynthetic bacteria use as a source of electrons instead of water?
a. Oxygen (O2)
b. Hydrogen sulfide (H2S)
c. Organic compounds (e.g., CH3COO−)
d. Nitrate (NO3-)
Ch. 26 - Bacteria and Archaea
Freeman8th EditionBiological ScienceISBN: 9780138276263
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Table of contents
- Ch. 1 - Biology: The Study of Life13
- Ch. 2 - Water and Carbon: The Chemical Basis of Life14
- Ch.3 - Protein Structure and Function10
- Ch.4 - Nucleic Acids and the RNA World10
- Ch. 5 - An Introduction to Carbohydrates10
- Ch. 6 - Lipids, Membranes, and the First Cells11
- Ch. 7 - Inside the Cell10
- Ch. 8 - Energy and Enzymes: An Introduction to Metabolism10
- Ch. 9 - Cellular Respiration and Fermentation11
- Ch. 10 - Photosynthesis12
- Ch. 11 - Cell-Cell Interactions12
- Ch. 12 - The Cell Cycle8
- Ch. 13 - Meiosis12
- Ch. 14 - Mendel and the Gene23
- Ch. 15 - DNA and the Gene: Synthesis and Repair15
- Ch. 16 - How Genes Work16
- Ch. 17 - Transcription, RNA Processing, and Translation16
- Ch. 18 - Control of Gene Expression in Bacteria16
- Ch. 19 - Control of Gene Expression in Eukaryotes12
- Ch. 20 - The Molecular Revolution: Biotechnology, Genomics, and New Frontiers15
- Ch. 21 - Genes, Development, and Evolution12
- Ch. 22 - Evolution by Natural Selection16
- Ch. 23 - Evolutionary Processes13
- Ch. 24 - Speciation15
- Ch. 25 - Phylogenies and the History of Life13
- Ch. 26 - Bacteria and Archaea15
- Ch. 27 - Diversification of Eukaryotes16
- Ch. 28 - Green Algae and Land Plants16
- Ch. 29 - Fungi18
- Ch. 30 - An Introduction to Animals9
- Ch. 31 - Protostome Animals15
- Ch. 32 - Deuterostome Animals17
- Ch. 33 - Viruses16
- Ch. 34 - Plant Form and Function16
- Ch. 35 - Water and Sugar Transport in Plants16
- Ch. 36 - Plant Nutrition13
- Ch. 37 - Plant Sensory Systems, Signals, and Responses16
- Ch. 38 - Flowering Plant Reproduction and Development16
- Ch. 39 - Animal Form and Function17
- Ch. 40 - Water and Electrolyte Balance in Animals16
- Ch. 41 - Animal Nutrition16
- Ch. 42 - Gas Exchange and Circulation16
- Ch. 43 - Animal Nervous Systems16
- Ch. 44 - Animal Sensory Systems16
- Ch. 45 - Animal Movement11
- Ch. 46 - Chemical Signals in Animals16
- Ch. 47 - Animal Reproduction and Development16
- Ch. 48 - The Immune System in Animals16
- Ch. 49 - An Introduction to Ecology15
- Ch. 50 - Behavioral Ecology16
- Ch. 51 - Population Ecology16
- Ch. 52 - Community Ecology20
- Ch. 53 - Ecosystems and Global Ecology17
- Ch. 54 - Biodiversity and Conservation Ecology18
Chapter 26, Problem 3
Unlike plant cell walls that contain cellulose, bacterial cell walls are composed of ___________.
Verified step by step guidance1
Understand the structure of bacterial cell walls: Bacterial cell walls are primarily composed of a substance called peptidoglycan, which is a polymer consisting of sugars and amino acids.
Compare bacterial cell walls to plant cell walls: Plant cell walls are made of cellulose, a polysaccharide, whereas bacterial cell walls contain peptidoglycan, which provides structural support and shape to the bacteria.
Explore the composition of peptidoglycan: Peptidoglycan is made up of repeating units of two types of sugars, N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM), linked together by short peptide chains.
Consider the function of peptidoglycan: The peptidoglycan layer is crucial for maintaining the integrity and shape of the bacterial cell, protecting it from osmotic pressure and environmental stress.
Recognize the significance of peptidoglycan in bacterial classification: The presence and thickness of peptidoglycan in bacterial cell walls are used to classify bacteria into Gram-positive and Gram-negative groups, which have different structural characteristics.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Bacterial Cell Wall Composition
Bacterial cell walls are primarily composed of peptidoglycan, a complex polymer consisting of sugars and amino acids. This structure provides rigidity and protection, distinguishing bacterial cells from plant cells, which have cellulose-based walls. Peptidoglycan's unique composition is crucial for maintaining cell shape and integrity in bacteria.
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Introduction to Bacterial Cell Walls
Peptidoglycan Structure
Peptidoglycan is a mesh-like layer that forms the cell wall of most bacteria, composed of repeating units of N-acetylglucosamine and N-acetylmuramic acid linked by short peptide chains. This structure is essential for bacterial survival, providing mechanical strength and preventing osmotic lysis. The cross-linking of peptides gives peptidoglycan its rigidity and resilience.
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Differences Between Plant and Bacterial Cell Walls
Plant cell walls are primarily made of cellulose, a polysaccharide that provides structural support and protection. In contrast, bacterial cell walls are composed of peptidoglycan, which is unique to bacteria and serves similar protective functions. Understanding these differences is crucial for studying cell wall synthesis and targeting bacterial infections with antibiotics.
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Related Practice
Textbook Question
What are organisms called that use inorganic compounds as electron donors in cellular respiration?
a. Phototrophs
b. Heterotrophs
c. Organotrophs
d. Lithotrophs
Textbook Question
Evaluate these statements about Koch's postulates, which are used to establish a causative link between a specific microbe and a specific disease. Select True or False for each statement.
T/FThe microbe must be present in individuals suffering from the disease and absent from healthy individuals.
T/FThe microbe must be isolated and grown in pure culture.
T/FIf organisms from the pure culture are injected into a healthy experimental animal, the disease symptoms should appear.
T/FThe microbe does not have to be isolated from the experimental animal as long as the disease is present.
Textbook Question
What has metagenomic analysis allowed researchers to do for the first time? a. sample organisms from an environment and grow them under defined conditions in the lab b. isolate organisms from an environment and sequence their entire genome c. study organisms that cannot be cultured (grown in the lab) d. identify important morphological differences among species
Textbook Question
Biologists often use the term 'energy source' as a synonym for 'electron donor.' Why?