Textbook Question
The innermost layer of the root cortex is the
a. Core
b. Pericycle
c. Endodermis
d. Pith
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Ch. 35 - Vascular Plant Structure, Growth, and Development
Urry11th EditionCampbell BiologyISBN: 9789357423311
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Table of contents
- Ch. 1 - Evolution, the Themes of Biology, and Scientific Inquiry8
- Ch. 2 - The Chemical Context of Life8
- Ch. 3 - Water and Life6
- Ch. 4 - Carbon and the Molecular Diversity of Life9
- Ch. 5 - The Structure and Function of Large Biological Molecules9
- Ch. 6 - A Tour of the Cell6
- Ch. 7 - Membrane Structure and Function6
- Ch. 8 - An Introduction to Metabolism6
- Ch. 9 - Cellular Respiration and Fermentation10
- Ch. 10 - Photosynthesis7
- Ch. 11 - Cell Communication7
- Ch. 12 - The Cell Cycle10
- Ch. 13 - Meiosis and Sexual Life Cycles10
- Ch. 14 - Mendel and the Gene Idea14
- Ch, 15 - The Chromosomal Basis of Inheritance7
- Ch. 16 - The Molecular Basis of Inheritance9
- Ch. 17 - Gene Expression: From Gene to Protein9
- Ch. 18 - Regulation of Gene Expression10
- Ch. 19 - Viruses6
- Ch. 20 - DNA Tools and Biotechnology8
- Ch. 21 - Genomes and Their Evolution8
- Ch. 22 - Descent with Modification: A Darwininan View of Life6
- Ch. 23 - The Evolution of Populations5
- Ch. 24 - The Origin of Species6
- Ch. 25 - The History of Life on Earth6
- Ch. 26 - Phylogeny and the Tree of Life7
- Ch. 27 - Bacteria and Archaea8
- Ch. 28 - Protists7
- Ch. 29 - Plant Diversity I: How Plants Colonized Land7
- Ch. 30 - Plant Diversity II: The Evolution of Seed Plants7
- Ch. 31 - Fungi5
- Ch. 32 - An Overview of Animal Diversity4
- Ch. 33 - An introduction to Invertebrates6
- Ch. 34 - The Origin and Evolution of Vertebrates7
- Ch. 35 - Vascular Plant Structure, Growth, and Development8
- Ch. 36 - Resource Acquisition and Transport in Vascular Plants8
- Ch. 37 - Soil and Plant Nutrition10
- Ch. 38 - Angiosperm Reproduction and Biotechnology8
- Ch. 39 - Plant Responses to Internal and External Signals8
- Ch. 40 - Basic Principles of Animal Form and Function8
- Ch. 41 - Animal Nutrition7
- Ch. 42 - Circulation and Gas Exchange7
- Ch. 43 - The Immune System6
- Ch. 44 - Osmoregulation and Excretion6
- Ch. 45 - Hormones and the Endocrine System8
- Ch. 46 - Animal Reproduction8
- Ch. 47 - Animal Development8
- Ch. 48 - Neurons, Synapses, and Signaling6
- Ch. 49 - Nervous Systems8
- Ch. 50 - Sensory and Motor Mechanisms5
- Ch. 51 Animal Behavior6
- Ch. 52 - An Introduction to Ecology and the Biosphere7
- Ch. 53 - Population Ecology10
- Ch. 54 - Community Ecology9
- Ch. 55 - Ecosystems and Restoration Ecology8
- Ch. 56 - Conservation Biology and Global Change6
Chapter 35, Problem 5
Suppose a flower had normal expression of genes A and C and expression of gene B in all four whorls. Based on the ABC hypothesis, what would be the structure of that flower, starting at the outermost whorl?
a. Carpel-petal-petal-carpel
b. Petal-petal-stamen-stamen
c. Sepal-carpel-carpel-sepal
d. Sepal-sepal-carpel-carpel
Verified step by step guidance1
Understand the ABC model of flower development: The ABC model explains how the identity of floral organs is determined by the expression of three classes of genes: A, B, and C. Each gene class is responsible for the development of specific whorls in the flower.
Identify the role of each gene class: Gene A is responsible for sepals, Gene B for petals and stamens, and Gene C for stamens and carpels. The combination of these genes determines the identity of the floral organs in each whorl.
Analyze the given gene expression: The problem states normal expression of genes A and C, and expression of gene B in all four whorls. This means gene A is expressed in the first whorl, gene B in all whorls, and gene C in the third and fourth whorls.
Determine the structure of each whorl: Based on the ABC model, the first whorl with gene A expression will form sepals. The second whorl with gene A and B expression will form petals. The third whorl with gene B and C expression will form stamens. The fourth whorl with gene C expression will form carpels.
Match the structure to the options: The sequence of floral organs from outermost to innermost whorl is sepal-petal-stamen-carpel. Compare this sequence with the given options to identify the correct answer.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
ABC Model of Flower Development
The ABC model explains how the identity of floral organs is determined by the expression of three classes of genes: A, B, and C. Class A genes specify sepals, A and B together specify petals, B and C specify stamens, and C alone specifies carpels. This model helps predict the arrangement of floral organs based on gene expression patterns.
Recommended video:
Guided course
04:08
Flower Anatomy
Gene Expression in Floral Whorls
Floral organs are arranged in concentric whorls, typically four: sepals, petals, stamens, and carpels. The expression of specific genes in these whorls determines the type of organ formed. In the ABC model, the presence or absence of gene expression in each whorl dictates the organ identity, crucial for understanding flower structure.
Recommended video:
Guided course
06:40Introduction to Regulation of Gene Expression
Mutations and Gene Expression Patterns
Mutations affecting gene expression can alter the normal pattern of floral organ development. In the given scenario, the expression of gene B in all whorls suggests a mutation or alteration from typical expression patterns, leading to a change in organ identity. Understanding these patterns is essential for predicting the resulting flower structure.
Recommended video:
Guided course
06:40Introduction to Regulation of Gene Expression
Related Practice
Textbook Question
Heartwood and sapwood consist of
a. Bark
b. Periderm
c. Secondary xylem
d. Secondary phloem
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Textbook Question
The phase change of an apical meristem from the juvenile to the mature vegetative phase is often revealed by
a. A change in the morphology of the leaves produced
b. The initiation of secondary growth
c. The formation of lateral roots
d. The activation of floral meristem identity genes
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Textbook Question
Which of the following arise(s), directly or indirectly, from meristematic activity?
a. Secondary xylem
b. Leaves
c. Dermal tissue
d. All of the above
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Textbook Question
Which of the following would not be seen in a cross section through the woody part of a root?
a. Sclerenchyma cells
b. Parenchyma cells
c. Sieve-tube elements
d. Root hairs
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Textbook Question
On this cross section from a woody eudicot, label a growth ring, late wood, early wood, and a vessel element. Then draw an arrow in the pith-to-cork direction.
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