The amount of information that students must learn is constantly growing, making it crucial that students not simply memorize facts, but rather learn how to learn. In my classroom and in this text I emphasize basic principles, but I place them in the meaningful context of classic and modern experiments. Thus, in observing the process of science, students learn for themselves the type of critical thinking that leads to the formulation of hypotheses and experimental questions and, thence, to the generation of new knowledge.
Classic Principles. Our present understanding of genes is built on the foundation of classic experiments, a number of which have led to discoveries recognized by the Nobel Prize. These classic experiments are described so that students can appreciate how ideas about genetic processes have developed to our present-day understanding. These experiments include:. Do you like this book? Please share with your friends, let's read it!!
Search Ebook here:. Book Preface An Approach to Teaching Genetics The structure of DNA was first described in , and since that time genetics has become one of the most exciting and ground-breaking sciences. The Genetics Place Companion Website contains interactive iActivities and narrated animations that help students visualize and understand processes and concepts that are illustrated in the text. The text is ideally suited for students who have had some background in biology and chemistry and who are interested in learning the central concepts of genetics.
Problem solving is a major feature of the text and students have the opportunity to apply critical thinking skills to a variety of problems at the end of each chapter. Pedagogical features such as Principal Points, at the beginning of each chapter, and Keynotes, strategically placed throughout the chapter, are useful learning tools. The authors have restructured each chapter around a conceptual framework of five or six big ideas.
The text also contains a wealth of pedagogical features such as Chapter Overviews, Concept Check questions, New Inquiry Figures and each chapter ends with a Scientific Inquiry Question that asks students to apply scientific investigation skills to the content of the chapter. The book has a well-deserved reputation for being the most accurate biochemistry textbook in the market. Widely praised in its previous edition for currency, and clarity of exposition, the new edition has been thoroughly revised and updated to reflect recent changes in this dynamic discipline.
It covers all the statistical tests a biology student would need throughout their study; demonstrates their uses and rationale; and describes how to perform them using both a calculator and the SPSS computer package. Reflects the dynamic nature of modern genetics by emphasizing an experimental, inquiry-based approach. This text is useful for students who have had some background in biology and chemistry and who are interested in learning the central concepts of genetics.
This student resource contains chapter outlines of text material, solutions to all end-of-chapter problems, key terms, suggestions for analytical approaches, problem-solving strategies, and a variety of additional questions for student practice. Also featured are questions that relate to chapter specific animations and iActivities. NOTE: Used books, rentals, and purchases made outside of Pearson If purchasing or renting from companies other than Pearson, the access codes for the Enhanced Pearson eText may not be included, may be incorrect, or may be previously redeemed.
Check with the seller before completing your purchase. This package includes the Enhanced Pearson eText and the bound book. This guide gives current and future educators practical help for rediscovering the value, potential, richness, and adventure of a diverse classroom-while developing the capacity to professionally address the differential learning and transition needs of culturally and linguistically diverse CLD students.
Ideal for pre- and in-service teachers, district and building administrators, school specialists, and paraprofessionals, it presents the latest tools, procedures, strategies, and ideas for ensuring effective teaching and learning for students of any native language.
Included are new ways to reach and maximize relationships with parents, caregivers, and extended family members by partnering with them in appropriate pedagogical practices. The Enhanced Pearson eText features embedded video.
The structure also suggested a simple method for replication: if the strands are separated, new partner strands can be reconstructed for each based on the sequence of the old strand. This property is what gives DNA its semi-conservative nature where one strand of new DNA is from an original parent strand. Although the structure of DNA showed how inheritance works, it was still not known how DNA influences the behavior of cells.
In the following years, scientists tried to understand how DNA controls the process of protein production. The nucleotide sequence of a messenger RNA is used to create an amino acid sequence in protein; this translation between nucleotide sequences and amino acid sequences is known as the genetic code. With the newfound molecular understanding of inheritance came an explosion of research.
In this theory, Ohta stressed the importance of natural selection and the environment to the rate at which genetic evolution occurs. This technology allows scientists to read the nucleotide sequence of a DNA molecule.
At its most fundamental level, inheritance in organisms occurs by passing discrete heritable units, called genes, from parents to offspring. These different, discrete versions of the same gene are called alleles. In the case of the pea, which is a diploid species, each individual plant has two copies of each gene, one copy inherited from each parent. Diploid organisms with two copies of the same allele of a given gene are called homozygous at that gene locus, while organisms with two different alleles of a given gene are called heterozygous.
The set of alleles for a given organism is called its genotype, while the observable traits of the organism are called its phenotype.
When organisms are heterozygous at a gene, often one allele is called dominant as its qualities dominate the phenotype of the organism, while the other allele is called recessive as its qualities recede and are not observed.
Some alleles do not have complete dominance and instead have incomplete dominance by expressing an intermediate phenotype, or codominance by expressing both alleles at once. When a pair of organisms reproduce sexually, their offspring randomly inherit one of the two alleles from each parent. These observations of discrete inheritance and the segregation of alleles are collectively known as Mendel's first law or the Law of Segregation. Geneticists use diagrams and symbols to describe inheritance.
A gene is represented by one or a few letters. In fertilization and breeding experiments and especially when discussing Mendel's laws the parents are referred to as the 'P' generation and the offspring as the 'F1' first filial generation. When the F1 offspring mate with each other, the offspring are called the 'F2' second filial generation. One of the common diagrams used to predict the result of cross-breeding is the Punnett square. When studying human genetic diseases, geneticists often use pedigree charts to represent the inheritance of traits.
Organisms have thousands of genes, and in sexually reproducing organisms these genes generally assort independently of each other. This means that the inheritance of an allele for yellow or green pea color is unrelated to the inheritance of alleles for white or purple flowers. This phenomenon, known as 'Mendel's second law' or the 'law of independent assortment,' means that the alleles of different genes get shuffled between parents to form offspring with many different combinations.
Some genes do not assort independently, demonstrating genetic linkage, a topic discussed later in this article. Often different genes can interact in a way that influences the same trait. In the Blue-eyed Mary Omphalodes verna , for example, there exists a gene with alleles that determine the color of flowers: blue or magenta.
Another gene, however, controls whether the flowers have color at all or are white. When a plant has two copies of this white allele, its flowers are white—regardless of whether the first gene has blue or magenta alleles. This interaction between genes is called epistasis, with the second gene epistatic to the first.
Many traits are not discrete features e. These complex traits are products of many genes. The degree to which an organism's genes contribute to a complex trait is called heritability. For example, human height is a trait with complex causes. The molecular basis for genes is deoxyribonucleic acid DNA. DNA is composed of a chain of nucleotides, of which there are four types: adenine A , cytosine C , guanine G , and thymine T.
Genetic information exists in the sequence of these nucleotides, and genes exist as stretches of sequence along the DNA chain. DNA normally exists as a double-stranded molecule, coiled into the shape of a double helix. Thus, in its two-stranded form, each strand effectively contains all necessary information, redundant with its partner strand. This structure of DNA is the physical basis for inheritance: DNA replication duplicates the genetic information by splitting the strands and using each strand as a template for synthesis of a new partner strand.
Genes are arranged linearly along long chains of DNA base-pair sequences. In bacteria, each cell usually contains a single circular genophore, while eukaryotic organisms such as plants and animals have their DNA arranged in multiple linear chromosomes. These DNA strands are often extremely long; the largest human chromosome, for example, is about million base pairs in length.
While haploid organisms have only one copy of each chromosome, most animals and many plants are diploid, containing two of each chromosome and thus two copies of every gene. Many species have so-called sex chromosomes that determine the gender of each organism. In evolution, this chromosome has lost most of its content and also most of its genes, while the X chromosome is similar to the other chromosomes and contains many genes.
The X and Y chromosomes form a strongly heterogeneous pair. When cells divide, their full genome is copied and each daughter cell inherits one copy. This process, called mitosis, is the simplest form of reproduction and is the basis for asexual reproduction.
Asexual reproduction can also occur in multicellular organisms, producing offspring that inherit their genome from a single parent. Offspring that are genetically identical to their parents are called clones. Eukaryotic organisms often use sexual reproduction to generate offspring that contain a mixture of genetic material inherited from two different parents.
The process of sexual reproduction alternates between forms that contain single copies of the genome haploid and double copies diploid. Diploid organisms form haploids by dividing, without replicating their DNA, to create daughter cells that randomly inherit one of each pair of chromosomes.
Most animals and many plants are diploid for most of their lifespan, with the haploid form reduced to single cell gametes such as sperm or eggs.
Some bacteria can undergo conjugation, transferring a small circular piece of DNA to another bacterium. The diploid nature of chromosomes allows for genes on different chromosomes to assort independently or be separated from their homologous pair during sexual reproduction wherein haploid gametes are formed. In this way new combinations of genes can occur in the offspring of a mating pair.
Genes on the same chromosome would theoretically never recombine. However, they do, via the cellular process of chromosomal crossover. During crossover, chromosomes exchange stretches of DNA, effectively shuffling the gene alleles between the chromosomes. The first cytological demonstration of crossing over was performed by Harriet Creighton and Barbara McClintock in Their research and experiments on corn provided cytological evidence for the genetic theory that linked genes on paired chromosomes do in fact exchange places from one homolog to the other.
The probability of chromosomal crossover occurring between two given points on the chromosome is related to the distance between the points. For an arbitrarily long distance, the probability of crossover is high enough that the inheritance of the genes is effectively uncorrelated. The amounts of linkage between a series of genes can be combined to form a linear linkage map that roughly describes the arrangement of the genes along the chromosome.
Genes generally express their functional effect through the production of proteins, which are complex molecules responsible for most functions in the cell.
Proteins are made up of one or more polypeptide chains, each of which is composed of a sequence of amino acids, and the DNA sequence of a gene through an RNA intermediate is used to produce a specific amino acid sequence. This process begins with the production of an RNA molecule with a sequence matching the gene's DNA sequence, a process called transcription.
This messenger RNA molecule is then used to produce a corresponding amino acid sequence through a process called translation.
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