Big Idea 3: Living Systems Store, Retrieve, Transmit and Respond to Information Essential to Life Processes


Genetic information provides for continuity of life and, in most cases, this information is passed from parent to offspring via DNA. The double-stranded structure of DNA provides a simple and elegant solution for the transmission of heritable information to the next generation; by using each strand as a template, existing information can be preserved and duplicated with high fidelity within the replication process. However, the process of replication is imperfect, and errors occur through chemical instability and environmental impacts. Random changes in DNA nucleotide sequences lead to heritable mutations if they are not repaired. To protect against changes in the original sequence, cells have multiple mechanisms to correct errors. Despite the action of repair enzymes, some mutations are not corrected and are passed to subsequent generations. Changes in a nucleotide sequence, if present in a protein-coding region, can change the amino acid sequence of the polypeptide. In other cases, mutations can alter levels of gene expression or simply be silent. In order for information in DNA to direct cellular processes, information must be transcribed (DNA→RNA) and, in many cases, translated (RNA→protein). The products of transcription and translation play an important role in determining metabolism, i.e., cellular activities and phenotypes. Biotechnology makes it possible to directly engineer heritable changes in cells to yield novel protein products.

In eukaryotic organisms, heritable information is packaged into chromosomes that are passed to daughter cells. Alternating with interphase in the cell cycle, mitosis followed by cytokinesis provides a mechanism in which each daughter cell receives an identical and a complete complement of chromosomes. Mitosis ensures fidelity in the transmission of heritable information, and production of identical progeny allows organisms to grow, replace cells, and reproduce asexually.

Sexual reproduction, however, involves the recombination of heritable information from both parents through fusion of gametes during fertilization. Meiosis followed by fertilization provides a spectrum of possible phenotypes in offspring and on which natural selection operates.

Mendel was able to describe a model of inheritance of traits, and his work represents an application of mathematical reasoning to a biological problem. However, most traits result from interactions of many genes and do not follow Mendelian patterns of inheritance. Understanding the genetic basis of specific phenotypes and their transmission in humans can raise social and ethical issues.

The expression of genetic material controls cell products, and these products determine the metabolism and nature of the cell. Gene expression is regulated by both environmental signals and developmental cascades or stages. Cell signaling mechanisms can also modulate and control gene expression. Thus, structure and function in biology involve two interacting aspects: the presence of necessary genetic information and the correct and timely expression of this information.

Genetic information is a repository of instructions necessary for the survival, growth and reproduction of the organism. Changes in information can often be observed in the organism due to changes in phenotypes. At the molecular level, these changes may result from mutations in the genetic material whereupon effects can often be seen when the information is processed to yield a polypeptide; the changes may be positive, negative or neutral to the organism. At the cellular level, errors in the transfer of genetic information through mitosis and meiosis can result in adverse changes to cellular composition. Additionally, environmental factors can influence gene expression.

Genetic variation is almost always advantageous for the long-term survival and evolution of a species. In sexually reproducing organisms, meiosis produces haploid gametes, and random fertilization produces diploid zygotes. In asexually reproducing organisms, variation can be introduced through mistakes in DNA replication or repair and through recombination; additionally, bacteria can transmit and/or exchange genetic information horizontally (between individuals in the same generation). Viruses have a unique mechanism of replication that is dependent on the host metabolic machinery. Viruses can introduce variation in the host genetic material through lysogenesis or latent infection.

To function in a biological system, cells communicate with other cells and respond to the external environment. Cell signaling pathways are determined by interacting signal and receptor molecules, and signaling cascades direct complex behaviors that affect physiological responses in the organism by altering gene expression or protein activity. Nonheritable information transmission influences behavior within and between cells, organisms and populations; these behaviors are directed by underlying genetic information, and responses to information are vital to natural selection and evolution. Animals have evolved sensory organs that detect and process external information. Nervous systems interface with these sensory and internal body systems, coordinating response and behavior; and this coordination occurs through the transmission and processing of signal information. Behavior in the individual serves to increase its fitness in
the population while contributing to the overall survival of the population.


Chi-Square Practice Problems #1

Chi-Square Practice Problems #2

Pedigree Analysis

Polytene Chromosomes of Drosophila



Enduring understanding 3.D: Cells communicate by generating, transmitting and receiving chemical signals.
Enduring understanding 2.E: Many biological processes involved in growth, reproduction and dynamic homeostasis include temporal regulation and coordination.
Enduring understanding 3.B: Expression of genetic information involves cellular and molecular mechanisms.


Essential knowledge 3.D.1: Cell communication processes share common features that reflect a shared evolutionary history.
Essential knowledge 2.E.2: Timing and coordination of physiological events are regulated by multiple mechanisms.
Essential knowledge 3.B.2: A variety of intercellular and intracellular signal transmissions mediate gene expression.
Essential knowledge 3.D.2: Cells communicate with each other through direct contact with other cells or from a distance via chemical signaling.
Essential knowledge 3.D.3: Signal transduction pathways link signal reception with cellular response.
Essential knowledge 3.D.4: Changes in signal transduction pathways can alter cellular response.
Essential knowledge 3.B.2: A variety of intercellular and intracellular signal transmissions mediate gene expression.
Essential knowledge 2.E.1: Timing and coordination of specific events are necessary for the normal development of an organism, and these events are regulated by a variety of mechanisms.




Chapter 11 Cell Communication

Chapter 11 Presentation pdf


Enduring understanding 3.A: Heritable information provides for continuity of life.
Enduring understanding 3.C: The processing of genetic information is imperfect and is a source of genetic variation.


Essential knowledge 3.A.2: In eukaryotes, heritable information is passed to the next generation via processes that include the cell cycle and mitosis or meiosis plus fertilization.
Essential knowledge 3.C.2: Biological systems have multiple processes that increase genetic variation.




Chapter 13 Presentation-Meiosis and Sexual Life Cycles




Crossing Over Animation

Recombination of UNLINKED Genes Due to Independent Assortment Animation

Recombination of LINKED Genes Due to Crossing Over Animation

Recombination of LINKED Genes Due to Crossing Over Animation II

Meiosis Animation

Meiosis Animation II

Meiosis I Nondisjunction

Meiosis II Nondisjunction


Enduring understanding 3.A: Heritable information provides for continuity of life.
Enduring understanding 4.C: Naturally occurring diversity among and between components within biological systems affects interactions with the environment.

Essential knowledge 3.A.3: The chromosomal basis of inheritance provides an understanding of the pattern of passage (transmission) of genes from parent to offspring.
Essential knowledge 4.C.2: Environmental factors influence the expression of the genotype in an organism.
Essential knowledge 4.C.4: The diversity of species within an ecosystem may influence the stability of the ecosystem.




Chapter 14 Presentation-Mendel and the Gene Idea


Complete Dominance Animation

Recessive Allele Animation


For information on How to Work With Drosophila follow the link. This information will be valuable to you while performing your fruit-fly lab.



Enduring understanding 3.A: Heritable information provides for continuity of life.
Enduring understanding 3.C: The processing of genetic information is imperfect and is a source of genetic variation.


Essential knowledge 3.A.4: The inheritance pattern of many traits cannot be explained by simple Mendelian genetics.
Essential knowledge 3.C.1: Changes in genotype can result in changes in phenotype.




Chapter 15 Presentation-The Chromosomal Basis of Inheritance


X-Linkied Inheritance Animation

Determining The Correct Gene Order Animation

DNA Inversion

Meiotic DNA Inversion

Reciprocal Translocation

Meiotic Reciprocal Translocation


Enduring understanding 3.A: Heritable information provides for continuity of life.
Enduring understanding 3.C: The processing of genetic information is imperfect and is a source of genetic variation.


Essential knowledge 3.A.1: DNA, and in some cases RNA, is the primary source of heritable information.
Essential knowledge 3.C.1: Changes in genotype can result in changes in phenotype.




Chapter 16 Presentation-The Molecular Basis of Inheritance




Nucleotide Polymerization by DNA Polymerase

Overview of DNA Replication

DNA Mutations

Molecular Level DNA Mutations

DNA Repair

DNA Synthesis Animation

Enduring understanding 3.A: Heritable information provides for continuity of life.
Enduring understanding 3.C: The processing of genetic information is imperfect and is a source of genetic variation.


Essential knowledge 3.A.1: DNA, and in some cases RNA, is the primary source of heritable information.
Essential knowledge 3.C.1: Changes in genotype can result in changes in phenotype.





Chapter 17 Presentation-Frome Gene to Protein



Plasmids

Chapter 16 DNA as Hereditary Material




Chapter 17 Presentation Transcription and Gene Expression

Gene Flow

Chapter 17 Presentation Transcription Translation and Gene Expression


The Three Steps of Translation

Translation and Peptide-Bond Formation

Overview of mRNA Processing

Overview of Eukaryotic Gene Expression

Bacterial Transcription
You don't have to be concerned with the details associated with the drag and drop features of this animation, just look at the big picture and see how this process occurs.

Bacterial Translation

Molecular Level DNA Mutations

DNA Mutations

DNA Mutations II

DNA Mutation--Nonsense and its Affect on Phenotype

Complete Dominance Animation Notice the DNA to RNA to Protein theme here; tie it into what you learned earlier in the year.

Recessive Allele Animation Notice the DNA to RNA to Protein theme here as well, and again try to tie it into what you've learned earlier in the year.


Enduring understanding 2.E: Many biological processes involved in growth, reproduction and dynamic homeostasis include temporal regulation and coordination.
Enduring understanding 3.B: Expression of genetic information involves cellular and molecular mechanisms.
Enduring understanding 4.A: Interactions within biological systems lead to complex properties.


Essential knowledge 3.B.1: Gene regulation results in differential gene expression, leading to cell specialization.
Essential knowledge 3.B.2: A variety of intercellular and intracellular signal transmissions mediate gene expression.
Essential knowledge 2.E.1: Timing and coordination of specific events are necessary for the normal development of an organism, and these events are regulated by a variety of mechanisms.
Essential knowledge 3.B.2: A variety of intercellular and intracellular signal transmissions mediate gene expression.
Essential knowledge 4.A.3: Interactions between external stimuli and regulated gene expression result in specialization of cells, tissues and organs.




Chapter 18 Presentation-The Genetics of Viruses and Bacteria


The following links will assist you in your basic understanding of the operon:


Bacterial Conjugation Animation

Plasmid Cloning Animation

Hfr Animation



A good interactive tutorial regarding the lac operon
The
lac operon with NO CAP/cAMP explanation
The
lac operon including explanations of CAP and cAMP
The
lac operon including explanations of CAP and cAMP along with a quiz
The
lac operon from the W.H. Freeman website accompanying the Griffiths Text
The
lac operon from the W.H. Freeman website accompanying the Pierce Text
The
lac operon from the Sumanasinc website
The
trp operon from the W.H. Freeman website
Repression with and without inducers along with a quiz
Protein synthesis and quiz
mRNA synthesis and quiz

Enduring understanding 3.A: Heritable information provides for continuity of life.
Enduring understanding 3.C: The processing of genetic information is imperfect and is a source of genetic variation.


Essential knowledge 3.C.3: Viral replication results in genetic variation, and viral infection can introduce genetic variation into the hosts.
Essential knowledge 3.A.1: DNA, and in some cases RNA, is the primary source of heritable information.




Chapter 19 Presentation-Eukaryotic Genomes: Organization, Regulation, and Evolution


Levels of Chromatin Structure Animation

Dimensional Structure of Nuclear Chromosomes


Enduring understanding 3.A: Heritable information provides for continuity of life.

Essential knowledge 3.A.1: DNA, and in some cases RNA, is the primary source of heritable information.




Chapter 20 Presentation-DNA Technology and Genomics


Dideoxy Sequencing Method of DNA

PCR Gene Amplification

RFLP Analysis and Gene Mapping

RFLP Analysis and Gene Detection


Enduring understanding 3.C: The processing of genetic information is imperfect and is a source of genetic variation.
Enduring understanding 4.C: Naturally occurring diversity among and between components within biological systems affects interactions with the environment.


Essential knowledge 3.C.1: Changes in genotype can result in changes in phenotype.
Essential knowledge 4.C.1: Variation in molecular units provides cells with a wider range of functions.




Chapter 21 Presentation-The Genetic Basis of Development



Enduring understanding 3.A: Heritable information provides for continuity of life.
Enduring understanding 3.C: The processing of genetic information is imperfect and is a source of genetic variation.


Essential knowledge 3.A.1: DNA, and in some cases RNA, is the primary source of heritable information.
Essential knowledge 3.C.2: Biological systems have multiple processes that increase genetic variation.



Chapter 27 Presentation-Prokaryotes


The Nitrogen Cycle