Gene Expression & Regulation

How does genetic code determine your characteristics?

3.1.2

Explain how DNA and RNA code for proteins and determine traits.

Unpacking:

• Explain the process of protein synthesis:

o Transcription that produces an RNA copy of DNA, which is further modified into the three types of RNA

o mRNA traveling to the ribosome (rRNA)

o Translation – tRNA supplies appropriate amino acids

o Amino acids are linked by peptide bonds to form polypeptides. Polypeptide chains form protein molecules. Proteins can be structural (forming a part of the cell materials) or functional (hormones, enzymes, or chemicals involved in cell chemistry).

• Interpret a codon chart to determine the amino acid sequence produced by a particular sequence of bases.

• Explain how an amino acid sequence forms a protein that leads to a particular function and phenotype (trait) in an organism.

3.1.3

Explain how mutations in DNA that result from interactions with the environment (i.e. radiation and chemicals) or new combinations in existing genes lead to changes in function and phenotype.

Unpacking:

• Understand that mutations are changes in DNA coding and can be deletions, additions, or substitutions. Mutations can be random and spontaneous or caused by radiation and/or chemical exposure.

• Develop a cause and effect model in order to describe how mutations: changing amino acid sequence, protein function, phenotype. Only mutations in sex cells (egg and sperm) or in the gamete produced from the primary sex cells can result in heritable changes.

3.2.3

Explain how the environment can influence the expression of genetic traits.

Unpacking:

Develop a cause-and-effect relationship between environmental factors and expression of a particular genetic trait. Examples include the following:

• lung/mouth cancer – tobacco use

• skin cancer – vitamin D, folic acid and sun exposure

• diabetes – diet/exercise and genetic interaction

• PKU – diet

• heart disease – diet/exercise and genetic interaction

3.3.1

Interpret how DNA is used for comparison and identification of organisms.

Unpacking:

• Summarize the process of gel electrophoresis as a technique to separate molecules based on size. Students should learn the general steps of gel electrophoresis – using restrictions enzymes to cut DNA into different sized fragments and running those fragments on gels with longer fragments moving slower than faster ones

• Interpret or “read” a gel.

• Exemplify applications of DNA fingerprinting - identifying individuals; identifying and cataloging endangered species.

3.3.2

Summarize how transgenic organisms are engineered to benefit society.

Unpacking:

• Generalize the applications of transgenic organisms (plants, animals, & bacteria) in agriculture and industry including pharmaceutical applications such as the production of human insulin.

• Summarize the steps in bacterial transformation (insertion of a gene into a bacterial plasmid, getting bacteria to take in the plasmid, selecting the transformed bacteria, and producing the product).

3.3.3

Evaluate some of the ethical issues surrounding the use of DNA technology (including cloning, genetically modified organisms, stem cell research, and Human Genome Project).

Unpacking:

• Identify the reasons for establishing the Human Genome Project.

• Recognize that the project is useful in determining whether individuals may carry genes for genetic conditions and in developing gene therapy.

• Evaluate some of the science of gene therapy. (e.g. Severe Combined Immunodeficiency and Cystic Fibrosis)

• Critique the ethical issues and implications of genomics and biotechnology (stem cell research, gene therapy and genetically modified organisms)

4.1.2

Summarize the relationship among DNA, proteins and amino acids in carrying out the work of cells and how this is similar in all organisms.

Unpacking:

• Recall that the sequence of nucleotides in DNA codes for specific amino acids which link to form proteins.

• Identify the five nitrogenous bases (A, T, C, G and U) found in nucleic acids as the same for all organisms.

• Summarize the process of protein synthesis.

Note: Students are not expected to memorize the names and/or structures or characteristics of the 20 amino acids. The focus should be on the fact that side chains are what make each of the amino acids different and determine how they bond and fold in proteins.(Relate to Bio.3.1.2