Science Notes

06/12/2009 10:54

CSI Online Activity: Click on CSI the experience

Investigation Discovery Game

Forensics Analysis: Blood stain analysisballistics, Misc.


  • Alleles - Different forms of the same gene.

  • Base - One of the four different chemical units which comprise DNA. The sequence of DNA bases codes for the amino acid sequence of proteins. These four bases are: adenine, cytosine, guanine, thymine, in DNA and RNA, uracil substitutes for thymine.

  • Biotechnology - The development of a product or products using biological agents.

  • Chromosomes - Tiny thread-like structures inside each cell. Chromosomes carry the genes.

  • Co-dominance - A circumstance where the two alleles (or genes) for a specific trait are equally strong: a mixture of the two phenotypes results: An example is pink snapdragons develop from a red and white cross.

  • Crossing Over - The process in which genes are exchanged between two chromosomes.

  • DNA (deoxyribonucleic acid) - The substance within the chromosomes that carries the hereditary instructions for producing proteins and RNA's.

  • Dominant - A gene or allele that is expressed or "shown" in the phenotype. Dominant genes mask or "hide" recessive genes.

  • Genes - Tiny biochemical structures inside each cell that determine particular hereditary traits, such as eye color and blood type. Each gene is a segment of DNA that carries instructions for producing the chainlike molecules that make up proteins.

  • Gene expression - The process by which a cell makes a protein from RNA according to the instructions carried by a gene.

  • Genetic variation - Refers to the differences in inherited traits that exist among the members of a species.

  • Genetics - The scientific study of heredity.

  • Genome - A set of all the genes a species has on its chromosomes. The human genome consists of 50,000 to 100,000 genes.

  • Genotype - The underlying genetic makeup of a trait or the overall genetic makeup of an individual. It is the two genes an individual carries for a trait.

  • Heredity - The passing of genetic traits from parent to offspring.

  • Heterozygous - Two different alleles for the same trait.

  • Homozygous - Only one allele is present for a particular trait. Both genes are identical.

  • Hybrid - An organism that has heterozygous alleles (or genes) for one or more traits.

  • Meiosis - Reproduction in sex cells where the daughter cells produced have half the number of parent chromosomes.

  • Mendel, Gregor - So-called "father of modern genetics". Austrian monk who discovered how genetic "factors" were passed down.

  • Mitosis - Reproduction of non-sex cells where the daughter cells produced have the same number of chromosomes as the parent cells.

  • Mutation - A change in a gene. It may produce a new trait that can be inherited.

  • Phenotype - The observable appearance of a trait or the overall appearance of an individual.

  • Protein - Chemical building blocks in the body made of smaller units called amino acids. Proteins exist in every cell.

  • Recessive - An allele or gene that is not expressed or "shown" in the phenotype because it is "hidden" by the dominant gene.

  • RNA (ribonucleic acid) - Similar to DNA, it plays a key role in the production of proteins.

  • Trait - A physical characteristic, such as hair color


"What are Genes?"


"What are SNPs?"


"Where do Your Genes Come From?"


"What is a Phenotype?"



Mitosis and Meiosis
Who's Your Daddy Activity (Punnett Squares)


Amy Couch's Presentation on DNA forensics

Other Helpful Links 

Extra Credit Assignment