• Unit 10: Gene Expression

    In this unit, we learn about the universal genetic codes deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). We call DNA and RNA universal because we find them in every known organism. As we learned in Unit 7, the DNA and RNA in every organism are made up of the same few ingredients.

    However, extremely slight differences often account for the differences between species. What makes a dog different from a toadstool? What accounts for the differences within species? What makes you different from your neighbor? This unit will give you a greater understanding of the genetic code and its impact on your life.

    Completing this unit should take you approximately 5 hours.

    • 10.1: DNA Replication and Synthesis

      Cells make copies of their DNA before they divide into identical daughter cells. This process is called DNA replication or synthesis. Chromosomes for sister chromatids after the copying of DNA. This allows cells to receive genetic information and produce proteins for identical phenotypes.

    • 10.2: DNA Transcription

      Genes are expressed by the production of proteins through two processes: transcription and translation. Transcription is the process of using the DNA code as a template to make mRNA messages. Translation involves the ribosome interpreting that message to build proteins.

    • 10.3: Translation and Synthesis

      Now that we have learned about transcription, let's review the second process of gene expression with a series of lectures on translation. Translation refers to how the ribosome uses messenger RNA (mRNA) and transfer RNA (tRNA) to attach amino acids together to make proteins.

    • 10.4: Regulating Gene Expression

      Gene expression must be regulated through much of life. During certain times of development, growth, or repair, genes must be turned on and off. This helps cells interact with their environment and maintain homeostasis.

    • 10.5: Using DNA Technology

      DNA technologies have benefited our society in many ways. For example, today's scientists use the concepts you have studied in this course to improve our criminal justice system, enhance our food supply, and treat previously incurable diseases.

      Forensic scientists have developed next-generation DNA sequencing techniques using ever-smaller amounts of DNA evidence to identify criminals who have escaped criminal justice for years. These technologies have simultaneously allowed us to exonerate individuals who have been wrongly convicted and imprisoned for crimes they did not commit.

      Humans have used selective breeding techniques to artificially alter the genomes of plants and animals for thousands of years. However, today's biochemists use modern genetic manipulation techniques to quickly and efficiently modify the DNA in plants to create genetically modified organisms (GMOs). Farmers plant these genetically modified seeds to grow crops that produce more edible plant material, grow well in drought conditions, resist diseases, and repel destructive insects.

      Scientists have also created the gene-editing technique called CRISPR to swap faulty genes with healthy ones to treat human genetic disorders that cause debilitating diseases and cancers.

    • Unit 10 Assessment