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Biology LibreTexts


  • Page ID
    • BIS2A success tips
    • Biology as a Science
    • Enzymes and allosteric regulation
    • Eukaryotes
    • Photosynthesis
    • Introduction to Prokaryotes
    • DNA replication
    • Transcription
    • Translation
      The process of translation in biology is the decoding an mRNA message into a polypeptide product. Put another way, a message written in the chemical language of nucleotides is "translated" into the chemical language of amino acids. Amino acids are linearly strung together via covalent bonds (called peptide bonds) between amino and carboxyl termini of adjacent amino acids.
    • Regulation of gene expression
      Regulation is all about decision making. Gene regulation is, therefore, all about understanding how cells make decisions about which genes to turn on, turn off or to tune up or tune down. In the following section we discuss some of the fundamental mechanisms and principles used by cells to regulate gene expression in response to changes in cellular or external factors. This biology is important for understanding how cells adjust changing environments.
    • Mutations
    • The mitotic cell cycle
    • Activation Energy*
    • Atoms to Bonds
    • Cashing in on Redox
    • Fermentation
      This section discusses the process of fermentation. Due to the heavy emphasis in this course on central carbon metabolism the discussion of fermentation understandably focuses on the fermentation of pyruvate. Nevertheless, some of the core the principles that we cover in this section apply equally well to the fermentation of many other small molecules.
    • Glycolysis
      Glycolysis is the first metabolic pathway discussed in BIS2A. Because of its ubiquity in biology, it is hypothesized that glycolysis was probably one of the earliest metabolic pathways to evolve (more on this later). It is a 10-step pathway that is centered on the processing of glucose for both energy extraction from chemical fuel and for the processing of the carbons in glucose into various other biomolecules (some of which are key precursors of many much more complicated biomolecules).
    • Membranes and transporters
    • Mendel's Inheritance
      Gregor Mendel is (now) famous for having discovered the concept of genes (though he simply called them “factors”).
    • Protein structure
    • Protein Translocation
      In this section we will discuss two major modes of protein localization. We will begin with the components of the endomembrane system. This system involves co-translational translocation across membranes, and later delivery and processing through various organelles via vesicles and motor protein-mediated transport. It is employed for proteins that function within the compartments of the endomembrane system, for proteins embedded in the plasma membrane, and for secreted proteins.
    • Respiration
    • Models and Simplifying Assumptions
    • Functional groups
      A functional group is a specific group of atoms within a molecule that is responsible for a characteristic of that molecule. Many biologically active molecules contain one or more functional groups. In Bis2a we will discuss the major functional groups found in biological molecules. These include: Hydroxyl, Methyl, Carboxyl, Carbonyl, Amino and Phosphate.
    • Equilibrium vs. homeostasis
    • Potential Energy in Biology
    • ATP
    • Pyruvate Oxidation and the TCA Cycle
      Under appropriate conditions pyruvate will be oxidized, leading to a loss of one carbon via decarboxylation, and creating acetyl-CoA. The resulting acetyl-CoA can enter any one of several pathways for the biosynthesis of larger molecules.  We will focus on its routing to a central metabolic pathway called the Tricarboxylic Acid (TCA) Cycle. Here the remaining two carbons in the acetyl group can either be further oxidized or serve as precursors for the construction of various other molecule
    • Meiosis
      The nuclear division that forms haploid cells, which is called meiosis, is related to mitosis. In mitosis, both the parent and the daughter nuclei are at the same ploidy level—diploid for most plants and animals. Meiosis employs many of the same mechanisms as mitosis. However, the starting nucleus is always diploid and the nuclei that result at the end of a meiotic cell division are haploid.