Protein Synthesis, Cell Transport, and Biological Macromolecules Flashcards

Protein Synthesis

• Overview of Protein Synthesis: Protein synthesis consists of two major fundamental steps:
  • Transcription: The process by which genetic information encoded in $\text{DNA}$ is copied into $\text{mRNA}$.
  • Translation: The process by which the sequence of $\text{mRNA}$ is decoded to assemble a protein.

Cellular Transport and Solutions

• Mechanisms of Cellular Transport:

  • Simple Diffusion: The net movement of molecules from an area of high concentration to an area of low concentration across a concentration gradient without requiring cellular energy.
  • Osmosis: The net movement of water molecules from an area of high water concentration to an area of low water concentration across a membrane.
  • Endocytosis: An active cellular transport process where the cell engulfs external materials and brings them into the cell interior using a vesicle.
  • Exocytosis: An active cellular transport process where the cell releases materials out into the extracellular environment using a vesicle.
  • Facilitated Diffusion: The movement of molecules from an area of high concentration to low concentration through a membrane transport protein, requiring no energy expenditure.

• General Transport Categories:

  • Passive Transport: Moves substances down a concentration gradient from high concentration to low concentration without utilizing cellular energy ($\text{ATP}$).
  • Active Transport: Moves substances against a concentration gradient from low concentration to high concentration, requiring the consumption of cellular energy ($\text{ATP}$).

• Cellular Response to Solution Tonicity:

  • Hypertonic Solution: A solution with a higher solute concentration than the cytoplasm. Water leaves the cell, causing the cell to shrink.
  • Isotonic Solution: A solution with an equal solute concentration relative to the cell cytoplasm. Water moves equally into and out of the cell, maintaining cell size.
  • Hypotonic Solution: A solution with a lower solute concentration than the cytoplasm. Water enters the cell, causing the cell to swell and potentially burst.

Organic Macromolecules Essential for Life

• The Four Major Organic Macromolecules:
  • Carbohydrates:
    • Primary Function: Provides quick energy.
    • Monomer: Monosaccharides.
    • Examples: Glucose, Starch.
  • Lipids:
    • Primary Functions: Long-term energy storage, insulation, and forming structural membranes.
    • Monomer Components: Glycerol + fatty acids.
    • Examples: Fats, oils.
  • Proteins:
    • Primary Functions: Structural support, catalytic enzymes, and molecular transport.
    • Monomer: Amino acids.
    • Examples: Muscle.
  • Nucleic Acids:
    • Primary Function: Store and transmit genetic information.
    • Monomer: Nucleotides.
    • Examples: $\text{DNA}$, $\text{RNA}$.

Enzymes and Enzymatic Processes

• Enzyme Definition and Function:

  • An enzyme is a biological catalyst (protein) that speeds up chemical reactions by lowering the required activation energy.

• Components and Stages of Enzymatic Reactions:

  • Active site: The specific location on an enzyme where substrate molecules bind.
  • Substrate: The reactant molecule that binds to the enzyme.
  • Enzyme-substrate complex: The intermediate structure formed when the substrate is bound to the enzyme's active site.
  • Products: The resulting molecules released after the reaction completes (such as Water, Carbon, and Hydrogen components).
  • Diagram Components: Diagrams tracing the process illustrate structural transitions through stages labeled 'A' and 'B', covering Diagram 2 and Diagram 3, demonstrating substrate binding, active site engagement, and product formation.

• Enzymatic Reaction Example (Lactose Breakdown):

  • Identification: Lactose functions as the sugar (substrate), whereas Lactase functions as the specific enzyme.
  • Reaction Outcome: Lactase breaks down lactose into two monosaccharides: Glucose + galactose.

Cellular Respiration

• Definition: Cellular respiration is the biological process cells utilize to break down glucose and produce cellular energy in the form of $\text{ATP}$.

• Locations of Respiration Steps:

  • Glycolysis: Occurs within the Cytoplasm.
  • Krebs Cycle: Occurs within the Mitochondrial matrix.
  • Electron Transport Chain (ETC): Occurs within the Inner mitochondrial membrane.

• Oxygen Requirements Across Respiration Steps:

  • Anaerobic Step: Glycolysis (does not require oxygen).
  • Aerobic Steps: Pyruvate oxidation, Krebs cycle, and Electron Transport Chain ($\text{ETC}$) (require oxygen).

Feedback Loops and Homeostasis

• Feedback Mechanism Definitions:

  • Positive Feedback: A biological feedback loop that increases or amplifies a change away from a baseline state.
  • Negative Feedback: A biological feedback loop that reverses or reduces a change to maintain physiological homeostasis.

• Classification of Biological Feedback Examples:

  • Body Temperature Regulation: Negative feedback loop.
  • Giving Birth: Positive feedback loop.
  • Blood Glucose Regulation: Negative feedback loop.
  • Ripening Fruit: Positive feedback loop.