Cells!

*Enduring Understanding 4 A: Interactions within biological systems lead to complex properties.

-Essential Knowledge 4. A. 2: The structure and function of subcellular components, and their interactions, provide essential cellular processes.

• a. Ribosomes are small, universal structures comprised of two interacting parts: ribosomal RNA and protein. In a sequential manner, these cellular components interact to become the site of protein synthesis where the translation of the genetic instructions yields specific polypeptides.
• b. Endoplasmic reticulum (ER) occurs in two forms: smooth and rough. Evidence of student learning is a demonstrated understanding of each of the following:
  • 1. Rough endoplasmic reticulum functions to compartmentalize the cell, serves as mechanical support, provides site-specific protein synthesis with membrane-bound ribosomes and plays a role in intracellular transport.
  • 2. In most cases, smooth ER synthesizes lipids.
• c. The Golgi complex is a membrane-bound structure that consists of a series of flattened membrane sacs (cisternae). Evidence of student learning is a demonstrated understanding of the following:
  • 1. Functions of the Golgi include synthesis and packaging of materials (small molecules) for transport (in vesicles), and production of lysosomes.
• d. Mitochondria specialize in energy capture and transformation. Evidence of student learning is a demonstrated understanding of each of the following:
  • 1. Mitochondria have a double membrane that allows compartmentalization within the mitochondria and is important to its function.
  • 2. The outer membrane is smooth, but the inner membrane is highly convoluted, forming folds called cristae.
  • 3. Cristae contain enzymes important to ATP production; cristae also increase the surface area for ATP production.
• e. Lysosomes are membrane-enclosed sacs that contain hydrolytic enzymes, which are important in intracellular digestion, the recycling of a cell’s organic materials and programmed cell death (apoptosis). Lysosomes carry out intracellular digestion in a variety of ways.
• f. A vacuole is a membrane-bound sac that plays roles in intracellular digestion and the release of cellular waste products. In plants, a large vacuole serves many functions, from storage of pigments or poisonous substances to a role in cell growth. In addition, a large central vacuole allows for a large surface area to volume ratio.
• g. Chloroplasts are specialized organelles found in algae and higher plants that capture energy through photosynthesis. Evidence of student learning is a demonstrated understanding of each of the following:
  • 1. The structure and function relationship in the chloroplast allows cells to capture the energy available in sunlight and convert it to chemical bond energy via photosynthesis.
  • 2. Chloroplasts contain chlorophylls, which are responsible for the green color of a plant and are the key light-trapping molecules in photosynthesis. There are several types of chlorophyll, but the predominant form in plants is chlorophyll.
  • 3. Chloroplasts have a double outer membrane that creates a compartmentalized structure, which supports its function. Within the chloroplasts are membrane-bound structures called thylakoids. Energycapturing reactions housed in the thylakoids are organized in stacks, called “grana,” to produce ATP and NADPH2, which fuel carbon-fixing reactions in the Calvin-Benson cycle. Carbon fixation occurs in the stroma, where molecules of CO2 are converted to carbohydrates.
    • Learning Objective LO 4.4: The student is able to make a prediction about the interactions of subcellular organelles.
    • Learning Objective LO 4.5: The student is able to construct explanations based on scientific evidence as to how interactions of subcellular structures provide essential functions.
    • Learning Objective LO 4.6: The student is able to use representations and models to analyze situations qualitatively to describe how interactions of subcellular structures, which possess specialized functions, provide essential functions.