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Module 7 Lesson 4 Progress Check

Prompt

Read pgs. 181-192, then answer the "Check Your Progress" questions (p192 #1, 2, 4, and 5) and submit your answers here.

Response

  1. Identify the role of the nucleus in a eukaryotic cell.

    The nucleus serves as the command center of eukaryotic cells. It is the largest organelle in the cell and is responsible for storing the cell's DNA, which contains the instructions needed for building the various proteins necessary for the cell to function. The nucleus also regulates gene expression, controls the growth and reproduction of the cell, and maintains the integrity of genetic information. Through the process of transcription, the DNA is used as a template to create messenger RNA (mRNA), which then exits the nucleus to be translated into proteins by ribosomes in the cytoplasm.

  2. Summarize the role of the endoplasmic reticulum.

    The endoplasmic reticulum (ER) is a network of membranous tubules and sacs called cisternae, playing a critical role in the synthesis, folding, modification, and transport of proteins and lipids. There are two types of ER: rough ER, which is studded with ribosomes and involved in protein synthesis and modification; and smooth ER, which lacks ribosomes and is involved in lipid synthesis, detoxification processes, and calcium ion storage. The ER is also involved in transporting these synthesized molecules to their destinations, such as the Golgi apparatus, lysosomes, or the cell membrane.

  3. Compare and contrast the structures found in plant and animal cells. Relate these structures to the function of each cell

    • Cell Wall: Plant cells have a rigid cell wall made of cellulose that provides structural support and protection. Animal cells lack a cell wall and have a more flexible cell membrane.
    • Chloroplasts: Plant cells contain chloroplasts, which are the sites of photosynthesis. Chloroplasts convert sunlight into chemical energy in the form of glucose. Animal cells do not have chloroplasts as they are not capable of photosynthesis.
    • Central Vacuole: Plant cells typically have a large central vacuole that stores water, waste products, and nutrients. It also maintains turgor pressure against the cell wall. Animal cells may have small, temporary vacuoles but nothing as prominent as the central vacuole in plant cells.
    • Lysosomes and Centrosomes: Lysosomes are more commonly found in animal cells and are involved in breaking down waste materials and cellular debris. Centrosomes, which are involved in organizing microtubules and regulating the cell cycle, are more pronounced in animal cells. Plant cells often have less conspicuous lysosomal and centrosomal functions.
    • Shape and Mobility: Animal cells are typically round and flexible, allowing for a variety of shapes. Some animal cells also have flagella or cilia for movement. Plant cells are more fixed in shape due to their rigid cell walls and do not have structures for movement.

  4. Hypothesize how lysosomes would be involved in changing a caterpillar into a butterfly.

    During the metamorphosis of a caterpillar into a butterfly, the caterpillar's body undergoes significant transformation inside the chrysalis. Lysosomes would play a critical role in this process. They contain digestive enzymes that can break down cellular components. It is hypothesized that when a caterpillar forms a chrysalis, lysosomes release enzymes that break down many of the caterpillar's tissues into their basic biological building blocks. These molecules can then be repurposed to form the cells, tissues, and organs of the emerging butterfly. This process of controlled cellular destruction and recycling, also known as autophagy, is fundamental to metamorphosis, allowing for the caterpillar's transition into a butterfly. Thus, lysosomes facilitate the breakdown of the old structure and the subsequent renewal into a new form.