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Questions and Answers
What is the primary composition of the cell membrane?
What is the primary composition of the cell membrane?
Which type of cell junction acts as an impermeable seal between cells?
Which type of cell junction acts as an impermeable seal between cells?
What is the primary function of gap junctions?
What is the primary function of gap junctions?
Which type of tissue is characterized by having contractile properties?
Which type of tissue is characterized by having contractile properties?
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How do desmosomes contribute to cellular structure?
How do desmosomes contribute to cellular structure?
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What role do fibroblasts play in the body?
What role do fibroblasts play in the body?
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What defines epithelial tissue?
What defines epithelial tissue?
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Which of the following is NOT a type of tissue?
Which of the following is NOT a type of tissue?
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Which type of cell is responsible for the production of hormones?
Which type of cell is responsible for the production of hormones?
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What are the three types of cell surfaces found in epithelial cells?
What are the three types of cell surfaces found in epithelial cells?
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What do epithelial cells secrete that lies beneath them?
What do epithelial cells secrete that lies beneath them?
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Which cells differentiate into ova and sperm?
Which cells differentiate into ova and sperm?
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Which of the following is NOT a type of immune cell?
Which of the following is NOT a type of immune cell?
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What feature is characteristic of epithelial tissues?
What feature is characteristic of epithelial tissues?
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Which cells are involved in protecting the body against infections?
Which cells are involved in protecting the body against infections?
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What is the function of the juxtaluminal junctional complexes in epithelial cells?
What is the function of the juxtaluminal junctional complexes in epithelial cells?
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Study Notes
Learning Objectives
- Describe the structure of the cell membrane
- Understand different types of cell organelles
- Describe how the three-dimensional structure of the cell is maintained
- Identify and understand the functions of different cell organelles
- Understand that the health of an individual depends on the normal functioning of cells
Cell Membrane
- The cell membrane is a phospholipid bilayer
- Hydrophobic lipid parts are oriented towards each other, away from the watery cellular fluids
- Polar heads are oriented towards the water-based solutions inside and outside the cell
- Contains proteins, glycolipids, and glycoproteins
- Plays a role in separating fluid compartments (mechanical barrier)
- Controls what enters and exits the cell (selective permeability)
- Allows cell-to-cell recognition and interaction
- Involved in cell signaling
Intracellular Organelles
- Nucleus: Control center, responsible for transmitting genetic information and protein synthesis
- Mitochondria: Site of ATP synthesis, powerhouse of the cell
- Rough Endoplasmic Reticulum (RER): Sugar groups are attached to proteins; proteins are packaged in vesicles for transport to Golgi apparatus & other sites. External face of RER synthesizes phospholipids
- Smooth Endoplasmic Reticulum (SER): Site for lipid and steroid synthesis; lipid metabolism, and drug detoxification
- Lysosomes: Sites of intracellular digestion
- Golgi Apparatus: Packages, modifies and segregates proteins; for secretion from the cell; inclusion in lysosomes and incorporation into plasma membrane
Cytoskeletal Elements
- Microtubules: Support cell shape; intracellular & cellular movement; form centrioles, cilia, and flagella
- Intermediate Filaments: Stable cytoskeletal elements; resist mechanical forces
- Microfilaments: Involved in muscle contraction & other intracellular movement; help form the cell's cytoskeleton
- Centrioles: Part of the centrosome; organize microtubule network during mitosis (for cell division); form bases of cilia and flagella
Cilia and Microvilli
- Cilia and microvilli are cell surface specializations
- Cilia help move substances across the cell surface
- Microvilli increase surface area
Cell Junctions
- Tight junctions: Impermeable junctions that prevent the passage of molecules through the intercellular space
- Desmosomes: Anchoring junctions that help hold cells together and resist tension
- Gap junctions: Communicating junctions that allow ions and small molecules to pass through; important for communication between cells (e.g., in heart cells and embryonic cells)
Tissues
- Tissues are collections of cells that work together to perform a function
- Nervous tissue: Composed of neurons for transmitting information
- Muscular tissue: Contains myocytes for contraction
- Epithelial tissue: Forms sheets or layers covering/lining surfaces
- Connective tissue: Supports other tissues (e.g., bones, tendons).
Cells with Special Functions
- Germ cells: Give rise to ova and sperm
- Blood cells: Red blood cells (erythrocytes), white blood cells (leukocytes)
- Immune cells: White blood cells involved in fighting infection (lymphocytes, macrophages)
- Endocrine cells: Secrete hormones for indirect cell communication (e.g., pancreatic islet cells)
Epithelial Tissue
- Epithelial tissue forms sheets of cells that cover surfaces or line body cavities.
- Polarity: Apical (free) surface faces a body fluid or the lumen, basal (attached) surface attaches to the underlying tissue.
- Cell junctions: Hold cells together
- Secrete basal lamina: An extracellular layer beneath epithelial cells
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Description
This quiz explores the intricate details of cell structure, focusing on the cell membrane and various organelles. You will learn about the phospholipid bilayer, selective permeability, and the functions of key organelles. A strong understanding of these concepts is crucial for recognizing the relationship between cell health and overall well-being.
