뒤로A Tour of the Cell: Structure, Function, and Organization
스터디 가이드 - 스마트 노트
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cPlasma membrane: A selectively permeable barrier that encloses the cell.
Cytosol: The semifluid substance inside the cell.
Chromosomes: Carry genetic information (DNA).
Ribosomes: Sites of protein synthesis.
Prokaryotic vs. Eukaryotic Cells
Prokaryotic Cells
Prokaryotic cells lack a nucleus and membrane-bound organelles. Bacteria and Archaea are prokaryotes.
External appendages: Structures such as flagella (for movement) and pili (for attachment).
Flagella: Long, whip-like structures for locomotion.
Fimbriae: Short, hair-like structures for attachment.
Cell wall: Provides shape and protection.
Plasma membrane: Controls entry and exit of substances.
Nucleoid: Region where DNA is located (not membrane-bound).
Ribosomes: Smaller than those in eukaryotes.
Bacterial Cell Shapes and Arrangements
Cocci: Spherical bacteria.
Bacilli: Rod-shaped bacteria.
Spirilla: Spiral-shaped bacteria.
Eukaryotic Cells
Eukaryotic cells have a nucleus and membrane-bound organelles. They include animal, plant, fungi, and protist cells.
Animal cells: Lack cell walls and chloroplasts.
Plant cells: Have cell walls, chloroplasts, and large central vacuoles.
Cell Organelles and Internal Structures
Nucleus: Contains most of the cell's DNA; surrounded by a double membrane called the nuclear envelope.
Endomembrane system: Includes the nuclear envelope, endoplasmic reticulum (ER), Golgi apparatus, lysosomes, vesicles, and plasma membrane.
Nuclear envelope: Double membrane with pores for transport.
Endoplasmic reticulum (ER): Network of membranes; rough ER has ribosomes and synthesizes proteins, smooth ER synthesizes lipids.
Golgi apparatus: Modifies, sorts, and packages proteins and lipids.
Lysosomes: Contain digestive enzymes for breaking down macromolecules.
Vesicles: Small membrane-bound sacs for transport.
Functions of Organelles
Phagocytosis: Process by which cells engulf large particles.
Autophagy: Digestion of a cell's own components.
Lysosomal enzymes: Involved in breaking down waste; defects can cause diseases (e.g., Tay-Sachs disease).
Other Key Organelles
Mitochondria: Site of cellular respiration and ATP production.
Chloroplasts: Site of photosynthesis in plant cells.
Cytoskeleton: Network of protein fibers (microtubules, microfilaments, intermediate filaments) that provide structural support and aid in cell movement.
Centrosomes and centrioles: Involved in cell division in animal cells.
Extracellular Matrix and Intercellular Junctions
Extracellular matrix (ECM): Network of proteins and carbohydrates outside animal cells that provides support and anchorage.
Intercellular junctions: Structures that connect adjacent cells (e.g., tight junctions, desmosomes, gap junctions in animals; plasmodesmata in plants).
Integration of Organelles and Levels of Organization
Organelles work together to maintain cell function. Cells are organized into tissues, organs, and organ systems in multicellular organisms.
From cell to tissue to organ to organ system to organism.
Key Terms and Phrases
The following table summarizes important terms related to cell structure and function:
Term | Definition |
|---|---|
Anatomy | Study of the structure of organisms and their parts |
Autophagy | Process by which cells digest their own components |
Bacteria | Domain of prokaryotic microorganisms |
Cell membrane | Phospholipid bilayer that encloses the cell |
Cell wall | Rigid structure outside the plasma membrane in plants, fungi, and some prokaryotes |
Chloroplast | Organelle in plant cells where photosynthesis occurs |
Cytoplasm | Contents of the cell excluding the nucleus |
Endoplasmic reticulum | Network of membranes involved in protein and lipid synthesis |
Golgi apparatus | Organelle that modifies and packages proteins and lipids |
Lysosome | Organelle containing digestive enzymes |
Mitochondrion | Organelle that produces ATP through cellular respiration |
Nucleus | Membrane-bound organelle containing DNA |
Ribosome | Structure that synthesizes proteins |
Surface-to-volume ratio | Ratio that limits cell size and affects exchange of materials |
Additional info: The table above is a selection of key terms from the provided list, with definitions added for clarity.
