| Term | Definition |
|---|---|
Four things every cell common to all types | Cell membrane, cytosol, chromosomes, ribosomes |
Eukaryotic cell compartmentalization | Organelles create localized environments, allowing incompatible processes to occur within the same cell |
Microscopes | Instruments used to understand and study cells where visible light is passed through a specimen and then through glass lenses |
Magnification | Ratio of image size to real size |
Resolution | Clarity of the image |
Contrast | Visible difference in brightness |
Scanning electron microscopes (SEMs) | Microscopes that focus a beam of electrons onto the surface of a specimen, providing a 3-D view |
Transmission electron microscopes (TEMs) | Microscopes that focus a beam of electrons through a specimen to study internal cell structure |
Prokaryotic cells | DNA sits unbound in a region called the nucleoid with no membrane-bound organelles, and cytoplasm is bound only by the plasma membrane |
Eukaryotic cells | DNA is enclosed in a nucleus, and cells contain membrane-bound organelles with cytoplasm in the region between the plasma membrane and nucleus |
Surface area-to-volume ratio | Ratio that helps set limits on how large a cell can be as it increases in size |
Nucleus | The cell's info center, enclosed by a nuclear envelope (double membrane) containing nuclear pores that regulate what enters/exits |
Nuclear lamina | Made of protein, sits on the nuclear side of the envelope and helps maintain the cell's shape; evidence also points to a nuclear matrix (framework of protein fibers inside the nucleus) |
Chromatin | DNA organized into discrete units called chromosomes; each contains one DNA molecule associated with proteins that condenses further during cell division |
Nucleolus | Site inside the nucleus where ribosomal RNA (rRNA) is synthesized |
Free ribosomes | Complexes of ribosomal RNA and protein that build proteins in the cytosol |
Bound ribosomes | Ribosomes on the outside of the ER or nuclear envelope that build proteins |
Endomembrane system | System that regulates protein traffic and performs metabolic functions, consisting of the nuclear envelope, endoplasmic reticulum (ER), Golgi apparatus, lysosomes, vacuoles, and the plasma membrane |
Smooth ER | Lacks ribosomes; synthesizes lipids, detoxifies drugs/poisons, and stores calcium ions |
Rough ER | Studded with ribosomes; produces glycoproteins and transport vesicles, and is considered the cell's "membrane factory" |
Golgi apparatus | The cell's shipping/receiving center made of flattened membranous sacs called cisternae; modifies products of the ER, manufactures certain macromolecules, and sorts/packages materials into transport vesicles |
Lysosomes | Membranous sacs of hydrolytic enzymes that digest macromolecules; have an acidic internal environment, are made by the rough ER, sent to the Golgi, and may bud from the trans face |
Phagocytosis | Process where lysosomes fuse with a food vacuole and digest its contents |
Autophagy | Process where lysosomes recycle the cell's own organelles and macromolecules |
Contractile vacuoles | Large vesicles derived from the ER and Golgi that pump excess water out of freshwater protist cells |
Central vacuoles | Found in mature plant cells; contain sap and store ions like potassium and chloride |
Mitochondria | Found in nearly all eukaryotic cells and are the site of cellular respiration |
Chloroplasts | Found only in plants/algae and are the site of photosynthesis |
Cristae | Folds in a mitochondrion's inner membrane that provide a large surface area for enzymes making ATP |
Mitochondrial matrix | Space inside the mitochondrial inner membrane containing enzymes |
Thylakoids | Membranous sacs inside a chloroplast stacked into a granum, containing chlorophyll in its internal fluid (the stroma) |
Peroxisomes | Specialized metabolic compartments that use oxygen to break fatty acids into smaller molecules and form hydrogen peroxide as a byproduct; in liver cells, they detoxify alcohol and other harmful compounds |
Glyoxysomes | Specialized peroxisomes in plant seeds that convert fatty acids into sugar for the seedling |
Endosymbiont theory | Theory proposing that mitochondria and chloroplasts evolved from free-living prokaryotes engulfed by an early ancestor of eukaryotic cells (evidence includes a double membrane, free ribosomes, and circular DNA molecules) |
Cytoskeleton | Network of fibers built from three structures: microtubules (thickest), intermediate filaments, and microfilaments (thinnest, also called actin filaments) |
Motor proteins | Proteins that use "feet" and ATP to let vesicles and organelles travel along cytoskeletal tracks |
Microtubules | Hollow rods built of tubulin dimers that shape the cell, guide organelle movement, and separate chromosomes during cell division; in animal cells they grow out from the centrosome |
Cilia and flagella | Extensions of the plasma membrane used for locomotion, anchored by a basal body; dynein drives their bending movement |
Microfilaments (actin filaments) | Form a cortex just inside the plasma membrane to support cell shape and make up the core of microvilli in intestinal cells |
Pseudopodia | Cellular extensions used by cells to crawl, driven by the motor protein myosin and actin |
Cytoplasmic streaming | Circular flow of cytoplasm in plant cells driven by actin-protein interactions |
Intermediate filaments | Sized between microtubules and microfilaments; the most permanent cytoskeletal fixtures that help support cell shape and fix organelles in place |
Plant cell wall | Proteins and cellulose fibers embedded to protect plant cells, maintain shape, and prevent excessive water uptake (includes primary wall, middle lamella with pectin, and secondary wall) |
Extracellular Matrix (ECM) | Elaborate matrix in animal cells made of glycoproteins like collagen, proteoglycans, and fibronectin, which bind receptor proteins called integrins |
Tight junctions | Animal cell junctions that press neighboring membranes together to prevent leakage of extracellular fluid |
Desmosomes | Anchoring junctions that fasten animal cells into strong sheets |
Gap junctions | Communicating junctions that provide cytoplasmic channels between adjacent animal cells |
Plasmodesmata | Channels in plant cells that connect adjacent cells, letting water, small solutes, and sometimes proteins/RNA pass between them |
Four things every cell common to all types | Cell membrane, cytosol, chromosomes, ribosomes |
Eukaryotic cell compartmentalization | Organelles create localized environments, allowing incompatible processes to occur within the same cell |
Microscopes | Instruments used to understand and study cells where visible light is passed through a specimen and then through glass lenses |
Magnification | Ratio of image size to real size |
Resolution | Clarity of the image |
Contrast | Visible difference in brightness |
Scanning electron microscopes (SEMs) | Microscopes that focus a beam of electrons onto the surface of a specimen, providing a 3-D view |
Transmission electron microscopes (TEMs) | Microscopes that focus a beam of electrons through a specimen to study internal cell structure |
Prokaryotic cells | DNA sits unbound in a region called the nucleoid with no membrane-bound organelles, and cytoplasm is bound only by the plasma membrane |
Eukaryotic cells | DNA is enclosed in a nucleus, and cells contain membrane-bound organelles with cytoplasm in the region between the plasma membrane and nucleus |
Surface area-to-volume ratio | Ratio that helps set limits on how large a cell can be as it increases in size |
Nucleus | The cell's info center, enclosed by a nuclear envelope (double membrane) containing nuclear pores that regulate what enters/exits |
Nuclear lamina | Made of protein, sits on the nuclear side of the envelope and helps maintain the cell's shape; evidence also points to a nuclear matrix (framework of protein fibers inside the nucleus) |
Chromatin | DNA organized into discrete units called chromosomes; each contains one DNA molecule associated with proteins that condenses further during cell division |
Nucleolus | Site inside the nucleus where ribosomal RNA (rRNA) is synthesized |
Free ribosomes | Complexes of ribosomal RNA and protein that build proteins in the cytosol |
Bound ribosomes | Ribosomes on the outside of the ER or nuclear envelope that build proteins |
Endomembrane system | System that regulates protein traffic and performs metabolic functions, consisting of the nuclear envelope, endoplasmic reticulum (ER), Golgi apparatus, lysosomes, vacuoles, and the plasma membrane |
Smooth ER | Lacks ribosomes; synthesizes lipids, detoxifies drugs/poisons, and stores calcium ions |
Rough ER | Studded with ribosomes; produces glycoproteins and transport vesicles, and is considered the cell's "membrane factory" |
Golgi apparatus | The cell's shipping/receiving center made of flattened membranous sacs called cisternae; modifies products of the ER, manufactures certain macromolecules, and sorts/packages materials into transport vesicles |
Lysosomes | Membranous sacs of hydrolytic enzymes that digest macromolecules; have an acidic internal environment, are made by the rough ER, sent to the Golgi, and may bud from the trans face |
Phagocytosis | Process where lysosomes fuse with a food vacuole and digest its contents |
Autophagy | Process where lysosomes recycle the cell's own organelles and macromolecules |
Contractile vacuoles | Large vesicles derived from the ER and Golgi that pump excess water out of freshwater protist cells |
Central vacuoles | Found in mature plant cells; contain sap and store ions like potassium and chloride |
Mitochondria | Found in nearly all eukaryotic cells and are the site of cellular respiration |
Chloroplasts | Found only in plants/algae and are the site of photosynthesis |
Cristae | Folds in a mitochondrion's inner membrane that provide a large surface area for enzymes making ATP |
Mitochondrial matrix | Space inside the mitochondrial inner membrane containing enzymes |
Thylakoids | Membranous sacs inside a chloroplast stacked into a granum, containing chlorophyll in its internal fluid (the stroma) |
Peroxisomes | Specialized metabolic compartments that use oxygen to break fatty acids into smaller molecules and form hydrogen peroxide as a byproduct; in liver cells, they detoxify alcohol and other harmful compounds |
Glyoxysomes | Specialized peroxisomes in plant seeds that convert fatty acids into sugar for the seedling |
Endosymbiont theory | Theory proposing that mitochondria and chloroplasts evolved from free-living prokaryotes engulfed by an early ancestor of eukaryotic cells (evidence includes a double membrane, free ribosomes, and circular DNA molecules) |
Cytoskeleton | Network of fibers built from three structures: microtubules (thickest), intermediate filaments, and microfilaments (thinnest, also called actin filaments) |
Motor proteins | Proteins that use "feet" and ATP to let vesicles and organelles travel along cytoskeletal tracks |
Microtubules | Hollow rods built of tubulin dimers that shape the cell, guide organelle movement, and separate chromosomes during cell division; in animal cells they grow out from the centrosome |
Cilia and flagella | Extensions of the plasma membrane used for locomotion, anchored by a basal body; dynein drives their bending movement |
Microfilaments (actin filaments) | Form a cortex just inside the plasma membrane to support cell shape and make up the core of microvilli in intestinal cells |
Pseudopodia | Cellular extensions used by cells to crawl, driven by the motor protein myosin and actin |
Cytoplasmic streaming | Circular flow of cytoplasm in plant cells driven by actin-protein interactions |
Intermediate filaments | Sized between microtubules and microfilaments; the most permanent cytoskeletal fixtures that help support cell shape and fix organelles in place |
Plant cell wall | Proteins and cellulose fibers embedded to protect plant cells, maintain shape, and prevent excessive water uptake (includes primary wall, middle lamella with pectin, and secondary wall) |
Extracellular Matrix (ECM) | Elaborate matrix in animal cells made of glycoproteins like collagen, proteoglycans, and fibronectin, which bind receptor proteins called integrins |
Tight junctions | Animal cell junctions that press neighboring membranes together to prevent leakage of extracellular fluid |
Desmosomes | Anchoring junctions that fasten animal cells into strong sheets |
Gap junctions | Communicating junctions that provide cytoplasmic channels between adjacent animal cells |
Plasmodesmata | Channels in plant cells that connect adjacent cells, letting water, small solutes, and sometimes proteins/RNA pass between them |
Path of a protein for secretion | Ribosome (Rough ER) -> Golgi Apparatus -> Transport vesicle -> Secretory vesicle -> Plasma membrane -> Exocytosis |
Endosymbiont Theory evidence | 1. Free ribosomes, 2. Double membrane, 3. Circular DNA molecules |
Why cells are compartmentalized | Organelles create localized environments, allowing incompatible processes to occur simultaneously within the same cell |
Cellular components used when a cell crawls | Microfilaments (actin) and myosin motor proteins extending pseudopodia |
Plant cell structural support under stress | Relies on the cell wall made of cellulose |
Animal cell structural support under stress | Relies on the extracellular matrix (ECM), a flexible network of proteins and carbohydrates like collagen |