Terms : Hide Images
| 15336947602 | Key Ideas | All organisms are made of cells The cell is the simplest collection of matter that can be alive All cells are related by their descent from earlier cells Though cells can differ substantially from one another, they share common features | 0 | |
| 15336972620 | microscopy | Most cells are between 1 and 100 μm in diameter, too small to be seen by the unaided eye Scientists use microscopes to visualize cells too small to see with the naked eye Lenses refract (bend) the light, so that the image is magnified | 1 | |
| 15336989960 | light microscope | visible light is passed through a specimen and then through glass lenses LMs can magnify effectively to about 1,000 times the size of the actual specimen Various techniques enhance contrast and enable cell components to be stained or labeled Most subcellular structures, including organelles (membrane-enclosed compartments), are too small to be resolved by light microscopy | 2 | |
| 15337004298 | magnification | the ratio of an object's image size to its real size | 3 | |
| 15337009346 | resolution | the measure of the clarity of the image, or the minimum distance between two distinguishable points | 4 | |
| 15337019853 | contrast | visible differences in parts of the sample | 5 | |
| 15337712252 | electron micropscope | Two basic types of electron microscopes (EMs) are used to study subcellular structures | 6 | |
| 15337719560 | scanning electron microscope | Scanning electron microscopes (SEMs) focus a beam of electrons onto the surface of a specimen, providing images that look three-dimensional | 7 | |
| 15337726697 | transmission electron microscope | Transmission electron microscopes (TEMs) focus a beam of electrons through a specimen TEM is used mainly to study the internal structure of cells | 8 | |
| 15337741072 | advances in light microscopy | Labeling molecules or structures with fluorescent markers improves visualization of details Confocal and other types of microscopy have sharpened images of tissues and cells New techniques and labeling have improved resolution so that structures as small as 10-20 μm can be distinguished | 9 | |
| 15337760117 | cell fractionation | Cell fractionation breaks up cells and separates the components, using centrifugation Cell components separate based on their relative size Cell fractionation enables scientists to determine the functions of organelles Biochemistry and cytology help correlate cell function with structure | 10 | |
| 15337796161 | eukaryotic vs. prokaryotic | The basic structural and functional unit of every organism is one of two types of cells: prokaryotic or eukaryotic Organisms of the domains Bacteria and Archaea consist of prokaryotic cells Protists, fungi, animals, and plants all consist of eukaryotic cells Eukaryotic cells are generally much larger than prokaryotic cells | 11 | |
| 15337802479 | basic features of all cells | Plasma membrane Semifluid substance called cytosol Chromosomes (carry genes) Ribosomes (make proteins) | 12 | |
| 15337816413 | prokaryotic cells | Prokaryotic cells are characterized by having: No nucleus DNA in an unbound region called the nucleoid No membrane-bound organelles Cytoplasm bound by the plasma membrane |  | 13 |
| 15337832687 | Eukaryotic cells | Eukaryotic cells are characterized by having: DNA in a nucleus that is bounded by a membranous nuclear envelope Membrane-bound organelles Cytoplasm in the region between the plasma membrane and nucleus A eukaryotic cell has internal membranes that divide the cell into compartments—organelles The plasma membrane and organelle membranes participate directly in the cell's metabolism |  | 14 |
| 15337844538 | plasma membrane | The plasma membrane is a selective barrier that allows sufficient passage of oxygen, nutrients, and waste to service the volume of every cell The general structure of a biological membrane is a double layer of phospholipids |  | 15 |
| 15337879721 | cell sizes | Metabolic requirements set upper limits on the size of cells The ratio of surface area to volume of a cell is critical As the surface area increases by a factor of n2, the volume increases by a factor of n3 Small cells have a greater surface area relative to volume | 16 | |
| 15337981334 | genetic instructions | The eukaryotic cell's genetic instructions are housed in the nucleus and carried out by the ribosomes The nucleus contains most of the DNA in a eukaryotic cell Ribosomes use the information from the DNA to make proteins | 17 | |
| 15351520010 | nucleus | The nucleus contains most of the cell's genes and is usually the most conspicuous organelle Pores regulate the entry and exit of molecules from the nucleus | 18 | |
| 15351524580 | nuclear membrane | The nuclear envelope/membrane encloses the nucleus, separating it from the cytoplasm The nuclear membrane is a double membrane; each membrane consists of a lipid bilayer | 19 | |
| 15351531428 | nuclear lamina | The shape of the nucleus is maintained by the nuclear lamina, which is composed of protein | 20 | |
| 15351542901 | chromatin | DNA and its associated proteins | 21 | |
| 15351547245 | chromosomes | Chromatin that becomes condensed during cell division In the nucleus of human cells, DNA is organized into 46 discrete units or 46 chromosomes | 22 | |
| 15351553806 | nucleolus | The nucleolus is located within the nucleus and is the site of ribosomal RNA (rRNA) synthesis | 23 | |
| 15351558652 | ribosomes | Ribosomes are complexes of ribosomal RNA and protein | 24 | |
| 15351563966 | locations of protein synthesis | Ribosomes carry out protein synthesis in two locations: In the cytosol (free ribosomes) On the outside of the endoplasmic reticulum or the nuclear envelope (bound ribosomes) | 25 | |
| 15351583357 | endomembrane system | regulates protein traffic and performs metabolic functions in the cell it is a complex and dynamic player in the cell's compartmental organization | 26 | |
| 15351605198 | Components of the endomembrane system | Nuclear envelope Endoplasmic reticulum Golgi apparatus Lysosomes Vacuoles Plasma membrane These components are either continuous or connected through transfer by vesicles | 27 | |
| 15351620095 | endoplasmic reticulum | The endoplasmic reticulum (ER) accounts for more than half of the total membrane The ER membrane is continuous with the nuclear envelope Tubules and cisternae (sacs) Membrane separates lumen (cisternal space) from cytosol |  | 28 |
| 15351622834 | Smooth ER vs Rough ER visual difference | smooth: lacks ribosomes rough: studded with ribosomes | 29 | |
| 15351654929 | Smooth ER functions | Synthesizes lipids - oils, phospholipids, steroids -Sex hormones (adrenal glands) Metabolizes carbohydrates Detoxifies drugs and poisons (liver cells) -Add hydroxyl groups, water-soluble, flush easier -More smooth ER, higher tolerance Stores calcium ions (muscle cells) -Stored in the lumen, nerve stimulated to release | 30 | |
| 15351669517 | Rough ER function | Has bound ribosomes, which secrete proteins Created externally, enter the lumen, folded into 3D shape, kept separate from free ribosome creations -Insulin from pancreatic cells Distributed by transport vesicles Is a membrane factory for the cell, carried to new locations by transport vesicles | 31 | |
| 15351677670 | Golgi apparatus | The Golgi apparatus consists of flattened membranous sacs called cisternae (pita bread) | 32 | |
| 15351685472 | golgi apparatus function | Functions of the Golgi apparatus - UPS, FedEx: Modifies products of the ER, transferred in vesicles Manufactures certain macromolecules Sorts and packages materials into transport vesicles Products move in only one direction: Cis - receiving, closer to ER Trans - shipping Each layer has a unique mix of enzymes Transport vesicles carry unique products - zip codes | 33 | |
| 15351697409 | lysosome | a membranous sac of hydrolytic enzymes that can hydrolyze macromolecules Lysosomal enzymes can hydrolyze proteins, fats, polysaccharides, and nucleic acids Lysosomal enzymes work best in the acidic environment inside the lysosome, cytosol has neutral pH -Major leaks lead to cellular digestion, death | 34 | |
| 15351709090 | food vacuole | Some types of cell can engulf another cell by phagocytosis; this forms a food vacuole A lysosome fuses with the food vacuole and digests the molecules Lysosomes also use enzymes to recycle the cell's own organelles and macromolecules, a process called autophagy | 35 | |
| 15351717143 | vacuole | Vacuoles are large vesicles derived from the endoplasmic reticulum and Golgi apparatus Selective as to the solution that is inside | 36 | |
| 15351721253 | contractile vacuole | found in many freshwater protists, pump excess water out of cells | 37 | |
| 15351725777 | central vacuole | found in many mature plant cells, hold organic compounds and water | 38 | |
| 15351730249 | vacuole in plants and fungi | Carry out enzymatic hydrolysis like lysosomes Hold reserves of proteins (seeds) Poisonous or unpalatable compounds Pigments | 39 | |
| 15351754858 | mitochondria | the sites of cellular respiration, a metabolic process that uses oxygen to generate ATP in nearly all eukaryotic cells | 40 | |
| 15351759796 | chloroplasts | Found in plants and algae, are the sites of photosynthesis Chloroplasts contain the green pigment chlorophyll, as well as enzymes and other molecules that function in photosynthesis Chloroplasts are found in leaves and other green organs of plants and in algae | 41 | |
| 15351762661 | Peroxisomes | Oxidative organelles Specialized metabolic compartments bounded by a single membrane Produce hydrogen peroxide and convert it to water Perform reactions with many different functions | 42 | |
| 15351770522 | mitochondria and chloroplasts similarities | similarities with bacteria: Enveloped by a double membrane Contain free ribosomes and circular DNA molecules Grow and reproduce somewhat independently in cells | 43 | |
| 15351778900 | endosymbiont theory | An early ancestor of eukaryotic cells engulfed a nonphotosynthetic prokaryotic cell, which formed an endosymbiont relationship with its host The host cell and endosymbiont merged into a single organism, a eukaryotic cell with a mitochondrion At least one of these cells may have taken up a photosynthetic prokaryote, becoming the ancestor of cells that contain chloroplasts | 44 | |
| 15351841848 | mitochondria structure | Have a smooth outer membrane and an inner membrane folded into cristae The inner membrane creates two compartments: intermembrane space and mitochondrial matrix Some metabolic steps of cellular respiration are catalyzed in the mitochondrial matrix Cristae present a large surface area for enzymes that synthesize ATP | 45 | |
| 15351843915 | chloroplast structure | Thylakoids, membranous sacs, stacked to form a granum Stroma, the internal fluid | 46 | |
| 15351849144 | plastids | any of a class of small organelles, such as chloroplasts, in the cytoplasm of plant cells, containing pigment or food. | 47 | |
| 15351872917 | cytoskeleton | The cytoskeleton is a network of fibers extending throughout the cytoplasm It organizes the cell's structures and activities, anchoring many organelles | 48 | |
| 15351888580 | role of cytoskeleton | Support and Motility The cytoskeleton helps to support the cell and maintain its shape (like a dome tent), it is dynamic It interacts with motor proteins to produce motility Inside the cell, vesicles and other organelles can "walk" along the tracks provided by the cytoskeleton | 49 | |
| 15351898881 | components of cytoskeleton | Three main types of fibers make up the cytoskeleton: Microtubules are the thickest of the three components of the cytoskeleton Microfilaments, also called actin filaments, are the thinnest components Intermediate filaments are fibers with diameters in a middle range | 50 | |
| 15351903561 | microtubles | Microtubules are hollow rods constructed from globular protein dimers called tubulin | 51 | |
| 15351905563 | dimers | two slightly different polypeptides | 52 | |
| 15351908439 | functions of microtubules | Shape and support the cell, disassemble/reassemble Guide movement of organelles Separate chromosomes during cell division | 53 | |
| 15352479546 | Centrosome | In animal cells, microtubules grow out from a centrosome near the nucleus The centrosome is a "microtubule-organizing center" | 54 | |
| 15352481503 | centrioles | The centrosome has a pair of centrioles, each with nine triplets of microtubules arranged in a ring, "9+0" w/triplets | 55 | |
| 15352484605 | cilia and flagella | Microtubules control the beating of cilia and flagella, microtubule-containing extensions projecting from some cells Flagella are limited to one or a few per cell, while cilia occur in large numbers on cell surfaces Locomotion and movement of fluid Sperm, algae Lining of trachea, lining of oviducts Cilia and flagella also differ in their beating patterns | 56 | |
| 15352490528 | cilia and flagella similarities | Cilia and flagella share a common structure A core of microtubules sheathed by the plasma membrane, "9+2" A basal body that anchors the cilium or flagellum, similar in structure to a centriole, "9+0" w/triplets A motor protein called dynein, which drives the bending movements of a cilium or flagellum | 57 | |
| 15352496150 | How dynein "walking" moves flagella and cilia | Dynein arms alternately grab, move, and release the outer microtubules The outer doublets and central microtubules are held together by flexible cross-linking proteins Movements of the doublet arms cause the cilium or flagellum to bend | 58 | |
| 15352501440 | microfilaments | Microfilaments are thin solid rods, built from molecules of globular actin subunits The structural role of microfilaments is to bear tension, resisting pulling forces within the cell Bundles of microfilaments make up the core of microvilli of intestinal cells Microfilaments that function in cellular motility interact with the motor protein myosin For example, actin and myosin interact to cause muscle contraction, amoeboid movement of white blood cells, and cytoplasmic streaming in plant cells | 59 | |
| 15352509398 | intermediate filaments | Intermediate filaments are larger than microfilaments but smaller than microtubules They support cell shape and fix organelles in place Intermediate filaments are more permanent cytoskeleton elements than the other two classes Made from proteins that are similar to keratin Maintained after cell death Builds a cage around the nucleus, others build nuclear lamina | 60 | |
| 15352514988 | extracellular components | Most cells synthesize and secrete materials that are external to the plasma membrane These extracellular materials are involved in many cellular functions | 61 | |
| 15352518359 | cell walls of plants | The cell wall is an extracellular structure that distinguishes plant cells from animal cells Prokaryotes, fungi, and some protists also have cell walls The cell wall protects the plant cell, maintains its shape, and prevents excessive uptake of water Plant cell walls are made of cellulose fibers embedded in other polysaccharides and protein | 62 | |
| 15352520411 | plant cell wall layers | Primary cell wall: relatively thin and flexible Secondary cell wall (in some cells): added between the plasma membrane and the primary cell wall Middle lamella: thin layer between primary walls of adjacent cells | 63 | |
| 15352524995 | plasmodesmata | channels that perforate plant cell walls Through it, water and small solutes (and sometimes proteins and RNA) can pass from cell to cell | 64 | |
| 15352529374 | extracellular matrix of animal cells | Animal cells lack cell walls but are covered by an elaborate extracellular matrix (ECM) The ECM is made up of glycoproteins such as collagen, proteoglycans, and fibronectin ECM proteins bind to receptor proteins in the plasma membrane called integrins | 65 | |
| 15352532124 | cell junctions | Neighboring cells in an animal or plant often adhere, interact, and communicate through direct physical contact There are several types of intercellular junctions that facilitate this: Plasmodesmata Tight junctions Desmosomes Gap junctions | 66 | |
| 15352543256 | types of animal cell junctions | Tight junctions Desmosomes Gap junctions All are especially common in epithelial tissue | 67 | |
| 15352548090 | cell function overall | Cellular functions arise from cellular order For example, a macrophage's ability to destroy bacteria involves the whole cell, coordinating components such as the cytoskeleton, lysosomes, and plasma membrane | 68 |
