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48 Cards in this Set
- Front
- Back
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Organisms
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-single-celled, such as most prokaryotes and protists
-muti-celled, such as plants, animals, and most fungi |
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Light Microscopes
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-can be used to explore the structures and functions of cells
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Magnification
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-an increase in the specimen's apparent size
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Resolving Power
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-the ability of an optical instrument to show two objects as separate
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Cell Theory
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-all living things are composed of cells
-all cells come from other cells |
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Electron Microscope
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-EM
-uses a beam of electrons, which results in better resolving power than the light microscope -can magnify up to 100,000 times -can distinguish between objects 0.2 nanometers apart |
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Scanning Electron Microscope
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-examines cell surfaces
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Transmission Electron Microscope
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-TEM
-useful for internal details of cells |
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Prokaryotic Cells
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-bacteria and archaea
-older than eukaryotic cells -appeared about 3.5 billion years ago |
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Eukaryotic Cells
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-plants, fungi, and animals
-the region between the nucleus and plasma membrane is the cytoplasm |
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Plasma Membrane
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-all cells are bound by a thin plasma membrane
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Ribosomes
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-tiny structures that build proteins
-all cells have DNA and ribosomes |
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Prokaryotes
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-smaller than eukaryotic cells
-lack internal structures surrounded by membranes -lack a nucleus -have a rigid cell wall |
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Eukaryotes
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-have organelles
-most important organelle is the nucleus which houses most of the DNA -the region between the nucleus and plasma membrane is the cytoplasm |
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Organelles
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-membrane-bound structures that perform specific functions
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Cytoplasm
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-the region between the nucleus and plasma membrane
-consists of various organelles suspended in fluid |
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Plant Cells
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-protective cell walls
-chloroplasts |
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Chloroplasts
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-convert light energy to the chemical energy of food
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Plasma Membrane
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-separates the living cell from its nonliving surroundings
-composed mostly of lipids (phospholipids) and proteins -fluid mosaic |
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Phospholipids
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-form a two-layered membrane, the phospholipid bilayer
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Phospholipid Bilayer
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-a two-layered membrane formed by phospholipids
-most have specific proteins embedded in them (help regulate traffic across the membrane and perform other functions) |
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Fluid Mosaic
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-molecules can move freely past one another
-diversity of proteins in the membrane |
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Plant Cells
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-rigid cell walls surrounding the membrane
-walls are made of cellulose, protect the cells, maintain cell shape, and keep the cells from absorbing too much water |
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Animal Cells
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-lack cell walls
-have an extracellular matrix -surfaces of most animal cells have cell junctions |
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Extracellular Matrix
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-helps hold cells together in tissues
-protects and supports them |
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Cell Junctions
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-structures that connect to other cells
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Nucleus
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-chief executive of the cell
-genes in nucleus store information necessary to produce proteins -proteins do most of the work of the cell -bordered by a double membrane called the nuclear envelope -pores in the envelope allow materials to move between the nucleus and cytoplasm contains a nucleolus |
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Nucleolus
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-where ribosomes are made
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Chromatin
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-fibers formed by long DNA molecules and associated proteins that are stored in the nucleus
-each long chromatin fiber constitutes one chromosome -number of chromosomes in a cell depends on the species |
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Ribosomes
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-responsible for protein synthesis
-components are made in the nucleolus but assembled in the cytoplasm -may assemble proteins suspended in the fluid of the cytoplasm or attached to the outside of an organelle called the endoplasmic reticulum |
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Protein Production
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-DNA directs protein production by transferring its coded information into messenger RNA (mRNA)
-mRNA exits the nucleus through pores in the nuclear envelope -a ribosome moves along the mRNA translating the genetic message into a protein with a specific amino acid sequence |
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Endomembrane System
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-formed by many membraneous organelles are interconnected either directly or through the transfer of membrane segments between them
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Endoplasmic Reticulum (ER)
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-one of the main manufacturing facilities in a cell
-produces an enormous variety of molecules -composed of smooth and rough ER |
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Rough ER
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-"rough" is due to ribosomes that stud the outside of the ER membrane
-ribosomes produce membrane proteins and secretory proteins -after it synthesizes a molecule, it packages the molecule into transport vesicles |
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Smooth ER
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-lacks surface ribosomes
-produces lipids, including steroids -helps liver cells detoxify circulating drugs |
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Golgi Apparatus
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-works in partnership with the ER
-receives, refines, stores, and distributes chemical products of the cells |
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Lysosome
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-a sac of digestive enzymes found in animal cells
-enzymes in a lysosome can break down large molecules such as proteins, polysaccharides, fats, and nucleic acids -have several types of digestive functions: -many cells engulf nutrients in tiny cytoplasmic sacs called food vacuoles -these food vacuoles fuse with lysosomes, exposing food to enzymes to digest the food -small molecules from digestion leave the lysosome and nourish the cell -can destroy harmful bacteria -can break down damaged organelles |
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Vacuoles
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-membraneous sacs that bud from the ER, Golgi, and Plasma Membrane
-contractile vacuoles of protists pump out excess water in the cell |
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Central Vacuoles
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-exist in plant cells
-store nutrients -absorb water -may contain pigments or poisons |
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Chloroplasts
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-cells require a constant energy supply to perform the work of life
-the organelles that perform photosynthesis -three major compartments: the space between the two membranes, the stroma, and the space within grana |
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Photosynthesis
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-most of the living world runs on the energy provided by photosynthesis
-the conversion of light energy from the sun to the chemical energy of sugar |
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Stroma
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-a thick fluid within the chloroplast
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Grana
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-the structures that trap light energy and convert it to chemical energy
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Mitochondria
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-the sites of cellular respiration, which produce ATP from the energy of food molecules
-found in almost all eukaryotic cells -contains its own DNA (along with chloroplasts) |
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Cytoskeleton
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-a network of fibers extending throughout the cytoplasm
-provides mechanical support to the cell -maintains its shape -contains several types of fibers made from different proteins: microtubules -dynamic -changes in the cytoskeleton contribute to the amoeboid motion of an amoeba |
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Microtubules
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-straight and hollow
-guide the movement of organelles and chromosomes |
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Flagella
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-aid in movement
-propel the cell in a whiplike motion -has the same basic structure as cilia |
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Cilia
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-aid in movement
-have the same basic structure as flagella -move in a coordinated back-and-forth motion -may extend from nonmoving cells -in the trachea, help sweep mucus out of the lungs |
