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140 Cards in this Set
- Front
- Back
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An adult human body consists of about______ cells.
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75 trillion
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There are at least ______________ varieties of cells.
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260 different
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Cells are measured in units called _________ .
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micrometers
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A micrometer equals ________.
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one thousandth of a millimeter
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A human egg cell is about ______ in diameter.
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140 micrometers
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A red blood cell is about ______ in diameter.
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7.5 micrometers
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Typically the shape of a cell makes possible its ________.
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functions
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It is not possible to describe a typical cell because
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cells vary greatly in size, shape, content, and function
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A composite cell includes _________.
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many known cell structures
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Three major parts of a cell are ___________
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nucleus, cytoplasm, and cell membrane
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The nucleus is enclosed by
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a nuclear envelope
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The nucleus contains
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DNA
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The cytoplasm is
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a mass of fluid that surround the nucleus and is itself encircled by the cell membrane
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The cell membrane surrounds
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the cytoplasm
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Specialized structures within the cytoplasm are called
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organelles
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Cytosol is
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a liquid that suspends organelles
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The cell membrane controls
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the entrance and exit of substances into and out of the cell
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The cell membrane is called selectively permeable because
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it allows the entry and exit of only certain substance
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The cell membrane is mainly composed of
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lipids and proteins
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Signal transduction is
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the process in which a cell receives and responds to incoming messages
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The cell membrane has a double layer of
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phospholipids
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The surfaces of the cell membrane are formed by
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phosphate groups of phospholiped molecules
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The interior of the cell membrane is formed by
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the fatty acids of phospholipid molecules
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The phospholipid bilayer is permeable to
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lipid-soluable substances such as lipids, steroid hormones, oxygen, and carbon dioxide
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The phospholipid bilayer is NOT permeable to
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water-soluable substances such as protein, sugars, nucleic acids, amino acids, and various ions
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______ help stabilize the cell membrane.
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Cholesterol molecules
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Five types of membrane proteins are
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1. receptor proteins
2. integral proteins 3. enzymes 4. cellular adhesion molecules 5. cell surface proteins |
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Receptor proteins function to
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receive and transmit messages into a cell
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Integral proteins function to
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form pores, channels, and carriers in cell membranes
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exhibition, exhibit (s)
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вЫставка (и) f.
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Cellular adhesion molecules function to
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enable cells to stick to each other
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Cell surface proteins function to
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establish the cell as "self" or not foreign
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Intercellular junctions connect
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cell membranes
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Three types of intercellular junctions are
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1. tight junctions
2. desmosomes 3. gap junctions |
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Tight junctions are located in cells that
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form sheetlike layers
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Tight junctions function to
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close spaces between cells
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Desmosomes are located in cells of
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the skin
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Desmosomes function to
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form a reinforced structural unit
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Gap junctions are located in cells of the
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heart muscle and muscle cells of the digestive tract
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Gap junction function to
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link the cytoplasm of adjacent cells and allow ions, nutrients, and other small molecules to move between them
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Two examples of cellular adhesion molecules are
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1. selectin
2. integrin |
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Selectin functions to
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coat white blood cells so that they can slow down in the turbulence of the bloodstream
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Integrin functions to
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anchor white blood cells to an injured blood vessed wall
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The cytoskeleton is
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protein rods and tobules that form supportive framework within a cell
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The sructure of endoplasmic reticulum is
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a complex of connected, membrane-bound sacs, canals, and vesicles
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The function of endoplasmic reticulum is
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to transport materials within the cell, to provide attatchment sites for ribosomes, and to synthesize lipids and proteins.
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Rough endoplasmic reticulum is studded with
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ribosomes
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The ribosomes are sites of
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protein synthesis
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Proteins move from the ER to the
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golgi apparatus
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Smooth endoplasmic reticulum is
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endoplasmic reticulum that lacks ribosomes
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Smooth endoplasmic reticulum contains enzymes that
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are used for lipid synthesis, fat absorption, and the break down of drugs
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Two places ribosomes are found are
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on endoplasmic reticulum and free floating in the cytoplasm
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Ribosomes are composed of
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RNA and proteins
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Ribosomes are the sites of
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protein synthesis
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The structure of the golgi apparatus is
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a group of flattened, membraneous sacs
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The golgi apparatus functions to
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package and modify proteins froms transport and secretion
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Vesicle trafficking is
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the movement of substances within cells by way of vesicles
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The structure of mitochondria is
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a membraneous sac with inner partitions
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The two layers of mitochondrrion are
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an outer membrane and an inner membrane
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Cristae are
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shelflike partition of the inner membrane of a mitochondrion
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Mitochondria function to
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release energy from food molecules and transform energy into usable forms
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Lysosomes function to
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digest worn out cellular parts of substances that enter cells
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Lysosomes contain
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digestive enzymes
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Peroxisomes contain
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enzymes called peroxidases
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Peroxisomes are most abundant in a cell of the
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liver and kidneys
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The enzymes of peroxisomes function to
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breakdown many important organic molecules
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The structure of a centrosome is
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a nonmembraneous structure composed of two rodlike centrioles
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A centrosome is usually located near the
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the nucleus
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Centrosomes function to
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distribute chromosomes to new cells during cell division and to initiate formation of cilia
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The structure of a cilium is
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a motile projection that is attatched to basal body beneath the cell membrane
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The function of a cilia is
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to propel fluid over a cellular surface
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The structure of a flagellum is
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a motile projection that is attatched to a basal body beneath the cell membrane
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The function of flagella are
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to enable sperm cells to move
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Vesicles are
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membraneous sacs
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Vesicles are formed by
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the pinching off of the cell membrane
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Vesicles function to
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store and transport substances within the cell
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Microfilaments are
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tiny rods of the protein actin that typically occur in meshworks of bundles
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Microfilaments cause
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various kinds of cellular movement
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Microtubules are
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long, slender tube with diameters larger than those of microfilaments
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Three functions of microtubules are
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to maintain the shape of a cell, and to provide movement in cilia and flagella
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Inclusions are
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chemical in the cytoplasm
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The nucleus contains
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DNA
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Chromosomes are
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extremely long molecules that contain DNA and proteins
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The nucleus is enclosed by
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the nuclear envelope
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Nuclear pores are
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round openings in a nuclear envelope
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________ move through nuclear pores.
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Messenger RNA and various other substances
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Nucleoplasm is
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the fluid inside the nucleus
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Two structures found in nucleoplasm are
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the nucleolus and chromatin
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The nucleolus is composed of
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RNA and protein
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The nucleolus is the site of
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ribosome production
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Chromatin is
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DNA and proteins called histones
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The cell membrane controls
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which substances enter or exit the cell
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Four types of physical processes are
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1. diffusion
2. facilitated diffusion 3. osmosis 4. filtration |
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Three types of physiological mechanisms are
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1. active transport
2. endocytosis 3. exocytosis |
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Diffusion is
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the tendency of atoms, molecules, and ions in a liquid or air solution to move from areas of higher concentration to areas of lower concentration
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A concentration gradient is
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the difference in concentrations
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Diffusional equilibrium is
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the condition of having a uniform concentration of substances throughout a solution
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Substances diffuse ________ a concentration gradient.
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down
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Two conditions that allow a substance to diffuse across a membrane are
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the permeability of the cell membrane to a substance and the existence of a concentration gradient across the membrane
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In body cells, oxygen usually diffuses _______ a body cell and carbon dioxide diffuses ________ a body cell.
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into, out
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A physiological steady state is
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where concentrations of diffusing substances are unequal but stable
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Five substances that cross the cell membrane through simple diffusion are
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1. a lipid-soluable
2. oxygen 3. carbon dioxide 4. steroids 5. general anesthetics |
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The three most important factors that influence diffusion rate are
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1. distance
2. concentration gradient 3. temperature |
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In general, diffusion is more rapid over ______ distances, ________concentration gradients, and at _________ temperatures.
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shorter, larger, higher
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Facilitated diffusion requires
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proteins channels or protein carriers.
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Substances that move across the cell membrane through facilitated diffusion are
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glucose and other sugars
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The hormone _____ promotes facilitated diffusion of glucose.
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insulin
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Osmosis is
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the diffusion of water molecules from a region of higher water concentration to a region of lower water concentration across a selectively permeable membrane.
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Osmotic pressure is
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the ability of osmosis to generatie enough pressure to lift a volume of water
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Water always tends to diffuse toward solutions of
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greater osmotic pressure
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Isotonic solutions are
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solutions with the same osmotic pressure as body fluids
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Hypertonic solutions are
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solutions with greater osmotic pressure than body fluids
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The advancement manual provides the basis for reductions in rate under this Uniform Code Of Military Justice (UCMJ) article.
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UCMJ Article 15 (non-judicial punishment, a.k.a NJP)
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Cells ________ in hypertonic solutions.
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shrink
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Cells ________ in hypotonice solutions.
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swell
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The process of forcing molecules through a membrane is
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filtration
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Filtration is commonly used to separate
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solids from water
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In the body the force for filtration is produced by
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blood pressure
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Movement against a concentration gradient is
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active transport
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Active transport is similar to facilitated diffusion because
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it requires protein channels or protein carriers
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Substances that move across the cell membrane through active transport are
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sugars, amino acids, and ions such as sodium, potassium, hydrogen, and calcium.
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Active transport requires cellular
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energy
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Endocytosis is the process of
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a cell engulfing a substance by forming a vesicle around the substance.
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Exocytosis is
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the process of secreting a substance from a cell stored in a vesicle.
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Three forms of endocytosis are
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phagocytosis, pinocytosis, and receptor-mediated endocytosis.
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Pinocytosis in endocytosis of
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tiny droplets of liquids
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Phagocytosis is endocytosis of
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solids
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Phagocytes are
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cells that can take in solid particles such as bacteria and cellular debris.
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Receptor-mediated endocytosis moves _______ into the cell.
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very specific kinds of particles
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In receptor-mediated endocytosis, a substance must bind to a _________ before it can enter the cell.
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receptor
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A ligand is
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a molecule that binds specifically to receptors.
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An example of a molecule that moves into a cell through receptor-mediated endocytosis is __________
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cholesterol
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Exocytosis is the reverse of
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endocytosis
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Cells secrete ______ through exocytosis.
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some proteins
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Nerve cells secrete _______ through exocytosis.
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neurotransmitters
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Transcytosis moves substances
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from one end of a cell to the other end of the cell
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A virus that uses transcytosis to infect humans is the
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HIV
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The cell cycle is
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the series of changes a cell undergoes, from the time it forms until the time it divides.
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Daughter cells are
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two cells that are products of cell division
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The four phases of the cell cycle are
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interphase, mitosis,
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