Chapter 3: Cell Biology Flashcards Preview

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Flashcards in Chapter 3: Cell Biology Deck (113):
1

cytology

the study of plant and animal cells

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cell theory

all living things consist of cells, and cells arise from pre-existing cells

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biogenesis

the theory that cells come from pre-existing cells

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Antoni van Leeuwenhoek

in the 1600s, this person was the first to ever observe cells. He also discovered bacteria, and used lenses to observe microscopic organisms.

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Robert Hooke

in the 1600s, this person designed his own microscope to study microscopic subunits of life, which he named "cells"

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Lorenz Oken

in 1805, he claimed that all organic beings originate from and consist of cells

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Jean Baptiste Lamarck

also the first person to come up with a theory on the mechanism of evolution, he also restated Oken's theory that organic beings originate from and consist of cells

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Matthias Schleiden and Theodor Schwann

in 1838 and 1839 they unified cell theory to include plant and animal kingdoms

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Rudolph Virchow

in 1858, he proposed that cells come from pre-existing cells, thus challenging the theory of spontaneous generation

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Louis Pasteur

around 1858, he disproved spontaneous generation by boiling liquid in a straight-necked flask, and a swan-necked flask

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micron

the unit of cell measure, equal to one millionth of a meter

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membrane

a casing around the outside of a cell and it's internal organelles that is made of a phospholipid bilayer

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organelle

a structure in a eukaryotic cell that performs a specific function

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ribosome

a part of the cell that makes proteins

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chromosome

an organized collection of DNA

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nucleoid

the area of DNA concentration in a prokaryotic cell

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compartmentalization

the evolutionary process by which cells have developed organelles, suited for the purpose of increasing the efficiency of cell metabolism

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cytoplasm

all of the contents of the cell, excluding the nucleus

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cytosol

the liquid part of the cytoplasm

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fluid mosaic model

the model for membrane structure which states that membranes are composed of a phospholipid bilayer that contains hydrophilic proteins

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pore complex

the group of proteins that surround a pore in the nuclear envelope and allow the transport of materials into and out of the nucleus

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nucleolus

the site for ribosome synthesis

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nuclear envelope

the porous double membrane that surrounds the nucleus, is embedded with ribosomal subunits, and has pore complexes lined with protein

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nuclear lamina

the layer of structural proteins that hold the nucleus together

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chromatin

a fiberous complex consisting of DNA and proteins in an uncondensed form (before DNA becomes rod-shaped)

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histone

a group of five proteins, characterized by a high amount of positively charged amino acids, that is associated with DNA 

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lumen

the cavity inside any tubular part of a structure

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cisternae or "faces"

the inner space of the endoplasmic reticulum, or flattened membrane sacs of the Golgi apparatus

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synthesis

the formation of macromolecules

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steroids

a versatile class of lipids that can be used in the formation of molecules like testosterone and cholesterol

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vesicle

membrane-enclosed sacks which hold proteins

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trans face

the part of the Golgi apparatus that lies closest to the cell's plasma membrane

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cis face

the part of the Golgi apparatus that lies closest to the nucleus or endoplasmic reticulum

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docking molecules

a chemical "address label" that indicates a protein's destination

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membrane fusion

the merging of membranes to allow the movement of materials

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exocytosis

the process of releasing materials through the plasma membrane

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phagocytosis

the process of engulfing extracellular particles by surrounding them with extensions of the plasma membrane called "pseudopods"

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tonoplast

the membrane of a water vacuole

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osmosis

the process by which water moves from an area of greater concentration to an area of lesser concentration (hint: diffusion)

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DNA homology

a similar genetic sequence due to common ancestry

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glycoprotein

proteins that have a carbohydrate chain covalently linked to amino acid side chains

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autophagy

"self-eating", a form of organelle recycling by the decomposition of those organelles

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water vacuole or central vacuole

a vacuole that maintains the cell's water balance, stores toxic waste, and stores proteins that aren't immediately needed

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contractile vacuole

a vacuole that collects excess water in the cytoplasm from osmosis, and expels it through a por in the plasma membrane

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peroxisome

an organelle that houses reactions which produce hydrogen peroxide (a cell toxin), as well as peroxidase enzymes, which break the hydrogen peroxide into water and oxygen

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actin

a globular protein of which microfilaments are made

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nanometer

one one-thousandth of a micron

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microvilli

fingerlike extensions of the plasma membrane that increase the cell's surface area

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dystrophin

a protein that acts as an anchor for microfiliaments in muscle cells (hint: it can cause muscular dystrophy if it is defected)

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dimer

a molecule that has two subunits

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centrosome

a region of a eukaryotic cell where centrioles are located

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centrioles

a pair of structures made from microtubules that enable chromosomal movement during cell division

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flagella

relatively long structures made of microtubules that enable propulsion or movement of substances outside of the cell

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cilia

short, hair-like projections made of microtubules that serve to propel organisms using a rowing motion

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protein motor molecule

proteins that enable movement between microtubules (hint: dynein)

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peptidoglycan

polymers of modified sugars cross-linked by short polypeptides (chains of amino acids)

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chitin

a structural polysaccharide

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cellulose

a structural polymer consisting of strands of glucose with alternate beta linkages

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pectin

a molecule that binds cellulose molecules together in cell walls

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plasmodesmata (singular, plasmodesma)

cytoplasmic channels that run through adjacent plant cells

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selective permeability

describes the plasma membrane's ability to allow certain molecules to pass through more easily than others 

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extracellular matrix

an integrated network of collagen, carbohydrates, and proteins that provides support and communication for animal cells

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integrin

a class of plasma membrane proteins that have short glycoprotein receptors for binding to fibronectins

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oligosaccharide

a short polysaccharide (fewer than 15 simple sugars) that plays a role in cell-cell recognition

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epithelial cells

sheets of tightly packed cells that line organs and body cavities

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tight junction

adjacent cell interactions that do not allow for any intercellular space between the cells

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desmosomes

a type of cell junction, where "rivets" bind adjacent cells with keratin fibers

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gap junctions

allow the transfer os small molecules between 2 adjacent cells

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signal transduction

the ability to induce a reaction in another part of the cell

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antigens

foreign molecules in an organism that ellicit an immune response

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proteoglycans

a family of glycoproteins that have a core polypeptide with numberous carbohydrate chains attached

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fibronectins

a family of glycoproteins consisting of two polypeptides linked by bonds

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integral proteins or transmembranal proteins

proteins that are located inside the plasma membrane

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peripheral proteins

proteins that are embedded into the surface of the plasma membrane

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passive transport

the movement of  molecules across the cell that does not require the expenditure of energy (ATP) (hint: diffusion)

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diffusion

the movement of molecules from an area of high concentration to an area of low concentration (hint: entropy)

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concentration gradient

the relative density of one chemical substance versus another

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facilitated diffusion

the passive transport of molecules down a concentration gradient with the aid of special transport proteins located in the cell membrane

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osmosis

the passage of water across a membrane from an area of high concentration to low concentration

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solute

a substance dissolved in a solution

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solvent

the dissolving agent of a solution

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hypertonic

higher relative concentration of solute

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hypotonic

lower relative concentration of solute

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isotonic

same relative concentration of solute

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turgid

the rigidness of a plant due to its water vacuoles being filled

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flaccid

the lack of rigidity in a plant due to its water vacuoles being less full

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plasmolysis

the pulling away of the plasma membrane from the cell wall due to excessive water loss

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ATP

a molecule that stores energy in its phosphate bonds for later use. It is the "energy currency" of cells

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active transport

the pumping of molecules against the concentration gradient (low --> high) with the expenditures of ATP

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pumps

transmembranal proteins which move molecules and ions across the cell membrane

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electrogenic pump

a protein that actively transports ions resulting in an ionic and voltage gradient. This gradient is a form of stored energy used to feul other processes.

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cotransport

a coupled passage of two materials across a membrane

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depolarization

a change in the voltage (charge difference) across the membrane resulting from the movement of Na+ through channels into the cell

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resting potential

the voltage (charge difference) across the membrane of a cell while it is in an unexcited state

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endocytosis

the import of materials to the cell by infolding of the flasma membrane

96

pinocytosis

also called "cell drinking," the cell forms vesicles to take in fluid

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receptor-mediated endocytosis

vesicles form only when molecules are hooked into the receptor proteins

98

hypercholesterolemia

a condition resulting from a deficiency in the receptor protein responsible for transporing LDL (low density lipoprotein) out of the bloodstream and into the cell. The defect in the receprot protein means that the receptors cannot grab the LDL, and LDL plaque could build up along the arterial wall.

99

magnification

the extent to which an image is enlarged by a lense

100

resolution

the clarity of an object, which is a measure of how close two points can be and still be distinguished from each other

101

freeze fracturing

a process in which a frozen specimen is split under a vacuum and then shadowed with a platinum/carbon mix, resulting in a replica of the fractures surface

102

differential centrifugation

the process of separating a mixture by spinning it at a given speed, causing the heavier materials to drop to the bottom

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pellet

the material in the bottom of a centrifuge after differential centrifugation

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supernatant

the material that is not at the bottom of the centrifuge after differential centrifugation

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E face

in a freeze fractured cell membrane, this is the side closest to the exterior

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P face

in a freeze fractured cell membrane, this is the face closest to the cytoplasm

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nutrition (food)

consists of raw materials for growth and reproduction, and is a source of energy

108

autotrophic

means "self-making," and describes an organism that extracts energy from light or chemical bonds other than carbon-carbon bonds

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photosynthesis

the transformation of light energy into chemical energy stored in the bonds of carbon compounds such as sugars

110

heterotrophic

means "other-feeding," and describes an organism that extracts energy from carbon-carbon bonds formed in other organisms

111

microfilament

a component of the cytoskeleton that is 7nm in diameter, and is made up of twisted double strands of actin protein. It controls muscle contraction, the formation of the cleavage furrow in cell division, the movement of pseudopodia, and provides structural support to microvilli.

112

intermediate filament

a component of the cytoskeleton that is 8-12nm in diameter, consists of rope-like proteins, and makes up the nuclear lamina. Most of them belong to the keratin family.

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Microtubule

a component of the cytoskeleton that is 25nm in diameter, and is comprised of a spiral of protein subunits. It separates and moves chromosomes in cell division.