Chapter 3: Cell Biology Flashcards
cytology
the study of plant and animal cells
cell theory
all living things consist of cells, and cells arise from pre-existing cells
biogenesis
the theory that cells come from pre-existing cells
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.
Robert Hooke
in the 1600s, this person designed his own microscope to study microscopic subunits of life, which he named “cells”
Lorenz Oken
in 1805, he claimed that all organic beings originate from and consist of cells
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
Matthias Schleiden and Theodor Schwann
in 1838 and 1839 they unified cell theory to include plant and animal kingdoms
Rudolph Virchow
in 1858, he proposed that cells come from pre-existing cells, thus challenging the theory of spontaneous generation
Louis Pasteur
around 1858, he disproved spontaneous generation by boiling liquid in a straight-necked flask, and a swan-necked flask
micron
the unit of cell measure, equal to one millionth of a meter
membrane
a casing around the outside of a cell and it’s internal organelles that is made of a phospholipid bilayer
organelle
a structure in a eukaryotic cell that performs a specific function
ribosome
a part of the cell that makes proteins
chromosome
an organized collection of DNA
nucleoid
the area of DNA concentration in a prokaryotic cell
compartmentalization
the evolutionary process by which cells have developed organelles, suited for the purpose of increasing the efficiency of cell metabolism
cytoplasm
all of the contents of the cell, excluding the nucleus
cytosol
the liquid part of the cytoplasm
fluid mosaic model
the model for membrane structure which states that membranes are composed of a phospholipid bilayer that contains hydrophilic proteins
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
nucleolus
the site for ribosome synthesis
nuclear envelope
the porous double membrane that surrounds the nucleus, is embedded with ribosomal subunits, and has pore complexes lined with protein
nuclear lamina
the layer of structural proteins that hold the nucleus together
chromatin
a fiberous complex consisting of DNA and proteins in an uncondensed form (before DNA becomes rod-shaped)
histone
a group of five proteins, characterized by a high amount of positively charged amino acids, that is associated with DNA
lumen
the cavity inside any tubular part of a structure
cisternae or “faces”
the inner space of the endoplasmic reticulum, or flattened membrane sacs of the Golgi apparatus
synthesis
the formation of macromolecules
steroids
a versatile class of lipids that can be used in the formation of molecules like testosterone and cholesterol
vesicle
membrane-enclosed sacks which hold proteins
trans face
the part of the Golgi apparatus that lies closest to the cell’s plasma membrane
cis face
the part of the Golgi apparatus that lies closest to the nucleus or endoplasmic reticulum
docking molecules
a chemical “address label” that indicates a protein’s destination
membrane fusion
the merging of membranes to allow the movement of materials
exocytosis
the process of releasing materials through the plasma membrane
phagocytosis
the process of engulfing extracellular particles by surrounding them with extensions of the plasma membrane called “pseudopods”
tonoplast
the membrane of a water vacuole
osmosis
the process by which water moves from an area of greater concentration to an area of lesser concentration (hint: diffusion)
DNA homology
a similar genetic sequence due to common ancestry
glycoprotein
proteins that have a carbohydrate chain covalently linked to amino acid side chains
autophagy
“self-eating”, a form of organelle recycling by the decomposition of those organelles
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
contractile vacuole
a vacuole that collects excess water in the cytoplasm from osmosis, and expels it through a por in the plasma membrane
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
actin
a globular protein of which microfilaments are made
nanometer
one one-thousandth of a micron
microvilli
fingerlike extensions of the plasma membrane that increase the cell’s surface area
dystrophin
a protein that acts as an anchor for microfiliaments in muscle cells (hint: it can cause muscular dystrophy if it is defected)
dimer
a molecule that has two subunits
centrosome
a region of a eukaryotic cell where centrioles are located
centrioles
a pair of structures made from microtubules that enable chromosomal movement during cell division
flagella
relatively long structures made of microtubules that enable propulsion or movement of substances outside of the cell
cilia
short, hair-like projections made of microtubules that serve to propel organisms using a rowing motion
protein motor molecule
proteins that enable movement between microtubules (hint: dynein)
peptidoglycan
polymers of modified sugars cross-linked by short polypeptides (chains of amino acids)
chitin
a structural polysaccharide
cellulose
a structural polymer consisting of strands of glucose with alternate beta linkages
pectin
a molecule that binds cellulose molecules together in cell walls
plasmodesmata (singular, plasmodesma)
cytoplasmic channels that run through adjacent plant cells
selective permeability
describes the plasma membrane’s ability to allow certain molecules to pass through more easily than others
extracellular matrix
an integrated network of collagen, carbohydrates, and proteins that provides support and communication for animal cells
integrin
a class of plasma membrane proteins that have short glycoprotein receptors for binding to fibronectins
oligosaccharide
a short polysaccharide (fewer than 15 simple sugars) that plays a role in cell-cell recognition
epithelial cells
sheets of tightly packed cells that line organs and body cavities
tight junction
adjacent cell interactions that do not allow for any intercellular space between the cells
desmosomes
a type of cell junction, where “rivets” bind adjacent cells with keratin fibers
gap junctions
allow the transfer os small molecules between 2 adjacent cells
signal transduction
the ability to induce a reaction in another part of the cell
antigens
foreign molecules in an organism that ellicit an immune response
proteoglycans
a family of glycoproteins that have a core polypeptide with numberous carbohydrate chains attached
fibronectins
a family of glycoproteins consisting of two polypeptides linked by bonds
integral proteins or transmembranal proteins
proteins that are located inside the plasma membrane
peripheral proteins
proteins that are embedded into the surface of the plasma membrane
passive transport
the movement of molecules across the cell that does not require the expenditure of energy (ATP) (hint: diffusion)
diffusion
the movement of molecules from an area of high concentration to an area of low concentration (hint: entropy)
concentration gradient
the relative density of one chemical substance versus another
facilitated diffusion
the passive transport of molecules down a concentration gradient with the aid of special transport proteins located in the cell membrane
osmosis
the passage of water across a membrane from an area of high concentration to low concentration
solute
a substance dissolved in a solution
solvent
the dissolving agent of a solution
hypertonic
higher relative concentration of solute
hypotonic
lower relative concentration of solute
isotonic
same relative concentration of solute
turgid
the rigidness of a plant due to its water vacuoles being filled
flaccid
the lack of rigidity in a plant due to its water vacuoles being less full
plasmolysis
the pulling away of the plasma membrane from the cell wall due to excessive water loss
ATP
a molecule that stores energy in its phosphate bonds for later use. It is the “energy currency” of cells
active transport
the pumping of molecules against the concentration gradient (low –> high) with the expenditures of ATP
pumps
transmembranal proteins which move molecules and ions across the cell membrane
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.
cotransport
a coupled passage of two materials across a membrane
depolarization
a change in the voltage (charge difference) across the membrane resulting from the movement of Na+ through channels into the cell
resting potential
the voltage (charge difference) across the membrane of a cell while it is in an unexcited state
endocytosis
the import of materials to the cell by infolding of the flasma membrane
pinocytosis
also called “cell drinking,” the cell forms vesicles to take in fluid
receptor-mediated endocytosis
vesicles form only when molecules are hooked into the receptor proteins
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.
magnification
the extent to which an image is enlarged by a lense
resolution
the clarity of an object, which is a measure of how close two points can be and still be distinguished from each other
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
differential centrifugation
the process of separating a mixture by spinning it at a given speed, causing the heavier materials to drop to the bottom
pellet
the material in the bottom of a centrifuge after differential centrifugation
supernatant
the material that is not at the bottom of the centrifuge after differential centrifugation
E face
in a freeze fractured cell membrane, this is the side closest to the exterior
P face
in a freeze fractured cell membrane, this is the face closest to the cytoplasm
nutrition (food)
consists of raw materials for growth and reproduction, and is a source of energy
autotrophic
means “self-making,” and describes an organism that extracts energy from light or chemical bonds other than carbon-carbon bonds
photosynthesis
the transformation of light energy into chemical energy stored in the bonds of carbon compounds such as sugars
heterotrophic
means “other-feeding,” and describes an organism that extracts energy from carbon-carbon bonds formed in other organisms
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.
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.
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.
