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105 Cards in this Set
- Front
- Back
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Name 4 of the basic properties of cells
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-self-regulation
-evolve -acquire and utilize energy -maintain and utilize energy -reproduce -genetic program -enzyme-catalyzed chemical reactions |
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Viruses
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non-cellular macromolecular packages that can function and reproduce only within living cells.
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virion
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a virus existing as a particle (not within a living host cell)
-they are unable to reproduce and metabolize |
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what is a virion composed of?
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-small amount of genetic material
-a capsid (capsule surrounding the material) |
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What is determined by the type of protein found on the viruses surface?
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defines the cell types the virus can infect.
-protein is able to bind only to a particular surface component of it's host cell |
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Two types of viral infection:
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1) viral arrests the normal synthetic activities of the host cell and redirects the cell to manufacture viral nucleic acids and proteins. Eventually causes infected cell to rupture.
2)Does not lead to the death of the host cell but instead integrates viral DNA known as a provirus. |
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Benefit of compartmentalization of Biological membranes:
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-allows specialized activities to proceed independently of one another
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Signal Transduction
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information is carried by extracellular messenger molecules is translated into changes that occur inside of a cell
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Receptors combine with specific _______
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ligands
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Name Three qualities of plasma membrane:
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1)compartmentalization
2)selectively permeable membrane 3)scaffold for biochemical activites 4)responding to external siganls 5)intercellular interaction 6) energy transduction |
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Energy transduction refers to
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energy being converted from one form to another
-ex chemical energy from carbohydrates and fats to ATP |
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Fluid mosaic model consists of
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-lipid bilayer
-proteins |
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The three types of proteins are:
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-integral
-peripheral -lipid anchored |
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amphipathic means
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contain both hydrophylic and hydrophobic compartments
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Integral proteins
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-transmembrane proteins, they pass entirely through the lipid bilayer
-domains on both extracellular and cytoplasmic sides of the cell |
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Peripheral proteins
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-located completely outside the bilayer
-attached to the membrane by non-covalent bonds |
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lipid-anchored proteins
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-located outside the bilayer
-covalently linked to a lipid molecule situated within the bilayer. |
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Biological membranes are ____
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Asymmetrical
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Outer leaflet of membrane contains
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glycolipids and glycoproteins (lipids and proteins with carbohydrates attached)
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membrane fluidity is determined by:
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-the nature of the lipids
-the temperature |
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Unsaturated ______ fluidity
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-increases
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cooling _____ fluidity
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decreases
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a) warming - __________ structure
b) cooling - _________ structure |
a) liquid crystal
b) crystalline gel |
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In regards to membrane fluidity, how do cells respond to changing conditions
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-by altering the types of phospholipids they are made of (saturated or unsaturated)
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•in response to changes in temperature*, lipid
composition of membranes can be changed by: |
1) desaturation of lipids
2) exchange of lipid chains |
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Lipid Rafts
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-microdomains within a membrane that possess decreased fluidity due to the presence of cholesterol, glycolipids, and phospholipids containing saturated fatty acids.
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GPI
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(glycosyl-phosphatdyinositol)
-Tend to accumulate in rafts |
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Transition temperature
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temperature at which the state of the lipid bilayer changes
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How do lipids move within the leaflet of a biological membrane?
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- they move laterally and with ease.
BUT lipid movement to a different leaflet is much slower |
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1. Which of the following statements accurately
describes the crystalline gel state of a biological membrane? A)it is found above a transition temperature B)it is found below a transition temperature C) it is the preferred state in membranes D)its lipids are not highly ordered E) it does not depend on the type of lipid |
B) when temperature is low it is said to be crystalline gel
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Name 4 basic mechanisms by which solute
molecules move across membranes |
1 simple diffusion
2 diffusion through a channel 3 facilitated diffusion 4 active transport |
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Which of the 4 mechanisms of moving solutes across membrane are passive?
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simple diffusion
diffusion through a channel facilitated diffusion |
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which of the 4 mechanisms of moving solutes across a membrane require a transporter?
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facilitated diffusion "facilitative tranporter"
active transport "Active transporter" |
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3 types of channels for diffusion through a channel
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1) voltage-gated
2) ligand- gated 3) mechano - gated |
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Voltage-gated channels respond to
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difference in ionic change on the two sides of the membrane
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Ligand-gated channels respond to
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binding of a specific molecule (ligand-receptor) *** CFTR is an example of this**
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Active Transport
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Energy requiring process where a substance minds to a transmembrane protein, changing its conformation, to allow passage of a substance
-goes against concentration gradient |
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Glycocalyx
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assembly of carbohydrate groups attached to proteins and lipids on the outside of the plasma membrane
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ECM
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extracellular matrix
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cell-ECM interactions define
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tissue and organ function
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proteoglycans
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proteins with chains of polysaccharides
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Plant cell walls are composed of
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cellulose, hemicellulose, pectin, and proteins
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cells bind to ECM via _____ and this influences cell survival and cellular activities
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integrins
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cytosol
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-protein synthesis, metabolic pathways
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lysosomes
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degradation of cellular material
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endosomes
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sorting, recycling
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peroxisomes
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oxidation of toxic molecules
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mitochondria undergo fusion and fission T or F
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T
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The two membranes of mitochondria
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-outer mitochondrial membrane (OMM)
-inner mitochondrial membrane (IMM) |
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Where are porins found? What is the
function of these proteins ? |
-porins are found in the OMM.
-They are integral membrane proteins and therefore allow the passage of large molecules |
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The IMM forms double-layer folds/sheets known as
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cristae
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Cristae benefits
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-contain the machinery necessary for oxidative phosphorylation (ATP synthesis)
-increase membrane surface area |
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Aqueous compartments of the mitochondria
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1) inter-membrane space
2)matrix |
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The mitochondrial matrix contains
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-mitochondrial ribosomes
-mitochondrial DNA |
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The 2 Steps in oxidative phophorylation
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1) electron chain and proton pumping
2)proton movement down electrochemical gradient powers ATP synthesis |
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electron transport chain in the _____ mitochondrial membrane
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inner
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Describe step 1 in oxidative phosphorylation
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-high-energy electrons are passed from FADH2 and NADH
-Participate in energy releasing reactions along electron transport chain. -move protons outward across IMM -energy released is stored in the form of electrochemical gradient across the membrane |
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Describe step 2 in oxidative phosphorylation
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-controlled movement of protons back across the membrane through an ATP synthesizing enzyme.
-This provided energy allows the phosphorylation of ADP to ATP. |
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Apoptosis
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-programmed cell death
-coordinated sequence of events leads the death of a cell |
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Apoptosis can be characterized by:
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-shrinkage of cell
-fragmentation of chromatin -blebbing on the surface -engulfment by phagocytosis -loss of attachment to neighbors |
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What causes a cell to be committed to apoptosis?
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Proapoptotic proteins stimulate mitochondria to leak proteins.
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Collagen is produced where?
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in the biosynthetic secretory system
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polar
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membranes are asymmetrical because they perform different functions
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The outer nuclear membrane is continuous with
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The membrane of the endoplasmic reticulum
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GFP
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green fluorescent protein
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4 steps of vesicular transport
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1) movement of vesicle
2) tethering vesicle to target 3) docking of vesicle to target 4) fusing of vesicle and target |
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Protein used in tethering?
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Rabs
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Protein used in docking?
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SNAREs
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lumen
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interior of the endoplasmic reticulum
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What is the difference between the smooth and rough ER?
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the rough ER is covered in bound ribosomes where the smooth ER has none
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Sarcoplasmic reticulum
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is the smooth endoplasmic reticulum of skeletal and muscular cells.
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The production of steroid hormones and detoxification of liver cells occurs in the
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smooth endoplasmic reticulum
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The folding and glycosylation of proteins takes place where?
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the rough endoplasmic reticulum
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ribosomes synthesize polypeptides from ______
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mRNA
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All protein translation begins on ____ _________
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free ribosomes
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How is the site of translation determined?
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a "signal sequence" in the protein being translated
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Where is the signal sequence in a protein ?
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amino-terminus
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Once a protein enters the ER, it is committed to being discreted by the cell.
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False
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ERGIC
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Endoplasmic Reticulum-Golgi intermediate compartment
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Material moves from
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the ER to the Golgi to the Plasma membranes and other compartments.
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how many cisternae are there per stack in the golgi complex?
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less than 8 per stack
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What is the composition of the golgi complex?
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cis golgi network
cis cisternae medial cisternae trans cisternae trans golgi network |
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All the cisternae of the golgi contain the same enzymes.
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False. They contain different enzymes, the proteins are modified stepwise as they move through the golgi complex
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Fully modified proteins are exported from the _____ ______ and then enter the ___ _____ ______
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trans cisterna
trans golgi network |
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The protein coat on transport vesicles serves two purposes. What are they?
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1) they help to form the vesicle
2)helps select cargo inside/on the vesicle |
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COPI proteins move in the _______ direction.
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retrograde, able to bring cargo back from the distal parts of the golgi (TGN)
this may be because cargo needs to be refined in golgi |
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Golgi enzyme is being transported from trans-Golgi cisterna to a cis cisterna. What is it being transferred by?
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COPI protein
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During vesicle trafficking, which of the following
proteins functions most proximal to fusion of the vesicle and target membranes? A) Rabs B) SNAREs C) COPI D) COPII E) myosin |
B) SNAREs do. they occur at the docking stage
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7. What is a lipofuscin granule?
A)a form of secretory granule B)the product of lysosomal fusion with the PM C)an autophagolysosome D)a residual body retained within a cell E) none of the above |
D)
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tonoblast
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the vacuolar membrane of a plant vacuole
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What are the structural components of the cytoskeleton?
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1)microtubules
2)actin microfilaments 3)intermediate filaments |
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What is the largest sized skeletal element?
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microtubules
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Microtubules are a polymer of what protein?
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tubulin
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What are the two major types of microtubules?
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axonemal and cytoplasmic
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In microtubules heterodimers of tubulin assemble into long __________
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protofilaments
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Central site of microtubule assembly is known as
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MTOC
Microtubule organizing center **occurs at centrosome** |
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What are the two classes of MAPs (microtubule associated proteins)
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Motor Maps
-kinesin and dynein (move material) Non-motor maps -control organization in cytosol |
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Kinesin is ___ end directed
Dynein is ____ end directed |
Kinesin is plus end directed
Dynein is minus end directed |
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What positions mitochondria within the cell?
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kinesin
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epithelial cells are an example of what class of intermediate filaments?
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I and II
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Intermediate filaments
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provide structural support.
-they are exclusive to multicellular organisms |
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dimer structures are _____
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polar
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Assembled filaments are ________
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non polar
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Actin microfilaments are polymers of the protein _____
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actin
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What is the difference between G-actin and F-actin?
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G-actin is globular
-G actin is an individual molecule while F-actin is a polymerized microfilament |
