Biol 1090 Flashcards
(117 cards)
1
Q
Enucleation
A
The process where cells (red blood cells) eject their nucleus.
2
Q
Differentiation
A
Cells specialize
3
Q
Miller Urey Experiment and key takeaways
A
Simulated conditions on early earth and found that that simple inorganic compounds in the presence of energy can form simple then later more complex organic compounds. Some of which are amino acids.
4
Q
Primordial Hypothesis
(Oparin’s and Haldane’s)
A
Commonly accepted conditions on primative earth favored chem rxns that synthesis more complex organic compounds from simpler inorganic precursors.
5
Q
Cell Theory
A
- All living organisms are composed of 1 or more cells
- Cell is the most basic unit of life (first 2 by Schleidon and Shwann)
- All cells come from cells (Virchow)
6
Q
Basic Properties of Cells
A
- Highly complex and organized
- Activity controlled by genetic programing
- Can reproduce
- Assimilate and Use energy
- Carry out chem rxns (enzymes)
- Engage in mechanical activities (engulf)
- Respond to Stimuli
- Capable of self regulation
- Evolve
7
Q
Prokaryotes
A
Bacteria and Archaea
- no defines nucleus or organelles
- single celled orgs
- 1-10 nanometers
- small ribosomes
- reproduce asexually
- genetic material in nucleoid
- DNA is circular fashion (plasmid)
8
Q
Eukaryotes
A
Fungi, plants, animals, protozoa
- multicellular organisms
- 10-100 nanometers
- nucleus and organelles
- ribosomes are large
- genetic material in nuclear compartment (chsomes)
9
Q
Eukaryotes - Animals
A
- lysosomes
- microvilli
10
Q
Eukaryotes - Plants
A
- cell walls
- vacuoles (turgor pressure)
- chloroplasts
- plasmodesmata (connect neighboring plant cells)
11
Q
Virus Genome
A
DNA or RNA
12
Q
Virus
A
macromolecular packages that can function and reproduce only with living cells.
13
Q
Virion
A
Inanimate particle outside cells
14
Q
Virus Baltimore Classification
A
Retrovirus - RNA type, can insert a copy of its genome into a DNA host cell
Hepadnavirus - DNA type
Filovirus - single stranded negative sense DNA
Adenovirus - resperatory illness
Bacteriophage - Infects and replicates within bacteria and archaea
15
Q
Negative Sense RNA
A
must be transcribed to mRNA
16
Q
Positive Sense RNA
A
can be directly translated into proteins
17
Q
Host Range
A
Narrow - infect cells in just a specific part of humans
Wide - (rabies) can infect humans, bats, foxes, racoons
18
Q
Non-lytic
A
Viral DNA or RNA inserts into host genome (provirus). Infected cell can survive often with impaired function
19
Q
Lytic
A
Production of virus particles ruptures and kills the cell
20
Q
Monopartite
A
Entire genome occupies one nucleic acid molecule
21
Q
Multipartite
A
Genome occupies several nucleic acid segments
22
Q
RNA Vaccines
A
Tricking body cells into producing fragments of a virus (antigens).
Can be made more effective by incorporating instructions for a replicase (to make more antigens)
23
Q
HIV
A
Retrovirus - inserts copy of genome into DNA host cell (stays in DNA forever_
24
Q
Hepadnavirus
A
Hepatitis B
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Filovirus
Ebola
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Adenovirus
Cold and Flu
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Bacteriophage
Attack bacteria and archaea
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Slime molds
- eukaryotic single celled organisms
- reproduce with spores
- many nuclei
- can move around and respond to environment
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Virus (Yes) can/are
- complex and organized
- controlled by genetic programing
- reproduce (yes and no)
- evolve
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Only in plant cells
- chloroplasts
- cell wall
- vacuoles
- plasmodesmata
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Only in animal cells
- lysosomes
- microvilli
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Phospholipid bilayer properties
- trilaminar (lipid bilayer)
- made of lipids (phospholipids)
- hydrophobic and hydrophilic parts (phospholipids are amphipathic)
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Phospholipids Structures/patterns
Micelle - circular no lumen
Liposome - circular two layers lumen
Bilayer sheet - (trilaminar)
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Phospholipids (structure)
- 2 fatty acyl molecules (esterified 1,2)
- glycerol
- phosphate (3 by phosphate residue)
- variable portion of head group (choline, serine, inositol)
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Sphingolipid
- glycerol replaced with sphingosine
- amide linked to fatty acid and phosphate group
enriched in nervous system (signal transduction + cell recognition)
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Fluid mosaic includes
- phospholipids
- peripheral, transmembrane proteins
- cholesterol
-
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Lipid Rafts
Portions of the bilayer that include a higher concentration of specific proteins like sphingolipids or cholesterol
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Types of membrane proteins
- integral
- peripheral
- lipid anchored
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Integral proteins and functions
- transport of nutrients and ions
- cell-cell communication
- attachment
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How can temperature affect lipid structure
- denaturation of lipids
- exchange of lipid chains
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Transmembrane protein structure
- hydrophobic portion within bilayer (alpha helices) (transmembrane protein domain)
-
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TM4SFs Tetraspanins
- 4 alpha helices
- 2 extracellular domains
cell, adhesion, motility, proliferation
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Simple Diffusion
- passive
- non-mediated
- will concentration gradient (down)
- small uncharged particles (CO2, O2)
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Diffusion through Channel
- passive
- non-mediated
- through channels
- small charged particles
Na+, K+, Ca2+, Cl-
- down concentration gradient
- channels are selective
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Facilitated Diffusion
- passive
- mediated
- substrate binds directly to facilitative transporter
- change in conformation allows compound to be released on other side
- down concentration gradient
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Active Transport
- active
- mediated
- substrate binds to active transporter
- hydrolysis of an ATP molecule allows molecules to be released on other side
- against gradient
Na+/K+ transporter (maintains action potential)
- 3Na+ out, 2K+ in for each ATP
- against gradient
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Ion Channels
Allows channels to respond to stimuli
1) voltage-gated (Na+, K+)
- respond to changes in charge (action potential)
2) Ligand-gated (acetylcholine)
- responds to binding of a specific molecule on surface of ligand
- causes a conformational change to channel
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Ways of targeting ion channels
TTX - Na+ channel blocker
- binds to voltage-gated Na+ channels and blocks passage of Na+ (inhibits firing of action potentials)
Curare - competitive antagonist
- occupies same position on receptor and causes no response
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Symporter
- rely on chem gradient of another molecule to push a compound up its concentration gradient
- Na+ glucose symporter (2Na+ 1 glucose) (Na+ is with gradient into cell)
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Antiporter
- concentration gradient of one molecule is used to transfer a second molecule in opposite direction
- Na+/H+ exchanger
- Na+ into cell, H+ out of cell
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Cell Structure (hypertonic, hypotonic, isotonic)
Hypertonic - more solute out of cell, shrink
Isotonic - normal
Hypotonic - more solute in cell, burst/lysed
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Signal Transduction
- binding of ligand to a receptor
- signal transduction via second messenger (cAMP, calcium, G-protein)
- cellular response
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Glycogenolysis
epinephrin converting glycogen in liver to glucose
- glycogenin(acts as a primer to polymerize first glucose molecule) surrounded by glucose units
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Anchor Proteins
- interact with components of the ECM
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ECM (extracellular matrix) roles
Abundant in connective tissues
- cell adherence
- communication between cells - - cell shape, mechanical support, structural integrity
- serves as barrier, filters out some particles
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ECM components
- proteins (collagen)
- glycoproteins (laminin, fibronectin)
- proteoglycans (proteins with chains of polysaccharides)
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Plant Cell Walls (ECM)
- cellulose, hemicellulose, pectin, proteins
- structural support
- protection
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Theory of Endosymbiosis and Evidence
- organelles from euk cells with two membranes (mit, chlo) are formerly free living prokaryotes taken inside one another in endosymbiosis
Evidence:
1) binary fission of mitochondria and plastids
2) circular DNA in organelles like bacteria
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Aerobic cellular respiration
Converting glucose to energy (stored in ATP) in the presence of oxygen
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Outer Mitochondrial Membrane
- contains many enzymes (monoamine oxidases)
- has porins (for ATP, sucrose)
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Inner Mitochondrial Membrane
- high protein to lipid ratio (3:1)
- double layers fold called cristae
- rich in cardiolipin - phospholipid (optimal membrane function)
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Mitochondrial Matrix Makeup
Matrix - high protein content, gel like consistency, contains mitochondrial ribosomes and DNA
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Substrate level phosphorylation
*specific to glycolysis
- hydrolysis rxns release enough energy to phosphorylate ADP to ATP
12% or ATP
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Oxidative phosphorylation
- chemical energy of organic molecules is transferred first to electron carriers to create an electrochemical gradient to power ATP synthesis
88% of ATP
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Electron Carriers
Oxidized - accepts e
Reduced - donates e
NAD+, NADH
FAD, FADH2
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Photosynthesis
building carbs using energy from sunlight and CO2
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Light-Dependent Reactions
- occurs in thylakoid membranes
- chlorophyll is light harvesting complex
-e enters ETC
H+ pumped into thylakoid lumen
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Light-Independent Reactions
Calvin Cycle
- occurs in stroma
- ATP and NADPH made in light reaction used to make CH2O
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Apoptosis
Death of a cell in a coordinated sequence of events
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Roles of Apoptosis
bmp - expression of non-active MnpReceptors in duck embryonic limbs results in webbed feet (reduces apoptosis)
Plants - uses apoptosis to cause fenestrated leaves
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Apoptotic Cells (characteristics)
- shrinkage
- blebbing (bulging of plasma membrane)
- fragmentation of DNA or nucleus
- engulfment by phagocytosis
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Cytochrome C
causes production of caspases
- disrupts cell adhesion
- destroy lamins
- breaks down cytoskeleton
- activates DNase
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Apoptosis and Diseases
too little - cancer
too much - alzheimers, parkinsons
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Cytoplasmic Endomembrane system
- ER
- endosomal transport vesicles
- golgi complex
- lysosomes
- vacuoles
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Secreted Proteins (mucin)
- synthesized in rough ER
- processed in the ER
- processed in golgi
- concentrated in vesicles
- delivered to plasma membrane for secretion
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GFP Tracking
Green Fluorescent Protein from Jellyfish
- can be fused with other cellular proteins
- can be expressed in cells when fused
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Vesicular Transport
uses transport vesicles
- movement - uses cytoskeleton and motor proteins (anterograde or retrograde)
- tethering - via RAB proteins
- docking - uses SNARE proteins (provides energy for fusion)
- fusion - fuses vesicle and target membrane
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Exocytosis + Endocytosis
Exocytosis - e.g organelle to plasma membrane
e.g secretion of neurotransmitters
Endocytosis - e.g PM to organelle
e.g Activity-dependent internalization pf AMPA receptors
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Rough ER
- have ribosomes
- protein processing
- synthesis of membrane phospholipids
- glycosylation of proteins
- protein folding and quality control (chaperone)
- Protein synthesis, modification, and transport
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Smooth ER
-no ribosomes
- lipid synthesis
- production of steroid hormones
- detoxification
- sequestration (storage of Ca2+)
Ca2+ in cytosol is:
- bound by Ca2+ binding proteins
- forced through pumps and transporters
- or sequestered (in sinks)
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Where are proteins translated (free vs. bound)
- free - cytosolic prots, peripheral membrane prots, prots to nucleus, mitochondria, peroxisomes, or chloroplasts
- bound - secreted prots, integral membrane prots, soluble prots associated with lumen of endomembrane system
* all protein translation begins on free ribosomes not associated with the ER
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Signal Sequence
to target ribosomes to ER membrane
- amino terminus
- contains consecutive hydrophobic amino acids
- directs synthesis to ER compartment
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Endocytic Pathways of Protein Sorting
1) protein retained in ER
2) transported to golgi (futher modifications), and delivered to distal parts of secretory pathway (maybe outside the cell)
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Zellweger Syndrome
- no peroxisomes made (mutation)
- autosomal recessive
- brain development defects
- hypomyelination
- apnea
- abnormal renal function
- does not survive a year
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Cystic Fibrosis
- mutation in CFTR
- deletion of 3 nucleotides
- loss in phenylalanine (508)
- proteins degraded in ER fail to reach surface
OR
- CFTR transporter affected
- cannot produce proper lubricating fluid in lungs
- sticky lung
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ER to Golgi pathway
Proximal to distal
Cis to Medial to Trans
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Golgi Complex Structure
- smoot flattened cisternae
- about 8 cisternae per stack
- few to thousand of stacks per cell
- curved
- polarity
- cisternae biochemically unique (different enzymes to modify)
- membrane supported by protein skeleton (actin, spectrin)
- scaffold linked to motor proteins that direct movement of vesicles into and out of golgi
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CGN and TGN
CGN - sorting station (should proteins continue on to next golgi or back to ER)
TGN - sorts proteins into different types of vesicles (diff destinations)
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Golgi Function
Processing plant
- sorts
- modifies
- ships (vesicles)
- synthesis of polysaccharides and modification of proteins and lipids
(glycosylation and proteolytic modification)
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Coat Proteins
COPI (retrograde/reverse), COPII (anterograde/forward)
- helps form vesicles
- helps select "cargo"
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Regulated and constitutive secretory pathways
Constitutive (continual) - mucin secretion
Regulated - insulin and neurotransmitter release
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Lysosomes
- digestive organelles
- 25 nm to 1 (weird u)m
- internal pH or 4.6 (proton pump or H+-ATPase regulated)
- contains hydrolytic enzymes (acid hydrolases)
- membrane has glycosylated proteins that act as a protective lining against acidic lumen
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Coatomers
Clathrin and AP complex - AP/clathrin coated vesicles move from TGN to other vesicles and help form endocytic vesicles to move from PM to endo/lysosomes
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Autophagy
normal dissembly of unecessary or disfunctional cell components (organelle turnover) by lysosomes
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Degredation (lysosomes)
recycling of PM components and destroying pathogens (only in phagocytic cells)
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Lysosome Functions
Autophagy and degredation of internalized material
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Plant Vacuoles
Intracellular digestion - regulate cytoplasmic pH (pH about 5) acid hydrolases
- sequestration of toxic ions
Mechanical support - regulate turgor
Storage - store amino acids, sugar, CO2 in form of malate, and chemical storage (anthocyanin)
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Cytoskeleton Function
1) structural support
2) spatial organization within cells
3) intracellular transport
4) contractility and motility
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Components of the Cytoskeleton
- Microfilaments (MF)
- Microtubules (MT)
- Intermediate filaments (I)
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Microtubules (MT)
Polymer of alpha-tubulin and beta-tubulin
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Types of Microtubules
Axonemal MT:
- highly organized and stable
- part of structures involves in cell movement
Cytoplasmic MT:
- loosely organized and unstable
- located in cytosol
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MT assembly/disassembly
- rapid turnover of MTs in vivo
- shrinking occurs rapidly at plus end (catastrophe)
- formation if MT is regulated
- MTOC is central site of MT assembly
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MT Proteins (MAPs)
- modulate assembly (MAP2 or Tau)
- mediate interaction with other cells (vesicles/organelles)
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Classes of MAPs
1) Non Motor MAPs - control MT organization in cytosol (Tau)
2) Motor MAPs - kinesin and dynein
- use ATP to generate force
- can move material along MT tract
- can generate slide force between MTs
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Non motor MAPs
Control MT organization in cytosol
- stabilize MTs
- stimulate assembly
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Defects in Tau
- cause neurofibrillary tangles
- cause alzheimer's disease
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Motor MAPs
- power intracellular transport
- kinesin (+end directed)
- dynein (- end directed)
They move along MT
- can generate a sliding force btw MTs
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Kinesin and i Dynein in Zebrafish
- survival mechanism
- in dark melanin granules are dispersed outward by kinesin (appears darker)
- in light melanin granules are aggregated forward by dynein (lightly coloured)
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MTOC
Central site of MT assembly
- only in euk cells
2 types:
1) basal bodies (cilia, flagella)
2) centrosomes (spindle formation)
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Actin Molecules
- central component of MFs
- monomer: G-actin or globular
- polymer: F-actin or fibrous
Actin binds and slowly hydrolyzes ATP
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Intermediate Filaments
- arrangement of non fibrous alpha helical proteins
- non polar
provides structural support and mechanical strength
- stable compared to MTs and MFs
- not used in transport
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Microfilaments
- double helix of actin monomers
- maintains cell shape
- cell movement
- vesicle transport
- muscle contraction
- cytokinesis
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Actin Associated Motor Proteins
Myosins (motor proteins):
- primarily move towards the + end of MF
1) conventional myosins: type 1, for muscle contraction
2) unconventional myosins: type 1 and type III-XVIII
- generate force
- contribute to motility in non muscle cells (lamellipodium/push)
(pull)
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Functions of the Nucleus
- storage repair and replication of genetic material
- expression if genetic material (transcription, RNA splicing)
- ribosome biosynthesis
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Nuclear Lamina
- made of lamins (intermediate filaments) only found in animals cells (the lamin)
- bound to inner membrane
- provide structural support for nuclear envelope
- attachment sites for chromatin
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Nuclear Pore complex
- composed of NUPs (nucleoporins)
- octagonal symmetry/basket like
- projects into cytoplasm and nucleoplasm
Transport:
- passive: under 40 kDA, rapid, 100 molecules/minute/pore
- regulated: larger molecules, slow, 6 molecules/minute/pore
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