Midterm 2 Flashcards
What does it take to make a cell? 
- Information (dna & rna)
- Chemistry
- Compartments
Eunucleation 
Mechanism by which maturing red blood cells reject the nucleus during differentiation 
Differentiation
The process of developed mint during which cells of multicellular organisms become specialized information, is important to make cell and create different specific cell types 
Miller Urey experiment
In 1952 chemical experiment that stimulated conditions thought to exist on early earths, and to test the chemical origin of life under those conditions 
Operons and haldaries primordial soup hypothesis
Putative conditions on primitive earth, favourite chemical reactions that made more complex organic compounds from simpler organic compounds 
Abiogenesis 
Chemical origin of life, organic compounds plus energy in the form of electricity and UV produce simple organic compounds 
First group of intermediate products from abiogenesis 
Formaldehyde, hydrogen cyanide 
Second group of intermediate products in abiogenesis 
Urea, formic acid and amino acids 
Conclusion of abiogenesis experiment 
Amino acids can be generated in conditions to mimic those of earlier during later experiments showing that other chemical reactions can generate simple sugars. The base is found in nucleotides and lipids needed to form primitive membranes. 
 Compartments
Single or double lipid layer, membrane, examples, including mitochondria, chloroplast cell nucleus 
Roles of compartments 
Establish physical boundaries that enable cells to carry a different metabolic activities, generate a micro environment, especially temporarily regulate biological process 
Who discovered sell an early microscope
Robert Hooke 
The cell theory 
By Matthias, Jacob show Leiden and Theodore Schwann
1. All living organisms made of one or more cells
2. Cell is the most basic unit of life.
3. All cells arise, only from pre-existing cells 
Basic properties of cells 
- Highly complex and organized
- Activity controlled by a genetic program.
- Can’t reproduce and make copies of themselves
- Assimilate and utilize energy
- Carry out many chemical reactions
- Engage in mechanical activities.
- Respond to stimuli
- Capable of self regulation,
- Evolve 

Prokaryotes
Include bacteria, and archaea
were the only form of life, millions of years ago
single celled organism
1 to 10 µm
have no nucleus or organelles ribosomes are present but small reproduce asexually
genetic material is found in nucleotide in a circular fashion plasmid 
Eukaryotes 
Protozoa are single celled, eukaryotes, fungi, plants, and animals
Eukaryotic cells are found in multicellular organisms, but can be unicellular to
size is 10 to 100 µm
has a nucleus and organelles ribosomes are large
genetic materials found in nuclear compartment and arranged as chromosomes 
Difference btw Animal and plant cells 
Animal cells have lysosomes and microvilli and plant cells do not
Plant cells have cell walls, vacuoles, chloroplast, and plasmodesmata and animal cells do not 
Viruses 
macromolecular packages that function and only reproduce within living cells/host are not considered to be cells or alive but have four of the nine basic properties of cells
What 4 properties of cells do viruses have? 
They are complex evolve, genetic controlled, can reproduce (only within a host)
Virion
A virus that exists outside of a host made up of small amount of DNA and RNA that encodes hundreds of genes 
Bacteriophage 
Virus that infects and replicate within bacteria and archaea has a capsid head DNA a collar sheet and is the Victor cookie monster robot has a spikes, a tail and a base plate 
Two main types of viral infection 
Lytic and nonlytic 
Lytic
Production of virus particles ruptures and kills cells. Example influenza. 
Non-lytic 
Also known as integrative, or lysogenic, infected cells can survive often with impaired function 
Viral dna is inserted in host genome
Provirus
Viral dna is inserted in host genome
How do viruses work? 
Once inside a cell viruses hijack cellular machinery to synthesize, nucleic, acids and proteins, as parts are than assembled to make new virus particles to infect other cells 
Virus life cycles
1- virions attach to host cell
2- virion penetrates cell and its dna is uncoiled
3- early transcription- enzymes are synthesized
4- late transcription- dna is replicated
5- late transcription - capsid proteins are synthesized
6- vitions mature
7- virions are released
5 genes encoded by rna genome
Phosphoprotein, matrix protein, glycoprotein and viral rna polymerase
How do rna vaccines work
By tricking the body cells into producing a fragment of a virus, an antigen from an RNA template
Strategy to make homemade vaccines at a lower dose 
In corporate instructions for making replicase, which can make lots of copies of RNA template producing antigens 
Function of plasma membranes 
1- define cell boundary
2- define enclose compartments
3- control movement of material into and out of cell
4- allow response to external stimuli
5- enable interactions between cells
6- provide scaffolds for biochemical activities
Structure of plasma membrane
Trilaminar
Made of phospholipid bilayer
6nm thick
Hydrophilic phospholipid heads exposed to either fluid and hydrophobic tails are buried
Amphipathic mlc
Mlc that have both hydrophobic (non-polar) and hydrophilic (polar) regions
Ex. Phospholipids
Where does Phospholipid synthesis occur
Occurs in the cytosol and outer endoplasmic reticulum membrane, which is all the molecular machinery for synthesis and distribution multi step process 
Steps of phospholipid synthesis 
1- in cytosine fatty acids are attached by attachment of coA mlc
2- the activated fatty acids bond to glycerophosphaye and are inserted into cytosolic leaflet
3- the phosphate is removed by a phosphate enzyme
4- choline already linked to phosphate is attached via choline phosphotransferase
5- flippase transfer some of phospholipids to other leaflet
Choline
Head group of phospholipid
Choline phosphotransferase
Integral protein/enzyme that gives head to phospholipid
The fluid mosaic model of biological membranes 
Proposed by Seymour, Jonathan Sigur and Garth Nicholson in 1972
Plasma membrane is viewed as a two dimensional liquid that restricts the diffusion of membrane components dim, different proteins are embedded in the phospholipid by layer. Components are mobile and components can interact 
Dynamics of plasma membrane 
Lipid movement
Lipids move easily within leaflet, but the lipid movement from one leaflet to another, is difficult and slow 
Dynamics of plasma, membrane protein, movement 
Membrane proteins diffuse within the bilayer
movement of proteins is restricted rapid movement especially limited. Long range. Diffusion is slow. 
Fryc edidn experiment
Fused, blue mouse surface, pro Tien, cell and green human surface broken sell through forced sell diffusion, and after a short period of time the surface proteins of both cells defuse around the unified membrane and mingle rather than being locked in original location 
Properties of membranes 
Membranes are approximately 6 nm thick. They are stable, flexible and capable of self assembly.
Three classes of membrane proteins 
 Integral
Peripheral
Lipid anchored 
Integral proteins 
Membrane proteins, span, lipid bilayer 
Integral proteins functions 
One transport of nutrients and ions
2. Cell to cell communication gap junction,
3. Attachment, example skin cells attaching to body 
Difference between outer leaflet and inner leaflet 
Biological membranes are asymmetrical
Outer- glycolypids and glycoproteins
Less dynamic
Inner more dynamic, less cholesterol
Involved in vesicle formation
Fluidity of biological membranes
Temperature is an important variable of fluidity fluidity is crucial to function 
Warming of membrane,  
Increases fluidity liquid crystal 
Cooling of membrane 
Decreases fluidity 
 Unsaturated lipids
Increase fluidity 
Saturated lipids 
Reduce fluidity 
How can lipid composition of membranes be changed in response to temperature changes? 
One. Desaturation of lipids
To exchange of lipid chains . 
Why is balance between ordered rigid structure and disordered structure important 
Allows mechanical support and flexibility, membrane assembly, and modification and dynamic interactions between membrane components. Example proteins can come together reversibly 
How does cholesterol affect fluidity of biological membrane? 
Cholesterol modulate membrane, fluidity it, accessible by directional regulator of membrane, fluidity because high temperatures, it stabilizes the membrane and raises the melting point, whereas as low temperature is it in circulates between the phospholipids, and prevents them from clustering together and stiffening
It ultra the packaging and flexibility of lipids if added to a liquid crystal membrane, fluidity decreases, if added to a crystalline gel, membrane fluidity increases 
Transmembrane protein domain 
A peptide sequence that is largely hydrophobic and charged and spins across the plasma membrane
It permanently attaches the protein to the plasma membrane

What is the most common protein structure element crossing biological membranes? 
The alpha Helice
What are the nine amino acids with hydrophobic side chain? 
Lysing alanine, failing leucine Prolene phenylalanine methionine and tryptophan 
Tetraspanins
A family of membrane proteins found in all multicellular eukaryotes 
Have four transmembrane, alpha helices, and two extra cellular domains, one short, and one longer some Tetris pendants can be glycosylated on extracellular Loop 
Function of tetraspanins
Play a role in adhesion, motility, proliferation and more 
Four basic mechanisms of moving molecules across membranes 
1) simple diffusion (passive)
2) diffusion through a channel (passive)
3) facilitated diffusion (passive)
4) active transport (active)
Simple diffusion 
Is down a concentration gradient, (high concentration to low concentration)
works for very small on charge molecules like oxygen and carbon dioxide  (not water)
Diffusion through channels 
A form of passive transport,
effective for small charged molecules ions like Na+ K+ Ca2+ Cl-
Ions move down a concentration gradient
channels are selective only allowing particular ions to pass,
formed by integral membrane proteins,
typically subunits that line an aqueous pore
Ion channels
Can be open or closed important to provide channel with ability to respond to different stimuli. Example neurotransmitters can be turned on or off two types voltage gated, and ligand gated.
Two types of ion channels
Voltage gated and ligand gated
Voltage gated ion channel
 Example, sodium and potassium ion channels some channels can respond to changes in charge across membrane
Ligand gated channels 
Ion channels like acetylcholines receptor that respond to finding of specific molecule on its surface a ligand binding of a ligand produces confirmational change in structure of receptor/channel
Ligand
Molecule that binds to an ion channel to change its confirmation
Toxins, targeting ion channels
Tetroxin, TTX
Curare
Tetroxin
is a potent neurotoxin from puffer fish that blocks sodium ion channel and inhibits the firing of action potential by neurons prevents nervous system from carrying messages to muscles, including the diaphragm which causes death via respiratory failure
Curare
 Is a toxin targeting ion channel that’s a mixture of organic compounds found in different plant originating from South America. It’s used as a paralyzing poison and hunting tool. It’s a competitive antagonist of nicotinic acetylcholine receptor and occupies the same spot on the receptor, as acetylcholine with greater affinity and elicits no response, it’s a non-depolarizing muscle relaxant
Facilitated diffusion 
Compound binds specifically to integral membrane proteins, called facilitated transporter, change in transport conformation allows the compound to be released on other side of membrane compound moves down a concentration gradient
Example is of carriers are glucose transporters and symporter and anti-Porcher
Glucose transporters
Type of facilitated transport,
Most animals import glucose down a concentration gradient, via this facilitator
1 transport is ready to accept the glucose molecule
2) glucose is accepted by transporter. 3) intracellular site of transporter opens
4) glucose is released, and the cycle repeats.
Na+ & glucose Symporter
A carrier facilitated transport
Cells need to move substances from a low concentration to high concentration. Examples of the reabsorption of glucose in the kidney in this case cells can’t rely on a concentration gradient, so they rely on the chemical gradient of another molecule that will not reach extracellular and intracellular equilibrium in this case is sodium .
Na+ and glucose symporter steps
1) simultaneous binding of two sodium ions, and one glucose to the transporter with outward facing binding sites
2) this causes a confirmation change in the transporter occluded
3) eventually the transporter adopts an inward-facing confirmation that allows
4) the dissociation of the two sodium molecules to the cytosol and as a result, the glucose molecule gets pushed in as well
5) return of the outward facing confirmation to repeat the cycle
Anti-Porter
A third type of carrier for facilitated transport concentration of gradient of one molecule is used to transport other molecules in opposite directions. An example is sodium protein exchanger in the nephron of the kidney this anti-porter transports sodium ions into the cell and protons out of the cell is responsible for maintaining pH and sodium levels in specific kidney cells
Active transport
Compound binds specifically to integral membrane protein called active transporter
 Change in the conformation of the transfer caused by the hydrolysis of an ATP molecule allows molecules to be released on other side of the membrane using this mechanism compounds can move across a concentration gradient. It requires energy in the form of ATP molecules.
Na+/K+ pump
ATPase maintains cellular, sodium and potassium concentration using ATP. three sodium ions exit the cell and two potassium ions Enter for each ATP molecule hydrolyze commonly referred to as the NA plus/K plus pump.
 Why is the sodium potassium pump important
It’s important to maintain concentration of sodium ions outside than inside the cells cells spend energy to achieve and sustain the sodium chemical gradient required for nonstop activity of the sodium glucose symporter
How is cell size maintained
 Through active transport
Hypertonic—> shrunk
Hypotonic —> swollen
Isotonic—-> normal
Lysed—> very hypotonic, bursting
Transmembrane, proteins and signal transduction
Transmembrane proteins play a big role in signal transduction as they convert extra cellular signal into intracellular signal signal transduction allows cells to rapidly respond to events happening in their environment, such as grow survive, differentiate move
Ligand
Small molecule that binds to receptors like in binding changes. Confirmation of the receptor proteins ligand does not enter the cell confirmation change causes other proteins inside of cell or membrane to become activated.
Three stages of signal transduction
1) binding of ligand to receptor
2) signal transduction via second messengers like cAMP, calcium or G-protein
3) cellular response- cellular growth, division, store of glucose molecules as glycogen
Examples of disease caused by defect in signal transduction
Cancer, diabetes, different brain disorders
Glycogenolysis
A type of signal transduction, how epinephrine a.k.a., adrenaline activates conversion of glycogen stored in the liver to glucose
Glycogen molecule
Glycogen in protein is surrounded by branches of glucose units
Glycogen is an enzyme that acts as a primer to polymerize the first glucose molecule then other enzymes take over
What enzyme releases glucose units?
Phosphorylase P
Role of anchor proteins in the cellular matrix
Anchor, proteins, playing important role in interacting with components of the extracellular matrix
Are ECM is abundant in connective tissues of animals
ECM
Extracellular matrix is an organized network of material produced and generated by cells
The outside of cells
Functions of ECM
- Cell adherence
- Communication between cells.
- Cell shape, mechanical support, and structural integrity.
- Serves as barrier filters out some particles.
Extracellular matrix and ageing wrinkles
Wrinkles are caused by fibrosis of connective tissues of the skin fibrosis is scarring and thickening. They develop from inquiry, extra pairs of injured elastin, fibers, and collagen fibers.
Components of the extra cellular matrix
Proteins like collagen, glycoproteins proteoglycans
proteoglycans
Proteins with chains of poly saccharide’s
Cell walls
Are cells of bacteria, plants and fungi have walls that act as the extra cellular matrix. They are composed of cellulose, hemicellulose pectin, and
Cell wall function
provide structural support to cells and proteins equivalent to skeleton protect the cell from mechanical damage and pathogen attacks.
function of the cytosol
Protein synthesis, many metabolic pathways and ribosome assembly
Function of the nucleus
Contains genome, DNA and site of RNA synthesis
Function of the ER
Synthesis of lipids and proteins
Function of the Golgi apparatus
Protein, modification, packaging of proteins and lipids
Functions of lysosomes
Degradation of cellular material
Function of endosomes
Sorting and recycling
Function of mitochondria
ATP synthesis and apoptosis
Chloroplast function
Photosynthesis ATP synthesis
Peroxisome’s function
Oxidation of toxic materials
Endo symbiotic theory
Sim biogenesis the theory of the origin of a eucaryotic cells from prokaryotic organisms. Siri holds that organelles in eucaryotic cells evolved through symbiosis of individual single celled prokaryotes symbiosis means living together close and long-term biological interaction theory holds that organelles with two membranes, like mitochondria and chloroplasts represent formerly free, living, prokaryotes, taken one inside the other.
Endo symbiotic, Siri evidence
One binary fission of mitochondria and plastids
2circular DNA inside these organelles similar to bacteria
Aerobic respiration
Converts in presence of oxygen energy, stored in food molecules glucose into chemical energy, stored in ATP this process produces carbon dioxide as a byproduct
Photosynthesis
Builds carbs, using energy from sun and carbon dioxide also produces oxygen
Outer mitochondrial membrane
Contains many enzyme with diverse, metabolic functions. Example monoamine oxidase is breakdown. Monoamine neural transmitters has porrins
Porrins
Large channels, permeable passive diffusion to many molecules when opened such as ATP and sucrose
Inner mitochondrial membrane
High protein to lipid ratio, 3 to 1 double layer, folds, called Christy, increase surface area and contain machinery for aerobic respiration and ATP formation rich in phospholipid called cardiolipin
Cristae
A double ear falls that increase membrane surface area and contain machinery for aerobic respiration and ATP formation
Cardiolipin
Characteristic of many bacterial membranes, and needed for optimal function of many enzymes
Aqueous compartments mitochondria has two
One intermembrane space
2) mitochondrial matrix
high protein, Contant gel like consistence space containing mitochondrial, ribosomes and DNA in mammals,
How many genes does mitochondrial dna encode
mitochondrial DNA and codes 37 genes
Photosynthesis two parts
Light dependent reaction and light. Independent reaction also known as Calvin cycle.
Light dependent reaction
Occurs in the thylakoid membrane chlorophyl in light harvesting complex electrons enter etc. Also in thylakoid membrane H plus is pumped into the silo quite a lumen. ATP and NADPH are made in the light reaction and are used to make carbohydrates in the light independent reaction.
Light independent reaction
Occur in the stroma of chloroplasts ATP and NADH pH make a light reaction used to make carbohydrate reduction of carbon dioxide to form carbohydrates
Apoptosis
Programmed cell death, a normal process that involves the death of cells in a coordinated sequence of events. Part of an organisms, growth and development. Example is inter-digital Seldes leading to the regression of soft tissue between embryonic digits in many vertebrates.
Apoptosis characteristics
Cells undergoing apoptosis show shrinkage,
blebbing, bulge or Protrusion of plasma, membrane fragmentation of DNA and nucleus loss of attachment to other cells, and engulfment by phagocytosis
Are intrinsic pathway of apoptosis
Initiated by intracellular stimuli like genetic damage, hypoxia and virus
BAX proteins
Killer proteins that cause change in the mitochondrial membrane and lead to leakage of cytochrome C
Apoptosis steps
BAX killer proteins, cause change in mitochondrial membrane and lead to leak of cytochrome C backs assembles on the outer mitochondrial membrane to form pores which release cytochrome C release of apoptonic mitochondrial proteins commits a cell to apoptosis cytochrome C assembles apoptosomes in cytoplasm
Apoptosomes activate executioner caspases which disrupt cell adhesion, destroy lamins blah blah
Caspases
Product in apoptosis which disrupt cell adhesion destroy nuclear filament breakdown cytoskeleton activate genome break down
Disease related to apoptosis
Cancer is caused by too little apoptosis and malignant cells do not die. Alzheimer’s is caused by too much apoptosis as with many degenerative diseases.
polarized structure of a secretory cell
Synthesized in the rough endoplasmic reticulum processed in the end of plasmic reticulum further processed in the Golgi, concentrated in vesicles, delivered to plasma membrane for secretion
Mucin
Secreted, protein, glycoprotein component of mucus
GFP
Green Fluorescent protein
from jellyfish
can be fused with cellular proteins fusion protein can be expressed in cells observations of this provide info on Endo Genesis proteins
I vesicular transport/trafficking
Transport of materials between compartments can be from organelle to plasma, membrane and vice versa or between organelles uses transport vesicles
Transport vesicles
Small spherical membrane, enclosed organelles that but off donor compartments infused with acceptor or recipient compartments
Target movement directed
Uses cytoskeleton and motor proteins,
sorting signals recognized by receptors
Key elements of vesicular transport
1) movement of vesicles uses cytoskeleton and motor proteins can be anterior grade or retrograde
2) tethering vesicles to target compartments via proteins from rAB family
3) docking of vesicle uses proteins, called snares snare assembly provides energy for fusion
4) fusion of vesicle and target membrane
Exocytosis
Vesicle travels from organelle to plasma membrane
ER to Golgi to plasma membrane
Anteriograde movement
Endocytosis
Vesicle travels from Plasma membrane organelle
Plasma membrane to Golgi to ER
Retrograde transport
Rough endoplasmic reticulum
Has many ribosomes proteins synthesis by many of these ribosomes
Smooth ER
Lacks ribosomes, primary site of lipid synthesis
Functions of the
Smooth ER
1) lipid synthesis,
2) production of steroid hormones,
3) detoxification 
4) sequestration/storage of calcium 2+ ions
Intracellular calcium handling
Cells invest significant number of energy to controls changes in calcium 2+ concentration
Why is calcium 2+ excluded from cytosol
Ca2+ does not bind water well, which will precipitate phosphates and make proteins insoluble so calcium in cytosol is handled
Calcium 2+ in cytosol…
Sound by range of calcium binding proteins
Forced through pumps and transporters
Sequestered into specific organelles, like the smooth ER
Functions of rough ER
1 synthesis of membrane phospholipids
2 glycosylation of proteins addition of carb to specific protein chain
3 protein, folding quality control involves activity of molecular chaperones, a specific type of proteins that assist in the folding process
4. Proteins synthesis, modification and transport of proteins targeted to ER targeted to other endomembrane compartments.
Endoplasmic reticulum
Compartment of flattened, sacs, and tubules
Where does all protein translation begin?
Translation is RNA to polypeptide, and all proteins. Translation begins on free ribosomes in cytoplasm . Translation is completed in one of two ways either on free ribosomes or ER bound ribosomes
Proteins translated completely on free ribosomes
Cytosolic proteins, peripheral membrane, proteins proteins, targeted to the nucleus, mitochondria peroxosomes chloroplasts 
If polypeptides don’t have a signal peptide, where do they go?
To cytosol
If polypeptides have an amino terminal signal, where do they go?
To chloroplast or mitochondrion
If polypeptides have an internal signal, where do they go
To the nucleus
Proteins completely translated on ER bound ribosomes
Secreted proteins, integral membrane proteins, soluble proteins associated with inside the lumen of Endo membrane system (proteins that function within the ER Golgi and lysosomes)
Endo membrane system
Comprises the ER, Golgi apparatus and lysosomes
Co translational import
- SRP signal recognition particle binds to signal sequence and stops the translation process
- SRP binds to SRP receptor to target hole translation complex to ER
- SRP is released and ribosome binds to translocon once done, protein synthesis, resumes.
-  Polypeptide enters ER through translocon, and is translated
in the end The signal peptide is reeved off and chaperoned folds the protein.
Proteins targeted to the mitochondria
The TOM complex is equivalent to the SRP complex and translocon
Endocytic pathways of protein sorting
Protein targeted to the ER lumen after fully Maiden properly fold it has one of two options
1) retained in the ER lumen if that is where it functions
2) it is transported from the ER to Golgi complex for further modifications, and then delivered to distal parts of the biosynthetic secretory pathway in some cases for another sensation could be outside of the cell example secreted hormones like mucin
Peroxisome
Organelle known as micro body found in all eucaryotic cells involved in a small number of enzymatic reactions,
Small number of enzymatic reactions that peroxisome’s are involved in
catabolism of long chain fatty acids reduction of reactive, oxygen species, and biosynthesis of plasmologens
Zellweger syndrome
No peroxisome’s made due to mutation in paroxysm assembly factor one autosomal recessive disorder that causes severe brain development defects. Patient usually doesn’t survive beyond one year.
Cystic fibrosis
Caused by mutation in CFTR causes degradation in ER of CFTR protein fails to reach the surface or other sites
Synthesis of integral membrane
Part of polypeptide enters cell
part stays within full phospholipid membrane
part leaves
N terminal signal sequences, direct proteins to their respective organelles once they arrive, other intrinsic sequences within proteins, direct them to the correct compartment or membrane
Three parts of the Golgi apparatus
Trans golgi network - near surface
Medial Golgi -in middle
Cis Golgi - closest to er (proximal)
Structure of Golgi complex
Smooth flattened disc like sister name eight or if you were sister in a stack range from a few to several thousand stacks per cell curved like shallow bowl
Shows, polarity, sis, medial, trans cisternae
Cis golgi networks
And acts as a sorting station sorts weather proteins should continue back to next Golgi station or go back to the ER
Trans. Golgi net work.
Sorts proteins into different types of vesicles, which go to plasma, membrane or other intracellular, destinations, example, lysosomes, proteins are modified stepwise as they traverse the Golgi
Golgi apparatus
Processing plant of the cell fully processed proteins are exported to the trans Golgi Nettwerk, and then sorted and delivered to their final destinations
Coat proteins
Help vesicles from the ER travel to the Golgi in between the Golgi sub compartments
Include COP 1 and COP II
Functions of coat proteins
- Help form the vesicle.
- Help select cargo material inside or on vesicle.
Constitutive, secretory pathway
Secretary vesicles can go to exocytosis without security
Regulated, secretory pathway
Secretary granule is regulated takes more time example the release of insulin and neurotransmitters
Coatomer
Cop 1 and 2
Protein complexes that assemble on the cytosolic surface of donor compartments at sites where budding takes place
COP I
Coded vesicles move in retrograde direction
COP II
Coded vesicles move an anterior grade direction
Key features of lysosomes
Digestive organelles
25 nm to 1 µm
pH of 4.6 (so acidic)
contains hydrolytic enzymes and acid Hydrolases
lysosomal membrane is composed of glycosylated proteins that act as a protective lining next to acidic lumen.
Function of lysosomes
Plays a role in maintaining in regulating sell, homeostasis by degrading intracellular components and providing cell degradation products
1. Autophagy
2. Degradation of internalized material
Autophagy
a normal disassembly of unnecessary or dysfunctional cellular components organelle turnover.
- Isolation membrane derived from ER engulf target organelles to form auto phagosome.
— Lysosome fuses with ER, derived auto phagocytic vesicle deform auto lysosome.
- Content of auto lysosome is enzymatically digested in released (exocytosis)
Degradation of internalized material
Recycling of plasma, membrane components like receptors and extracellular material
destroy pathogens, like bacteria and viruses (in phagocytic cells)
Phagocytic cell
Engulfs bacteria through a process called phagocytosis
Phagocytosis
The pathogen is degraded by lysosomes that associated with the pathogen, containing vesicle hydrolytic enzymes inside lysosomes, degrade and kill. The pathogen debris is released outside.
How do you neutrophils know to attack bacteria?
The cell bacteria is produce chemo attractants for which neutrophils white blood cells have receptors this allows the neutrophils to move in the direction of and target bacteria
Plant vacuoles
Vacuoles are fluid filled membrane bound they can take up to 90% of the cells volume
Plant vacuole function broad
vacuoles are involved in the regulation of cytoplasmic pH sequestration of toxic ions regulation of cell rigidity storage of amino acids sugars, and CO2 in the form of malate
Tonoplast
Vacuolar membrane that contains active transport systems that allow ions in molecules to transport looks like a dotted circle
Function of vacuoles specific
- Intracellular digestion (comparable to lysosomes.] slightly low pH of five, acid Hydro laces
- Mechanical support turgor pressure gives rigidity to plant supports soft tissues stretches well during growth.
- Storage of solutes and macromolecules chemical storage, toxic compounds and pigments like anthocyanin
Coatomer for endocytosis
Clathrin & AP (adaptor protein) complex
vesicles with these proteins move from trans Golgi Nettwerk to other vesicles, such as lysosomes endosome’s or plant vacuoles
Coated vesicles also help form endocytotic vesicles to move from plasma membrane to endosomes or lysosome
Microtubule associated non-motor proteins
Control microtubules organization inside a cell
power intracellular transport
Kinesin & dyenin
Use ATP to generate force
can move material along microtubule track
can generate sliding force between microtubules
Kinesin
+ end directed
Dyenin
- end directed
Motor proteins, and movement
- ATP binding to the leading head induces a confirmational change that swirls the training, trailing head, one on the left 180 greets towards the positive end of the microtubules the force generates a step.
- The new leading head quickly binds to a tubular subunit and releases it ADP moving its kinesin cargo forward.
- In the trailing head, ATP is hydrolyzed to ADP which leads to detachment from microtubule.
- ATP binds to leading head to repeat the reaction cycle.
MTOC
Microtubule organizing centre
Central site of microtubule assembly
Only found in eucaryotic cells
Two important types, basal bodies, and centrosome
Basal bodies microtubules
Associated with cilia and flagella
Centrosome microtubules
Associated with spindle formation motor Mabs can generate sliding force between microtubules, which is important during mitosis and chromosome segregation
Cytoskeleton
Composed of microtubules, microfilaments and intermediate filaments
Microtubules
Hollow tube formed from tubulin, dimers, alpha tubulin, and beta tubulin
Polar
Similar to microfilaments
Microfilaments
Double helix of actin monomers
Thinnest polymer of actin proteins
Intermediate filaments
Strong fibre made of intermediate filament proteins subunits, 10 to 12 nm in diameter
exclusive to multicellular animal cells not polar, so not used in transport composed of keratin’s in the cytoplasm and especially abundant in axons of neurons, composed of lemons in the nucleus
Intermediate, filament function
provide structural support and mechanical strength table in comparison to microtubules or microfilaments
Micro tubule function
Cell shape and support cell movement by cilia and flagella cell division, chromosome segregation, vesicle transport, and organelle arrangement
Micro filament function
Cell shape and support cell movement by crawling cell division, cytokinesis, vesicle transport, muscle contraction
Myosin’s
Super family of motor proteins associated with microfilaments divided into two broad groups. Conventional myosins and unconventional myosins
Conventional myosins
Type two primary motors for muscle contraction
Unconventional myosin
Type one and type 3 to 18
Generate force and contribute to motility of non-muscle cells
Directed sell motility
Coordinated activity of actin binding proteins, controlled microfilament formation in a Lamela podium and to allow directed cell movement
Lamellipodium
Actin projection on the leading edge of a cell looks like a mane of a horse
Prolific
Actin binding protein, that enhances growth of filaments think pro positive
Cofilin
Actin binding proteins that disassembles actin filaments think coffin stop
Capping protein
Blocks the exchange of subunit at the positive end
Actin
Enzyme that binds and slowly hydrolyzes ATP
Phalleidin
Toxin found in mushrooms lethal after a few days, when injected into bloodstream prevents the deep polarization of actin fibres
Three functions of the nucleus
1) storage, replication and repair of genetic material
2) expression of genetic material (transcription of mRNA)
3) ribosome biosynthesis
Nucleosome
10 nm fiber, composed of four histone proteins
Chromatin
Condensed DNA, which coils, and then coils coils to form chromatids
What can damage DNA?
UV light exposure replication airs, chemical exposure, cellular metabolism, ionization, radiation, DNA repair, machinery come and fix it
Nuclear envelope
Nuclear membrane pores, and Lamina
Two parallel phospholipid bilayer’s separated by 10 to 15 nm of space composed of the outer nuclear membrane and the inner nuclear membrane
Outter nuclear membrane, ONM
Binds ribosomes and is continuous with rough endoplasmic reticulum
Inner nuclear membrane
Has integral proteins and connects nuclear lamina
Importance of nuclear envelope
Separates nuclear content from cytoplasm, separates transcription and translation processes. Selective barrier that allows limited movement between nucleus and cytoplasm small molecules and ions can passively diffuse through it, but large proteins and RNA requires active transport.
The nuclear lamina
Supports the nuclear envelope thin meshwork of filament proteins, called lemons, intermediate filaments found in animal cells only plants have lemonade, but not made of lemon proteins
Where and how is nuclear lamina bound?
Nuclear lamina is bound to the inner membrane of the nuclear envelope by integral proteins
Nuclear lamina function
Provides structural support for nuclear envelope
attachment sites for chromatin
Nuclear pore
Gateways between cytoplasm and nucleus 3000 to 4000 pores per nucleus complex structure that involves arrangement of different types of proteins
Where are nuclear pores found?
pores are found where inner and outer membrane fuses
Nuclear pore complex
Composed of nuclear Porins, a large family of proteins, octagonal symmetry, basket, like projects into cytoplasm and nuclear plasm
Supra molecular complex
Very big from a protein arrangement point of you 315 to 30 times the size of a ribosome
How many molecules per minute purport can the nucleus take in?
100
How small must molecules be to diffuse within the nucleus for
40 KDA or less
Regulated movement of a larger molecule through nuclear pore how long does it take?
Six molecules per minute per pore
NLS
Nuclear localized signal
Several positively charged amino acids within proteins sequence regulated movement of proteins, requires it
