intro to cellular process PDF

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EXAMINABLE CONTENT -CSF SLIDES -LECTURE (NOT LAB) GUIDE -WHAT IS SAAID IN THE LECTURE -ABLE TO RECOGNISE THE CELL PARTSCELL THEORY All organism are composed one or more cells The cell is the basic unit of structure and organization All cells arise only from pre-existing cells Universal similarities ...

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INTRO TO THE CELL Tuesday, 15 March 2022

10:18 AM

EXAMINABLE CONTENT -CSF SLIDES -LECTURE (NOT LAB) GUIDE -WHAT IS SAAID IN THE LECTURE -ABLE TO RECOGNISE THE CELL PARTS

CELL THEORY - All organism are composed one or more cells - The cell is the basic unit of structure and organization - All cells arise only from pre-existing cells Universal similarities between cells - DNA has the heritable material, RNA as a messenger and proteins as the workers - Major cellular organelles- functions and arrangements within the cell - ATP as an energy source The centra dogma DNA--> RNA--> protein

PROKAROYTE VS EUKAROYOTE humans are eukaryote cell - they are bigger than prokaryotic cell Similarities Eukaryotic cells- have membrane-bound organelles sand are much larger- key difference Prokaryote cells- lack a membrane- bound nucleus

CYTOPLASM

Nucleus

Cytoplasm

Cytoplasm is everything inside the plasma membrane including the organelles nut not nucleus Fluid portion-cytosol - Water plus dissolved and suspended substance (eg ions, atp, proteins, lipids) MAJOR ORGANELLES -NUCLEUS -ENDOPLASMIC RETICULUM GOLGI APPARTUS -LYSOSOMES MITOCHONDRIA- not part of Endomembrane RIBOSOOMES- don't Have a membrane

THE endomembrane system - Endomembranecontinuous along with plasma membrane to move thing Around or outside of the cell Plasma membrane is the part of endomembrane system Because what inside the membrane needs to be kept physically separated from other

parts of the cells

PLASMA MEMBRANE - Critical purpose- things that determines what comes in and out - physical properties - Double layer of phospholipids with embedded proteins physical barrier - keeping water away from one side of a membrane to the other you can create a barrier Body is largely made of water - we are hydrophilic Fats and lipids are hydrophobic Double layer of phospholipids have hydrophilic and hydrophobic components, layering themselves n a way that keeps the water away from one side of a membrane to the

other creating a barrier Fat in cell membrane provide a barrier to water PHOSPHOLIPID - Hydrophilic polar heads (phosphate) - Hydrophilic lipid tails (fatty acids) - Arranged as a double layer around cytplasm, tail to tail

P LA SM A M ME EMBRA NE P PR RO T EINS - Membrane proteins mediate movement of hydrophilic substances Hydrophobic things can pass through the small gaps Hydrophilic can't pass the lipid barrier - need help of the proteins INTERGAL PROTEINS Embedded (partially or fully) into the membrane eg. Transmembrane pro contact extracellular and cytoplasmic area. PERIPHERAL MEMBRANE PROTEINS Associated with the membrane, not actually embedded in it- close to the They respond in response to a receptor molecules chamber or associate

oteins: integral membrane proteins that fully span the entire membrane,

e membrane but don't interact with the lipid part of it a channel

JOBS OF PLASMA MEMBRANE PROTEINS TRANSPORT - These channels are important for excitable tissue and neurons secti - Considered transports, gated or selective or not - Ions and molecules go from one side of membrane to other and the - Could be passive diffusion- Passive diffusion is from high concentration to low concentration - Active transport is from low concentration gradient up to a high con - ATP required for pumping of ions ENZYMES - Lots of reactions occurring in our cells is enzymatic - Carry out chemical reaction, may or may not be part of a team of en SIGNAL TRANSDUCTION

on ey pass through a channel

ncertation gradient

nzymes

SIGNAL TRANSDUCTION - External signaling molecule causing transduction of information to t Not all cells have the same job, same proteins are not represented on ea depending on the cell type for example neurotransmitter proteins for yo Even within a certain type of cell, the proteins are not always going to be there is a change in any kind of signal or messenger, there'll be a change cell with the respect of what's going on in the cell, moving it's not static CELL-CELL RECOGNITION - Use of glycoproteins (carbohydrate + protein) as molecular signatur - GAGS + Protein are a type of glycoprotein - this is the basis of tissue INTERCULLAR JOINING - Gap junctions or tight junctions - Hold 2 cells together to enable communication or stop linkage betw to be pumping in coordinated fashion) ATTACHMRNT TO THE CYTOSKELETON AND EXTRACELLULAR MATRIX (EC fibronectin mediates contact between cell surface integrins and ECM (e MEMBRANES ARE NOT STATIC THE FLUID MOSIAC MODEL - The membrane is mosaic of protein molecu The saturation status of lipids depends on the fluidity and the ability of m

NUCLEUS - Enclosed by double lipid bilayer called nuclear envelope, continuous Function M ti

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the inside of the cell ach of our cells around our body they are going to be CELL SPECFIC ou brain e the same, they'll be responding to different conditions at the time. If I what proteins are represented on the outside or on the membrane of a CELL SPECFIFC-

res of the extracellular side of the cell e typing

ween cell spaces or too keep them tightly working- cardiac muscle (want it

CM) .g. collagen) can facilitate movement

ules bobbing in a fluid bilayer of phospholipids. molecules to pass through

s with rough ER

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- Most important jobs of the nucleus is to house/protect DNA in Euka damage the Dna so the DNA can undergo transcription and make th - Makes RNA and assemble ribosomes - Pores regulate movement of substance (eg protein and mRNA) in an - Molecule segregation to allow temporal and spatial control of cell f nuclear PORE- exit and entry of material through nuclear pores, large thi NUCLEOLUS- rRNA production, assembly of small and large subunits of r - Make RNA and assemble ribosomes

Mrna- messenger Rna- makes ribosomes INSIDE THE NUCLEUS DEOXYRIBONUCLEIC ACID- DNA - Nucleic acid that encodes our phenotype - Condensed to fit inside the nucleus DNA strands need to be packed to fit into nucleus 1. DNA wrapped 2x around group of 8 histones, to form nucleosomes 2. As cell prepares for cell division, chromatin condenses further to ch chromosomes

aryotic cells from harmfulln reactions undertaking in cytoplasm that could he transcription products required by our body nd out unctioning like RNA transcripts' themselves and ribosomes will travel ibosomes (dark interior in the nucelus- because more concentrated)

collectively knows as chromatin romatin fiber then condenses further into loops then stacks as

3.

DNA double helix- lose form, doesn’t exist inside the nucleus as a whole Chromatin fiber- highly condensed MOST OF THE TIME OUR DNA IS PRESENT AS CHROMATIN AND CHROMA

Chromosome- comprises many genes, each gene contributes to a pheno Gene- A DNA segment contributed to phenotype/function Humans diploid 2N=46 - 23 pair chromosomes one from eac parents

ATIN FOBRE

otype or a function

23 pair chromosomes, one from eac parents - 22 autosomes, 2 sex chromosomes PACKAGING OF THE NUCLEUS - If it was a double helix it wouldn't fit into cells - Can't always be a chromosome because then actual transcription co - All DNA in one cell stretches out to 2 meters 3 billion base pairs in each cell manage to fit into a space of 6 omicrons a Accessibility is determined by the extent of coiling

Metaphase

UNDERGOING CELL DIVISON - Easier to organize when condensed chromosomes that’s why DNA g metaphase before cell Davison and then cell division split in 2, have the chromosome on one side and half on the other For protein and Rna, Need access and transcription factors to access dna transcribed (easier when chromatin are jumbled up)

ould occur because that would determine it accessibility

across- HOW

goes into half of

a to be

RIBOSOMES Made up of two different ribosomal RNA subunit made in the nucleus an assemble in the nucleus, exit through nuclear pore and ten cytoplasm FUNCTIONS - Protein production - translation, found in two places within the cell 1. Free in the cytoplasm - making protein to be used in cytosol (nonendomembrane destinations), all RNA transcripts will initially dock onto ribosome subunit 2. Attached to RER- a protein that ultimately needs to go through the endoplasmic reticulum, It will be making protein (endomembrane) t to go through the ER system

ENDOPLASMIC RETICULUM The ER is an extensive network of tubes and tubules, stretching out form nuclear membrane - The Smooth ER is continuous to the Rough ER.

ROUGH ER - Its rough because of the ribosomes When ribosomes docks on the ER, it synthesis the protein and end up in the lumen - protein enter lumen within the rough ER for folding Rough ER membrane surrounds the protein to form transport vesicles de for the Golgi

nd they

. a

that need

m the

estined

Main function is production of - Secreted protein - things that leave the cell - Membrane protiens -required all the time, some of them will be nee inside the cell - Organelle proteins - required to stay inside the cell

SMOOTH ER - Extends from the rough ER - Lacks ribosomes so doesn't make protein MAJOR FUNCTION - Housing unit for proteins and enzymes - Synthesis lipids, that might go on to form plasma membrane lipids, steroids and phospholipids - Storage of cell specific proteins, not all cells make all proteins For example liver cells required a lot of enzymes for detoxification ad for release and muscles cell- calcium ions (calcium ion stored in here signals

eded

including

r glucose electrical

impulse where muscle needs to contract and it's called cycle emergence - Function of SER are very tissue/cell specific

GOLGI APPARATUS - Warehouse of the cell- received proteins that have been made from and modifies them - Cis is closest the ER- receiving versicles that have come form the ER entering the Golgi - they are entering the Golgi because they require type pf modification or packaging, different processes that can occu which is glycosylation, modification of protein an d carbohydrate gr occur CONCEPT - enzymes and protein can pass through vesicles and can go th multiple vesicle steps, ultimately vesicle will levae the space "shipping" f Golgi - Trans face FUNCTION - Modify - Sort - Package and transport protein recieved from the rough ER using en each cisternae Certain cells types have a lot of Golgi in them knows as secretory cells be they have a need to make a lot of mucus

m the Er and e some ur where oups can rough face of the

zymes in

ecause

DESTINATION - Once left the Golgi, they can either make some more membrane fo membrane renewal, (fusing), secretion- going to the extracellular flu making lysosomes - Each sac or cisternae contains enzymes of different function s - Protein move cis to trans from sac to sac - Mature at the exit cisternae - Travel to destination - Modification occur within each sac (formation of glycoproteins, glyc and lipoproteins)

LYSOSOMES

r uid and

colipids

LYSOSOMES Contains powerful digestive enzymes- highly acidic - to destroy compoun Vesicles formed from Golgi membrane Membrane protein pump H+ in t maintain acidic pH - they have a particu membrane protein in them which pump hydrogen ions in which keep th those enzymes can the work to break down the molecules that enter the lysosome one way or another MAIN FUNCTION IS DIGESTION OF - Substances that enter a cell - pathogen or antigen- some kind of imm disease molecule - Organelles within a cell that are starting to die and need to be repla be absorbed by lysosomes and busted up in the nutrients recycled. (autophagy) - Entire cell (autolysis)- entire cell is not functioning and the lysosome entire cell can be endemically destroyed Disease - when lysosomes can't work properly

MITOCHONDRIA Main function- generation of ATP through cellular respiration - Outer and inner membrane Not part of the endo-membrane system - doesn't tend to share its molec across or transporting or shipping vesicles around. Cells that require a lot of energy will have a large number of mitochondr ribosomes as well- where they can write proteins -they have their own little genome, - can encode mitochondrial specific p

nds

ular he ph. low, e

mune or ced- can

es- the

cule

ia - own products

CYTOSKELETON -support system of the cells Fibers or filaments that help to maintain the size shape and integrity of t - Acts as scaffolding across the cell - Involved in intracellular transportation and cell movement THREE TYPES OF FIBFRES - Microfilaments - smallest (7nm)- tends to be associated around the of the cell and associated with microvilli, they are compromised of a found around the periphery and lining the interior of cell Function Bear tension and weight by anchoring cytoskeleton. To plasma mem proteins and promote amoeboid motility if required (macrophage) They are dynamic- don't stay the same all the time- assembled and disas as required ( a cell will have differing amount of microfilaments dependi what's going on

- Intermediate filament - 8-12 cm, made up of different types of prot keratin, found throughout the cytoplasmFunction Bear tension and weight throughout the cell eg during cell anchorin Acts as scaffold for cellular organelles eg the nucleus Usually the most permanent of cytoskeleton- because it is always scaffolding - least dynamic - Microtubules - associated with cell division, transport of different ve around a cell for different reasons - 25 nm FUNCTION - Support cell shape and size

the cell

outside actin,

mbrane sembled ng on

ein -

g

esicles

- Guide for movement for organelles - eg vesicles from Golgi to mem - Chromosome organization - cell division - Support and movement of cilia/ flagella Assembled and disassembled as required- are dynamic Motor protein- driven by ATP, can walk along the microtubule and carry with it, need to get from the Golgi to the outside of the cell transported microtubule Microtubule forms and dissociated when no longer required (dynamic)

brane

a vesicle along a...