Lecture 5: Cell Structure Flashcards
Define cell
Basic structural and functional units of the body
Where do cells arise from
pre-existing cells
cells have optimal balance between _____ and _____
cells have optimal balance between (SA) and (size)
x3 universal similarities of cells
i. DNA = heritable; RNA = messenger; proteins = workers
ii. Organelles for functions and arrangements within cell
iii. Energy source is ATP
what is the central dogma
DNA > RNA > PROTEIN
what type of cells have
- Membrane bound organelles
- Large
eukaryotic cells
what type of cells
- Lack membrane-bound nucleus
Can see DNA… just clumped in middle
prokaryotic cells
eukaryotic and prokaryotic cells both contain
plasma membrane
cytosol
DNA
RNA
protein
ribosomes
what is the fluid portion of the cytoplasm
cytosol
what does cytosol contain
H2O + suspended and dissolved substances (ions, ATP, proteins)
the cytoplasm is…
everything inside the plasma membrane like organelles; NOT NUCLEUS
x6 major organelles in the cytoplasm
- nucleus
- endoplasmic reticulum (rough & smooth)
- Golgi apparatus
- lysosomes
- mitochondria
- ribosomes
what system are these major organelles in
1. nucleus
2. endoplasmic reticulum (rough & smooth)
3. Golgi apparatus
4. lysosomes
endomembrane system
function of the endomembrane system
packaging, labelling, shipment of molecules
what acts as a “Physical barrier that separates the inside of the cell from the outside. (dictate size and shape)”
plasma membrane
functions of the plasma membrane
controls the passage of substances into/out of cell
Selectively permeable physical barrier (barrier provided by fats in membrane)
what structure has “double layer phospholipids + embedded proteins form”
plasma membrane
what phospholipid is hydrophilic
phospholipid polar heads (phosphate)
what phospholipid is hydrophobic
phospholipid lipid tails (fats in cells)
what collectively forms a phospholipid bilayer?
phospholipid polar head + phospholipid lipid tails
true or false
“Proteins on membrane change all the time and are cell specific and dynamic”
true
Proteins on membrane change all the time
- cell specific and dynamic
describe the fluid mosaic model of membranes
molecules bobbing in a fluid bilayer of phospholipids
function of the plasma membrane proteins
initiate and maintain movement of hydrophilic substances
What does it mean when plasma membrane proteins…
“contain regions that are hydrophilic and hydrophobic = so they can interact with molecules”
amphipathic
how do proteins stay embedded in the plasma membrane
Protein sides next to tails = hydrophobic;
protein sides facing outside/inside = hydrophilic
- enables then to stay imbedded within the membrane; amphipathic
x2 of plasma membrane proteins
integral (transmembrane) proteins
peripheral membrane proteins
what type of membrane protein
“embedded into the membrane (protein sides are hydrophobic to stay imbedded)”
integral transmembrane proteins
function of the peripheral membrane proteins
- associated with hydrophilic portion of membrane;
- not embedded in hydrophobic portion
(allow cell-to-cell identification and facilitate intercellular communication or transport)
name the x6 types of protein functions
- transport
- enzymic activity
- signal transduction
- cell-cell recognition
- intercellular joining
- attachment to cytoskeleton + ECM
what does transport protein function do?
< Allow ions/molecules through channel in protein… ions or molecules to pass through
< Passive or active (pump) processes
what protein function…
- Carry out chemical reaction
- Specific active site + substrate enter to be cleaved, processed to make a different compound
enzymic activity
how membrane proteins undergo signal transduction
External signalling molecule causing communication of info to inside of cell
Molecule elicits a change in shape… enables cell signalling to occur
true or false about cell-cell recognition
- Use of glycoproteins (carbohydrates + protein) as molecular signatures of extracellular side of the cell
- Tissue typing
true
- Use of glycoproteins (carbohydrates + protein) as molecular signatures of extracellular side of the cell
- Tissue typing
what does the protein function uses cell junctions for
intercellular joining (cell joining with adjacent cell)
- communication
- rigidity
- stability
- anchoring
what membrane protein function does…
- Fibronectin (chickdrumbstick on top of protein) connection between cell surface integrins and ECM (collagen)
- Facilitate movement
Attachment to cytoskeleton (microfilaments) and ECM attachment
Membrane bound proteins are c_____ s_____ and d_____ repertoire…. constantly _____
Membrane bound proteins are (cell) (specific) and (dynamic) repertoire…. constantly (changing)
true or false
the nucleus is the smallest organelle in the cell
false
the nucleus is the LARGEST organelle in the cell
x4 functions of the nucleus
- house/protect DNA
- make RNA; assemble ribosomes
- pores regulate substance movement in/out (protein + mRNA)
- molecule segregation = temporal + special control of cell function
what encloses the nucleus
double lipid bilayer = nuclear envelope
x2 membranes of the nuclear membrane
outer membrane - continuous with the rER
inner membrane
x3 components of the nucleus
- nucleolus
- nuclear pores
- DNA
function of the nucleolus
ribosomal RNA (rRNA) production;
assembly of small/large subunit of ribosomes
function of nuclear pores
control entering and exit of substances
how is DNA present
chromatin/chromatin fibres
DNA wrapped x___ around group of x8 _____ which form _____
- collectively called: _____
DNA wrapped (x2) around group of x8 (histones) which form (nucleosomes)
- collectively called: (chromatin)
how does cell prepare for cell division
chromosome condenses = chromatin fibres
> fibres condense further into loops
» stacks as chromosomes
what is a chromosome
consist of many genes
what is a gene
DNA segment that contributes to phenotype/function
where are ribosomes made/assembled
nucleolus then leave controlled via the pores
function of ribosomes
Translation of RNA into proteins
location of where ribosomes can be found x2
- Free in cytoplasm = make proteins for use IN cytosol (non-endomembrane destinations)
- Attached to RER = make non-cytosolic proteins/endomembrane
true or false
Location of ribosomes dictates what proteins they make
true
Location dictates what proteins they make
structure of ER in general terms
Network of tubes and tubules, stretch out from nuclear membrane
x2 types of endoplasmic reticulum (ER)
rough ER
smooth ER
structure of the roughER
extension of nucleus/nuclear envelope
x3 things the rER produces
- secreted proteins
- produce membrane proteins
- produce organelle proteins
are ribosomes attached to the rER or sER
rough ER
location where ribosomes begin translating protein + their name
cytosol
> cytosolic ribosomes
if detected the protein will… secrete proteins, produce membrane proteins, produce organelle proteins and taken to…
ER dock to continue making polypeptide chain until chain ends up inside of the RER
- RER ribosomes
protein prep before transportation to golgi
Proteins enter lumen with rough ER for folding
> RER membrane surrounds protein
» form transport vesicles for golgi
structure of the smooth ER
extension off rER
lack ribosomes… DO NOT make proteins
function of the smooth ER
- housing unit for proteins + enzymes
- synthesises lipids (steroids and phospholipids)
- storage of cell/tissue-specific proteins
what organelle is considered the “warehouse”
golgi
function of the golgi
- protein modification, packaging, transport from rER received from using enzymes in each cisternae
- addition of carbohydrates/glycoproteins
process that occurs in the golgi
Leave RER and vesicles > golgi > modified > leave in vesicle
golgi form x3 types of vesicles + their function
i. secretory vesicles (proteins for exocytosis)
ii. membrane vesicles (PM molecules)
iii. transport vesicles (molecules to lysosome)
true or false…
“the golgi has an end-membrane system - shared membranes”
true
processes that occur in the golgi
Modicication occur within sac (form glycoproteins, glycolipids, lipoproteins)
> travel to destination
» mature at the exit cisternae
»> proteins move cis to trans from sac to sac
»» each sac or cisternae contains enzymes of different functions
lysosome contain _____ _____ enzymes that are highly _____
lysosome contain (powerful) (digestive) enzymes that are highly (acidic)
why are lysosomes bound in a ‘bag’
to keep partitioned from the rest due to its highly acidic nature
function of the lysosomes x3
- for the digestion of…
i. substances that enter the cell (pathogens)
ii. cell components (eg. Organelles) autophagy
iii. entire cells autolysis
can building blocks like amino acids and lipids be recycled once digested
true
what are these key components part of…
< types of vesicles formed by golgi membrane
< membrane proteins to pump H+ in to maintain acidic pH
< rest of cells protected by membrane; kept partitioned from rest
lysosomes
what happens when a cell needs more energy
more ATP is made
> greater number of mitochondira
function of the mitochondria
making ATP via cellular respiration
x3 components + function of the mitochondria
< outer mitochondrial membrane
< inner mitochondrial membrane; contains folds
< mitochondrial matrix = fluid filled interior cavity
true or false
“the transfer of phosphate to another molecule generates energy”
true
what organelle of the cell has these functions
- scaffold for cell
- Intracellular transportation + cell movement
- Consist of fibres/filaments that help maintain shape, size, and integrity of cell
cytoskeleton
order the cytoskeleton components from smallest to largest
microfilaments > intermediate filaments > microtubules
what gives microfilli shape/movement of cells
microfilments
x2 functions of the microfilaments
bear tension + weight by anchoring cytoskeleton to plasma membrane proteins
Promote amoeboid motility if required (macrophage)
where are the microfilaments located?
around the periphery and lining of interior of cell
what protein makes up microfilaments
actin
how is actin assembled in microfilaments
actin molecules assembled in 2 long chains twisted around each other
true or false
microfilaments are “Dynamic = assembled and disassembled as required”
true
x2 functions of the intermediate filaments
- Bear tension + weight throughout cell (ie Anchoring)
- Scaffold for cellular organelles (ie Nucleus)
what component of the cytoskeleton is “distributed amongst the cytoplasm”
intermediate filaments
what are intermediate filaments made of
range of different materials – keratin
true or false
intermediate filaments are “most permanent and less dynamic”
true
x4 functions of the microtubules
- support cell shape + size
- Guide for organelle movement (vesicles golgi> membrane)… motor proteins walking
- Chromosome organisation (cell division)
- Support + movement of cillia/flagella
location of microtubules
extends from centriole into cytoplasm/nucleus
what component of the cytoskeleton contains “tubulin dimers (alpha and beta) = coiled to form a tube”
microtubules
true or false
microtubules are “Dynamic = assembled and disassembled as required”
true
