CSF: Intro to the cell Flashcards
cell theory (3pts)
- all living organisms are composed of one or more cells
- the living cell is the basic unit of structure and organisation
- all cells arrise from preexisting cells
The central Dogma equation
DNA -> RNA -> PROTEIN
what are 6 things prokaryote AND eukaryote cells have
Plasma membrane, cystol, DNA, RNA, protein and ribosomes
Prokaryote nucleases are not…
membrane bound
what are two things that make eukaryote different than pro?
- organelles are membrane-bound
2. they are larger than prokaryote
what is the cytoplasm/what does it contain
everything inside plasma membrane including organelles, not the nucleus though
what is the fluid portion of the cytoplasm called and made up of
the cystol
water + dissolved and suspended substances - ions, ATP, proteins, lipids etc
what is the function of the plasma membrane
its a physical barrier seperating the inside/outside of the cell
whats the general function of the plasma membrane
double layer of phospholipids with embedded proteins
what does hydrophilic mean
loves water
what does hydrophobic mean
hates water aka fats therefore, lipids in membrane provide a barrier to water
what makes up the head of a phospholipid
a hydrophilic phosphate head (polar)
what makes up the tail of a phospholipid
a hydrophobic lipid tail
what word describes hydrophilic and hydrophobic sections in plasma membrane proteins
amphipathic
describe intergral proteins
imbedded - partially or fully - into the membrane
what are transmembrane proteins
- fulls span the entire membrane
- contact extracellular and cytoplasmic areas
What are peripheral membrane proteins
- associated with the membrane but not actually embedded in it
what do TRANSPORT plasma membrane proteins do?
channels, transporters may be general or selective, gated or not
what do ENZYMES plasma membrane proteins do?
- carry out chemical reaction, possibly part of enzyme team
what do SIGNAL TRANSDUCTION plasma membrane proteins do?
- external signalling molecule
- transduction of info to cell inside
what do CELL-CELL RECOGNITION plasma membrane proteins do?
- glycoproteins as molecular signatures on the extracellular side of cell
what do INTERCELLULAR plasma membrane proteins do?
e.g gap junctions or tight junctions
what do Attachment to the cytoskeleton and ECM plasma membrane proteins do?
- fibroconectin helps contact between cell surface integrins and ECM (e.g. collagen)
- can facilitate movement
whats the best model to describe plasma membrane
fluid mosaic model
Whats the nucleus enclosed in
double lipid layer nuclear envelope, continuous with rough ER
how does shit get in and out of the nucleus
through nuclear pores
what happens in the nucleolus
- rRNA production
- assembly of small and large subunits of ribosomes
Three functions of DNA and its pores
- house/protect DNA
- make RNA & assemble ribosomes
- pores regulate substance movement in and out
whats so great about molecule segregation?
- molecule segregation to allow temporal and spatial control of cell function
what does DNA code for?
our phenotype
What proteins is DNA wrapped around to pack is densely
it wraps twice around a group of 8 histones
when DNA wraps twice around a group of 8 histones what is this called
it forms nucleosomes or chromatin
what does chromatin condense down to to become a chromosome?
Chromatin fiber condenses further into loops to become a chromosome.
Chomosome idea
comprised of many genes
gene idea
a DNA segment that contributes to phenotype/function
Humans are diploid, what does this mean?
2N = 46
- 23 pairs of choromosomes, (1 from each parent
- 22 autosomes
- 2 sex chromosomes
how far does DNA stretch out to
2 meters
accessibility is determined by what
extent of coiling
ribosome structure
2 subunits, burger - top big bottom small, made of ribosomal RNA (rRNA) in protein complex
where is Rrna made
nucleolus
how does rRNA get made/leave nucleus
subunits assemble in nucleolus, leave through nuclear pores
function of ribosomes (protein)
- protein production (translation)
function of ribosomes (free))
making proteins to be used in cystol (non-endomembrane destinations)
function of ribosomes (RER)
making non-cytosolic proteins/endomembrane
what is the ER
extensive network of tubes and tubules - stretches out from nuclear membrane
two types of ER
smooth ER and rough ER
RER description
continuous with nuclear envelope dotted with attached ribosomes
how do proteins and ER get folded?
proteins enter lumen within ER for folding
3 major functions of RER
production of proteins:
- secreted
- membrane
- organelle
how does RER send things to golgi
RER membrane surrounds protein to form transport vesicles destined for golgi
smooth ER location
extends from rough ER
does the smooth ER have ribosomes?
no, it doesnt make proteins
three major function of smooth ER
- housing unit for proteins and enzymes
- synthesizes lipids - steroids and phospholipids
- storage of cell-specific proteins, not all cells make all proteins
are the smooth ER functions the same for every cell?
no, very cell/tissue specific
what does the smooth ER do in the liver?
houses enzymes for detoxification and for glucous release
what does the smooth ER do in the muscles?
calcium ions
what is a colloquial term for the golgi apparatus
the ‘warehouse’
how many sacs is the golgi made of and what are they called? (golgi description)
3-20 flattened membranous sacs called cisternae stacked on top of one another
functions of golgi
- modify, sort, package and transport proteins from RER vis enzymes in cisternae
golgi assists in the formation of
- secretory vesicles
- membrane vesicles
- transport vesicles
secretory vesicles golgi used for
proteins for exocytosis
membrane vesicles golgi used for
PM molecules
transport vesicles golgi used for
molecules to lysosome
two golgi faces and uses of those faces
cis face - receiving side closer to ER
trans face - shipping side further from ER
each sac or cisternae contains what?
enzymes of different functions
protein movement in golgi 1
-proteins move from cis to trans (sac to sac)
protein movement in golgi 2
- mature at exit cisternae
protein movement in golgi 3
- travel to destination
what occurs in each golgi sac?
modifications - formation of glycoproteins, glycolipids and lipoproteins
lysosome contain
powerful digestive enzymes
are lysosomes acidic or basic?
highly acidic, pump H+ to maintain acidic pH
main function of lysosomes is digestion of:
- substances that enter a cell
- cell components e.g. organelles - autography
- entire cells - autolysis
cell components e.g. organelles name
autography
entire cells name
autolysis
mitochondria main function:
generation of ATP through cellular respiration
three things mitochondria are made up of
- outer mitochondrial membrane
- inner mitochondrial membrane
- fluid filled interior cavity the mitochondrial matrix
why do cells have more ATP
when a cell requires more energy itll have more ATP
what special thing does mitochondria carry
separate small (37 gene) genome encoding mitochondria specific products
what is ATP
adenosine triphosphate - our energy currency
how do we get energy in terms of product transfer
one phosphate transfers to another molecule and provides energy
Cytoskeleton idea
structural support system of the cell
three fibres in cytoskeleton
- microfilmanets
- intermediate filaments
- microtubules
smallest cytoskeleton fiber
microfibers
medium cytoskeleton fibers
intermediate filaments
largest cytoskeleton fibres
microtubules
cytoskeleton fibres and filamentss help maintain what of the cell
size, shape and integrity of cell
two main cytoskeleton jobs
- act as scaffolding across the cell
- involved in intracellular transportation and cell movement
microfilament diameter
7nm
what are microfilaments comprised of
actin molecules - 2 long chains twisted
where are microfilaments found
periphery of interior of cell
function of microfilaments
- anchor cytoskeleton to plasma membrane proteins
- promote amoeboid mobility
Intermediate filaments diameter
8-12nm
intermediate filaments composition
keratin
intermediate filament location
cytoplasm
which is the most permanent cytoskeleton
intermediate
function of intermediate filmants
- scaffold for cellular organs i.e. nucleus
- bear tension and weight
microtubules diameter
25nm
microtubules composition
tubulin dimers (alpha and beta) coiled to form a tube
4 functions of microtubules
- support cell type
- guide for organelle movement
- chromosome organisation - cell division
- support and movement of cillia/flagella
are microfilaments dynamic?
yes they are dynamic - assemble and dissemble as required
are microtubules dynamic?
yes they are dynamic - assemble and dissemble as required
