S&F; Intro to the Cell Flashcards
(35 cards)
what is the cell theory?
all living organisms are composed of one or more cells
cell is the basic unit of structure and organisation
all cells arise from pre-existing cells
what are the universal similarites bt cells
dna is the heritable material, dna is messenger, and proteins are workers
major cellular organelles
atp as energy source
what are the similarites bt prokaryote cells vs eukaryote cells
both have plasma membrane, cytosol, dna, rna, protein and ribosomes
what are the differences bt prokaryote cells vs eukaryote cells
eukaryotic cells have membarne boudn organells, and are much larger
prokaryote cells lack a membrane bound nucleus
what does the cytoplasm consist of?
everything inside the plasma membrane not including nucleus
nucleus, er (smooth/rough), golgi apparatus, lysosomes, mitochondria, ribosomes)
cytosol???
liquid part of the cytoplasm
water + dissolved substances (ions, atp, proteins lipids)
what is the plasma membrane
selectively permeable barrier controlling what enters/exits
double layer of phospholipids w embedded proteins
what are phospholipids made of?
hydrophilic polar heads
hydrophobic lipid tails
double layer around cytoplasm, tail to tail
what are the two types of pm proteins?
integral and peripheral proteins
what are integral proteins? +example
they are embedded partially/fully into the membrane
transmembrane proteins; fully span the entire membrane and contacts both extracellular + cytoplasmic areas
what are peripheral membrane proteins?
they are associated with the membrane, but not actually embedded across it
what are the functions of plasma membrane proteins?
- transport; can be gated/not
- enzymatic activity; chemical reaction
- signal transduction; external signaling molecule causes communication of information
- cell-cell recognition; glycoproteins used as molecular signatures in extracellular
- intercellular joining; gap/tight junctions
- attachment to cytoskeleton + ecm; fibronectin. facilitates movement.
special definition of membrane
a membrane is a mosaic of molecules bobbing in a fluid bilayer of phospholipids. they are cell specific and dyname.
what are the features of the nucleus
enclosed by a double lipid bilayer called nuclear envelope
entry and exit through nuclear pores
contains nucleolus; rrna production, and assembly of small + large ribosomes
what are the functions of the nucleus
house/protect dna
make rna + assemble ribosomes
pores regulate movement of substances in and out
molecule segregation allows temporal and spatial control of cell function
how is dna made?
dna wrapped 2x around 8 histones -> nucleosomes -> chromatin -> chromatin fibres -> loops -> chromosomes
what is the function of ribosomes?
protein production (translation)
there are two units
where are the two places that ribosomes can be found?
- free in the cytoplasm; making proteins used in cytosol (non endomembrane destinations)
- attached to the rer; making non-cytosolic proteins/endomembrane
what is the er?
endoplasmic reticulum; extensive network of tubes + tubules stretching out from the nuclear membrane
has rer and ser
what are the features of the rough endoplasmic reticulum
continuous with nuclear envelope
dotted with attached ribosomes
proteins enter lumen within the rough er for folding
rough er membrane surrounds the protein to form transport vesicles for the golgi
what are the major functions of the rer
production of..
secreted proteins
membrane proteins
organelle proteins
what are the features of the smooth er
lacks ribosomes; doesn’t make proteins
extends from the rer
what are the major functions of the ser
housing unit for proteins/enzymes
synthesizes lipids (steroids + phospholipids)
storage of cell-specific proteins, not all cells make all proteins
what is the golgi aparatus made out of?
3-20 flattened membranous sacs (cisternae) stacked on top of each otehr
