lecture 6 - Part I cells Flashcards
plasma membrane
boundary between cell and outside environment
two components of the plasma membrane
phospholipid molecules
protein molecules
functions of the plasma membrane
transport in and out of the cell
selectively permeable
cell signalling
cell adhesion
phospholipids
fatty acids bound to glycerol
phosphate group replaces one fatty acids
what happens when phospholipids are placed in water
form double layer
hydrophobic heads – face outward
hydrophobic tails – face inwards
which cells have a cell membrane
all cells
some organelles aswell
nonmembrous organelles
not come-lyly closed by membranes
direct contact with cytosol
membranous cells
enclosed by membrane
nuclear membrane
encloses the nucleus
nucleus pores
control passage of molecules in and out of nucleus
nuclear lamina
network of protein filaments that maintain shape of the nucleus
what happens inside the nucleus
DNA combines with protein for chromatin
chromatin forms chromosomes
DNA is replicated in nucleus
site of genetic control
nucleolus
spherical and surrounded by a layer of condensed chromatin
cytosol
“soup”
all other organelles reside
where most cellular metabolism occurs
cytoplasm
collective term for organelles and cytosol
smooth ER
rich in enzymes
played a role in metabolic processes
functions of smooth ER
synthesis of lipids
metabolites energy
stores calcium
Rough ER
produce proteins for the rest of the cell
ribosome
located in rough ER
to make proteins for the rough er to distributed
what is the process of synthesis proteins from the rough ER
- when a polypeptide is synthesized on a ribosome it is threaded into the er through a pore
- when it enters the ER, new protein folds into 3D conformation
- in the lumen, enzymes can modify protein by adding carbs or liquids
- then secretary proteins depart wrapped is transport vesicles
what is the process of synthesizing membranes
some proteins made by the ribosomes in ER get placed into the ER membrane itself
hence, the er membrane becomes bigger
some breaks off and ends up in other organelles
vacuoles
sacs within the cell made out of the same material as the cell membranes
vesicles
very small vacuoles
made at the golgi apparatus
function of vesicles
carry protein molecules either to other organelles or cell membrane
golgi apparatus
received protein from the ER
cis region og GA
receives vesicles from ER
trans region of GA
vesicles but off from golgi apparatus and are moved to cell mebrane
functions of the golgi
processing proteins
sorting proteins
secretion of proteins
what does the golgi do in plant cells
polysaccharides are synthesized
peroximes
contain a variety of enzymes in order for the body to rid toxins
transfers hydrogen from various substances to oxygen
what is the intermediate product form the peroximes job
hydrogen peroxide
role of the peroximes
to protect cells from its own production of hydrogen peroxide
converts it into water
lysosomes
small bags filled with hydrolytic enzymes
acidic
function of lysosomes
break down proteins, carbs, nucleic acids and lipids
primary lysosomes
bud from golgi complex
secondary lysosomes
form from fusion of a primary with a vesicle
why do animal cells need lysosomes
to digest and use food for energy
why are lysosomes not needed in plant cells
plants cells have walls tough enough to keep large foreign objects out of the cell
autophagy
when lysosomes degrade worn out organelles
make their molecules available for new organelles
phagocytosis
amoebas and other protists eat by engulfing food particles
end-membrane systems
organelles either directly continuous or connected by transfer of vesicles
functions of the end-membrane system
synthesis of proteins transporting of protein into membranes and organelles metabolism movement of lipids detoxification of poisons
