W2 cell organelles Flashcards
what are all cells surrounded by
2 molecule thick plasma membrane
why are plasma membrane selectively permeable
allows maintenance of low entropy
what is the plasma membrane made of
integral and peripheral membrane proteins
what do plant and bacteria cells have that animals dont
cell wall for rigid support
what is the bacteria cells wall made of
peptidoglycans
what is the glycocalyx made of
capsule + slime layer
what is the glycocalyx
a gelatinous polysaccharide layer
how do you test cell walls in bacteria
using Gram’s stain
what colour does a gram positive stain give
blue/purple
what are organelles
tiny structures that perform specific functions embedded in cytoplasm
whats the role of the nucleolus
- ribosome synthesis
- contains ribosomes genes
- rRNA stored here
what is the nucleus nuclear membrane
double layer membrane around nucelus for controlled movement
what must things have to enter the nucleus
nucleus localisation sequence (NLS)
what is euchromatin
loosely packed and transcribed
what is heterochromatin
densely packed and plays regulatory roles
how does the packing of DNA affect e- micrscrope
- dense stop e- from passing
- loose allows e- to pass
what is a centriole
- adjacent to nucleus
- pair of microtubules
whats the role of the centrioles
- form centrosome
- organise mitotic spindles
what is a centromere
constricted region of chromosome
why is mitochondria folded into cristae
- contains the ETC
- ATP synthase
- increase SA for more ATP synthesis
why does mitochondria have its own DNA
- codes for 37 genes -> 13 in ETC
- due to endosymbiotic theory
what is the endosymbiotic theory
mitochondria was originally prokaryotic cells and formed a symbiotic relationship w cells
why is mitochondria only inherited from mum
- only acrosome and nuclear DNA from sperm enters oocyte
what is the function of mitochondria
- contain oxidative enzymes
- aerobic catabolism of fuels
- oxidative phosphorylation for ATP
how does mitochondria create energy
- carbon based fuels by oxidative phosphorylation
- generate reactive oxygen species and free radicals
what are ribosome subunits
- made of 1 small and large subunit
- each subunit is a complex of rRNA + proteins
what are polysomes
many ribosomes translating the same mRNA
what the functions of RER
- protein synthesis
- modify proteins
- destroy mis folded proteins
whats the function of golgi appartus
package things into vesicles
where do molecules enter/leave golgi apparatus
- enter from ER to cis face
- leave from trans face of golgi
- movement by vesicular trafficking
what is vesicular trafficking
- movement of vesicles
- fusing vesicles with other membranes
what are secretory pathways
- exocytosis
- secretory vesicles regulated by signals
what are digestive organelles
endosome
lysosomes
peroxisomes
what are the 3 types of endosomes
early
recycling
late
what are endosomes
incoming vesicles formed by endocytosis
what are lysosomes
- contain digestive enzymes
- break down old cells and viruses
- fuse with late endosomes
what are peroxisomes
catabolism of FAs + AA + polyamines for acetyl coA production
acetyl coA production creates hydrogen peroxide how is this removed
by the enzyme catalyse
