Lecture 2 Flashcards
Progeria
aging starts in first years of life
balding, wrinkled skin, alopecia, etc.
rare genetic disease,
avg lifespan of 14 years
mutation in a gene = disfunction protein which is imp for cell nucleus shape
nucleus
organelle in eukaryotic cells
distinguishes euk and prokaryotic cells
stores genetic info DNA and genome
cell nucleus shape
nucleus has 2 layers of lipid mb = nuclei envelope
has lamin proteins in cytoskeleton that support nuclear envelope
what processes occur in nucleus
transcription (RNA synth)
replication (DNA synth)
nucleus structrure
has pores = protein lined channels = reg transport of molec bn nuc nad cytoplasm
nucleolus = dense region of nucleus
= ribosomal RNA synth
+ ribosome assembly
genome organization inside the nucleus
DNA molecules combine with proteins to form fibres called chromatin = spaghetti formation
in mitosis and meiosis = chromatin coils and condense into visible chromosomes
organelles
mb enclosed compartments inside eukaryotic cells
organelles in plant and algae only
chloroplast and vacuoles
cytoplasm
all material in cell, other than nucleus and cell mb
so organelles included
cytosol
the cytoplasm includes the cytosol = the gel like fluid
cytoskeleton
network of proteins
support cell and nucleus shape
ER
network of interconnected mbs
brach through cytoplasm
RER
site of protein synth, (on)
(In)chemical mods
tagging nad folding
SER
lipid and steroid synth
Ca ion storage
glycogen degradation
Golgi apparatus
what
components + regions
site of protein mods and storign
2 components = flattened mb sacs = cistern
small mb-encloded organelles = vesicles
3 functionally distinct regions
= cis face, medial face and trans face
Golgi roles
receiving vesicles from RER that have proteins
adding carbs to proteins or modifying carbs all att in RER
modifying, packaging and sorting proteins before sent to cell/extra-cellular destination
pathway of protein
ER -> cis Golgi -> medial ->trans
a_ cell mb = to be secreted or part of mb itseld
b_lysosome = to fn as digestive enzyme
endosomes
mb bound vesicles
surr by single mb
direct enterring substances to lysosomes for deg or to plama for recycling
steps to endosome role in receptor mediated endocytosis
endocytosis = bringing stuff in
1. ligand binds to receptor
2. mb buds off and forms a coated vesicles
3. this fuses w endosomes
(separates receptor and ligand)
4. recycles receptor, goes back to mb
5. lysosomes degrades ligand
lysosomes
sacs w digestive enzymes to digest, proteins, lipids, nucleic acids, and old organelles
site of breakdown of foods/other cells or foreign objects
surr by single mb
int is more acidic than cytoplasm
endomembrane system components
7 compoenents
nuclear envelope
ER
golgi apparatus
endosomes
lysosomes
vesicles
plasma mb
interconnected
vesicles trasport substance bn each component
mitochondria
2 mb (outer and inner)
folds of inner mb = Cristae
space bn 2 mb = intermb space
interior = matrix
proteins involved in cell resp are imbeddd in inner mb
chloroplast
surr by 2 mb
thylakoid = site of photosynth
mb of thylakoid = thylakoid mb
stack of thylakoid = granum
interior = stroma
peroxisomes
destroy toxic peroxides
such as hydrogen peroxide (h2o2)
accumulated and broken down
vacuoles
storage comparetments in plants, fungi and protists
inc in water P to stiffen the cell
support plant body
reproduction (have pigments_
digestions
storage of toxic molecs and waste
compartmentalization is important
timing, want smth now, other things later
storage
diff conditions for diff processes (lysosomes w Lower ph)
chem conc and efficient chem rxns
pro cells share basic features
mb, nuclei, cytoplasm and ribosomes
some pro cells have specialized features
some have
cell wall and capsules
internal mb
cytoskeleton
flagella
pili
fijmbraie
some pro cells have a cell wall
so have a plasma mb, a peptidoglycan cell wall
gram (-) bacteria have a secondary outer mb
some have a capsule surr cell wall
made of polysaccharides
protects bacteria from attack by WBC
keep from drying out
help bacteria attach to eo
some have cytoskeleton
have filamentous proteins
same as those ones found in euk cells
involved in cell division, movement and maintaining shape
flagella
motility
adhesion
invasion
pili
motility
contact
adhesion
genetic exchange
fimbrae
contact and adhesion
SA imp
det amount of substances entering and exiting the cell
to fn optimally, cell must have a large Sa/V ratio
ex. why are skin cells small and many
easier to repair 1 small, than 1 large
if one is damaged or dead, others will take over
diffusion is easier w smaller cells
bigger = less efficient = takes more time for materials to find e/o = traffic problem
+
components become diluted
+
more metabolic demands to control + inc waste
phototroph
E source is light
chemotroph
E source is glucose, chemical cmpds
photoautotroph
inorganic cmpds for C source
+ E = light
photoheterotrop
organic cmpds for C source
+ E = light
chemoautotroph
inorganic cmpds for C source
E = chemical cmpds
chemoheterotroph
organic cmpds for C source
E = chemical cmpds
