overview of cells Flashcards
define life
probability of replication
robustness in an environment/ to the environment
how did cells first appear?
abiotic synthesis of small molecules
join into large macromolecules
packaged into protobionts
endosymbiosis
explains origins of eukaryotic organisms
what is the evidence for endosymbiosis
- chloroplasts and mitochondrai have own DNA, distinct inheritance
- ribosomes in organelles different size to those in cytoplasm, similar to bacteria size here
- mitochondria sensitive to anitbiotics
- double membrane
- divide independenly of nuclear division
what happened to genes during this process?
genes were lost
processes such as cell wall synthesis not needed to lost
how did the process of sequential endosymbiosis occur?
- primitive cell develops internal membranes becoming ancestral eukaryote
- this engulfs aerobic heterotrophic prokaryote to become modern-day mitochondria
- some also take up photosynthetic organisms resembling cyanobacteria
.4. ancestral photosynthetic eukaryote made!
what process made todays cells?
sequential endosymbiosis
who made the endosybiosis theory?
Lynn Margulis
how are plant and animal cells made differently in endosymbiosis
for animal cells the process stops and englufing the heterotroph making mitochondria
for plants it continutes allowing the photosynthetic pigment to be present
what is snythetic biology
- design and construction of new biological parts, devices or systems
- re-design of extisting natural systems for useful purposes
top down approach
re-engineer existing system by introducing new parts
bottom up approach
design and build new sytesms using basic chemicals an building blocks
functions of cell chemistry
food/gas
control of pH and temp changes
waste products
prokaryote features
no clear structure
unicellular
smaller
eukaryote features
defined structure
definded nucleus
can be multiculular
largerin size
how can we visualise cells?
too small for naked eye
whats the range of view of a light microscope?
1um
range of view of electron microscope
100um-0.1um
whats the effect of largeness of cells
longer diffusion rates
takes longer for chemical reactions
whats the solution to slow diffusion rates
compartmentalisiation
how does compartmentalisation work
organised by function and divided y boundaries and membranes
describe a simple monolayer membrane
one layer of lipids
hydrophobic tail
hydrophillic head
describe a bilayer membrane
two layers of lipids with tails pointing inwards
amphiphatic phospolipids
some characteristics of amphiphatic phosphilid bilayers
energetically favourable
form spontaneously
charactristic of animal cells
proteins made in the RER of ribosomes and exported out
proteins also made in nucleus
nucleus size
1-3um
nucleus charatceristics
site of cellular DNA storage, replication, translation, transciption
rough ER features
associated with nucleus
site of proteins translation for membranes or secretion
smooth ER featues
no ribosomes
involved in carbohydrate and drug metabolism and ion movement
how are things transported from the ER to the golgi
vesicles
membranes that budd off
golgi apparatus features
transport vesicles to here
what does the golig do to vesicles?
add proteins to decide where it goes
packages the vesicle and sends chemicals.
what is the cytoskeleton?
not an organelles but part of the cells organisation
whats the cytoskeleton involved in
movement and transport
proteins of the cytoskeleton
microtubules
actin
intermediate filaments
peroxisome
contain oxidative enzymes that produce hydrogen peroxide as a toxic byproduct
