cell structure Flashcards
three main things of cell structure
All living organisms are made up of one or more cells
Cells are the basic functional unit (i.e. the basic unit of structure and organisation) in living organisms
New cells are produced from pre-existing cells
structure of eukaryotic cells
Cell surface membrane
80s ribisomes
cell wall
cytoplasm
nucleus
mitochondria
vacuole
chloroplast
endoplasmic reticulum
golgi apparatus
vesiclwe
lysomes
centriole
microtubules
microvilli
cilia
flagella - sometimes (sperm)
cell surface membrane
phospholipid bilayer
controls the exchange of materians in and out of cell
partially permeable membrane
cell wall
structural support to the cell
cellulose murein chitin
contains microfibril, pectin , hemicellulose and middle lamella
nucleus
large and seperated from cytoplasm by double membrane
nuclear pores allow mRNA and ribosomes to travel out of the nucleus
contains chromatin - made of sections of linear DNA
nucleolus - site of ribosome production
mitochondria
site of aerobic respiration
surrounded by double membrane and folds of cristae
matrix (instead of cytoplasm) contains enzymes needed for aerobic respiration
contains small circular pieces of DNA and 70s ribosomes , both found in the matrix
Chloroplast
surrounded by double membrane
thykaloids (which contain chlorophyll) stack up to form grana - thykaloids are the light dependent stage
grana are joined by lamellae
chloroplasts are site of photosynthes
stroma is site of light independent stage (stoma is instead of cytoplasm)
ribosomes
complex of rRNA and proteins
80s in eukaryotic
70s in some organelles and prokaryotes
site of translation
endoplasmic reticulum
RER - covered in ribosomes to process proteins
SER - no ribosomes on surface
involved in the production , processing and storage of lipids, carbohydrates and steroids
golgi apparatus
flattened sacs of membrane
modifies proteins and lipids before packaging them to vesicles which then transport proteins and lipids to their required destination
vacuole
sac surrounded by tonoplast
vacuoles in animal cells are temporary and small
vesicle
membrane bound sac for transport and storage
lysome
specialist vesic with hydrolytic enzymes
break down waste materials like worn our organelles used extensively by the immune system
centrioles
hollow fibres made of microtubules
organise spindle fibres in cell division
not in flowering plants or fungi
microtubules
made up of dimers which are made of tubulin
dimers make protofilaments, these make a cylinder
the cytoskeleton is used to provide support and movement for the cell
microvili
cell membrane projections that increase surface area for absorbtion
cilia
hair like projections made from microtubules
allows movement of substances over cell membrane
flagella
made of long microtubules
provide cell movement
eukaryotic cells can be specialised
specific adaptations can include
shape of cell
organelles it contains or doesnt
redblood cell
biconcave and no nucleus means there is more space for haemoglobin to transport oxygen
Neurons
function for conduction of impulses-
adaptations:
cell body where most cell structures are
axon is covered with a fatty sheath which speeds up nerve impulses - can be up to 1m longto enable fast communication over long distances
structures in prokaryotic cell
circular dna
capsule
pili
70s ribosomes
cell wall - muerin
cell membrane
plasmids
flagellum
cell membrane infolds
capsule function
protection
helps bacteria from drying out
flaggelum
rotate to enable movement
plasmid
small loops of DNA that contain genes that can be passed between prokaryotes (eg. antibiotic resistance)
infolding of cell membrane in prokaryote
may allow photosynthesis or nitrogen fixation
pili
attatchment to other cell surfaces
involved in sexual reproduction
virus organeles
protein
capsid
dna or rna genome
can have phospholipid outer layer
virus are parasitic
can only reproduce by infecting living cells
