2.1.1 EUKARYOTES Flashcards
Eukaryote organelles
nucleus, nucleolus, nuclear envelope, rough and smooth endoplasmic reticulum (ER), Golgi apparatus, ribosomes, mitochondria, lysosomes, chloroplasts, plasma membrane, centrioles, cell wall, flagella and cilia
3 functions of nucleus
Organelle stores DNA (instructions for protein synthesis)
controls cell activity to regulate gene expression
involved in transcription to produce mRNA for protein synthesis
nucleus structure
nuclear membrane with nuclear pores spanning it
surrounding the nucleoplasm which holds the nucleolus and chromatin
nuclear membrane
made up of double lipid bilayer
surrounds nucleus
barrier from cytoplasm preventing unwanted substances in nucleus
has nuclear pores which selectively allow stuff like proteins through
nucleolus
dense sphere in nucleus
made up of RNA and proteins
- it transcribes and processes rRNA
- assembles rRNA into ribosome
- which is then transported into cytoplasm for protein synthesis
nuclear pore
allows needed substances in (steroid hormones) and out (eg mRNA) of nucleus
Rough endoplasmic reticulum structure
System of flattened membrane (cisternae)
Contains cisternae fluid
coated with ribosomes
RER function
RER’s ribosomes translate mRNA into amino acids, which are then assembled into polypeptides
RER modifies proteins for use in the cell.
RER checks proteins for proper folding and formation
protien is pinched off from rer into vesicle and moves to golgi
Smooth endoplasmic reticulum structure
cisternae flattened membranes that have fluid filled cavities
SER function
lipid-synthesis
cholestrol/lipids/steroid hormones
golgi apparatus structure
stacked membrane-bound, flattened sacs
golgi appartus function
modifies proteins (adds glucose for glycoprotein, adds lipid for lipoprotein, folds into 3d shape)
then these proteins are packaged into vesicles and pinched off to be stored in cell or moved to plasma membrane
mitochondria structure
rod shaped
surrounded by two membranes (inner membrane is highly folded into cristae)
it is filled with fluid-filled matrix
(in microscope lines go up down the cell)
mitochondria function
site of ATP production during aerobic resp
self-replicating so it can make more if needed
lots in muscle/liver cells/neurotransmitters where energy is most needed
chloroplast structure
found only in plant cells
surrounded by double membrane
inner membrane is continous stacks of flattened membrane-sacs called thylakoids
each stack of thylakoids is called granum
the fluid inside chloroplast is stroma
chloroplast function
site of photosynthesis
1- light trapped by chlorophyll to make ATP in grana
2- h reduces co2 using energy from ATP to make carbs
large permanent vacuole structure
surrounded by tonoplast membrane
filled w cell sap
large permanent vacuole function
filled w water and solutes to maintain cell stability
makes cell turgid when full of water
lysosome structure
small bags formed by golgi apparatus
surrounded by single membrane
contains hydrolytic enzymes
has wbc’s
lysosome function
engulfs old cell organelles and digests them to return them as digested components to be reused
cilia structure
protrusions from cell
surrounded by plasma membrane
contains microtubules
formed from centrioles
cilia function
moves mucus in your esophagus to clear and protect airway
protects lungs from pathogens by trapping them in mucus
undulipodia structure
sperm tail
ribosomes structure
80s = eukaryotes
made of rRNA
made in nucleolus
ribosomes function
protein synthesis
centrioles structure
consists of two bundles of microtubules at right angles to each other
the microtubules are made of tubulin
arranged in cylinder
centriole function
before cell division, spindle made of tubulin thread forms from centriole
chromosomes attatc to middle part of spindle and motor proteins walk along tubulin thread pulling chromosomes to opp ends
centriolesform cilia and undelopodia:
centrioles multiply and line upbeneath plasma membrane
microtubules then sprout outwards from each centriole forming cilium/undelepodium
cytoskeleton structure
rod like microfilaments made of subunit of protein actin
microtubules made of tubulin
cytoskeletal motor proteins are mlecular motors
they also allow hyrolysis of ATP
cytoskeleton function
microfilaments:
intermediate filaments anchors nucleus in place in cytoplasm
provides tensile strength in cell
microtubules:
forms mitotic spindle fibres, cilia, flagella
assists in cell-cell signaling
cellulose cell wall structure
outside the plants plasma membrane
made of bundles of cellulose fibres
Cellulose molecule is polymer made of b-glucose
molecules form a H bond with each other
forming larger microfibrils
These overlap, forming mesh like structure of cell wall
cellulose cell wall function
high tensile strength: prevents cell bursting when turgid
permeable to small molecules: allows water in needed for photosynthesis
plant cell vs animal cell
plants have:
cellulose cell wall
large permanent vacuole
chloroplast
animal cells:
lysosome
centrioles
how is the structure of a mitochondrion adapted for its function
Large surface area due cristae to allow more ATP production
Matrix contains enzymes for aerobic respiration
Double membrane allows compartmentalization for efficient ATP synthesis
