Ultrastructure of a cell 2.1.1 (g,h,i,j,k) Flashcards
what are the two types of cell?
prokaryotic
eukaryotic
where do cell reactions take place?
the cytoplasm
what is an organelle?
membrane-bound compartments
function of a membrane?
controls the movement of substances in and out of a cell and organelles
what is the nucleus?
contains the genetic information in the form of DNA
what is the double membrane in a nucleus?
the nuclear envelope
what allows molecules to move in and out of the nucleus?
nuclear pores in the envelope
what is chromatin?
the complex of DNA wound in histone proteins
what happens when chromatin coils and condenses?
chromosomes form
visible during division
what is the nucleolus?
area WITHIN the nucleus where ribosomes are produced
what is the mitochondria?
site of cellular respiration
structures in the mitochondria
cristae
matrix
inner membrane
outer membrane
DNA
what is the cristae?
the folding of the inner membrane
what is the matrix?
the fluid in the mitochondria
why does mitochondria have DNA?
allows it to reproduce and produce enzymes
what are vesicles?
membraneous sacs used for storage and transport
single membraned
what are lysosomes?
specialised vesicles which contain hydrolytic enzymes used to break down waste materials
what is the function of the cytoskeleton?
- maintain shape and stability
- control cell and organelle movement
- hold organelles in place
- allow the cell to move
what is the cytoskeleton made up of?
microfilaments
microtubules
intermediate fibres
what do microtubules do?
allow for the movement of cells and organelles
what are spindle fibres made up of?
microtubules
what do microfilaments do?
allow for the movement of cells
what do intermediate fibres do?
provide mechanical strength to cells
what are centrioles for?
composed of microtubules
used for the separation of chromosomes
NOT FOUND IN PLANTS
what are flagella for?
cell mobility
what is the formation of microtubules like in cilia and flagella?
ONLY IN EUKARYOTES
9 + 2
what are cilia for?
acts as sensors for cells
allow for adjacent cells to move
- found in trachea to help waft away mucus from lungs
what is secretion?
transport OUT of a cell
what is the smooth endoplasmic reticulum?
site of lipid synthesis
what is the rough endoplasmic reticulum?
site of protein synthesis and transport
are ribosomes membrane bound?
NO
where are ribosomes found?
in the cytoplasm
attached to the RER
what is the golgi complex?
site where proteins are modified and packaged into secretory vesicles
outline protein synthesis
mRNA leaves the nucleus at nuclear pores in the nuclear envelope
mRNA is translated into a protein at the ribosomes found at the RER
the RER packs the protein into a transport vesicle
transport vesicle carried by the cytoskeleton to the golgi complex
protein is modified and packaged into a transport vesicle which then undergoes exocytosis and fuses with the cell surface membrane and is expelled
what is a cell wall?
gives a cell it’s shape and rigidity
maintains the turgor pressure in a plant cell
protects plant cells from pathogens
what is a vacuole for?
membrane sacs which contain sap
important in maintaining turgor pressure
what is the membrane in a vacuole?
the tonoplast
what are chloroplasts?
sites of photosynthesis in plant cells
structures of a chloroplast?
stroma
grana
thylakoid
inner membrane
outer membrane
lamellae
DNA
ribosomes
what is the stroma?
the fluid enclosed in the chloroplast
what are the grana?
stacks of thylakoids
what are lamellae?
they link the grana together
DNA in a eukaryote
double helix
what size ribosomes in eukaryotes?
80S
larger
what size ribosomes in prokaryotes?
70S
smaller
cell wall in prokaryotes are made up of?
peptidoglycan
structures in a prokaryote
DNA
flagella
ribosomes
plasma membrane
cell wall
plasmid
eukaryote vs prokaryote size
eukaryotes are larger
eukaryote vs prokaryote DNA
eukaryotes have linear DNA
prokaryotes have circular DNA
eukaryote vs prokaryote ribosomes
eukaryotes have larger 80S
prokaryotes have smaller 70S
