Cell structure Flashcards
Eukaryotic Cell
A cell that contains a nucleus and other membrane-bound organelles
Ultrastructure
The structural features that are seen in a cell under an electron microscope
Nucleus
Contains all DNA in form of chromosomes that code for proteins.
Controls all metabolic processes in the cell.
Has an envelope that controls substances that move across nucleus.
Nucleolus
Contains proteins and RNA that are used to synthesize ribosomes.
Mitochondria
Site of aerobic respiration and production of ATP.
Double membrane- Cristae and fluid Matrix
Contains mitochondrial DNA mtDNA
Vesicles
Membranous sacs that have storage and transport roles.
Contain fluid
Lysosomes
Vesicles that contain hydrolytic enzymes.
Tasked with breaking down waste materials and pathogens.
RER
It Has ribosomes bound to the surface
Responsible for synthesis and transport of proteins
SER
Responsible for lipid and carbohydrate synthesis, and storage.
Golgi body
Contains compact structure formed of cisternae
Modifies and packages proteins into vesicles.
Ribosomes
80s
Constructed of RNA
Site of protein synthesis
Cell Surface Membrane
Partially permeable
Controls which substances enter and exit cell
Cell wall
Made of cellulose.
Rigid structure and high tensile strength
Freely permeable
Supports individual cells.
Cilia
Hair like extensions
Mobile/Stationary cilia.
Stationary important for sensory
Mobile beat in rhythm: causing movement of substances eg mucus.
9+2 arrangement two central + nine outer microtubules
Intermediate Fibres
Give mechanical strength to cells and help maintain integrity.
Cell Movement
Actin filament changes with the addition and removal of monomer subunits.
Subunits can only be added in the correct orientation.
Change shape at - end but not + end so faster rate at + so moves.
Treadmilling
Due to the difference in the rate of addition at either end, at certain concentrations, some subunits will be added at one end and removed in another.
Centrioles
Composed of microtubules.
Two centrioles form a centrosome - involved in assembly and organisation of spindle fibres in cell division.
Chloroplasts
An organelle is responsible for photosynthesis in plant cells.
Double membrane
The fluid inside called the stroma.
The network of membranes which form flattened sacs called thylakoids, many stacked called grana. which contain chlorophyll
Grana joined by lamellae
Protein Production Process
1)Proteins synthesized in ribosomes of RER.
2)Passed into cisternae of RER and packaged into transport vesicles
3)Vesicles move towards the Golgi body via cytoskeleton and fuse with the cis face of the Golgi body and enter.
4)Proteins are structurally modified and re-packaged into secretory vesicles from the trans face.
5)Secretory vesicles carry proteins that are being expelled from the cell at the CSF membrane.
5)Exocytosis occurs.
Or stored in lysosomes as hydrolytic enzymes.
Prokaryotic Cell
Cells with no membrane-bound nucleus or organelles.
Prok. Cell Wall
Rigid outer covering made of peptidoglycan
Prok. Ribosomes
70s, slightly smaller. Only freely suspended
Bacterial Flagellum
a tail-like structure which rotates to move the cell
no 9+2
energy from chemiosmosis
attached by the basal body and rotated by a molecular motor.
Plasmid
A circular piece of DNA
Allows for sharing of genes between microorganisms.
Chromosome (Nucleotide)
Singular circular chromosome- supercoiled to make it compact.
Grouped into operons which are on or off.
Pili
Hair-like structures which attach to other bacterial cells
Slime capsule
The protective slimy layer that helps the cell to
retain moisture and adhere to surfaces
Endosymbiotic Theory
The theory that mitochondria and chloroplasts and other eukaryotic organelles were formerly free-living bacteria (prokaryotes).
These prokaryotes were taken inside as an endosymbiont.
Endosymbiont
An organism that lives within the body or cells of another organism.
