cell structure and organisation Flashcards
cell theory
1- new cells are formed from already existing cells
2- a cell is a fundamental unit of structure
Prokaryotic cells
-DNA is not enclosed in a nuclear membrane
-DNA is circular
-contains flagellum,pili,capsule (sometimes)
-small ribosomes (free in cytoplasm_
-peptidoglycan cell wall
Eukaryotic cell
-DNA is bound in a nuclear membrane
-large ribosomes (free in cytoplasm and attached to rough ER)
-linear chromosomes
-cellulose cell wall (in plants)
-contains membrane bound organelles
Why are viruses not considered alive
-contain no cell membrane/ cytoplasm
-do not respire/ synthesise ATP
-do not grow
- requires a host cell to produce more virus particles
what makes up a virus
-protein coat (capsid)
-enzymes for virus replication
-a molecule of dna/rna essential for virus replication
-may also contain proteins, phospholipid bi-layer membrane (taken from host cell) and glycoproteins (act as receptor molecules to get the host cell to allow the virus into the cell)
PROKAYOTIC-mesosome
plasma membrane infolds
increases cell surface area to allow faster absorption of nutrients
PROKAYOTIC- plasmids/nucleoids
-circular DNA molecules containing gentic codes
-plasmids contain additional information (genes) e.g antibacterial resistance
PROKAYOTIC- peptidoglycan cell wall
-sugars and amino acid side chains
-beta and peptide bonds
-determines bacterial shape
EUKARYOTIC (both)- mitochondria
-double membrane
-inner membrane is folded to form CRISTAE (increase surface area for attachment of enzymes during ATP synthesis
-uses DNA and ribosomes to make their own proteins and self-replicate
EUKARYOTIC (both)- Rough Endoplasmic reticulum
-flattened membrane bound sacks found in the nuclear envelope
-ribsomes attach here
-transports the polypeptides from ribsomes to golgi body
-forms vesicles containing polypeptides
EUKARYOTIC (both)- smooth ER
-flattened membrane bound sacks found in the nuclear envelope
-can be attached to RER
-synthesis and transport of LIPIDS
EUKARYOTIC (both)- nucleolus
-dark stain in nucleus
-Made from condensed chromatids
-used to produce rRNA
EUKARYOTIC (both)- Golgi body
-formed from the fusion of transport vesicles created by the RER
-flattened membrane bound sacs (cisternae)
-modifies polypeptides to form proteins
-packages them into vesicles
EUKARYOTIC (animal)- centrioles
-creating spindle fibres in cell division
-micro tubules create flagella and cilia
EUKARYOTIC (plants)- chloroplasts
-double membrane with membrane bound sacs inside
