Structure Of The Cell Flashcards
Structure of Nucleus?
- nuclear envelope - double membrane
- nuclear pores
- nucleoplasm - granular, jelly-like material
- chromosomes - protein bound, linear DNA
- Nucleolus - smaller, inside nucleus, site of rRNA production and makes ribosomes
Function of nucleus?
- site of DNA replication and transcription (making mRNA)
- Contains genetic code for each cell
Structure of Endoplasmic Reticulum?
- Rough and Smooth both have folded membranes called cisternae
- RER have ribosomes on cisternae
Function of ER?
- RER - Protein Synthesis
- SER - Synthesise and store lipids and carbs
Structure of Golgi Apparatus
- folded membranes making cisternae
- secretory vesicles pinch off from the cisternae
Function of Golgi Apparatus?
- add carbs to proteins to form glycoproteins
- transport, modify and store lipids
- form lysosomes
- produce secretory enzymes
Lysosomes Structure?
- bags of digestive enzymes - can contain 50 different enzymes
Lysosomes function?
- hydrolyse phagocytic cells
- Autolysis - completely break down dead cells
- Exocytosis - release enzymes to the outside of the cell to destroy material
Mitochondria Function?
- Aerobic Respiration
- ATP production
- DNA to code for enzymes needed for respiration
Mitochondria Structure?
- double membrane
- inner membrane (cristae)
- fluid centre (mitochondrial matrix)
- loop of mitochondria DNA
Ribosomes structure?
- small, made up of two sub-units of protein and rRNA
- 80s - large ribosomes (eukaryotic cells, 25nm)
- 70s - smaller ribosomes (prokaryotic cells, mitochondria, chloroplasts)
Ribosomes function
Site of protein synthesis
Chloroplast structure?
- surrounded by double membrane
- contains thylakoids (folded membranes embedded with pigment)
- fluid filled stroma contains enzymes for photosynthesis
Chloroplast function?
Photosynthesis
Cell wall structure?
- Plants - made of microfibrils of the cellulose polymer
- Fungi - made of chitin - a nitrogen-containing polysaccharide
Cell wall function?
Structural strength of the cell
Plasma Membrane Structure?
- in all cells
- phospholipid bilayer - molecules embedded within and attached on the outside (proteins,carbs, cholesterol)
Prokaryotic cells compared to Eukaryotic Cells?
- Pro cells much smaller
- Pro cells have no membrane-bound organelles
- Pro cells have smaller ribosomes
- Pro cells have no nucleus
- Pro cells have cell wall made of murein
- Pro cells may also contain plasmids, capsule and flagella
Membrane-bound organelles?
Pro cells - mesosomes are in-foldings of the cell membrane that provide a large surface area for the attachment of the enzymes involved in respiration
Euk cells - mitochondria, chloroplasts, ER, Golgi
Vacuole Structure?
- filled with fluid surrounded by single membrane called a tonoplast
Vacuole function?
- make cells turgid and therefore provide support
- temporary store of sugars and amino acids
- pigments may colour petals to attract pollinators
