Cell structure and organisation Flashcards
What is the function of the nucleus, nucleolus, nuclear pore and nuclear envelope?
Nucleus - contains the DNA which codes for protein synthesis
Nucleolus - synthesis of RNA and ribosomes
Nuclear pore - allow transport of RNA out of nucleus
Nuclear envelope - separate DNA from cytoplasm
What is the function of the cell membrane?
Controls what goes in and out of cell
What is the function of mitochondria?
Site of aerobic respiration. Synthesises ATP. Cristae increase the SA on where the respiratory process takes place
What is the function of the rough endoplasmic reticulum (RER)?
Transport proteins which are synthesised by the attached ribosomes
What is the function of the smooth endoplasmic reticulum (SER)?
Synthesis and transport of lipids
What is the function of the Golgi body/apparatus?
Chemically modify proteins. Produce lysosomes and glycoproteins. Package proteins for secretion out of cell
What is the function of centrioles?
Are use in spindle formation (microtubules) in cell division
What is the function of ribosomes?
Protein synthesis
What is the function of lysosomes?
Contain and isolate digestive enzymes which are released and destroy organelles. Digestion of material that has been taken into the cell
What is the function of vesicles?
Animals - Act as a contractile vacuole to maintain osmotic pressure
Plants - Storage of ions and organic molecules
What is the function of chloroplasts?
Site of photosynthesis. Thylakoids contain photosynthetic pigments
What is the function of the cell wall?
Provide strength and support. Freely permeable to water
What is the function of the plasmodesmata?
Exchange of large organic materials via cytoplasmic streaming. Allows communication between adjacent cells
What size ribosomes are found in chloroplasts and mitochondria?
70s ribosomes
What size ribosomes are found in animal and plant cells?
80s ribosomes
How are proteins produced?
- One gene on the DNA codes for the amino acid sequence in one polypeptide
- Ribosomes synthesise the polypeptide
- The RER transports protein through the cell within it’s cisternae
- Protein packaged into transport vesicle
- The protein is chemically modified and either glycoproteins or lysosomes are produced
- Protein packaged into secretory vesicle and is secreted by exocytosis which requires ATP
- If stays in the cell then it’s a lysosome containing protease. Digests/hydrolyses worn out organelles
What does the DNA look like in a eukaryotic cell?
Linear DNA (nucleus)
What does the DNA look like in a prokaryotic cell?
Circular DNA (nucleoid/plasmid)
What is the size of ribosomes in a prokaryotic cell?
70s
What is the size of ribosomes in a eukaryotic cell?
80s
What are the cell walls of prokaryotes made of?
Peptidoglycan
What are the cell walls of eukaryotes (if they have them) made of?
Cellulose (plants)
Chitin (fungi/insects)
Do prokaryotes contain membrane bound organelles?
No
Do eukaryotes contain membrane bound organelles?
Yes