1.2 Ultrastructure of cells Flashcards
Define prokaryote
A prokaryote is a simple cell that lacks a nucleus and all membrane-bound organelles
Bacteria are prokaryotic cells
What is a genophore?
The genophore is a circular DNA molecule that contains the genetic material (i.e. bacterial ‘chromosome’)
What is a plasmid?
Plasmids are additional autonomous DNA molecules that can be transferred via bacterial conjugation
What is a bacterial cell wall composed of?
The bacterial cell wall is composed of peptidoglycan
What is the role of pilli?
The role of attachment pilli is to adhere to surfaces
What is the role of sex pilli?
The role of sex pilli is to allow bacteria to exchange genetic information (plasmids) via bacterial conjugation
How do bacterial cell divide?
Bacterial cells divide by binary fission (asexual reproduction)
* The circular DNA molecule is copied and then is anchored to the plasma membrane
* The DNA loops are drawn apart as the cell elongates, before dividing (cytokinesis) to form two clones
What is the role of the nucleas?
The nucleus is a double membrane structure (with pores) that stores DNA
It is the site of transcription (RNA synthesis)
What is the role of the nucleolus?
The nucleolus is a region within the nucleus where ribosomes are assembled
What is the role of the Endoplasmic
Reticulum?
The endoplasmic reticulum is a membrane network that transports materials
between organelles (via vesicles)
What is the role of the golgi apparatus?
The golgi apparatus is involved in the sorting, storing, modification and export
of secretory products from the cell
What is the role of ribosomes?
Ribosomes are responsible for protein synthesis (translation)
They can be found freely within the cytosol or may be embedded on the rough ER
What is the role of mitochondria?
Mitochondria are responsible for aerobic respiration (ATP synthesis via oxygen)
What is the role of mitochondria?
Mitochondria are responsible for aerobic respiration (ATP synthesis via oxygen)
