Prokaryotes and viruses Flashcards
5 kingdoms of living things?
Prokaryotes, animals, plants, fungi and protoctista
main differences between prokaryotic andd eukaryotic cells?
Prokaryotic have no membranes: so no nucleus, ERs, mitochondria, golgi etc
only living prokaryotes?
Bacteria
structures of ALL bacteria?
Cell membrane, cell wall, bacterial chromosome (DNA), 70s ribosomes and cytoplasm
Prokaryotic cell wall made of?
peptodoglycan (polysaccharides+ amino acids)
What is the structure of the bacterial DNA?
Circular- a loop- containing all of the necessary genes for a bacteria to be a bacterial cell. In an area called the nucleoid
Plasmids (O= optional/ only some have it)
Additional loop of DNA (not all have) containing only extra genes such as antibiotic resistance
Flagellum (O)
Rotating or waving ‘tail’ that makes bacterial cells motile (can move on their own)
Pilli/ pilus (O)
Hair like protein extensions. Attachment and exchange of genetic material from one bacterium to another (part of bacterial sexual reproduction)
(slime) Capsule (O)
Mucilaginous layer of slime, gives additional protection from drying out
cytoplasm contains?
enzymes and other soluble materials. jelly-like
why can the cell membrane be seen (and drawn) in bacterial cells?
The cells are not always turgid so the membrane is not pressed against cell wall
mesosome (O)
Infolding of cell membrane. Increase surface area for attachment of enzymes. Site of respiration
Chromatophore (O)
Infolding of cell membrane which has photosynthetic pigments attached: site of photosynthesis
Endosymbysis?
when an organism lives within the body or cells of another organism, usually in mutualistic relationship
Endosymbiotic theory? x2 points
Believed that prokaryotic cells entered eukaryotic cells and began a mutualistic relationship with them. Believed that some of these invading prokaryotic cells evolved into mitochondria and chloroplasts or present day eukaryotic cells
what allowed for entrance of prokaryotic cells into ancient prokaryotes?
Infolding of the plasma membrane
Examples of invading prokaryotes in endosymbiotic theory?
Cyanobacterium (containing chlorophlasts) and aerobic bacterium (respires aerobically) evolved into chloroplasts and mitochondria respectively
Evidence of endostymbiotic theory?
Mitochondria, chloroplasts and prokaryotic cells:
Are all the same size
Divide into two by binary fission
Have their own DNA which is circular (not linear)
Have their own ribosomes which are 70s
Are viruses living?
No because they have no cytoplasm and only one characteristic of life: that they reproduce
Characteristics of viruses?
Very small in size
Live in host cells
Use host cells to reproduce
Obligate parasites
Contain DNA or RNA
There is a wide variety
What are obligate parasites?
Organisms that cannot complete their life cycle without exploiting a suitable host
Structure of simplest possible virus?
Consist of a small piece of DNA or RNA surrounded by a protein coat called the caspid
Stricture of more complex virus?
Consists of DNA or RNA, can have 2 protein coats, outer lipoprotein envelope with protein molecules embedded, enzyme reverse transcriptase
