Topic 10: Prokaryotes Flashcards
What are prokaryotes characterized by?
Small mircoscopic size and unicellularity
What distinguishes prokaryotes from eukaryotes
Lack of
- membrane bound organelles
- circular genones
- lack of a nucleus
Do almost all prokaryotes have a cell wall?
Yes
What is peptidoglycan
A network of sugar polymers in bacterial cell wall that are cross-linked by short peptides that
What are the Structural functions that crontibuted to prokaryotic success
-cell srface structure
-endospores
- motility
- simple internal organization and DNA
- reproduction by binary fission
What is gram staining
A method to distinguish gram positive and gram negative bacteria
What do gram positive bacteria have in their cell wall
A thick layer of peptidoglycan that trap cyrstal violet crystals
What is the cell wall structure of gram negative bacteria
A thinlayer of peptidoglycan in between two lipid bilayrs
Which bacteria (negative/positive) are harder to treat since they are resistant to antibiotics
Gram negative
What is the function of a capsule in prokaryotes
Allows for adhesion to join cells and surfaces
Prokaryotes have a sticky poly saccharide protein layer called a ____
Capsule
What is the role of a capsule
Retain water, and protect cells from dessication, allow for invasion of the immune system in a host
What is an endospore
A dormant cell that develops in some prokaryotes when environment conditions become unfavourable and dissapear when favourable conditions are met
Has a coat that confers resistance
Prokaryotes have the ability to move ___
Actively
What movement do prokaryotes typically achieve?
Flagella (whip like movement)
Explain taxes (not bills you pay) and give two examples
The ability to move in response to stimulus (chemotaxes and phototaxes)
What are procakryote CELLS characterized by
Internal structure wihout complex compartmentalization
Prokaryotes have genomes consisting of small _____ __________
Circular chromosomes
Some small species of bacteria also have smallerDNA molecules called _____
Plasmids
What are plasmids
Compact rings of DNA containing a limited number of extra genes (that provide prokaryotes with moree diversity)
How do prokaryotes reproduce quickly
Through binary fission
Three factors that contribute to genetic diversity
- rapid reproduction
- mutations
- genetoc recombination
Mutation rates during binary fission is ___
Low
Are prokaryotes primitive
Nope
What is horizontal gene transfer
Gene recombination that occurs between individuals from different species
Rokaryotes engage in _____ _______, a process where genetic material is exchanged between individual cells
Genetic recombination
What are the three mechanisms of genetic recombination
- transformation
- transduction
- conjugation
