1.7. Bacteria Flashcards
(32 cards)
The earliest known fossil of prokaryotes
are about 3.5 billion years old
The Earth was formed about
4.5 billion years ago
Most biologists believe that eukaryotes evolved from prokaryotes about
2 billion years ago
The two groups of prokaryotes are
Bacteria and Archaea
The thing that distinguishes bacteria from Archaea
is its ability to form spores.
What is bacterial cell wall made up of?
A strengthening material called peptidoglycan.
What is peptidoglycan
A polysaccharide combined with amino acids
What is peptidoglycan also known as
Murein
What is benefit of cell wall being made with peptidoglycan
It makes the bacterial cell wall more rigid
What are the benefits of cell walls in bacteria
The cell wall protects the bacterium and is essential for its survival. It prevents the cell from blowing and bursting if water enters the cell by osmosis.
What does the cytoplasm in a bacterium not contain
any double membrane bound organelles (such as mitochondria)
What does the cytoplasm in bacterium not contain
any double membrane bound organelles (such as mitochondria)
The DNA molecule in bacteria is
Curcular
The DNA molecule in bacteria is found in a region called
Nucleoid
What is found in nucleoid in a bacteria
The DNA, proteins and small amounts of RNA
There may be more than one copy of DNA molecule in a given cell
What is the size if bacterial ribosomes
70S ribosomes
Some bacteria are able to swim because
They one or more flagella
Describe the structure of bacterial flagella and its how it performs its function
The bacterial flagellum is a simple hollow cylinder made of identical, protein molecules. it is a rigid structure, so it does not band unlike the flagella in eukaryotes. It is wave shaped and works by rotating at its base like a propeller to push the bacteria through its liquid environment. As a result, the bacterium moves forward with Corkscrew shaped motion.
What’s the function infolding of cell surface membrane that is found in some bacteria
In some bacteria, the self surface membrane falls into the cell, forming an extra surface on which certain biochemical reactions can take place.
What are some of the biochemical reactions that can take place in certain bacteria
In blue green bacteria, the infolded membranes contain for synthetic pigments which allow photosynthesis to take place
In some bacteria, nitrogen fixation takes place on the enfolded membrane.
What is nitrogen fixation
Nitrogen fixation is the ability to convert nitrogen in the air to nitrogen containing compounds such as ammonia inside the cell.
Why is the ability of bacterial cells to perform nitrogen fixation so crucial
All life depends on nitrogen fixation which the eukaryotes cannot carry out by themselves.
some bacteria are surrounded by an extra layer outside the cell wall. This may take the form of
A capsule or a slime layer