Chapter 1.3 Flashcards
How is prokaryote DNA organized? Where is it concentrated in the cell
- it is organized into single circular DNA
- concentrated in an area called the nucleoid region
Why study prokaryotes
- because they are incredibly diverse
- > this diversity is needed for medicine
- > as it is good to learn about the diseases they can cause
How are archae similar to prokaryotes and how are they similar to eukaryotes
- similar to prokaryotes in that they look similar
- similar to eukaryotes in that they contain many like metabolic pathways
Are archae photosynthetic and chemosynthetic
- yes
- > many are chemosynthetic
- > able to generate energy from inorganic compounds
- > such as sulfur and nitrogen based compounds
What are similarities between archaea and eukaryotes
- start translation with methionine
- contain similar RNA polymerases
- associate DNA with histones
What are differences between archaea and eukaryotes
- contain singular chromosomes
- divide by binary fission
- share a similar structure to bacteria
-note archaea are resistant to many antibiotics
What do all bacteria have in common
- they all contain cell membrane and cytoplasm
- some have flagella or fimbriae
Why is it difficult to come up with medicine to target only bacteria
- because they have structures that are analogous to eukaryotes
- but they do have structures that are distinct
- > makes it easier to target those structures with medicine
-eg; target the smaller bacteria ribosomes or their flagella
What are the three shapes of bacteria
- cocci(spherical)
- bacilli(rod shaped)
- spirilli(spiral shaped)
What are bacteria that require oxygen for metabolism referred to as? What are bacteria that do not use oxygen for metabolism referred to as?
Bacteria that require oxygen for metabolism
->obligate aerobes
Bacteria that do not use oxygen for metabolism
->anaerobes
What are the different kinds of anaerobes
obligate anaerobes
- > cannot survive in an oxygen-containing environment
- > presence of oxygen leads to the production of reactive oxygen-containing radicals
- > leading to cell death
facultative anaerobes
- > use oxygen for metabolism if oxygen is present
- > switch to anerobic metabolism if oxygen is not present
aerotolerant anaerobes
- > unable to use oxygen for metabolism
- > but are not harmed by its presence in the environment
What are the two barriers in the prokaryote responsible for protecting itself from the environment around it
- cell wall forms the outer barrier of the cell
- cell membrane is composed of phospholipids
- > it is the next layer after the cell wall
-together, the cell membrane and the cell wall form the envelope
What are the two functions of the cell wall in prokaryotes? How many types of cell walls are there? Name the two types
- cell wall provides structure
- it also controls the movement of solutes into and out of the bacterium
- note two types of cell walls are:
- > gram positive and gram negative
How do you determine if a bacteria has a gram positive cell wall or a gram negative cell wall through crystal violet staining and a counter stain called safranin?
- if the envelope absorbs the crystal violet stain
- > then it will appear deep purple
- > and it is gram positive
- if the envelope absorbs safranin counterstain
- > then cell is pink-red
- > cell is gram negative
What is the thick layer of gram-positive cells made up of? What other substance is the cell wall of gram-positive cells made up of?
- it is made up of peptidoglycan
- > a polymeric substance made up of amino acids and sugars
- > provides protection from a host organism’s immune system
- the cell wall is also made up of lipoteichoic acid
- > function is unknown
