Notesale: Turn your study into money

Document Preview

Extracts from the notes are below, to see the PDF you'll receive please use the links above

---

18
...

- Prokaryotes are divided into two domains: Bacteria and Archaea
...


• Have strong cell walls that contain peptidoglycan
• Some bacteria such as cyanobacteria are photosynthetic
• Some have two cell walls
Archaea
• tolerate extreme environments
•

have similar proteins to eukaryotic cells
...
most
are anaerobic
•

halophiles live in very salty environments like the Dead Sea
...
Some carry out photosynthesis

• Methanogens: (use CO2 and give off methane) are obligate anaerobes
...

Difference between bacteria and archaea
• Different cell walls protein
• Different lipids in plasma membrane
• Different ribosomal proteins and RNA
• Ribosomal proteins in archaea are similar to those in eukaryotes cells

•

Obligate aerobes: use oxygen in metabolic processes to create energy
...


•

Facultative anaerobes: use either oxygen-based metabolism or fermentation for
energy production
...


•

Obligate anaerobes :use the process of fermentation in the absence of oxygen to
create energy
...


Structure of prokaryotes
Macroscopic, unicellular
...


Chromosomes

- arranged differently from how they are in eukaryotic cells
...


Capsule

- Formed by a layer of polysaccharides
around the cell wall
- It prevents the cell from drying out
- Helping the cell attach to surfaces
- Protects cell from effects of antibiotics
- Helps prevent bacteria from being eaten by white blood cells
1
...
Providing the prokaryotes with new genetic material, thus
transferring the resistance of antibiotics
►

Size

- 1-10 micrometers long, 0
...
5 micrometers wide
...
Providing the prokaryotes with new genetic material, thus
transferring the resistance of antibiotics
►

Size

- 1-10 micrometers long, 0
...
5 micrometers wide
...

- Gram's stain is a technique to identify the amount of peptidoglycan in
bacteria
...


Binary fission (asexual)
- It’s the division of a cell into two genetically identical cells
- The prokaryotic chromosome replicates, the original and
new chromosome separate
...
Conjugation
Two prokaryotes attach to each other and exchange genetic information
The pilus attaches to the two cells to transfer genetic material to each other
New gene combinations are created and diversity of prokaryote populations is
increased
= genetic diversity

- The cell gets larger by elongating
- New piece of plasma membrane and cell wall forms and
separates the cell into two identical ones
- This occurs every 20 minutes: 1 bacterium= 1billion in an
hour
- They reproduce quickly so there is a higher chance of
error
-

2
...

Photoautotrophs: gain energy through photosynthesis, need light
...

(They are the base of some of food chains and release oxygen into the
environment)
Chemotrophs: don’t need light for energy
...
(keep nitrogen and other inorganic compounds
cycling through ecosystems)

Survival of Bacteria
They have several mechanisms to help them survive: a lack
of water, extreme temperature changes, lack of nutrients

1
...

They can resist extreme heat, extreme cold, dehydration,
and large amounts of UV radiation
...


Mutations

- Mutations: random errors in a DNA sequence
- Can help bacteria survive in changing environments
- Leads to changes like antibiotic resistance

and large amounts of UV radiation
...


Mutations

- Mutations: random errors in a DNA sequence
- Can help bacteria survive in changing environments
- Leads to changes like antibiotic resistance
- Mutations allow for genetic diversity in an asexually reproducing population
...
They help fertilize fields,
recycle nutrients, protect the body, and produce foods and medicines
►

Nutrient cycling and nitrogen fixation

- Saprobes are decomposers, returning vital nutrients to the environment
...
coli live in human intestines make vitamin K
►

Food and medicines

- Bacteria are responsible for some food production like cheese and yogurt
- Commercial production of vitamins
- Can be used to fight disease/produce antibiotics

Disease causing bacteria
- Only a small percentage of bacteria cause disease
- Bacteria multiply quickly at the site of infection and spread to other parts of the
body
They cause disease in two ways:
•
•
•

Bacteria secrete a toxin into the nervous system
...

Bacteria cause diseases in plants and destroy crops
...

Bacteria that secrete acids can cause cavities in teeth
...


important



---