Chapter 2 Flashcards
Viruses
Can infect all types of organisms
-Animals, Plants & Bacteria
Obligate intracellular parasites. AKA To replicate they must gain access to a cell.
Considered to not be living as:
1) They do not grow or increase in size
2) Do not respond to external stimuli
3) Have a cellular structure.
Virus Process
Attach to specific receptors on cells
Some viruses now enter the cell. Others inject their genetic material
Either way they now hijack the cell to produce more viruses
Exit the cell by lysing (bursting the cell)
Retro viruses
Use RNA as their genetic material.
Can transcribe their RNA as DNA
Prokaryotic Cell
- Traits
- Small Cells
- Always Unicellular
- Non Nucleic or membrane bound organelles
- DNA is circular/with proteins
- Ribosomes are small
- No cytoskeleton
- Motion by rigid flagellum
- Cell division by binary fission
- Reproduction is always a-sexual
- Great verity of metabolic pathways
Eukariotic Cell
- Traits
- Larger Cells
- Often Multi Cellular
- Always have nuclei
- other membrane bound organelles
- DNA is linear
- Large Ribosomes
- Always has a cytoskeleton
- mobility by flagellum & cilia
- Cells divide by myosis & mitosis
- Reproduction is either sexual or asexual
- Common metabolic pathways
Bacteria Doubling Equation
b=Bx2n
b = number of bacteria at the end B = Number if bacteria at the start - 2 n = Number of generations - 3
b = 2x2^3 = 2x8 = 16
Bacteria Genetic Recombinations
They do not have zygotes or gametes but do have four forms of genetic recombination.
1) Transduction
2) Transformation
3) Conjugation
4) Transport/Insertion
Transduction
After a virus infects a bacteria it picks up some bacteria info by mistake - it then carries that on by mistake
Bacterial genetic information recombination
Transformation
Foreign chromosomes fragment (plasmid) is released during cell lysis
That then enters into a new cell.
That DNA can then become incorporated into recipients genome.
Bacteria Genetic Information Recombination
Transposon Insertion
Mobile Genetic elements called transposons move from position to position
Heteromorphic Bacterium
Automorphic Bacterium
Hetero
Can not synthesise their own food so depend on other organisms
Auto
Can synthesise from inorganic material.
Operon
Clusters of genes that share the same promotors and are transcribed as a single mRNA
Vector
A person, animal or microorganism that carries & transmits an infectious organism.
Aerobic & Anaerobic Bacterium
Aerobic - Metabolism in the presence of oxygen
Anaerobic - Metabolism in the absence of oxygen.
