What is a species?
Breed freely
Produce fertile offspring
Carl Linnaeus
Taxonomy (organizes species based on morphology)
Binomial Nomenclature
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What is a species?
Breed freely
Produce fertile offspring
Carl Linnaeus
Taxonomy (organizes species based on morphology)
Binomial Nomenclature
Binomial Nomenclature
2 part latin name assigned to each species
Genus name + species name
Genus name is capitalized and species name is not
Everything is italicized
Taxonomy
The science of naming, identifying, and classifying organisms according to different groups
Each group is called a taxon
7 total taxons
Taxons
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Did King Phillip Come Over For Good Soup
6 Kingdoms
Plantae
Animalia
Fungi
Protista
Eubacteria
Archaebacteria
Plantae
Multicellular
Eukaryotic
Animalia
Multicellular
Eukaryotic
Fungi
Multicellular
Eukaryotic
Protista
Uni/Multi-Cellular
Eukaryotic
Eubacteria
Unicellular
Prokaryotic
Archaebacteria
Unicellular
Prokaryotic
3 Domains
Archaea
Bacteria
Eukarya
Viruses
Not considered living
Lack cellular structure
Cannot metabolise energy
Obligate parasites (cannot reproduce on their own)
Viral particles
Can be between 10-300 nm in size
Structure of virus
Genetic material (DNA/RNA) is surrounded in a protein coat called a capsid
Capsid is made of caposmeres
Also can be another layer called the enveloppe that surrounds the capsid and is found in animal viruses
The enveloppe is derived from the membrane of the host animal cell
Protein spikes may protrude from the viral particle
Strains of viruses
Designed to attack different organisms
Virus classification
Classified based on genetic material
Shape of protein coat
Type of host
Presence of enveloppe
Genetic material determines traits and what protein is manufactured
Inherited by parents
Virus shapes
Cylindrical
Polyhedral
Spherical
Bacteriophage
Bacteriophage
Virus that only infects bacteria
Can kill good bacteria that live in our guts which can cause irritable bowel syndrome or crohns disease
DNA vs RNA
Deoxyribonucleic acid (double stranded)
Ribonucleic acid (single stranded)
DNA
blueprint that codes all proteins required to function
DNA → mRNA → Protein
How does a virus infect a cell
By inserting its nuclei acid into the cell
The viral acid then enters one of two cycles
The Lysogenic cycle
Only DNA viruses and retroviruses
Done before the lytic cycle
Viruses can be in this cycle for years
Attachment and entry - The virus attaches to the host cell
Integration - viral nucleic acid becomes a part of the host cells nuclei. Acid through insertion by protein spikes. Provirus is a viral section of DNA that has become part of the host cells DNA
Multiplication of genome - the host cell replicates normally including the viral genome
Cell division - two identical cells with viral DNA are now the result
The lytic cycle
All viruses eventually go through this cycle
Viruses can switch back and forth between cycles
Attachment - virus attaches to the host cell
Insertion - viral genetic material enters the cell
Replication - the viral DNA communicates with the cells RNA which translates through the ribosome into viral proteins
Assembly - new viral proteins are assembled into viruses
Lysis and release - the host cell is destroyed and the viruses are released into the host
RNA viruses
enter host cells and provide its own instructions
Does not interact with DNA
Retroviruses
Intruct host cell to translate viral RNA into DNA using an enzyme called Reverse Transcriptase
External stimuli can activate the viral DNA causing it to produce viral proteins
Ex: HIV is a retrovirus that causes AIDS which impacts the immune system
Immune Response
Non-Specific (Skin, mucous, general white blood cells)
Specific (Cellular immunity, antibody immunity)
Vaccines can provide:
Active immunity (stimulate the body to produce antibodies against the disease (long term immunity))
Passive immunity (Antibodies are given from one individual to the other individual (usually temporarily))
Passive immunity ex: Breast milk and placenta
3 lines of defense
1st line (mucous, skin)
2nd line (Inflammatory response like ma)
3rd line (B Cells and T Cells)
RNA Virus Vaccine
The vaccine injects mRNA into the body
Cells use mRNA to make protein that mimics viral proteins structure
The immune system recognizes the protein as foreign, mounts a defense, and creates memory cells
If the body encounters the virus in the future, the immune system will know how to deal with it.
Prokaryotes
Single celled organisms with no membrane bound organelles
Contain cell membrane, cytoplasm, ribosomes, single stranded DNA, cell wall
Eukaryotes
Single/ multi cellular organisms with membrane bound organelles
Kingdom Archaea Structure
Cell wall of protein
Doesn’t respond to anitbiotics
DNA, RNA, Protein synthesis mechinery
Extremophiles
Reproduction
Kingdom Eubacteria Structure
Cell wall of peptidoglycan
DNA, RNA, protein synthesis machinery
Mesophiles
Reproduction
Kingdom Archaea and Eubacteria Similarities
Single celled prokaryotes
Ribosomes, cell wall
Common ancestor
Size/shape
mesophiles
Methods of classification
Shape
Gram staining
Habitat
Nutrition
Shape
Coccus
Bacillus
Spirochetes
Gram Staining
Gram negative (Pink) means it has a thin layer of peptidoglycan covered by a layer of lipids
Gram positive (Purple) means it has a thick layer of peptidoglycan
Habitat
Mesophiles like moderate temp (15-40)
Extremophiles
Methanogens produce methane gas and are found in some animals guts and decompose sewage
Thermophiles love heat
Halophiles love salt
Nutrition
Autotrophs make their own organic compounds
Chemoautotrophs rely on the oxidation of inorganic substances
Photoautotrophs use light
Heterotrophs break down organic compounds from their surrounding environment
Binary Fission
A type of asexual reproduction where there is a separation of the parent cell into two new daughter cells
Conjugation
Where two bacterial cells connect with a protein bridge and plasmid is transferred to one of the cells which leads to 2 genetically modified bacteria
Transformation
Bacteria takes up DNA through the cell wall from surrounding environment
Transduction
when a virus injects foreign DNA into bacterium
Endospore Formation
If survival conditions are not ideal bacteria will form a thick wall (endospore) around DNA and cytoplasm
Protists
Eukaryotes
Uni/Multi cellular
Aerobic
Lack specialized features
No embryos or complete sex organs
Some are motile
Most diverse group of eukaryotes and are classified together because they don’t fit anywhere else
Endosymbiosis
Theory that eukaryotes evolved from prokaryotes
Involves one organism taking permanent residence in another organism and eventually evolving as one
Backed by the fact that mitochondria and chlorplast have their own DNA and are the same size as a prokaryote suggesting they derived from Binary fission and formed a eukaryotic cell together.
Symbiosis
Symbiosis of mitochondria occured earlier than chloroplast
Importance of protists
Cover lakes and oceans and are the basis for marine and freshwater food chains
Animal like protists
Heterotrophs
Some are parasites
Can reproduce asexually or sexually
Move using
cilia ( hair like projections)
Flagella ( Tail like projections)
Pseudopods ( Temporary projections that push its body, fluid within the cell is pushedagainst the cell wall which causes it to extend)
Plant like protists
Use photosynthesis (photoautotrophs)
Can reproduce asexually or sexually
Ex : Euglenoid
unicelullar
flagella
phoautotroph during the day
heterotroph at night
Fungus like protists
Consume nutrients from living or dead organisms (decomposes)
Some water moulds are parasites