Biology Unit 1 (Biodiversity)

Exam Review

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

1. Attachment and entry - The virus attaches to the host cell

2. 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

3. Multiplication of genome - the host cell replicates normally including the viral genome

4. 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

1. Attachment - virus attaches to the host cell

2. Insertion - viral genetic material enters the cell

3. Replication - the viral DNA communicates with the cells RNA which translates through the ribosome into viral proteins

4. Assembly - new viral proteins are assembled into viruses

5. 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