Biology Module 2

Diversity of Living Things

Taxonomy

Def. The branch of biology that identifies, names, and classifies species based on natural features.

Based on 3 main groups of evidence:

* Anatomical (structure of an organism)
* Physiological (Functions of an organism)
* DNA

Levels of classification

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species (Do Kings Play Chess On Fine Green Sand)

Domains

Def. Largest classification category

There are 3 \____________:
1. Bacteria
2. Archaea
3. Eukarya

Kingdoms: Bacteria & Archae

Cell type: Prokaryote
\# of cells: Unicellular
Reproduction: Asexual

Kingdoms: Plantae & Animalia

Cell type: Eukaryote
\#of cells: Multicellular
Reproduction: Sexual

Kingdoms: Protista

Cell type: Eukaryote
\#of cells: Unicellular & Multicellular
Reproduction: Asexual & Sexual

Kingdoms: Fungi

Cell type: Eukaryote
\#of cells: Mostly Multicellular
Reproduction: Sexual

Species

Def. A group of organisms that look alike and can be interbreed under natural conditions to produce fertile offspring

Binomial Nomenclature

Def. A method of naming organisms by using two names

* The first part of the name is Genus and the second is species

Phylogeny

Def. The history of the evolution of a species or group of organisms

Eukaryotes

Def. organisms containing nuclei and other types of membrane-bound organelles

Prokaryotes

Def. Organisms with cells lacking a true nucleus and most other organelles

Prokaryotes v. Eukaryotes

________________

* Smaller in size
* Cell division is NOT by mitosis and meiosis
* Example: E. Coli (Bacteria)

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* Larger in size
* Cell division BY mitosis and meiosis
* Example: Cat (Animals)

Binary Fission

Def. A form of asexual reproduction in which one cell splits into two

Steps:
1. DNA duplicates
2. Cell elongates
3. Septum begins to form
4. Septum completes, distinct walls form
5. Cells divide

Bacteria

- Many \___________ have one or more plasmids in their cytoplasm
- Plasmid: a small loop of DNA that usually carries a small loop of DNA
- Ribosomes: used for protein synthesis
- Flagella: used for movement, some bacteria attach to other cells or surfaces

Bacteria - Shapes and Prefixes

- Bacteria have three common \_____________
1. Coccus - Round
2. Bacillus - Rod Shaped
3. Spirillum - Spiral

- The \_________ are:
1. Diplo - Pair
2. Staphylo - Clumps
3. Strepto - Strings

Bacteria - Reproduction

Bacteria \______________ by:
1. Binary Fission (20 mins)
2. Conjugation
- One bacteria passes a copy of a plasmid to a nearby cell through a hollow pilus
3. Endospores
- Endospores are dormant structure that forms inside certain bacteria in response to stress (poor conditions)
4. Transportation
- Bacteria picks up a loose fragment of DNA from its surroundings

Classifying Bacteria

- The main way to classify \____________ is by gram stain
- This technique divides \_____________ into two groups
1. Gram-Positive - have a thick protein layer on their cell wall and stain purple
2. Gram-Negative - have a thin protein layer in their cell wall and stain pink

Positive Uses of Bacteria

* Exposure to our initial ________ through the birth canal prepares our immune system to respond to pathogens
* _________ is essential in the production of foods such as cheese, soya sauce, and chocolate
* Biotechnology - ________ have restriction enzymes that cut virus DNA as it enters them

Viruses

* Don’t fit into the 6 kingdoms
* They differ from eukaryotic and prokaryotic cells


1. Outside a cell, they are non-living (dormant)
2. They are not cellular
3. Smaller than bacteria which are smaller than human cells

Virus classification

* Classified by size and shape of capsid
* Poly hedral - a many-sided virus
* Spherical
* Helical - a virus with a spiral cylinder shape
* Complex

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Lytic code & Lysogenic cycle (2.#)

IMPORTANT

1. Attachment - Proteins on the surface of the virus bind to protein receptors on the surface of the host’s cell membrane
2. Entry - The virus injects its genetic material (RNA or DNA) into the host cell

2\.1. Provirus formation - The viral DNA becomes a part of the host’s cell membrane

2\.2. Cell division - Provirus replicates with hosts chromosome

2\.3. Provirus leaves the host’s chromosome


3. Replication - The host cell makes more viral RNA or DNA and proteins
4. Assembly - New virus particles are assembled
5. Lysis & Release - The host cell breaks open and releases new viral particle

Vaccines

* Vaccines are weakened parts of a virus
* When altered viruses are injected, they trigger an immune system response that created a memory to fight it when you come into contact with the real thing

Positive Uses of Viruses

* One solution to bacteria becoming immune to antibiotics is bacteria phages which infect bacteria
* they are very specific so only certain bacteria phages kill certain bacteria, all it takes is to inject the correct phage to kill the correct bacteria
* Gene therapy is also an option
* gene therapy is when biologists use viruses to inject the correct (non-faulty) DNA into a cell to give it the correct instructions