Biology Module 2

Diversity of Living Things

Taxonomy

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)

___________________

• 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

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