The last 2 days in class, we have started a new unit about the diversity of life. We covered the first two sections of notes on classification and fungi.

Classification of Life: looking at evolutionary history by studying past and present diversity

• taxonomy: identifying, naming and classifying species
• Carolus Linnaeus, 1707 to 1778: Swedish physician and botanist (plant biologist), created binomial nomenclature
• Binomial nomenclature: two-part scientific name for an organism, includes the genus and species, in Latin
• Homo (genus) sapiens (species)

• classification system has a heirarchy: domain, kingdom, phylum, class, order, family, genus, species
• Cladistic Revolution: organisms used to be grouped by appearance but now they are grouped by common ancestors and genetics
• Cladistic Analysis: looking for clades, or branches, of an ancestor and all its descendents
• this new way of organizing species is based on a strict code of cladistic analysis

• Life is classified into three domains: bacteria, archaea and eukarya
• Bacteria and Archaea: prokaryotic
• Eukarya: eukaryotic, include 4 kingdoms: animalia, fungi, protista, plantae

• Dichotomous Key: pairs of opposing statements in a list, helps classify an organism

The Fungi Kingdom

• decomposers: rot and break down dead animals and plants, feces and organic material
• chemical recyclers
• eukaryotic, usually multicellular, more closely related to animals than plants
• heterotrophic, absorb nutrients
• release hydrolytic enzymes to break down food
• some are parasitic or pathogenic

• hyphae: thread-like tubes that cover membranes and cytoplasm, make up the body
• mycelium: networks of tubular hyphae, subterranean
• reproduce by releasing spores (produced sexually or aseuxually), carried by the wind, can grow in moist environments

• Fungi can be...

• eaten
• added to bread dough to make it rise
• be added to milk to make cheese
• used to ferment beer and wine
• used to make medicine, like antibiotics
• helpful to plants (lichen and tree: symbiotic relationship)

Tonight (2/16) for Homework

1. Finish Protist Lab, UP 27-31
2. Read Chapter 15 on Protists
3. UP 39-40 and 41-43
4. Nature project due 3/2
5. Moodle Notes

next scribe: Yvette

On Thursday in class, we finished pages 6 and 7 in the notes packet and learned about Punnett squares.

Page 6 and 7 Notes: Test Crossing and Probability

• test crossing: the mating between an individual of unknown genotype and an individual of a homozygous recessive genotype
• test crossing is used to determine the unknown genotype

In Mendel's experiments: a purple flower with an unknown genotype 'B_' (unknown second allele) and a white flower with a homozygous recessive genotype 'bb' are bred. If the genotype of the purple flower is homozygous dominant or 'BB', all offspring will be purple. If the genotype of the purple flower is heterozygous dominant or 'Bb',

some of the offspring will be white.

http://www.monteweston.com/Biology/Coll10.html

• probability: what is the chance that the offspring will exhibit a particular genotype of phenotype?

• What is the chance that two parents will have two girls? There is a 50% chance that each baby is female because the father can give the child either an X (the child is female) or Y chromosome (the child is male). Multiply 50% (or 1/2) by 50% (1/2) to get 25%. There is a 25% that both children will be girls.

UP pg 55-57: Punnett Squares and 1-factor crosses

• Punnett Squares are used to find the different possibilities of phenotypes and genotypes in the offspring of two parents.

If two heterozygous dominant purple flower (Bb) are bred, the offspring possible phenotypes and genotypes include:

Phenotype: purple or white

Genotype: BB (homozygous dominant), Bb (heterozygous dominant) and bb (homozygous recessive)

The Punnett Square for this situation looks like this:

Phenotype: 75% of the offspring will be purple and 25% of the offspring will be white. The ratio of purple to white flowers is 3:1.

Genotype: 25% of the offspring have the genotype BB, 50% have Bb and 25% have bb. The ratio of BB to Bb to bb is 1

:2:1.

This is a 1 factor cross because the we are finding possibilities for just one gene.

http://wiki.answers.com/Q/What_is_a_Punnett_square

With certain genes, an offspring with a heterozygous genotype will exhibit a mixed phenotype. This is called a blending of genes. For example, one parent has curly hair and a homozygous dominant genotype HH. The other parent has straight has and a homozygous recessive genotype hh. The offspring will have the genotype Hh but in this case the dominant gene doesn't completely mask the recessive gene. Instead, the genes "blend" and the child has wavy hair.

http://www.geekinheels.com/2009/11/02/genetic-diagram.html

Homework: UP pg. 45-49 and 55-57 and work ahead if you are ready to.

next scribe: Kiran

October 13, 2011

Today in class, we went through the notes about viruses and watched a video about the flu. Here's a basic overview of the notes.

Viruses: Living or non-living?

• viruses are between life and non-life
• Living characteristics: contain genes (RNA or DNA), are highly organized (complex protein structure
• Non-living characteristics: not made of cells, cannot reproduce on thier own: viruses don't have the necessary structures to reproduce so they must use the structures of living cells

Structure

• nucleic acid, the genetic material, is inside a protein coat
• often include: head (where genes are held), tail, tail fibers

The virus in the animation on the left is called a T4 Bacteriophage. It is easy to see the structure of this virus.

http://www.emc.maricopa.edu/faculty/farabee/biobk/biobookdiversity_1.html

Reproduction: Lytic and Lysogenic Cycles

Lytic Cycle

1. virus injects genes into a host cell
2. "hijacks" cell structures and uses them to make copies of itself
3. viruses eventually causes the cell to lyse (burst)
4. viruses are released to find a new host cell

Lysogenic Cycle

1. virus injects genes into host cell
2. viral genes are incorporated into normal cell genes
3. genes are passed on without the cell making copies of the virus
4. while in lysogenic cycle, cell does not lyse
5. environmental changes will trigger the viral genes to switch to the lytic cycle

http://terra.dadeschools.net/Books/Biology/BiologyExploringLife04/0-13-115075-8/text/chapter16/concept16.5.html

Plant Viruses

• affect plants: interfere with growth and damages crops
• most plant viruses have RNA not DNA
• viruses are designed to get past plant epidermis and cell walls
• no cure for the majority of plant viruses
• humans have created plants that are resistant to certain viruses

Examples: Tobacco mosiac virus (TMV) and tomatoes, PRSV and papaya

Animal Viruses

• many have a phosolipid outer layer, just like a cell's plasma membrane: allows viruses to slip in and out of the cell through endocytosis and exocytosis
• reproduce in cell's cytoplasm: needs ribosomes to make viral proteins
• RNA and DNA viruses
• RNA viruses: HIV, mumps, common cold, polio
• DNA viruses: chicken pox, herpes, hepatitis

http://www.sciencegateway.org/resources/biologytext/cb/virus/virus.html

HIV: the cause of AIDs

• Retrovirus: reproduces by the use of viral DNA molecules
• normally, cells use DNA to produce RNA (transcription)
• HIV has cells use RNA to produce DNA (reverse transcription)
• RNA then makes proteins
• viral genes now in cell's genes, cell is producing viral proteins
• Drugs for HIV: inhibit reverse transcription or inhibit production of the viral proteins

http://www.visualphotos.com/photo/2x4142081/hiv_virus_particles_computer_artwork_hiv_human_f0013163.jpg

The full notes are on Moodle. The video we watched featured influenza, the flu, and was basically a review of the notes.

Homework: review viruses, moodle notes, work on group project script, work on textbook notes sheet

NEXT SCRIBE: Yvette