Gen Bio 116 - Exam 1

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Systematics

Diversity of organisms and evolutionary relationships

How many types of systematics are there?

2 types. Taxonomy and phylogenetics.

Binomial nomenclature

Unique 2-part name. Genus + specific epithet.

Hierarchical classification

Levels (Domain, Kingdom, etc.). Higher levels are more inclusive.

Species

Basic level of hierarchical classification.

Taxon

Grouping at any 1 level.

Character

Defined attribute of a species. States is an alternate form.

Phylogenetics

Study of evolutionary history of a species or groups of species. Based on character similarities based on shared ancestry.

Homologous

Share common evolutionary history. Common ancestor with that character.

Analogous

Similar adaptations from different lineages. Independently acquired. Doesn’t share a common ancestor with that character.

What are Taxon B and Taxon C?

Sister Taxa

What is Taxon F?

Basal taxon

What is the arrow pointing to?

Polytomy

What is this group?

Polyphyletic, distantly related species not including CA.

What is this group?

Monophyletic, CA and ALL of its descendants.

What is this group?

Paraphyletic, CA and SOME of its descendants.

Evolution

Accumulation of genetic changes within a population over time.

Natural selection

Mechanism of evolution, acts on variation.

General characteristics of viruses

Noncellular, obligate intracellular parasites, cannot reproduce on own, very small, genetic material, and structure.

Obligate intracellular parasites

Invade susceptible host cells. Use host resources and processes.

Structure of Viruses

Capsid which is a protein coat. It determines shape and role in attachment.

Capsomere

Protein subunit

Envelope

From host plasma membrane during budding. Bilayer membrane outside capsid.

Bacteriophages (phages)

Viruses that infect bacteria.

Virulent phages

Kill host at end of cycle, only use lytic cycle.

Lytic cycle

Attachment/entry - Phage remains separate from host - Phage DNA replication, phage protien synthesis, self-assembly - cell lyses + phage exits

Temperate phage

Replication of phage genome without destroying host cell, use lysogenic + lytic cycle.

Lysogenic cycle

Attachment/entry - Phage DNA integrates into host genome - Host cell divides, prophange DNA passed on to daughter cells.

Features of a prokaryotic cell

Cytoplasm, Cell wall, Plasma membrane, Capsule, Pill, Flagellum, Nucleoid region, Chromosome, Ribosomes, and Plasmids.

Cell wall functions

Maintain cell shape and prevent bursting in hypertonic environment.

Peptidoglycan

Polymer (sugars + polypeptides), domain bacteria. Not in archaea or eukaryotes.

Bacterial Flagellum

Motor, hook, filament

Bacterial Flagellum function

H+ pumped out across plasma membrane by electron transport chain - form gradient - diffuse into cell through motor - produces force - hook turns - filament rotates

Binary fission

1 cell to 2 cells, optimal conditions: 1-3 hours. 2 identical cells created.

Prokaryotes reproduce…

Asexually (exact copies). Still have high levels of genetic diversity.

Mutation

Genetically different, probability is 1 in 10 million.

Reproduce rapidly (prokaryotes)

2 × 10^10 new cells per day in intestine. 9 million mutations per day.

Transformation

Harmless strain turned into virulent.

Transduction

Occurs during phage replication. Fragment of host DNA packaged into new phage. Phage transfers DNA to another cell. Incorporated into genome.

Conjugation

Genetic material transferred between living prokaryotic cells. F+ uses pilus to attach to F- cell through a mating bridge.

Extremophiles

Like extreme conditions (ex: pH, Temperature, and concentration)