Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
11 Cards in this Set
- Front
- Back
|
Prokaryotes
|
-Cells are small 1-5 Um
-Lack membrane bound organelles -DNA is circular and organized into a nucleoid mass -Genetically haploid -Can have extrachromosomal DNA-plasmids -One copy of each gene -Self replicating |
|
|
Eukaryotes
|
-Membrane enclosed structures or organelles (nucleus, mitachondria, and chloroplast)
-DNA is linear and organized into chromosomes, usually diploid -Nucleus divides following mitosis cells divide by mitotic division -Sexual reproduction occurs following meiosis and gamete fusion. -Size easier to see |
|
|
E. Coli Genome
|
-4,639,221 bp
-4288 protein coding genes -115 structural RNA's -A typical cell has 1900 different proteins under any one growth condition. |
|
|
Homo sapiens
|
-3.2 Gb (3,200 Mb)
-31,000 protein encoding genes - |
|
|
Phylogenetics
|
The study of evolutionary ties between life forms
|
|
|
How do we measure the relatedness of two organisms?
|
-Morphology
-Metabolic capabilities -Habitat -Gene content -Changes at nucleotide level |
|
|
Carl Woese
|
-Mid 1970's revolutionized our thinking about the relationships between organisms
|
|
|
Molecular Chronometers
|
-Help define phylogenetic relationships
-Something that everything has -Func'ts needed for something to be a molecular chronometer a)distribution b)function c)comparisons d)change |
|
|
16s rRNA as the molecular chronometer
|
-Needs to be universally distributed
-It should be functionally homologous- have the same function in all cells -The structure should be sufficently conserved so that sequences can be accurately aligned -The molecule should change at a rate that is commensurate with the evolutionary distance being measured -Sequence difference between ribosomal RNA's are an excellent measure of evolutionary change |
|
|
Constructing a phylogenetic tree
|
1. Align all sequences this is the most critical step
2. Measure the number of changes between each pair. This is a measure of evolutionary distance, Ed. This number is usually corrected for multiple changes at a single position. 3.Relationships between sequences are plotted graphically where the length of the lines joining each sequence is proportional to the number of changes (or distance) between the sequences. *Alternative approaches: Parsimony, measures the minimum number of changes needed to diverge two lineages from a commoon ancestor; Maximum likelihood, measures the most probable pairings. |
|
|
Metabolic Diversity
-Energy can be obtained in three ways |
1. Organic Chemicals
~glucose, acetate ~chemoorganotrophs 2. Inorganic Chemicals ~ H2, H2S, Fe2+, NH4-, ~ Chemolithotrophs 3. Light ~Phototrophs |
