lecture four

Question 1

Eukaryotes characteristics

Answer 1

have a nucleus, larger with varying internal structure, nucleur envelope and membrane enclosed organelles

Question 2

Bacteria

Answer 2

single celled, no nucleus, DNA in nucleolus, smaller, not much internal structure, most diverse domain (Protists), has peptidoglycan as cell wall

Question 3

Archaea

Answer 3

single celled, halophiles, live in extreme environments (Protists), they are prokaryotes, no nucleus or organelles .

Question 4

How did the work of Carl Woese alter our perception of the three domains?

Answer 4

created the third branch- archaea

Question 5

relatively how big are each domain?

Answer 5

Bacteria is the largest domain, then archaea with eukarya branching off

Question 6

Does the slice of the pie that represents Eukaryotes seem about right to you?

Answer 6

No - it is represented as larger than it is because of huma bias (we mainly see eukaryotes, so we think that they are the most abundant.

Question 7

Bacterial conjugation

Answer 7

ACTIVE: sex pilus between two bacteria, genomes linear, sections of code exchanged (sometimes plasmids), take up into genome, passed vertically

Question 8

Bacterial transformation

Answer 8

PASSIVE: segments of DNA passes from donor cell to recipient cell - often from lysed bacterial cells -taken up into genome, vertical transfer

Question 9

Bacterial transduction

Answer 9

: viral horizontal gene transfer, bacteriophages inject their own genetic material, can incorporate parts of the bacterial genome, viral “babies” pass this segment to other bacteria, can be incorporated into their genome and passed vertically.

Question 10

how does Horizontal Gene Transfer do to our picture of the tree of life?

Answer 10

Bacteria led to the development of chloroplasts and mitochondria by HGT. phylogenetic trees are based on vertical gene transfer, so HGT causes the tree to be more of a tangled web of life.