17. Bacterial Diversity

Question 1

what are three points of why bacteria is important?

Answer 1

recycling organic material

recyling carbon dioxide

fixing nitrogen

Question 2

define an autotroph

Answer 2

bacteria that uses photosynthesis for energy

Question 3

define a heterotroph

Answer 3

bacteria that gets nutrients by consuming other organisms

Question 4

define a symbiont

Answer 4

bacteria that live in and around eukaryotic hosts

Question 5

what is a microbiome?

Answer 5

the gut bacteria

Question 6

define what a pathogen is

Answer 6

bacteria that causes disease by secreting toxins. it can be secreted molecules or outer membrane compartments of gram - negative bacteria

Question 7

what type and what is the name of the reproduction method of prokaryotes?

Answer 7

asexual reproduction called binary fission

Question 8

what are the 5 steps of binary fission?

Answer 8

initiation of cell division: DNA of a bacterial chromosome begins to replicate at the origin of replication

origin of replication replicates (so theres two)

one of the origins rapidly makes to the opposite side of cell, while chromosomes replicate and cell grows/elongates

final size will be twice of original, plasma membrane pinches inwards by a tubulin like protein

two new daughter prokaryotes

STUDY IMAGE

Question 9

why is there such a high level of genetic diversity in bacteria?

Answer 9

because of their very high reproduction rate - a new generation every 20 minutes, means that mutations probablities increase

Question 10

what are the three horizontal gene transfers? give a description for them

Answer 10

transformation: naked DNA is taken up from the enviorment by bacterial cells
transduction: use of bacteriophages to transfer DNA between cells
conjugation: direct transfer of DNA through plasmids from one bacterial cell to another

Question 11

what is transformation?

Answer 11

it alters the genotype of a cell (recipient) by the naked DNA (from the donor). occurs when bacteria cells takes up genetic material from its surroundings, which when recombination occurs the DNA will be intergrated into the bacterial choromsome.

used to clone and create insulin

Question 12

what is transduction?

Answer 12

bacteriophages packing bacterial DNA instead of their own DNA in their capsid during replication in a bacteria donor cell. Prevents new phages being made as the phage has bacterial DNA. When the phage injects the recipient, the bacterial DNA will be released and infected

Question 13

what is conjugation?

Answer 13

mating between F+ plasmids (male) and F- (female). Involves transfer of the F plasmid from the donor to the recipient via the mating bridge or pilus (unknown which). It results the F- becoming a F+ as it gets a F plasmid

Question 14

what is the F+

F-

pilus

plasmid

Answer 14

F+ is the donor cell that contains DNA from the F plasmid

F- is the reciever cell that has no F plasmid

pilus are short filamentous projection on bacterial cells

plasmid is a small circular DNA molecule that can replicate indepndanntly of the bacterial chromosome

Question 15

what are four ways benefit can benefit you?

Answer 15

photosynthesis in plants - energy

digestion in eukaryotes

make you happier - bacteria in soil can raise cerotonin levels

protection from bad bacteria

Question 16

how do mutaions and rapid reproduction lead to the genetic diversity found in bacteria?

explain what happens and three points of diversity

Answer 16

because bacteria has been around for 3.5 billion years, adaptation have occured and very short generation times - 20 minutes allow gnetic diversity to occur. these contribute to horizontal gene transfer which is accidental to

give new genes

new combinations meaning new novel niches

fast forward evolution

Question 17

what are two types of genes that can be transferred by horizonal gene transfer?

Answer 17

novel sugar utilisation

anitbiotic resistance genes

Question 18

what is the antibiotic resistance gene?

Answer 18

natural selection occuring in bacteria. if theres one bacteria thats resistnat to antibiotics, and that person is given antibiotics, natural selection will mean that bacteria survives and reproduces. creating genertions of stronger bacteria

Question 19

explain how horizonal gene transfer contributes to the rise of antibiotic resistnant bacteria? give a real life example.

Answer 19

in china, there is a very high concentration of pig farming and people. Polymixins are given to pigs as an antibiotic due to the high concentrations, which was proven not to be able to go through HGT.

in 2011, polymixin was proven it could go through HGT. the resistane spread very quickly because of a large amount of usage.

it has spread and is found in humans