bacteria

Question 1

prokaryotes

Answer 1

• smaller, simpler type of cell that DOES NOT have a membrane-bound nucleus
• all bacterial cells

Question 2

eukaryotes

Answer 2

• larger, complex type of cell that does have a membrane-bound nucleus
• plants, animals, fungi and protists

Question 3

archaebacteria

Answer 3

• oldest of all living organisms on earth
• hypothesized to be the ancestors to all of life’s kingdoms: can thrive in hot/acidic/salty conditions – conditions that scientists think existed on earth billions of years ago
• can inhabit Earth’s most inhospitable regions

Question 4

why do archaebacteria get their own kingdom?

Answer 4

• chemical properties of their cell wall and membrane are different from eubacteria
• out of 1700 genes more than 50% are different than eubacteria

Question 5

phyla of archaebacteria

Answer 5

• anaerobic methanogens: live in animal gut/bottom of marsh where all methane gas on earth is produced
• halophiles: live in salty conditions, like the dead sea
• thermophiles: can tolerate hot/acidic conditions, like hot spings

Question 6

eubacteria

Answer 6

• single chromosome forms a loop or small piece of floating DNA called a plasmid
• cell wall: complex carbs, protection
• cell membrane
• flagella: locomotion and transportation
• pili: important for replication

Question 7

eubacteria colony shapes

Answer 7

coccus: spherical
bacillus: rod
spirillum: spiral/worm-like
mono: one
diplo: two
strepto: chain
staphylo: clump

Question 8

binary fission

Answer 8

• bacterial cells grow at an exponential rate when given the right type and amounts of nutrients.
• their mode of reproduction is asexual, by doubling themselves: can translate into a doubling of the population every 20 minutes

Question 9

binary fission steps

Answer 9

• chromosomes duplicate and copies get separated
• cell elongates and copies of chromosomes move towards the poles
• cell divides into two daughter cells

Question 10

plasmids

Answer 10

• small, circular DNA (in addition to bacterial chromosomes)
• often carry genes with advantages (like resistance to antibiotics)
• can transfer plasmids to other bacteria through conjugation

Question 11

conjugation steps

Answer 11

• F+ cell (donor) with plasmid makes contact with F- cell (recipient) via their tubule pilus
• conjugation tube form at site of contact bridging the 2 cells
• single-stranded DNA of the plasmid gets transferred to the recipient cell
• conjugation tube disconnects. Single-stranded DNA from each cell duplicates making both F+ cells and DNA is the same

Question 12

binary Fission vs. conjugation

Answer 12

conjugation increases population diversity due to the transfer of genes

Question 13

antibiotics

Answer 13

• compounds used to kill or harm specific bacteria (example: pneumonia, tuberculosis, meningitis, etc)
• approx. 100 different antibiotics now
• bacteria are living things and reproduce quickly and is easy for them to become resistant to antibiotics

Question 14

how antibiotics work

Answer 14

• antibiotics are specific to types of bacteria
• some inhibit cell’s ability to turn glucose into energy
• some inhibit a cell from constructing cell wall
• all results in death of bacterium (no reproduction of new bacterium)
• only affect certain parts of a cell

Question 15

antibiotic resistance

Answer 15

antibiotics kill all bacteria except the ones that are resistant, then the resistant ones reproduce and become the majority