BACTERIA

Question 1

Characteristics of bacteria

Answer 1

Unicellular (one cell), but some stick together in colonies
Prokaryotic – have no membranes around organelles, no organized nucleus, vacuole, mitochondria and chloroplast
Have a single chromosome – DNA loop
Reproduce asexually by binary fission
Grow in moist environments
Can be divided into 2 domains Archaea (archaebacteria) and Bacteria (eubacteria)

Question 2

Bacteria shapes

Answer 2

cocci; singular: coccus – round or spherical
bacilli; singular: bacillus – Rod shaped
spirilla; singular: spirillum – Spiral shape

Question 3

Aggregations

Answer 3

Both archaea & bacteria have members that form aggregations
Strepto = chain
Mono = single
Diplo = two
Staphylo = clumped

Question 4

Extremophiles

Answer 4

Means able to live in extreme conditions. Most archaea are extremophiles.

Question 5

Thermophiles

Answer 5

Can withstand extreme heat live in hot springs and deep sea vents, enduring temperatures over 100ºC. Example: Archaea Methanopyrus.

Question 6

Acidophile

Answer 6

Can live in extremely acidic conditions in volcanic craters and mine drainage lakes, enduring pH levels lower than 3. Example: Archaea Picrophilus

Question 7

Halophiles

Answer 7

Can live in extremely salty water. Live in salt lakes and inland seas, enduring salt concentrations above 20%. Example: Archaea Halococcus.

Question 8

Mesophiles

Answer 8

Bacteria that live in moderate conditions.

Question 9

Binary fission vs conjugation:

Answer 9

Asexual Reproduction by binary fission (most common in proks).
1) A copy of its original chromosome is made
2) Cell elongates to certain size
3) Chromosomes separate
4) Cell builds a partition between each of them called septum
5) Original cell splits into 2 IDENTICAL CELLS

Sexual Reproduction by conjugation
1) Can occur in less favourable conditions
2) DNA is exchanged between two different cells producing NEW genetic combinations

Question 10

Plasmids

Answer 10

Small loops of DNA that are separate from the main chromosome, with different genes.
Can be used as a tool for genetic engineering.

Question 11

Gram staining

Answer 11

Separates bacteria into two groups based on the cell wall’s response to a stain:
Gram + = thick protein layer on cell wall, stain purple.
Gram – = thin protein layer on cell wall, stain pink.