Chapter 20 Bacteria

Question 1

Is bacteria prokaryotic or eukaryotic?

Answer 1

Prokaryotic
No organelles or nucleus

Question 2

Parts of bacteria (label in diagram)

Answer 2

Cell membrane
Cell wall
Ribosomes
Storage capsule
Cytoplasm
Slimy capsule
Flagella
Loop of DNA
Plasmid

Question 3

Nuclear material in bacteria

Answer 3

Contains loop of DNA and Plasmid which have genes which is responsible for bacterial resistance

Question 4

Shapes of bacteria

Answer 4

Cocci-pneumonia(infection around lungs)
Bacilli- E.coli (found in raw sewage)
Spiral- cholera (found in dirty water)

Question 5

Bacteria nutrition 2 types

Answer 5

Heterotrophic
Autotrophic

Question 6

Heterotrophic bacterial nutrition

Answer 6

Parasitic - feed of live host (pneumonia)

Saprophytic- feed of dead sources (bacteria of decay carbon cycle)

Question 7

Autotrophic bacterial nutrition

Answer 7

Photosynthetic- make food from light (purple sulphur bacteria)

Chemosynthetic - make food from chemical reactions (nitrifying bacteria)

Question 8

Bacteria respiration

Answer 8

Anaerobic - does not require O2 (bacteroids)

Aerobic- requires O2 (streptococci)

Question 9

Bacteria reproduction

Answer 9

Asexual- binary fission
Loop of DNA is replicated and cytoplasm is split into 2 daughter cells identical to the parent bacterium.

Happens every 20mins in favourable conditions.(pH , food , temp , oxygen)

Question 10

What happens if a bacterium reproduces in unfavourable conditions

Answer 10

Endosperm forms as some type of protection

Question 11

Endospore formation

Answer 11

When conditions are harsh , contents of bacterial cell shrink and endospore forms within

When conditions become suitable again , endospore begins to germinate

Question 12

Why should thawed food be eaten quickly?

Answer 12

When food is in the freezer it responses by producing endospores

When thawed , endospore begins to germinate

Question 13

Growth curve A

Answer 13

Lag phase (low no.)
Bacteria is adapting to their environment

Question 14

Growth curve B

Answer 14

Log phase (high no.)
Bacteria activity dividing cause plenty of food water space

Question 15

Growth curve C

Answer 15

Stationary phase (constant no.)
Reproduction rate=death rate
Increase of competition and toxins

Question 16

Growth curve D

Answer 16

Decline phase (low no)
Increase of toxins is killing bacteria

Question 17

Growth curve E

Answer 17

Survival phase (low no.)
Most are dead
Some surviving as endospore