Prokaryotes

Question 1

What are prokaryotes

Answer 1

Consists of only single-celled organisms from domains Bacteria and Archaea.
‘pro’ meaning before
‘kary’ meaning nucleus
Single-celled organisms with no membrane-bound organelles.
smallest organisms on Earth.
Have existed on Earth for more than 3.5 billions years.
Dominant forms of life in every imaginable habitat.
Bacteria like a warm, dark, and moist environment

Question 2

Domain archaea

Answer 2

Oldest of all organisms on Earth
Hypothesized to be the ancestors to all life’s kingdoms
Can inhabit Earth’s most inhospitable regions
Can thrive in very hot, very acidic, and very salty conditions (conditions that scientists think existed on Earth billions of years ago)

Question 3

Phyla of Archaea

Answer 3

Main Phyla of Archaea

Anaerobic methanogens:
mainly live in the gut of animals, or at the bottom of marshes
release methane as a waste product

Halophiles:
“salt-loving” bacteria living in extreme salty conditions, such as the Dead Sea

Thermoacidophiles:
Bacteria that can tolerate very hot temperatures and acidic conditions
Live near deep sea vents, hot springs, volcanic crater lakes, and old mine drainage lakes

Question 4

What are bacteria

Answer 4

unicellular organisms that have cell walls outside their plasma membrane but are not made of cellulose (plants) or chitin (fungi)

Question 5

Structure of bacteria

Answer 5

Cell Wall: supports & protects content of cell
Cell membrane: controls passage of materials into cell
Cytoplasm: contains ribosomes
Ribosome: synthesize proteins
Genetic Material: DNA/ chromosome (single-loop)

plasmid:
Circular DNA
Replicate independently
code for special characteristics that are not vital for survival (i.e. antibiotic resistance)

Pili:
Hair like projection
Connect one bacterium to another
Allow transfer of plasmid
Flagellum:
Help bacteria move forward

Question 6

Classification of Bacteria (cell shape):

Answer 6

Cell Shape (find space on your paper to draw shapes)
Cocci –sphere-shaped
Staphylococcus aureus 🡪 Food poisoning
Streptococcus (genus) 🡪 Stepped throat
Bacillii –rod shaped
Ecoli bacteria in your intestines
Capnocytophaga sputigena 🡪 Blood poisoning, gum disease, meningitis
Spirochetes –spiral/curve shaped
Bacteria that cause Lyme disease and syphilis

Question 7

Classification of Bacteria (gram stain test):

Answer 7

GRAM STAIN: bacteria are classified by their reaction to a dye made of crystal violet and iodine called gram stain

Cell wall made of peptidoglycan

Gram-Positive (+)
Cells appear purple
i.e. Mycobacterium
Non Pathogenic

Gram-Negative (-)
Cells appear Cells appear light pink
i.e. E. coli, H. Influenza, N. meningitidis
Pathogenic

Question 8

Classification of Bacteria (movement):

Answer 8

Many are not motile (do not move) or
sessile

Rolling motion
Some spiral bacteria roll/twist

Glide
Some aquatic bacteria use gas vesicles to move up/down or glide on slimy mucous that they secrete

Flagella
Tail rotates around base to move

Question 9

Classification of Bacteria (metabolism):

Answer 9

process of producing energy by breaking down food through chemical reactions .
Autotrophic bacteria produce their own food by assembling inorganic chemicals (abiotic in origin)
Heterotrophic bacteria get their nutrients from organic chemicals found in other living organisms.

Question 10

Types of Metabolism

Answer 10

Obligate Aerobes - need oxygen obtained from respiration to get energy from food.
Facultative Aerobes - can live with or without oxygen. They perform regular respiration when oxygen is present and Fermentation when there is no oxygen.
Obligate Anaerobes - cannot live in environments where oxygen is present.

Question 11

Bacteria Reproduction (binary fission)

Answer 11

The parent cell divides to form 2 daughter cells.
Each daughter cell gets an exact copy of the DNA.
Since reproduction occurs so quickly, mutations are very common and create diversity in bacteria.

Question 12

Bacteria Reproduction (conjugation)

Answer 12

One bacterial cell passes a copy of a plasmid to a nearby cell through a pilus
Increases genetic diversity allowing both cells to survive

Question 13

Bacteria Reproduction (transformation)

Answer 13

Some bacteria pick up pieces of DNA from the environment or nearby bacteria that have died
Increases genetic diversity

Question 14

Helpful bacteria three types

Answer 14

natural recyclying
health and medicine
clean-up

Question 15

Bacteria Reproduction (transduction)

Answer 15

Some bacteria may receive new genetic material through viruses
Viruses that infect bacteria carry genes from one cell and inject them into another
Increases genetic diversity

Question 16

Natural recycling

Answer 16

They are decomposers
They convert nitrogen gas into useable nitrogen so plants can grow
Provide oxygen

Question 17

health and medicine

Answer 17

They keep you healthy!
They help make insulin
Help digestion
Release of vitamins

Question 18

Clean-up (bioremediation)

Answer 18

i.e . flavobacterium: eat the toxic compounds from oil spills

Question 19

Infectious bacteria

Answer 19

Bacteria make you sick by producing TOXINS (examples: leprosy, anthrox, lyme disease, e.coli, “flesh eating disease”)

Question 20

How can Bacterial Diseases be prevented?

Answer 20

Good personal hygiene and sanitation:
Wash hands frequently with soap for at least 30 seconds;
Avoid touching nose, mouth, and eyes;
Cover mouth and nose when coughing or sneezing;
Avoid public areas where there is close contact with contaminated food, water, fecal material or body fluids from infected individuals;

Antimicrobial drugs:
For example, antibiotics, for bacteria;

Quarantine:

Question 21

How was antibiotics discovered

Answer 21

In 1928, Alexander Fleming noticed a fungus growing on a Petri plate that was growing bacteria
This fungus created a “bacteria-free” zone. This is now known as penincillin

Question 22

What is antibiotic resistance

Answer 22

Antibiotic means against life. They are used to slow down growth of or kill bacteria.
They do not work on viruses.
Overuse of antibiotics can cause bacteria to adapt and become resistant over time so that the antibiotic is no longer effective.

Question 23

Antibiotic problems

Answer 23

Problem #1:
Since bacteria reproduce so quickly, there is a high rate of mutation in the plasmid to create antibiotic-resistance.
Problem #2:
Another problem in society is related to people not taking their prescribed course of pills.
Problem #3:
Do antibacterial soaps really work?

Question 24

Bacteria and Human Health:

Answer 24

Clostridium botulinum causes
food poisoning

Streptococcus pyogenes causes
strep throat
Streptococcus mutans causes
tooth decay

Bacteria can cause disease in different ways. Some cause disease by producing and releasing toxins, ex) food poisoning. Others contain toxic chemicals but they are not released until the cell dies, ex) a strain of E.coli. Antibiotics are usually used to kill bacteria.