Lesson 4: Prokaryotes

Question 1

What domains are prokaryotic?

Answer 1

bacteria/eubacteria and archaea

Question 2

What does prokaryotic mean?

Answer 2

• unicellular (single celled) which lack membrane-bound organelles (nucleus)
• smallest organisms on earth

Question 3

Where do prokaryotes live?

Answer 3

• inside and on the surface of other organisms
• in water and soil
• deep within the earth
• in boiling hot springs
• various other extreme environmental conditions

we have more prokaryotic cells than eukaryotic ones in our bodies (due to the amount of bacteria in us)

Question 4

Why are prokaryotes important?

Answer 4

• involved in nutrient cycling, digestion of foods in our guts, production of vitamins
• have commercial uses like in the production of cheese, yogurt, and antibiotics

Question 5

How are prokaryotes harmful?

Answer 5

there are infectious bacteria called pathogens that are responsible for many human illness and deaths every year

Question 6

How many groups in the domain eubacteria/bacteria?

Answer 6

12 seperate groups, with 6 that are considered particularly important

Question 7

Bacteria characteristics

Answer 7

• under the microscope, you can see the cell wall, membrane, and cytoplasm
• contains single looped chromosome in an area called the nucleoid
• ribosomes are scattered throughout the cell
• often have pili or flagella for movement
• some are surrounded by a sticky capsule (protective coating/barrier).. this prevents water loss, resists temperature changes, and keeps out antibiotic and virus

Question 8

What are plasmids?

Answer 8

small loop of DNA with additional genes (these genes are not essential but may be helpful to the cell).. bacteria will sometimes have plasmids in their cytoplasm

Question 9

Bacteria shapes?

Answer 9

• round (coccus)
• rod (bacillus)
• spiral (spirochete/spirilla)

also can exist alone or in pairs, chains, or clusters
- in pairs= diplo
- in chain= strepto
- in cluster= staphilo

Question 10

E. coli (escherichia coli)

Answer 10

• many of these in your gut
• many harmful strains that can cause serious urinary and abdominal infections along with food poisoning

Question 11

Shigella dysenteriae

Answer 11

• possible cause to stomach aches
• symptoms: abdominal cramps, fever, diarrhea
• very contagious

Question 12

Domain Archaea

Answer 12

• cell walls and membranes have a unique chemical makeup
• they have a unique genetic code
• most inhabit extreme environments