Prokaryotic Life

Characteristics

Reproduction

Evolution

A bacterium such as E. coli has the basic structure typical of most prokaryotes: cell wall, cell membrane, and cytoplasm. Some prokaryotes have flagella that they use for movement. The pili are involved in cell-to-cell contact. The cell walls of eubacteria contain peptidoglycan.

Structure

CharacteristicsSmall

– Few micrometers in length

Unicellular

No nucleus

No membrane bound organelles

May have flagella for movement

Energy- How do bacteria acquire energy?

Prokaryotes can be autotrophs or heterotrophs

-Autotrophs: -Self producers, by sunlight or organic chemicals

-Chemoautotrophs-Photoautotrophs

-Heterotrophs:

- Consumes energy from other organisms

Characteristics

Bacterial Reproduction

Binary Fission- Parent cell splits into two identical daughter cells

Conjugation-Sharing genetic information-Results in genetic variation

Binary Fission Video

Video

Did you know? Fun Facts• There are 10 times more bacterial cells living on and in you,

than your own body cells.

• You have more bacterial DNA than human DNA on you.

• All the bacteria living in/on you weighs about the same as a human brain.

Binary Fission-Asexual Reproduction

What must happen first before the cell can divide?

-Conjugation (sexual) : swapping genes over a bridge between two bacteria

Think:

Which of these two types of reproduction is more beneficial and

why?

Do they both have advantages?

Think Question

What’s the Difference?

Cell Enlargement Vs. Cell Division

Prokaryotic Cell Cycle

G1- Gap 1 Phase Growth

S- Synthesis of DNA (DNA Replication)

G2- Gap 2 Phase The bacterial cell prepares to divide

Prokaryote success depends on various selective pressures

Like other organisms, if prokaryotes can survive their environment they will then survive and reproduce

Obstacles that bacteria have to overcome: – Temperature– Food– Chemical balance– Antibiotics– Antimicrobials

Evolution

Evolutionary Success

Rapid reproduction time– Successfully passing on

genetic information from parents to offspring

Diversity - FOUND EVERYWHERE- Air, soil, water, on plants, animals, and humans!

Examples of Bacterial Evolution:

Bacterial resistance to antibiotics-As bacteria evolves, medicine also needs to evolve in order to effectively treat the bacterial infections

-Mrsa– Methicillin-resistant Staphylococcus

aureus (MRSA) infection is caused by a strain of staph bacteria that's become resistant to the antibiotics commonly used to treat ordinary staph infections.

– Most MRSA infections occur in people who've been in hospitals or other health care settings, such as nursing homes and dialysis centers

Example of Bacteria Evolution

Resistance to antimicrobials (hand sanitizer)

-Formulas constantly change to keep up with bacteria evolution

- Knocks out the weak bacteria- Strong bacteria survive, and

these go on to reproduce

Bacteria can share genetic content. This is why bacteria are so successful: the sharing of advantageous traits may enable evolving species to become even more successful.

Evolution of antibiotic resistant bacteria

Successful Evolution

• Bacteria can reproduce very rapidly! – E. coli can reproduce in just 20 minutes!

• Environments exert natural selection on populations causing them to change.

Evolution of Prokaryotes

• http://ed.ted.com/lessons/how-antibiotics-become-resistant-over-time-kevin-wu

Evolution of Prokaryotes

• http://ed.ted.com/lessons/how-antibiotics-become-resistant-over-time-kevin-wu