Bacteria

Bacteria Review

-Size, Shape, and Structure

-Obtaining Energy

-Reproduction

Bacteria are microscopic, prokaryotic organisms.....

Prokaryotes

-unicellular

-do NOT contain a nucleus

-do NOT contain other membrane bound organellES

Bacteria Kingdoms

• Archaebacteria: live in extreme conditions

• Eubacteria: found in every environment on Earth (even in and on you!)

Open Ended

Why can't bacteria cells be seen with the naked eye?

Multiple Select

What are the three basic qualities of prokaryotic organisms, including bacteria? Select all that apply.

• Do NOT contain a nucleus

• Contain membrane bound organelles such as a nucleus or mitochondrion

• Unicellular

• Do NOT contain membrane bound organelles

• Multicellular

Size

Bacteria cells are microscopic and cannot be seen with the naked eye.



   -Their size ranges between 1-5 $\mu m$  

   -Approximately 10-20x SMALLER
    than eukaryotic cells (us!)

Bacteria Come in 3 Basic Shapes...

• Coccus (spherically shaped)

• Bacillus (rod-shaped)

• Spirilla (spiral-shaped)

Bacterial DNA

• Contain one or two coiled/circular chromosomal DNA

• Many also contain plasmids: specialized DNA that can replicate independently from chromosomal DNA

• Plasmids occur in greater numbers

Other Bacteria Cell Structures

• Cell is filled with cytoplasm

• Protected by cell membrane and cell wall

• Many also have a capsule and appendages to assist in movement and attaching to surfaces

Multiple Choice

True or False. Bacteria cells (prokaryotes) are typically 10-20x LARGER than human cells (eukaryotes).

• True

• False

Multiple Select

Bacteria cells generally come in one of three basic shapes. Select all shapes that apply.

• Spherical

• Spiral

• Triangular

• Hexagonal

• Rod

Open Ended

Bacteria cells contain two forms of DNA. What do we call these two forms?

Obtaining Energy

Bacteria cells live in a wide range of environments, and therefore must be adaptable. Because of this, bacteria obtain food energy in various ways.

Heterotrophs vs Autotrophs

• Heterotrophs: must consume organic material (food) in order to obtain energy (like us!)

• Autotrophs: Obtains energy by producing their own organic material by converting CO₂ into carbohydrates!

Heterotrophic Bacteria

• Consume food molecules by feeding on organic waste

• Consume food molecules by feeding off of a living host

Autotrophic Bacteria

• Photosynthetic Bacteria: convert light into food energy

• Chemosynthetic Bacteria: convert chemicals from surrounding environment into food energy

Multiple Choice

True or False. Bacteria can be both heterotrophic or autotrophic.

• True

• False

Bacterial Reproduction

Asexual Reproduction

• one parent organism

• offspring are genetically identical to parent organism

Binary Fission

• Forms two genetically identical cells

• Can occur RAPIDLY under ideal conditions (food, oxygen, warm temperatures, moisture)

Conjugation

• Two bacteria attach to each other and combine genetic DNA

• Increases genetic variation

• NO NEW ORGANISM FORMED

Endospores

• Thick internal wall built around bacteria's chromosome

• Occurs when environmental conditions are unfavorable

• Allows bacteria to remain dormant for extended period of time

Multiple Select

What are the main differences between sexual reproduction and asexual reproduction? Select all that apply.

• Asexual reproduction requires two parent organisms while sexual reproduction requires only one.

• Offspring of sexual reproduction are genetically unique from parent organism while offspring of asexual reproduction are genetically identical to parent organism.

• Sexual reproduction requires two parent organisms while asexual reproduction requires only one.

• Offspring of asexual reproduction are genetically unique from parent organism while offspring of sexual reproduction are genetically identical to parent organism.

Multiple Choice

Binary fission is an example of....

• Sexual reproduction

• Conjugation

• Asexual reproduction

• Formation of endospores

Open Ended

Why is it beneficial for a bacterial organism to perform conjugation?