Lecture Exam 5 Biology Flashcards

Three most common shapes of prokaryotes

Spherical (Coccus), Rod-Shaped (Bacillus), Spiral (Spirochaete, Spirillum)

Gram-positive Bacterium

Thick cell wall due to peptidoglycan. Retains staining.

Gram-negative Bacterium

Thinner cell wall. Do not stain.

Capsule

The mucopolysaccharide layer that lies outside the cell wall of
bacteria. Protects the cell as well as helps it adhere to surfaces.

Slime layer

A layer that protects a bacterial cell from dessication, loss of
nutrients and chemical insult. Give the capacity to survive sterilization.

Fimbriae

Long appendage on many gram-negative and some gram-positive bacteria
that helps it adhere to other bacteria and animal cells as well as
some inanimate objects.

The three key features of prokaryotic biology.

1. They are small
2. They reproduce by binary fission
3. They have short generation times

What process does bacterium Streptococcus pnemoniae demonstrate?

It demonstrates Transformation (The process of bacteria absorbing DNA
from its environment)

Eukaryotic flagella

Microtubule based structures anchored at the cell membrane by centrioles.

Prokaryotic flagella

Powered by a motor that is on the cytoplasmic membrane and uses the
proton gradient between the periplasm and the cytosol to power the motor.

Taxis

A reaction of a cell or organism to an outside stimulus.

Attraction

towards a stimulus

Repulsion

away from a stimulus

Nucleoid

Where the genetic material is found in a Prokaryote

Endospore

Structure formed by bacteria during unfavorable conditions that
contains dna and a small amount of cytoplasm encased by a protective
outer covering.

Three Mechanisms of Genetic Recombination in Prokaryotes

transduction, transformation, conjugatioin

Plasmid

A linear or circular double-stranded DNA that is capable of
replicating independently of the chromosomal DNA

R plasmid

called resistance plasmid that confers certain bacterial strain the
acquired ability to resist the antimicrobial activity of some drugs

Pilus

Short, filamentous projection on a bacterial cell, used for adhering
to other bacterial cell for mating or to animal cells.

Obligate Aerobe

organism that requires oxygen to grow

Obligate Anaerobe

Organism that lives and grows in the absence of oxygen. Dies when
exposed to oxygen.

Facultative Anaerobe

Can live in either oxygen or no oxygen environments.