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29 Cards in this Set

  • Front
  • Back
What are the major characteristics of eukaryotic cells
A. Membrane bound Nucleus
B. Multiple chromosomes and mitotic apparati
C. Membrane bound organelles
D. Membranes contain sterols
What are the major characteristics of prokaryotic cells
A. Nucleus is not surrounded by a membrane
B. Single, circular chromosome
C. No membrane bound organelles
D. Membranes lack sterols
E. Multiply by fission
What are the gross morphological types of bacteria
Cocci, Bacilli, and Spiral
What are the steps of the gram stain
1. Heat fix bacteria on glass and stain with crystal violet (purple or blue color)
2. Fix crystal violet inside the cell with I2-KI
3. Wash with acetone/alcohol
4. Counterstain (red or pink if negative)
How do gram positive bacteria react to the gram stain
They retain the crystal violet and appear blue
How do gram-negative bacteria respond to the gram stain
The crystal blue is washed out, and they appear pink due to the counterstain
What are the two main cell envelope differences between gram positive and negative bacteria
Gram negative contain an outer membrane and periplasmic space
What is the structure and function of the peptidoglycan
Possessed by almost all bacteria; responsible for cell shape; protects against mechanical and osmotic injury; target of many antibiotics; substrate for lysozyme
What are the major components of the bacterial cytoplasmic membrane
Phospholipids (PE,PG and CL) and proteins
What are the characteristics of the outer membrane that gram negative bacteria contain
Phospholipids; very few enzymatic activities; receptors; porin proteins; LPS; murein lipoproteins; barrier function
How is the outer membrane of enteric organisms characterized
By the Enterobacterial common antigen (ECA)
What are the characteristics of the periplasmic space of gram negative bacteria
20-40% cell mass; Contains low weight solutes, degradative enzymes, binding proteins, peptidoglycan; contents can be released by osmotic shock
What are zones of adhesion
Areas of continuity between the cytoplasmic membrane and the outer membrane (300/cell). Involved in the translocation of a variety of molecules from the cytoplasmic membrane to the outer membrane
Where can capsules be found
Gram positive or negative bacteria. Not all bacteria contain a capsule
What do capsules consist of
Either polysaccharides or polymers of specific amino acids
What are the functions of capsules
Virulence factors (less susceptible to phagocytosis; Protect against desiccation)
What are the four different types of flagella
A. Monotrichous (polar, single)
B. Lophotrichous (polar, several)
C. Amphitrichous (bipolar, single)
D. Peritrichous (cover entire surface)
Can bacteria detect differences in the concentration of an attractant or repellant over the length of the cell
No. They detect gradients in a temporally dependent manner
What are the two types of pili (fimbriae)
Common (somatic) pilli (responsible for adherence to environment)
Sex (Responsible for adherence to other cells, found on F+ cells)
Where are endospores found
Only gram positive bacteria, mostly rods
What are some characteristics of endospores
High resistance; contain almost no water; contain Ca2+ and dipicolinic acid; Require environmental shock to induce germination
Does the nuclear body (nucleoid) contain ribosomes?
What are mesosomes
Invaginations of the cytoplasmic membrane. Septal mesosomes function in cell division and lateral mesosomes function in secretion
What are the bacterial ribosomes
70S, comprised of 50S and 30S
What are bacterial biofilms
Structured communities of bacterial cells in a self produced polymeric matrix that adhere to an inert or living surface. Can provide survival and antibiotic resistance
What bacterial cell components are found only in gram-negative bacteria
Periplasmic space, outer membrane, zones of adhesion
How does the peptidoglycan layer (cell wall, murein) of gram negative bacteria differ from the murein layer of gram positive bacteria
Gram negative have a layer that is only one molecule thick. Gram positive have multiple layers that are cross linked in three dimensions
How is the direction of flagellar motion related to the swimming/tumbling behavior of motile bacteria
What are the functions of bacterial endospores
Provide resistance, ensure survival