Ch.3 Flashcards
What are the two types of lenses found in a light microscope?
ocular and objective
What is the definition of resolving power when using a microscope?
ability to distinguish two objects that are very close together
Why can a stain stick to the plasma membrane of a cell? What charge is the dye and what charge is the plasma membrane?
- Basic dyes carry positive charge
- Attracted to negatively charged plasma membrane causing an electrostatic attraction
What is a differential stain? List the differential stains mentioned in lecture
- Differential staining used to distinguish different groups of bacteria
1. Gram stain: Gram postive and Gram negative
2. Acid-fast stain used to detect organisms that do not readily take up dyes
What is the correct order for all the stains used in the Gram Stain
- crystal violet
- iodine
- alcohol
- safranin
Where is the cell wall of Gram + bacteria found?
- purple
- thick peptidoglycan
- located on the outer membrane
Where is the cell wall of Gram - bacteria found?
- pink
- thin peptidoglycan layer inbetween 2 phospholipid layers: cytoplasmic membrane and outer membrane
What are the proper terms to describe bacterial shapes?
- coccus: spherical shaped
- bacillus: rod shaped
- spirillum: spiral shaped
What are the properties of the cytoplasmic membrane (the cell membrane/plasma membrane)
- Cytoplasmic membrane defines boundary of cell
- Phospholipid bilayer embedded with proteins
– Selective gates
– Sensors of environmental conditions
– Enzymes - Hydrophobic tails face in; hydrophilic tails face out
- Fluid mosaic model: proteins drift about in lipid bilayer
How do most solutes (ions, charged molecules, large molecules, polar molecules etc) pass through the plasma membrane?
Passive transport:
1. Simple diffusion: without help of transport proteins
2. facilitated diffusion: ions, charged molecules, large molecules, and polar molecules pass through with help of transport proteins
What are the functions of a bacterial cell wall?
- Cell wall is a strong and rigid structure that prevents cell from bursting
Which bacteria does Penicillin kill best and why?
- Penicillin interferes with peptidoglycan synthesis
- Prevents cross-linking of adjacent glycan chains
Which structure do both prokaryotes and Eukaryotes use to move through their environment?
flagella
What 2 movements best describe how bacteria navigate their environment
- pili help bacterial cells move with a twitching or gliding motility
- Flagella involved in motility
What are the 2 locations ASIDE from the nucleus in Eukaryotes and Nucleoid Region in prokaryotes where extrachromosomal DNA can be found?
- mitochondrial matrix inside mitochondria
- chloroplasts
What are endospores
- unique type of dormant cell
- Sporulation triggered by limited carbon or nitrogen
- Not a means of reproduction
What is phagocytosis
a white blood cell, called a phagocyte, surround and destroy foreign substances and remove dead cells
What are the 3 types of proteins found in the cytoskeleton?
- Actin filaments (microfilaments) allow movement
- Polymers of actin polymerize and depolymerize - Microtubules are thick, long, hollow made of tubulin
- Found in mitotic spindles, cilia, flagella
- Framework for organelle and vesicle movement - Intermediate filaments provide mechanical support
What is a nucleus and where is it found?
- contains the genetic information
- center of eukaryotic cell
- surrounded by nuclear envelope
What does the endosymbiosis theory tell us about mitochondria and chloroplasts?
Ancestors of mitochondria and chloroplasts were bacteria residing within other cells
What are the 3 types of endocytosis and what Domain of cells can do this?
- Phagocytosis
- Pinocytosis
- most common in animal cells
- Forms endosome, which fuses to lysosomes
- Material degraded in endolysosome - Receptor-mediated endocytosis
- allows cell to take up specific extracellular ligands that bind to surface receptors
* takes place in Eukarya domain
