Micro Ch. 3 Microscopy And Cell Structure

Front 1

What is resolution?

Back 1

shortest distance between two objects where they can be observed as two objects

Front 2

What things on the microscope improve resolution?

Back 2

condenser=focuses light
iris diaphragm=controls amount of light

Front 3

What are two types of electron microscope?

Back 3

transmission= electrons transmitted thru specimen (1D)
scanning= electrons scan surface (2D)

Front 4

What is a differential stain?

Back 4

distinguishes b/w 2 features, uses 2 or more dyes

Front 5

What is a simple stain?

Back 5

1 stain, allows to see cell shape, size, and arrangement

Front 6

What are the stages of a gram stain (differential stain)

Back 6

1- primary= crystal violet (all purple)
2- mordant= iodine (all purple)
3- decolorizer=alchohol (most important)(gram - clear, gram + purple)
4- counterstain=safranin (g.-red, g.+ purple)

Front 7

What are types of special stains?

Back 7

endospore stains
flagella stains
acid stain

Front 8

What is an endospore?

Back 8

resistant form of bacteria created under stress, forms only in Clostridium and Bacillus (found in soil and animal intestine)

Front 9

How does flourescent microscopy work?

Back 9

attached flourescent dye to antibody of bacteria
ex. mycobacterium, and streptococcus

Front 10

What are the different shapes of bacteria?

Back 10

coccus (round); rod bacillus; coccobacillus, vibrio, spirilium, spirochete

Front 11

How are bacterial cells grouped?

Back 11

-chains either diplococcus or multiple cocci
-packets
-clusters

Front 12

What is an example of diplococcus grouping?

Back 12

neisseria gonorrhea

Front 13

What is an example of chains of cocci?

Back 13

streptococcus

Front 14

What is an example of clusters?

Back 14

staphyloccocus or toxic shock syndrome

Front 15

How does flagella move?

Back 15

composed of flagallin, propels anti-clockwise (runs) and clockwise (tumbles), must have receptors to sense chemical attractant or detractant

Front 16

What are Pili?

Back 16

numerous appendanges that attach to different surfaces based on specific protein, found only in g.- bacteria ex. e-coli, cholera

Front 17

What is the role of Pili?

Back 17

twitching and gliding, conjugation, and cell recognition

Front 18

What is conjugation?

Back 18

sex pilus attaches between cells allowing passage of DNA, promotes better adaptation to environment

Front 19

What is a plasmid?

Back 19

small piece of DNA that carries a specific gene for a specific function. improves resistance against antibiotics

Front 20

What are the types of glycocalyx?

Back 20

capsule and slime layer, both are sticky and allow bacteria to remain in colony and stick to a surface

Front 21

What is a capsule?

Back 21

rigid, gelatinous layer connected to cell wall ex. dental plaque caused by streptococcus mutans

Front 22

What is a slime layer?

Back 22

diffuse, irregular loose aggregates of polysaccharides ex. biofilms

Front 23

What is the role of glycocalyx?

Back 23

-attachment
-prevents nutrient and water loss
-protection, prevents against phagocytosis

Front 24

What is the role of the cell wall?

Back 24

rigid structure determines shape and prevents bursting in dilute soln

Front 25

How is the cell wall removed?

Back 25

1-pcn prevents formation of peptidoglycan
2-lysozymes-breakdown peptidoglycan layer

Front 26

What is an example of a bacteria that lacks a cell wall?

Back 26

mycoplasma pneumoniae= causes walking pneumonia, not affected by pcn or lysozomes, has sterols that give rigidity

Front 27

What is the cell structure of gram positive bacteria?

Back 27

-thick layer of peptidoglycan connected by interbridge to cytoplasmic membrane. (pcn attacks here)
-contains techoic acid= antigenic that stimulates immune systen

Front 28

What is the cell structure of gram negative bacteria?

Back 28

-outermost layer=lipopolysaccaride, contains endotoxin that leads to allergic reaction and septic shock
-thin inner layer of peptidoglycan

Front 29

What is the cytoplasmic membrane (cell membrane)

Back 29

thin fluid phopholipid bilayer embedded with proteins, hydrophillic head, hydrophobic tails

Front 30

What is the role of the cell membrane?

Back 30

-selective barrier=controls what enters and leaves
-generate of energy in prokaryotes that respire or photosynthesize

Front 31

What is the role of the membrane protein?

Back 31

-active transport of nutrients that cannot pass through bilayer
-transport waste and secretions out of cell
-enzymes break down polymers too large to enter
-receptors sense and respond to environment

Front 32

What is simple diffusion?

Back 32

diffusion of small molocules of 02,C02, and H2O through bilayer, does not require energy

Front 33

What is active transport?

Back 33

special transport systems bring in amino acids, organic acids and salts into cell. requires ATP

Front 34

What is the chromosome?

Back 34

single circular double stranded DNA molecule that is foled and twisted in supercoiled in region of cytoplasm. every gene is essential for survial

Front 35

What are ribosomes?

Back 35

catalyses protein synthesis, composed of protein and rRNA, composed of 2 subunits