Microbio exam 1

Chapter 1, 3, & 4

1 mm is equal to?

1,000,000,000 pm 1,000,000nm 0.001m 0.1cm

after the light condenser what structure does the light pass through?

specimen

100 nm is how many micrometers

0.1 micrometers

what microscope would be used for urine?

Phase contrast microscopy: color contrast and allows for exam of internal and living structures

what microscope is best to view internal cell structures

phase-contrast microscope

what microscope uses visible light

differential interference contrast microscope

what is not used to view living cells

scanning electron microscope

what is the path of light through the compound microscope

Light source — condenser — specimen — objective lens — ocular lens

what is the purpose of an ocular lens?

Magnify the image from the objective lens

A student is looking at a bacterial specimen using the oil immersion lens, but has forgotten to put immersion oil on the slide. How will the specimen appear?

somewhat fuzzy and have poor resolution

resolution of a microscope can be improved by…

changing the wavelength of light

define resolution in the microscopy

the ability to distinguish fine structure and detail in specimen

what role does iodine play in the gram stain?

iodine is a mordant which intensifies the primary stain

when oculars magnify by 20 and the objective magnifies by 100 what is the total magnification

2,000 times magnified

why do electron microscopes have higher resolving power than light microscopes?

electrons have a smaller wavelength than the visible light

what lens is on an electron microscope but not on light microscopes?

projector lens

what microscope would you be able to see a microscope on?

transmission electron microscope

what do both electron and light microscopes have

the objective lens

what do the electrons do when they interact with a specimen

They may be absorbed, reflected, or refracted by the specimen.

why would a specimen smaller than 200 nm not be seen in a light microscope?

anything smaller than 200 nm cannot be seen with visible light

what happens to the light rays when they hit the specimen

They are reflected, refracted, or absorbed by the specimen.

what does the ocular lens do?

recreates the image in the viewer’s eye

what does it mean when light rays are being divergent

the light rays spread out

In the brightfield microscope when does magnification begin?

The objective lens

what is the role of lenses in microscopy

lenses focus on light or electrons to create a magnified image of a specimen

acidic dye associates with what type of stain?

capsule stain

basic dye associates with what stain

negative stain

crystal violet associates with what stain

simple stain

methylene blue associates with what stain

simple stain

nigrosin associates with what stain

negative stain

The gram stain is performed in what order?

Crystal violet, iodine, alcohol-acetone, safranin

What does iodine do as a mordant in the gram stain?

Prevent the crystal violet from leaving the cells

What is the order of preparing a slide?

Making a smear, fixing, staining

What color is gram positive bacteria after adding the counterstain

purple

What color is gram negative bacteria after decolorization

colorless

you stain bacillus with malachite green with heat ad counterstaining with safranin, what is the green structures?

endospores

what step is critical for differentiating cells from positive and negative

alcohol-acetone

if you were tested for syphilis but did not have syphilis what would be observed?

no fluorescence in the sample

if there was gram positive and gram negative bacteria in a sample and the decolorizer step was missed what would the result of the gram stain be?

It would be purple (gram postive)

where is the genteic information stored

nucleus

what is the structural framework for a cell

cytoskeleton

where is ATP made

mitocondria

what carries instructions from the nucleus to the cytoplasm

mRNA

What is the rough ER covered in

ribosomes

what is the endomembrane system parts

golgi apparatus, ER, lysosomes, and vesicles

what organelle breaks down worn out organelles

lysosomes

where are lipids made in the cell

smooth ER

what is a selective barrier and regulates materials in and out of the cell

plasma membrane

parts of Eukaryotic cells

Flagella that wave, composed of microtubules

cellulose or chitin-containing cell wall

mitocondria

lysosomes

endoplasmic reticulum

golgi apparatus

80s ribosomes

Prokaryotic cells

Flagella that rotate, composed of flagellin

70s ribosomes

peptidogycan-containing cell wall

circular chromosome, not enclosed within a nuclear envelope

what is the order from cytoplasm to external environment

plasma membrane, cell wall, capsule

What structures do all bacterial cells have?

Ribosomes, cytoplasm, plasma membrane, nucleoid

what type of bacteria does this wall belong to and what are the aroows pointing to?

what type of bacteria does this cell wall belong to and what are the arrows pointing to?

what is likely to be antigens which host antibodies bind with to mark for phagocytes?

Capsule

Cell wall

flagella

fimbriae

what are antibacterial ideas that would be toxic to bacteria?

Inhibition of peptidoglycan

interfering with translation at 70s ribosomes

inhibition of fimbriae synthesis

what is the purpose of Pili in a bacterial cell?

Conduit for transfer of DNA from one cell to another

What is the purpose of the capsule in a bacterial cell?

protection from phagocytes

What is the purpose of the cell wall in a bacterial cell?

protection from osmotic lysis

What is the purpose of the plasma membrane in a bacteria cell?

The location of the respiratory enzymes

Nucleoid containing DNA

Genetic information of the cell

What is the function of the 70s ribosomes in a bacteria cell?

Protein synthesis

What is the function of the fimbriae in a bacteria cell?

The attachment to other bacteria and to other surfaces.

What is the purpose of flagella in a bacterial cell?

Motility, allows to move away and to stimuli

If the the capsular polysaccharide can no longer synthesize, what happens?

It will enter a host and immediately be phagocytized.

When a bacteria no longer can produce fimbriae, what will happen to the cell?

It would no longer be able to adhere to the host’s tissue and can establish infections

What structure of bacteria is responsible for the signs and symptoms of a UTI?

Fimbriae

What does streptomycin target in bacterial cells?

70S ribosome and inhibits protein synthesis

Why is gram-negative bacteria resistant to penicillin?

Gram-negative bacteria has an outer membrane on the cell wall which is difficult for it to penetrate

What are the signs of an urinary tract infection, or UTI

Increased urgency to urinate

Abdominal discomfort

painful urination

What are characteristics of prokaryotic cells?

They typically have a circular chromosome

Lack a plasma membrane

DNA is not enclosed within a membrane

lack membrane-enclosed organelles

Do prokaryotes have organelles?

Yes

Describe an axial filament.

looks almost like a corckscrew, spiral shaped usually with dual pink colors.

Describe what streptococci looks like.

a long string of spheres