BI276 midterm 1

the cell does NOT contain

monomers

which macromolecule is the most abundant in cell composition?

proteins

What did Carl Woese do?

devised the three domain system based on cellular organization (eukaryotes, archaea, and bacteria)

Cells that contain peptidoglycan in the cell wall are described as…

bacteria

cell walls that lack peptidoglycan are described as…

archaea

protists, fungi, plants, and animals are described as…

eukaryotes

A similarity between prokaryote and eukaryote is…

plasma emmbrane

A nucleoid is present in

prokaryote

a nucleolus and a nucleus is present in

eukaryote

chromosome organization in prokaryotes are…

circular and usually singular

ribosomes in eukaryotes are…

80S

chromosomes in bacteria

70S

how do prokaryotes divide?

binary fission

viruses are typically

acellular organisms

How do viruses replicate?

hijacks another organisms

Which one is smaller? viruses or prokaryotes?

viruses

fungi, protozoa, and algae are ________ forms of life

unicellular

what is not a type of microscope

ultra-sonic

magnification

ratio of the size of an image to the size of an object

resolution

ratio of the size of an image to size of an object

what does brightfield microscopy require?

good contrast

refractive index

measure of light bending ability of a medium

what does staining change to the brightfield specimen?

changes the refractive index to enhance visualization

what does the condenser do in bright field microscopy?

focuses light to produce a brightfield illumination

what is the limit of magnification on a brightfield microscope?

1500x

resolution limit of brightfield microscope

0.2um

what is the #1 commonly used stain?

gram/differential staining

step 1 of the staining procedure

flood the heat fixed smear with CV for 1 minute - all cells are purple

chromophore in basic dye

chromophore is the positive ion

CV, methylene blue, malachite green, and safranin are examples of what type of dye?

basic

eosin, acid fuchsin, nigrosin are examples of what type of dye

acidic

what does fixation do?

kills the cell and solidifies constituents

what does staining do in staining procedure?

increases visibility and difference in refractive index

what is the purpose of applying a mordant?

enhances affinity between dye and cell structure

what is the purpose of decolorization?

removing dye not firmly attached to cell substrate

simple stain

single dye/stain to visualize entire organisms

which one is a simple stain?

crystal violet

Acid fast stain

negative stain

Endospore stain

Flagellar stain

acid alcohol decolorizes…

non acid fast bacteria

Darkfield microscopy

which type of microscopy does NOT pretain to living specimens?

Confocal microscopy

phase contrast

Fluorophore

ability of substances to absorb short wavelengths of light an emit them at longer wavelengths

resolution of confocal microscopy

0.1um

lasers that excite a fluorochrome stained specimen

confocal light microscopy

what was robert hooke known for?

first to describe microbes

What was Antoni van Leeuwenhoek known for?

the first to describe bacteria

why is Ferdinand Cohn important?

founded the field of bacterial classification and discovered bacterial endospores

Who used the first microscope?

Robert Hooke

spontaneous

some forms of life could arise from nonliving matter spontaneously

Frencesco Redi experiment

proved that maggots do not arise from decaying meat in sealed jars but arose in unsealed jars when flies enterd

John Needham experiment

heated chicken broth poured into covered flasks were full of microorganisms when cooled

Lazzaro Spallanzani

suggested that microbes from air entered needham’s flasks

rudolf virchow

introduced the concept of biogenesis, which stated that living cells can only arise from preexisting living cells

who is responsible for aseptic technique?

louis pasteur

how was spontaneous generation disproved?

Aseptic Technique

which one is NOT louis pasteur’s contribution?

the concept of biogenesis

Who was awarded for their contributions to germ theory of disease?

Robert Koch

Koch’s first postulate

suspected pathogen must be present in all cases of the disease and absent from healthy animals