BIOL 250 Exam 1 Practice Questions and Correct Answers
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Course
BIO 250
Institution
BIO 250
Binary Fission Cell division in bacteria in which one cell divides into two cells
Why do bacterial cells not undergo mitosis and meiosis? 1) Prokaryotic cells do not possess the machinery to produce spindle fibers and therefore cannot move chromosomes around in the cell 2) Replication of DNA in a ...
BIOL 250 Exam 1 Practice Questions and
Correct Answers
Binary Fission ✅Cell division in bacteria in which one cell divides into two cells
Why do bacterial cells not undergo mitosis and meiosis? ✅1) Prokaryotic cells do not
possess the machinery to produce spindle fibers and therefore cannot move
chromosomes around in the cell
2) Replication of DNA in a prokaryote does not occur in one phase, but instead occurs
continuously
3) Most bacteria have only one circular chromosome that is attached to the cell
membrane
Bacteria undergo four different phases of growth. These phases, in order, are: ✅Lag,
log, stationary, death
Which of the following can influence the length of the lag phase of growth? ✅1)
Conditions of the new media that bacteria is transferred to
2) Conditions of the old media that bacteria is transferred from
3) Characteristics of the individual organism
A culture of E. coli contains 1000 cells/ml with a generation time of 30 minutes. How
many organisms would be present after a period of 2 hours? ✅16,000 cells/ml
Why is it impossible for a culture of bacteria, in a single tube, to remain in the log phase
of the growth cycle forever? ✅1) Nutrients in the media are depleted as the number of
bacteria increase
2) Metabolic wastes accumulate as the number of bacteria increase
3) Space is limited as the number of bacteria increase
4) Metabolic wastes accumulate and space is limited as the number of bacteria
increases
Bacterial growth is measured by estimating ✅The number of viable cells per milliliter of
culture
Which of the following techniques rely on the concept that under the proper conditions,
only living bacteria will divide and form a visible colony on agar? ✅Standard plate
count and serial dilution
Which type of bacteria can grow at low temperatures (below 25°C)? ✅Psychrophiles
, E. coli is a bacteria that can grow in the presence or absence of oxygen, which would
classify it as a/an ✅Facultative anaerobe
Which of the following types of organisms would thrive only in an environment in which
there was 85% CO2 and 15% O2? ✅Microaerophiles
A media that has a constituent that causes an observable change in the medium when
a particular biochemical reaction takes place is known as ✅Differential media
Chemicals such as penicillin disrupt cell wall synthesis. Penicillin is most effective
against replicating cells. In which phase of growth would you expect penicillin to be
most active? ✅log phase
In which of the following stages of growth does new growth occur at the same rate as
cell die off? ✅Stationary Phase
The theory of spontaneous generation states that: ✅living organisms arise from non-
living sources.
Koch's Postulates ✅1) The specific causative agent must be found in every case of the
disease.
2) The disease organism must be isolated in pure culture.
3) Inoculation of a sample of the culture into a healthy, susceptible animal must produce
the same disease.
4) The disease organism must be recovered from the inoculated animal.
Many antibiotics are produced by species of _______. ✅Fungi
Which of these statements fits best with the Germ Theory of Disease? ✅Disease can
be spread when a microbe is passed from person to person
Louis Pasteur ✅Disproved spontaneous generation through the use of swan-necked
flasks. Yeast selected, identified disease-causing organisms, vaccine development
o Yeast selection for desired wine flavor
o Identified 2 microorganisms that cause silkworm diseases
o 1st indiv was a vaccine (rabies)
Carolus Linnoeus ✅Created binomial nomenclature
Anton Van Leeuwenhoek ✅*Father of microbiology*. Saw "animalcules" in pond water.
Scraped plaque off of teeth. 300x total magnifaction to observe living mircroorganism
Robert Hooke ✅Built compound microscope. Coined the term "cells"
-used cork
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