MId-term key

Question 1

The following is a universal trait shared by all algae:

Answer 1

Containing chloroplasts

Question 2

What were the Small-subunit ribosomal RNA (and associated encoding gene) sequences used to come up with

Answer 2

Are widely used to establish phylogenetic relationships of (micro)organisms

Question 3

What adaptation is used in psychrophilic microorganisms

Answer 3

Less saturated (or unsaturated) lipids in the cytoplasmic membrane

Question 4

The lytic cycle of bacteriophage replication:

Answer 4

Occurs when the mature phage is released back in to the surrounding environment through host cell lysis

Question 5

In Woese’s theoretical RNA World , what “modern” biomolecules did RNA serve in place of?

Answer 5

enzymes

Question 6

what is the purpose of FtsI

Answer 6

Catalyzes the transpeptidation reactions in bacterial cell wall formation

Question 7

In what way have archaea been shown to be unique from the bacteria?

Answer 7

• Utilizing histone proteins
• At least one type of archaeon can carry out ATP generation in its outer membrane
• Distinct cell envelopes

Question 8

The archaeal cell envelope:

Answer 8

Often contains an S layer

For protection from predation/viruses
and to mediate adhesion

Question 9

The following is one of the lines of evidence that has helped us learn that mitochondria are ancestors of the Alphaproteobacteria

Answer 9

Mitochondria contain their own ribosomes that are distinct from those in the cell’s rough endoplasmic reticula, and these ribosomes are similar to modern day Alphaproteobacteria

Question 10

How does Protozoa reproduce and what form does it exist as during reproduction

Answer 10

• Can exist in either diploid or haploid phases

- Can reproduce through mitosis or meiosis

Question 11

All viruses/phages have at least the following:

Answer 11

Capsid

Genome

Question 12

Characteristics of Gram positive bacteria:

Answer 12

• Have a very narrow/thin periplasmic space

- Rely on teichoic acid and lipoteichoic acids to hold and anchor the cell wall to the cytoplasmic membrane

Question 13

In the BIOL2026 laboratory (and elsewhere for that matter), when using the compound microscopes, which objective lens requires the use of immersion oil

Answer 13

100×

Question 14

Who is widely credited with inventing the first microscope?

Answer 14

B. Robert Hooke

Question 15

Regarding bacterial cell size, are they similar size to eurkaya?

Answer 15

F

They are similar in size to typical archaeal cells

Question 16

Lipids typically make up the greatest fraction of microbial cells by dry weight.

Answer 16

F

Which of the following makes up most of the dry weight of a cell?
Elements in Living Cells

The most abundant element in cells is hydrogen (H), followed by carbon (C), oxygen (O), nitrogen (N), phosphorous (P), and sulfur (S). We call these elements macronutrients, and they account for about 99% of the dry weight of cells.

Question 17

One notable problem with Koch’s postulates regarding linking pathogens to diseases is that in certain cases it is too difficult to isolate/culture the suspected pathogen.

Answer 17

T

Question 18

Bacteria do not have a nuclear lipid membrane, however instead, histone proteins encircle the nucleoid region and essentially function similarly to a nuclear membrane.

Answer 18

F

Question 19

Use of catalases and antioxidants are two strategies that aerobic microorganisms use to deal with the oxidative stress caused by reactive/toxic oxygen species (ROS/TOS).

Answer 19

T

Question 20

In prokaryotic microorganisms, proton motive force (e.g. for ATP generation) is established across the cellular membrane.

Answer 20

T

Question 21

During the lysogenic cycle, bacteriophages always destroy their host.

Answer 21

F

Question 22

As of 2019, still very few bacteria that can be detected in nature have been isolated in pure culture in vitro.

Answer 22

T

Question 23

Despite the earlier invention of the microscope that could be used to observe large cells (like in cork), optics were not advanced enough until the late 1800s to observe any bacteria.

Answer 23

F

Question 24

Archaea have solid flagella that form from the base, and bacteria have hollow flagella that form from the tip.

Answer 24

T

Question 25

Halobacterium is a genus of methane producing bacteria.

Answer 25

F

Question 26

Transcription and translation are less spatially isolated in prokaryotes than in eukaryotic microorganisms.

Answer 26

T

Question 27

In the model yeasts from the genus Saccharomyces explored in lecture, mitotic division only occurs when the organisms are in the 1n (haploid) state.

Answer 27

F

Question 28

The presence of thick peptidoglycan cell walls in mitochondria and chloroplast envelopes tells us that these organelles arose from ancient bacteria.

Answer 28

F

Question 29

Globally important infectious diseases in humans are caused by eukaryal microorganisms, bacteria, and viruses, but not archaea.

Answer 29

T

Question 30

The vast majority of bacteria humans encounter in the environment do not cause infectious diseases.

Answer 30

T

Question 31

Peptidoglycan makes up the cell wall of both Gram positive and Gram negative bacteria.

Answer 31

T

Question 32

Lysozyme does not affect archaeal cell walls.

Answer 32

T

Question 33

The crystal violet and bile salts in MacConkey agar, which inhibits the growth Gram positive bacteria, make this medium differential in nature.

Answer 33

F

Question 34

Negative staining techniques allow the observer to see unstained bacteria and other microorganisms on a colored background.

Answer 34

T

Question 35

A chemolitheterotroph gets its energy/electrons for redox from reduced inorganic minerals and its carbon for anabolism from carbon dioxide.

Answer 35

F

Chemolithoheterotrophs

use inorganic compounds as an energy source
reduced organic compounds as a carbon source.

Chemotrophs use fermentation and respiration to obtain energy.

Question 36

____________ is one means used by bacteria to pass particles across the cytoplasmic membrane that does not require the use of energy/ATP.
(Hint: there were multiple discussed in lecture.)
.

Answer 36

facilitated transport, co-transport (symport or antiport ok) or passive transport Accepted osmosis and names of specific transporters for 0.5 points

Question 37

____________ is one means used by bacteria to pass particles across the cytoplasmic membrane that does not require the use of energy/ATP.
(Hint: there were multiple discussed in lecture.)

Answer 37

facilitated transport, co-transport (symport or antiport ok) or passive transport Accepted osmosis and names of specific transporters for 0.5 points

Question 38

Explain the microbial growth curve in terms of what it measures, different phases, and what causes shifts between phases. What lab technique could be used to measure cells in a culture to plot a growth curve?

Answer 38

It measures the change in cell numbers in a culture over time under fixed resources (i.e. in a closed vial) (1pt)
Lag phase: microbes are preparing for steady growth/adjusting to new conditions/resources (2pt)
Log phase: once adjusted microbes are replicating at a constant and steady exponential rate (2pt)
Stationary phase: replication has either halted or it is now equal to the death rate because resources are used up/products are building up (2pt)
Death phase: nutrients are depleted, and waste levels are high; cells are dying at a steady exponential rate (2pt
A spectrophotometer (turbidity) or plating (pour or spread plate) for viable cells/CFUs (1pt)

Question 39

Describe flagella in eukaryal microorganisms (structure, function, energy source, etc.). What are some of the key differences with flagella found in bacteria?

Answer 39

Eukaryal flagella are within the cytoplasmic membrane (2pts) and use ATP (2pts) In eukaryal microorganisms: 9+2 axoneme/microtubule structure with dynein spokes/motor proteins (1pt) leads to a whip like motion (5pts overall)
Some functions are the same (e.g. motility and some adherence) but structure, location, motion, and energy source are very different: Bacterial flagella are outside of the cytoplasmic membrane (2pts) and use proton motive force (2pts) In bacteria: filament of multiple flagellin proteins that form from the tip (hollow); hook protein portion connects filament to basal body basal body- disk-like structure that turns filament like a propeller (1pt) (leads to runs and tumbles) (5pts total)