Mod 3 + 4 Flashcards
What does ‘normal flora’ mean?
Microbes that are commonly associated with the human body
What is an important component of the “One Health” philosophy?
That the health of the environment directly impacts on human health
“Germ-free” cows would not be able to survive because
They would not be able to digest cellulose
The major reason that microbes that cause plant diseases are problematic is because
They cause massive economic damage
The lichen symbiosis consists of which two partners?
Fungi and Algae
Photoautotrophic bacteria:
Use CO2 as their carbon source and light as their energy source
What valuable resource do members of the Archaea offer for biotechnology?
They make thermostable enzymes like DNA polymerases
Which of the following is an example of a “cloning vector”
Plasmid DNA
A plasmid is a small circular DNA molecule found in bacteria and some other microscopic organisms. Plasmids are physically separate from chromosomal DNA and replicate independently.
Describe the difference between food-borne infection and food-borne intoxication
Food-borne infection involves ingestion of a pathogenic microbe that can grow inside the human
body, leading to symptoms of disease – usually due to toxin production. Food-borne
intoxication involves ingestion of a microbially-formed toxin that is present in the food – in this
case the microbe responsible typically cannot grow well in the human body
Outline one common way to reduce the risk of food poisoning and why it sometimes does not
work
Risk factors for food poisoning exist at all points of the supply chain, including in the origins of
food (animals, plants, soil), then in storage, distribution, and processing, and finally in the
preparation and serving of the food. One way to reduce the risk of food ‘poisoning’ is to
ensure good hygiene practices of the people handling the food; unfortunately these kind of
human factors can be difficult to control since human behavious cannot be controlled in the
same way that e.g. a food manufacturing machine can
Which of the following are all products of the light reactions?
Oxygen, NADPH, ATP
Why might C4 photosynthesis have evolved in response to lower atmospheric CO2 levels?
Because rubisco was exposed to more atmospheric oxygen
Which of the following best describes products of the electron transport chain?
ATP and water
The electron transport chain produces ATP, water, H+, NAD+, and FAD
Scientists have discovered a new cell near a very hot water vent at the bottom of the ocean. This cell has no mitochondria, and it has a cell wall that lacks peptidoglycan. What kind of cell is this most likely to be?
Archea
Archaea are prokaryotic cells that lack peptidoglycan in their cell walls, as well as lacking a nucleus or mitochondria. They tend to live in extreme environments.
The plasma membrane is best described as,
The plasma membrane is a selective boundary around a cell, composed of a phospholipid bilayer that has proteins embedded within it, and sometimes spanning it. It provides a selective barrier for the cell, allowing specific molecules to move across it, both from the external environment into the cell and from the cell back out. As well as having a transport function, the membrane also serves as a boundary, protecting the interior of the cell from fluctuations in the external environment, however the interior environment still undergoes frequent change.
Both the concentration gradient and the electrical gradient affect the diffusion of __________ across membranes.
Ions
In __________ three __________ are attached to __________.
ATP / phosphates / a ribose sugar
Glucose absorbed by the body is broken down to form pyruvate as part of the process of cellular respiration. This process is best described as:
The breaking down of molecules to release energy is catabolism
Plants are able to convert solar radiant energy into what?
energy in molecular bonds
Mitochondria produce the majority of a cell’s:
ATP
The hormone insulin is a protein produced in the pancreas and then secreted into the blood stream after a meal to increase glucose uptake by tissues. Which of the following mechanisms would be used to secrete insulin from the pancreas?
Large molecules like the protein insulin cannot move across membranes and are secreted from the cell by exocytosis.
The body can convert glucose into fatty acids through which of these intermediate steps?
Acetyl-CoA
Glucose can be converted into fatty acids through several intermediates, including part of the citric acid cycle. This process involves the transfer of 2-carbon molecules as part of acetyl-CoA
Read the following statements and choose the correct option below:
A) Pasteur’s experiment with the swan-necked flasks was important because it proved Koch’s postulates
B) Pasteur’s work directly led to the invention of the microscope
A & B are both incorrect
Which statement best describes the current situation with tuberculosis?
This is a very problematic disease that is often resistant to antimicrobials
Microbes that are normal flora of animals are:
Sometimes pathogens of humans
Pollutant-degrading bacteria typically belong to which of the following nutritional types?
Heterotrophs
Global warming is partly due to increased atmospheric levels of CO2 and CH4.
Which of the following microbes would be the most helpful in reducing global warming?
Methanotrophs
Methanotrophs are organisms which are able to obtain energy by oxidizing methane (CH4).
Read the following statements and choose the correct option below:
A. E.coli is widely used in recombinant DNA technology because it is generally regarded as safe
(GRAS)
B. T4 DNA ligase is an enzyme produced by T4 bacteriophage
is incorrect and B is correct
Describe below four major types of microorganisms and the key features that distinguish them.
Bacteria: unicellular, independent replication and metabolism, smallest free-living organisms, simple
internal structure (no nucleus or complex membrane-bound organelles)
Fungi: uni- or multicellular, complex internal structure (eukaryotic – have nucleus and complex
membrane-bound organelles), heterotrophic metabolism (decomposers)
Protists - Protozoa: unicellular, complex internal structure (eukaryotic – have nucleus and complex
membrane-bound organelles), heterotrophic metabolism (predators)
Protists - Algae: unicellular, complex internal structure (eukaryotic – have nucleus and complex
membrane-bound organelles), photoautotrophic metabolism (photosynthetic)
*Archaea would have the same key features above as the Bacteria. They can be distinguished
from Bacteria by genetic or biochemical methods.
Which of the following definitions of normal flora is the most correct?
Microbes commonly associated with the human body, that usually don’t cause disease
Louis Pasteur’s contributions to microbiology include:
Pasteurisation, Vaccination, Fermentation
A low fibre and high-fat diet often results in
Low levels of Bacteriodetes and high levels of Firmicutes, and this is associated with bad gut health
Which of the following statements about the gut microbiome is FALSE?
Mother and child always have identical gut microbiomes
Which of the following is an example of a HETEROTROPH?
Methanotrophs
Heterotrophic decomposers…
Use complex organic molecules as their primary carbon and energy source
Which of the following microbes would be the BEST source of a polymerase enzyme for use in PCR:
Thermophilic archaea
Which of the following biological products would be most likely to be both effective and safe for use as a vaccine?
A protein antigen from the pathogen, produced in a GRAS GMO host
In biology, a central concept is that of ‘evolutionary fitness’. This is usually taken to mean:
An individual’s relative contribution to the next generation’s gene po
The carrying capacity of a population can be defined as:
The theoretical maximum number of individuals the environment can support
You have just discovered a new site that contains the fossilized remains of what appear to be
several new species of dinosaur – Congratulations! Which of the following species concepts
would be most useful to understand how many species are represente
Morphological species concept
Alpha, beta and gamma diversity
Alpha diversity is the species diversity present within each ecosystem on a landscape. Beta diversity is represented by the species diversity between any two communities. Gamma diversity of is the species diversity across the entire landscape, taken as one unit.
The amount of energy passing through an ecosystem is determined by the
Number of trophic levels in the ecosystem
A plant species releases spiky seeds that cling to the fur of animals, the plant relies on this for seed
dispersal and reproduction; the animal is unaffected. This is an example of what type of ecological
interaction?
Commensalism
Which of the following is the most important driver of succession?
The capacity for new arrivals to establis
The concept of a trophic cascade can be best understood a
Effects on predators through food webs on lower trophic level
Which interaction does NOT benefit any organism involved
Competition
What is the use of Population Viability Analysis (PVA)
To model the probability of a population surviving over tim
In order to demonstrate successful habitat restoration, what do you need?
A well-defined reference state that you want to use as a compariso
Most of Australia’s threatened and extinct mammals weigh between 35 g and 5.5 kg. The most
likely driver of this is:
Predation from introduced foxes and feral cats
Which of the following correctly describes ecosystem stability
When an ecosystem maintains consistent species richness and composition
Which of the following is NOT a true statement about pioneer plant species? They
are shade-intolerant
Which of the following is an example of mutualism
bees pollinating flowers
What is one of the commonly held hypotheses as to why food chains are rarely longer than 4-5
links
The Energy hypothesis: Significant amounts of energy are lost between tropic levels, typically
around 90%.
What would be the estimated population size if 10 individuals were marked in the first capture,
30 were captured in the second capture of which 5 were marked
60
30/5 x 10 = 60
Ecological meltdowns can occur in habitat fragments when the
Loss of predators allow animals lower trophic levels to increase in number
Which is correct regarding population growth
N(t+1) = N(t) + Births - Deaths + immigrants – emigrants
GMOs are regularly used in modern medicine to produce vaccines. Are these vaccines safe for use?
Yes, because they do not contain the whole organism that causes the disease
Why are GMO microbes especially useful for biotechnology?
They allow production of large amounts of useful proteins
Which of the following statements about the gut microbiome is most correct?
it varies according to diet
Why are bananas particularly at risk from fungal pathogens?
Because they have very low genetic diversity
Koch’s postulates are used to determine whether a particular micro-organism causes a particular disease. Which of the following steps would be the last step in that process?
Show that microbe X can be re-isolated from an experimentally-infected host
Koch’s postulates, in brief, involve the following steps in order:
1) Isolate a microbe from an affected individual
2) Make a pure culture of the microbe
3) Introduce the microbe into a healthy individual and have it develop the disease
4) Re-isolate the microbe from this individual and compare it to the first isolated microbe to confirm they are the same
John Needham conducted experiments on spontaneous germination using an open jar of water and hay. The water/hay mixture was boiled, and subsequently the water became cloudy, as microbes grew. What is needed in this experiment to make it actually useful as a test of the theory of spontaneous germination?
A control with an airtight seal on the jar
What is the main role of methanotrophs in the carbon cycle?
Metabolising methane to produce CO2
What category of micro-organism does the most to reduce the CO2 content of the atmosphere?
Algae
What advantages do yeast have compared to bacteria, when considering applications in biotechnology?
They are better for expressing eukaryotic genes
What is an example of a product most commonly manufactured in a GMO microbe?
Vaccine
A common name for Saccharomyces is
Brewers yeast
E. coli, Salmonella and Campylobacter are all bacteria that are commonly associated with food poisoning. What property of these bacteria means they are particularly likely to cause this illness?
They are well-adapted to colonise the human digestive tract
Photosynthetic bacteria:
use light as an energy source
What category of micro-organism does the most to reduce the CO2 content of the atmosphere?
Algae
Which of the following materials is NOT part of a global cycle?
Phosphorus
Restoration ecology seeks to:
restore degraded lands and habitats to as close as possible to their pre-disturbed condition.
The phylogenetic species concept is useful because it recognises that speciation (the formation of separate species) is:
an ongoing event
Which of the following is the most likely explanation for why the population growth curve for an animal population would have a ‘sawtooth’ appearance?
The animal reproduces once a year
In modelling the population of Grizzly Bears in North America, the reproductive rate is given as 0.69. This means that:
Although female bears give birth to whole cubs (not parts of a cub), this number is taken by averaging the number of cubs born to reproductive females in a population over multiple years.
Which of the following is the best measure of an organism’s biological fitness?
Its contribution to the next generation’s gene pool
A lake environment has recently lost a lot of water, and has changed from one large lake to a group of small, separate lakes. The lakes contains the following food chain: Algae -> Herbivorous Fish -> Predatory Fish. Which of the following effects would most likely occur?
All other answers are potentially correct
Algae declines
Herbivourous fish become abundant
Ecological meltdown
Predatory fish die out
