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
