Week 1 Lecture 1 Flashcards
What is microbiology?
Microbiology is the study of microscopic life such as Bacteria, Viruses, Fungi as in moulds, some algae and some parasites (worms, typanosomes, malaria etc)
Classify some common examples of microorganisms as correct organism type (e.g. influenza, tinea, red tide, giardia)
influenza is a virus
tinea is a fungus (mould)
red tide is an algae due to toxin-producing phytoplankton
Giardia is a parasite
What are the differences between PROkaryotes and EUkaryotes?
Prokaryotes:
Prokaryotic cells range in size from 0.3 - 5 µm
have a single, circular chromosome with a single copy of each gene arranged in a nucleoid. They have extrachromosomal circular DNA called plasmids containing genes with particular properties such as antibiotic resistance. Prokaryote cells are usually 1-5 µm wide. E. coli bacteria have 4.68 million base pairs of DNA, containing 4,300 genes.
Eukaryotes:
Eukaryote cells have membrane-bound organelles, including a nucleus, mitochondria, chloroplasts (in photosynthetic cells only) while prokaryotes do not. Eukaryote cells are generally larger and more complex than prokaryote cells. Cells range from around 2 µmto several hundred µm. DNA is arranged in multiple linear chromosomes. Human cells have 3 billion base pairs of DNA, containing 18,000 to 30,000 genes.
- Plant and bacterial cells have a cell wall, while animal cells have an internal cytoskeleton
what are algae?
algae are relatively simple eukaryotic photoautotrophs (Photoautotrophs are organisms that can make their own energy using light and carbon dioxide via the process of photosynthesis. The word photoautotroph is a combination of autotroph, the word for an organism that makes its own food, and the prefix photo-, which means “light”.) that lack the tissues (root, stems and leaves) of plants
Why does the mould Penicillium produce Penicillin? Describe why some soil organisms may produce antimicrobial substances?
if you make an antibiotic, you kill the competitors that want your food. to take out competitors who target their prey and reserve food for themselves and to protect themselves from other microorganisms
What are stromatolites?
They are photosynthetic cynobacteria that existed more than 3.5 billion years ago and the oxygen present is due to its microbial activity
What are extremophiles?
they are organisms that live in extreme environments and together they have the capacity to metabolise a huge range of chemicals (new pharmaceuticals produced by them). they take 20minutes to multiply.
what are biofilms?
they are colonies of bacteria in the form of plaque which is somewhat like cement to protect themselves. the reason why they produce in colonies because sometimes the mouth dries out and so the bacteria cant move around freely.
If many bacteria multiply ever 20 minutes why are we not covered in slime?
They need warmth, and moist environments and other factors to grow.
what are viruses and explain why a virus is not a cell?
they are a class of microorganisms which aren’t cells, they take over a host to replicate such as a cell they infect. They have no ribosomes and so they rely on the host cell for protein production. They have very small genomes 5000-670000 bases and can consist of DNA, RNA and are either single or double-stranded.
Viruses are not made out of cells, they can’t keep themselves in a stable state, they don’t grow, and they can’t make their own energy. Even though they definitely replicate and adapt to their environment, viruses are more like androids than real living organisms.
Why is it believed that mitochondria and chloroplasts organelles of eukaryote cells were once free-living cells?
it is believed so because these organelles have their own circular genome and their own ribosomes. This was achieved through a process of endosymbiosis where they came together to be a permanent part of eukaryote cells so that they produce energy for the cell’s use. Ribosomal RNA sequencing shows that these organelles evolved from bacteria. Some simple eukaryotes lack mitochondria/chloroplasts, cannot exist alone and live as parasites of other organisms (e.g. giardia)
Giardia hosts humans because they don’t have mitochondria to make energy
Who is Robert Hooke?
Robert Hooke first used microscopes todescribe cells when he published a pictureof mould in 1655. Van Leeuwenhoek was the first to drawbacteria in 1683. Microscopes were developed in the mid-1500s, first used for microbiology by Hooke and van Leeuwenhoek. Pasteur developed vaccines for anthrax, fowl cholera and rabies.
Who is Louis Pasteur?
Louis Pasteur (1822-1895) observed that microorganisms present on spoiled food were similar to microbes present in the air while others theorised that food spoilage occurred because organisms spontaneously generated from non-living material. Pasteur hypothesised that if he could sterilise food it would remain sterile unless contaminated. Some argued that the process of boiling changed the property of the air and prevented a spontaneous generation. Pasteur used swan-necked flasks to show that when air without particles entered the broth remained sterile
Who is Robert Kock?
Robert Koch (1843-1910) developed the germ theory of disease. First studied anthrax, caused by the bacteria Bacillus anthracis. Mostly occurs in cattle, Koch observed that Bacillus microbes were always present in the blood of cattle with anthrax. He demonstrated that a small amount of blood from a mouse infected with anthrax could transfer the disease when injected into a healthy mouse. He showed that the bacteria could be grown in culture for many generations when injected it would still cause anthrax. He observed that bacteria grew on potato slices in colonies and that each colony had specific characteristics, such as colour. He concluded that each bacterial colony represented a pure culture.
The causative organism, Mycobacterium tuberculosis, was difficult to identify as it has a waxy cell wall that is difficult to stain and is difficult to grow in culture
Koch developed a staining procedure for M. tuberculosis present in tissues
He cultured the bacteria on media containing coagulated serum
He used guinea pigs as a model of M. tuberculosis infection
Explain why it is important to know the type of microbe?
We need to know if the microbe will respond to antibiotics for example Viruses will not respond to antibiotics
Give microbial examples off nitrogen and carbon dioxide cycling. Also explain what is meant by a carbon dioxide sink?
Legume plants (eg lentils, peas) have bacteria present in their root nodules that convert nitrogen from the atmosphere (N2) into fixed nitrogen the plants can use for growth (NH3).
Plants use carbon dioxide in a process known as photosynthesis. During photosynthesis, plants give off oxygen as a waste product. Carbon dioxide moves from the air into the leaves of plants through tiny openings in the plant’s leaves.
A carbon dioxide sink is where Microorganisms take part in nutrient cycling where carbon and sulfur are converted into forms that can be taken up by plants
Briefly explain how ruminants contribute to global warming?
Methane is 25% more polluting than Carbon Dioxide due to the increase amount of agriculture and the fact that there are too many cows.
Define bioremediation?
It is the definition of some microorganisms that will break down pollutants, such as oil, pesticides and solvents
Describe why the human body is an ecosystem?
There are trillions of microbes living in and on our body especially in the abdomen area
List features that make viruses different from bacteria?
The size of viruses are 20-400nm while bacteria are 1000nm
Bacteria have peptidoglycan or lipopolysaccharide while a virus has no cell wall. A protein coat is present instead.
Bacteria have ribosomes while viruses do not.
Bacteria are unicellular (one cell) while viruses have no cells.
Which of the following best describes why some soil microorganisms produce antimicrobial substances?
(a) To protect themselves from other microorganisms
(b) To improve soil quality
(c) To inhibit the growth of other microorganisms
(d) To aid the production of biofilms
(e) To inhibit the growth of viruses
to inhibit the growth of other microorganisms
Which of the following is not an example of a biofilm?
(a) Moss growing on a rock
(b) Staphylococcus growing on a catheter
(c) Plaque build up on the surface of teeth
(d) Algal growth of the surface of water in a swimming pool
(e) A colony of Staphylococcus growing on a nutrient agar plate
d. The definition of a biofilm requires attachment of a community of microbes to a solid surface. The surface of water is not a solid surface. Biofilms use solid surfaces as anchor points and build a structure from exoproteins and exopolysaccharides.
Which of the following is not a eukaryotic cell?
(a) Algae (b) Tinea mould (c) Giardia (d) Yeast (e) Influenza
influenza
Prokaryotic cells have evolved quickly due to:
(a) Mitosis
(b) Meiosis
(c) Binary fission
(d) Endocytosis
(e) Apoptosis
Binary fission
