Bacteria, Viruses, Fungi + Yeast Flashcards
To which kingdoms do amoeba and bacteria belong?
amoeba - protista
bacteria - monera
which kingdom contains eukaryotic organisms between monera and Protista.
protista
Comment on the relationship between the mode of nutrition and the environmental roles of a saprophyte
saprophytes consume dead matter and are therefore reponsible for decomposition and nutrient recycling in the environment.
In the sexual reproduction of rhizopus, what is the significance of opposite strains of hyphae growing close together ?
The swellings form and grow towards each other and eventually touch.
In the sexual reproduction of rhizopus, describe the production progametangia.
This is the swellings at the tip of the hyphae.
In the sexual reproduction of rhizopus, what is the role of meiosis?
The zygospore germinates by meiosis.
State any 2 harmful effects of fungi?
Human disease such as athletes foot and ringworm.
Poisonous mushrooms
What are the circumstances under which sexual reproduction of the rhizopus occurs?
Lack of water
unsuitable temperature
unsuitable pH
Lack of nutrients
Is oxygen necessary during fermentation ?
No
Where in the cells does fermentation occur ?
cytosol
When preparing alcohol using yeast, from which substance did the yeast make the alcohol?
Glucose
When preparing alcohol using yeast, what is the optimum temperature and how was it maintained?
20C - 35C
using a water bath
When preparing alcohol using yeast, How did you know when the fermentation was finished ?
No more carbon dioxide was produced
When preparing alcohol using yeast, how did you test for the presence of alcohol and what is the colour of the positive result ?
Using the iodoform test
yellow
State the 2 sources of energy that bacteria can use make their food
Sunlight or energy from chemical reactions.
What is the difference between facultative anaerobes and obligate anaerobes ?
facultative respire in the presence or absence of oxygen while obligate respire only in the absence of oxygen.
In the growth curve of a bacteria, explain why some of them survive ?
They form endospores
During continuous flow batch processing, explain why its desirable to keep bacteria in the log phase of growth
To maximise yield
During continuous flow batch processing, at what stage of growth curve is the product removed ?
After stationary phase
To what kingdom do yeasts belong ?
Name another member of this kingdom
fungi
mushrooms/ rhizopus/ penicillium
Apart from a source of nutrition, give one other function of the agar.
Its a medium for growth
In relation to the growth of leaf yeasts in the lab, how can you be certain that the leaf is the only possible source of the yeast ?
You can use a sterilised piece of leaf as a control
In relation to the growth of leaf yeasts in the lab, what is the step taken to prevent the contamination of the lab by the yeast ?
seal the plates
In relation to the investigation of anaerobic respiration in yeast, name 2 steps taken to ensure anaerobic conditions.
Boil water then cool it to remove all oxygen.
Add layer of oil to prevent oxygen from entering.
In relation to the investigation of anaerobic respiration in yeast, what visible sign is there that fermentation is taking place ?
Bubbles of gas of carbon-dioxide.
In relation to the investigation of anaerobic respiration in yeast, if the apparatus was placed in an ice-bath, what effect would this have on the rate of respiration ?
it slows it down because the rate of enzyme action is reduced by the decrease in temperature.
Give an example of the beneficial effects of bacteria, aside from the production of antibiotics, and one example of a harmful effect of bacteria.
A beneficial effect of bacteria is decomposition.
A harmful effect of bacteria is food decay.
What is the method of asexual reproduction of bacteria called ?
Binary fission
Describe the process of binary fission.
The DNA replicates. The cell then elongates and each DNA moves to opposite sides of the elongated cell. A cell membrane grows in between them and the cell therefore splits into two.
Why is the overuse of antibiotics dangerous ?
Because it can lead to the development of antibiotic resistant bacteria.
How do certain bacterias survive in unfavourable conditions ?
They form an endospore
Name a fungus other than yeast that you have studied in your course.
Give one way this fungus differs from yeast
rhizopus
It is multicellular and it produces zygospores
In relation to the growth of leaf yeasts in the lab, mention 2 aseptic techniques you carried out to ensure a pathogen- free environment.
sterilising instruments
washing hands or wearing gloves
disinfecting bench and equipments
What type of agar is recommended for optimal growth of yeast and other fungi ?
malt agar
nutrient agar
In relation to the growth of leaf yeasts in the lab, describe how the plates were stored, from introduction of the yeast source until yeast growth was visible on the agar.
They were first stored right-side up for the first 1 or 2 days. Then they were stored upside down in an incubator for 2-7 days.
In relation to the growth of leaf yeasts in the lab, how did you identify the leaf yeast growing on the agar ?
They were present in pink colonies
In relation to the growth of leaf yeasts in the lab, suggest a reason why few or no leaf yeasts may have grown on the agar.
unsuitable temperature
no yeast on leaf
air pollution
State a feature of eukaryotic organisms
They have membrane-bound organelles
Give an example of a unicellular and a multicellular fungus
A unicellular fungus is yeast
A multicellular fungus is rhizopus
To which group of biomolecules does chitin belong ?
carohydrates
What is the type of nutrition found in fungi ?
saprophytic - they feed of dead matter or heterotrophic - they do not make their own food.
What is the importance of a decomposer ?
They recycle nutrients or minerals
What is the purpose of budding in fungi ?
reproduction
What part of the bacteria cell is responsible for protection ?
the capsule
What part of the bacteria cell is responsible for drug resistance ?
the plasmid
Name an organelle that is present in plant cells but absent in bacterial cells
mitochondria
chloroplasts
What is the role of an endospore ?
allows the bacteria to survive in unfavourable conditions
Explain the term chemosynthetic ?
This is the use of energy released from chemical reactions
Give an example of a chemosynthetic bacteria
Nitrifying bacteria
In relation to the growth of leaf yeasts in the lab, was the investigation carried out in a sterile or aseptic environment ?
Explain your answer
Aseptic
This means not all microbes were destroyed
What is the meaning of asepsis ?
This means free of pathogens
What is a pathogen ?
This is a disease causing organism
What is an antibiotic ?
This is a chemical produced by micro organisms to kill or stop the growth of other micro organisms
What is bioprocessing ?
This is the use of micro-organisms to form products
What is a bioreactor ?
This is a vessel in which products are made by micro organisms. it is vessel in which bioprocessing occurs.
Define osmosis
This is the movement of water through a semi permeable membrane from a high water concentration to a low water concentration
If there’s movement of water into an amoeba, why doesn’t it eventually burst?
This is due to the presence of a contractile vacuole. It expels water outside the cell.
Why is the movement of water less of a problem for species of amoeba that live in marine environment.
This is because the concentration of sea water and amoeba are similar
Define the term, selectively permeable
This means only certain substances are allowed through.
Define the term, prokaryotic
There are no membrane bound organelles.
Define the term, symbiotic
This is an arrangement where two organisms of different species that live in close proximity to each other both benefit.
Give a benefit of the presence of symbiotic bacteria
Digestion
Production of vitamins
What kingdom do rhizopus belong to ?
Name another member of this kingdom
fungi
yeast/ mushroom
Name a food on which rhizopus is commonly found
bread
Name the hyphae that anchors rhizopus to its food source
Rhizoids
Give an example of both a beneficial and harmful member of the fungi kingdom
beneficial - yeast
harmful - death cap
How does the genetic make up of the new yeast cell relate to that of the parent cell ?
Why is it so ?
Identical
Because they reproduce via mitosis.
Give an advantage and a disadvantage of asexual reproduction in yeast.
An advantage is that it is a rapid form of reproduction. A disadvantage is that there is an increased risk of disease and there is no variation.
Are fungus eukaryotes or prokaryotes ?
They are eukaryotes.
What is the importance of yeast to the brewing an baking industry ?
In the brewing industry, it is used in alcohol production.
In the baking industry, it is used in producing CO2.
Name the term used to describe an environment that is free from all micro-organisms.
Sterile
What is the role of rhizopus in nature ?
To act as a decomposer.
Give a structural difference between fungi and plants
Fungi have cell walls made of chitin while plants have cell walls made of cellulose.
Fungi have no chloroplasts while plants have chloroplast.
Name the method of asexual reproduction in rhizopus
Sporulation
Name the 3 general shapes of bacteria cells
rod shape
Spherical shape
Spiral shape
Differentiate between asepsis and sterility.
Asepsis means free of pathogens while sterility mens free of microbes.
Name the stages in a bacteria growth curve and explain the 3rd stage.
lag log stationary decline
During the stationary stage, the death rate equals the birth rate.
Distinguish between batch processing and continuous flow in food processing. Refer to the stages in the bacteria growth curve.
In batch processing, fixed amount of nutrients is added at the beginning while in continuous flow, the nutrients are continuously fed into the bioreactor.
All stages in the bacteria growth curve occur in the batch processing while in continuous flow only stage B is maintained throughout.
What is an obligate parasite and give an example.
An obligate parasite can only replicate in a cell. an example is a virus.
Name a virus that causes disease in plants
The mosaic virus
How do scientists distinguish between viruses ?
By their shapes and sizes
Why are viruses difficult to classify in a kingdom ?
Because they have no cell organelles
Give one way in which viruses are economically important.
They are used in making vaccines
Fungi maybe be classified into 2 groups based on their mode of nutrition. what are these 2 groups ?
parasitic and saprophytic fungi
In relation to the growth of leaf yeasts in the lab, what nutrient was added to the agar for the yeast
Malt extract.
In relation to the growth of leaf yeasts in the lab, how did you introduce the yeast to the petri dishes ?
BY attaching the leaves to the lid then replacing the lid.
Name 2 sources of energy used by autotrophic bacteria to make food.
solar energy
chemical energy
What are 2 structural features found in bacteria to support the claim that they are from the monera kingdom ?
They have no membrane-bound organelles.
They have a cell wall made of peptoglycan
Mention any 3 precautions you took when working with microbes.
There should be safe method of disposal
Disinfect the bench
Minimal opening
State any 2 characteristics of viruses that suggests that they are non living
They are non cellular.
They are obligate parasites.
Should antibiotics be prescribed for viral infections, why ?
No because they have no effects on viruses.
Define vaccination
This is when a non-disease causing form of pathogen is introduced into the body to prevent diseases.
How does the structure of saccharomyces differ from the other members of the fungus kingdom
It is unicellular.
When preparing alcohol using yeast, what substrate was used ?
glucose
When preparing alcohol using yeast, how does boiling half of the yeast suspension for 10 minutes act as a control ?
Suggest another control that could have been used.
It denatures the enzymes.
Water can be used rather than yeast.
When preparing alcohol using yeast, name an end product aside from alcohol
Carbondioxide
Name a structural feature found in fungi but not in animals
cell wall
Name a structural feature found in plants but not in fungi
chloroplast
Name a structural feature found in animal but not in monera
nucleus
Name a structural feature found in Protista but not in animal
contractile vacuole
Name the 5 kingdoms of life
monera protista animal plant fungi
What re the 2 kingdoms that contain single-cells organisms ?
Protista and monera
Autotrophic bacteria are subdivided into 2 groups based on what ?
The source of energy to make their food
In relation to the growth of leaf yeasts in the lab, what control did you use?
A closed plate
In relation to the growth of leaf yeasts in the lab, at what temperature are the agar plates incubated
20c - 25c
room temperature
Name 2 types of heterotrophic nutritions used by a bacteria
Saprophytic and parasitic
Distinguish between antibodies and antibiotics
Antibodies are proteins produced by the body to respond to an antigen while antibiotics are chemicals produced by microbes to destroy other microbes.
In relation to antibodies, distinguish between active and passive immunity.
active immunity are given by the antibodies produced in the body while passive immunity are given by the antibodies introduced into the body
In relation to the growth of leaf yeasts in the lab, how did you dispose the agar plates at the end of the experiment and explain why this is necessary.
immerse in autoclave
Virus are composed of 2 main biochemical components. What are they ?
proteins and DNA
Name a disease caused by viruses
measles, flu, polio
State 2 ways bacteria cells differ from human cells
Bacteria cells have cell walls but human cells do not.
bacteria cells have a flagellum but human cells do not.
Sexual reproduction in rhizopus is triggered by what ?
Dehydration
Give 2 advantages of zygospore formation to rhizopus.
They can survive drought
It allows for dispersal
During budding, what happens to the new cells formed in the process ?
They break away from the mother cell ?
How does the asexual production in rhizopus differ from that in yeast
Rhizopus produces spores.
What is the purpose of using agar when growing fungi or bacteria in the lab
to provide nutrients
Suggest a reason why leaf yeasts are more plentiful in July than in March.
More leaves are available
In relation to the growth of leaf yeasts in the lab, what was the purpose of a control ?
To show that the yeast came from the leaves.
Why are viruses not one of the 5 kingdoms
They are non cellular
In relation to the growth of leaf yeasts in the lab, from which plant did you collect the leaf sample an describe how the leaf sample was collected.
The sample was collected by cutting or picking the leaves.
In relation to the growth of leaf yeasts in the lab, what was the control used ?
An agar without leaves
In relation to the growth of leaf yeasts in the lab, why were the agar left the right side up for the first 24 hours ?
This is to allow the yeast fall from the leaf onto the agar.
Mention a feature of the monera kingdom
They are single celled
How does antibiotic resistance arise ?
This develops when surviving strains multiply
What is the function of the contractile vacuole in an amoeba ?
Osmoregulation.
Why are young people at more risk of becoming ill with swine flu than the older people ?
This is because older people may have been previously exposed to it and still have the antibodies produced to fight it .
Why are antibiotics used ?
To treat infections
Give a brief description of the structure of a virus
This is a DNA molecule surrounded by a protein coat
Give a role of rhizoids and explain how it carries this role.
They provide the rhizopus with nutrients. They do this by absorbing products from the substrate on which they are anchored to.
What is the mode of nutrition of a rhizopus ?
saprophytic
What happens during the lag phase ?
The bacteria is adapting to the environment
What is a nutrient medium ?
This is a material that supplies food
Name a test for alcohol
Iodoform test
Why does fermentation eventually cease ?
The alcohol kills yeast or the yeast dies
Give the function of a zygospore
For survival
Give a function of the gametangium
This produces gametes
Give a function of the sporangium
This produces spores
Give a feature of the rhizopus that suggests they belong to the fungi kingdom
spores
Is fermentation affected by temperature, explain ?
yes because the rate of activity of the enzymes is affected by temperature.
When preparing alcohol using yeast, what control was used ?
No yeast
Name a substance produced during aerobic respiration that is not produced during fermentation.
Water
