B6 - Understanding microbes Flashcards
What is bacteria?
Bacteria are tiny single-cell microorganisms, usually a few micrometers in length that normally exist together in millions.
What do scientists use to classify bacteria?
Scientists use the shape of bacteria to classify it.
Which is larger, a plant cell or a bacterial cell?
A plant cell is about 10x larger than a bacterial cell.
How do bacteria reproduce?
Bacteria reproduce asexually, by splitting in two.
What does a flagellum do?
Flagellum helps bacteria to move.
What does the cell wall do?
The cell wall helps bacterium keep its shape and prevents it bursting.
What does bacterial DNA do?
Bacterial DNA controls the bacterium’s activities and its replication.
What are the four shapes of bacteria?
- curved rod
- spherical
- spiral
- rod
What are aseptic techniques?
Aseptic techniques are precautions taken to ensure there is no contamination when growing bacteria.
What is binary fission?
Binary fission is the process of splitting in two.
Give examples of aseptic techniques.
- never leave lids off the container
- disinfect working area
- sterilise equipment before and after use
- wear disposable gloves
How do bacteria feed?
They consume organic nutrients such as carbohydrates and proteins.
If bacteria can use photosynthesis to create their own food, which energy source do they depend on?
They would depend on light energy.
Why is it difficult to stop bacteria?
They reproduce really quickly.
Give some examples of diseases that bacteria can cause.
- food poisoning
- cholera
- whooping cough
- typhoid
- tetanus
Why is it dangerous to eat food after its sell-by date?
Bacteria may have reproduced on it and could cause infections/diseases.
Is yeast a bacteria, fungus or virus?
Yeast is a single celled fungus.
Name the process by which yeast cells reproduce.
Yeast cells reproduce by budding.
Write down one structure found in yeast and plant cells but not animal cells.
Plant cells and yeast cells have cell walls.
Are viruses classed as living?
Scientists do not class viruses as living.
What is the difference between viruses and bacterium?
Viruses require a living host in order to survive and are not classed as living where as bacteria can survive without a living host and are living.
What conditions must be provided in order to maintain optimum growth of yeast?
- food
- optimum temperature
- optimum pH
- removal of waste products
Describe the structure of a virus.
Viruses are made up of strands of genetic material surrounded by a protein coat.
A plant virus will not harm a human. Suggest why.
Viruses attack different types of cell therefore they will not attack human cells.
Describe how viruses reproduce.
1) the virus attaches to a specific cell, called the host cell
2) the genetic material from the virus is injected into the host cell where it enters the nucleus to make mRNA
3) new viruses are made using material inside the host cell and the genetic material from the virus
4) the cell splits open, allowing the virus to leave but killing the host cell
Why do yeast cells start to die at high temperatures?
The enzymes become denatured.
