2018 Science T01W02 Flashcards
What is a micro-organism?
Micro-organisms are living beings that are invisible to the naked eye.
What is yeast?
Yeast is a micro-organism that is essential in the bread-making process.
Where does yeast get its energy from?
It gets its energy from sugar by breaking it down and producing Carbon Dioxide and Alcohol waste products.
Why does bread rise?
Carbon Dioxide gets trapped in the dough, creating pockets of gas which make the bread rise. When the dough is heated during baking, the heat causes the pockets of gas to expand, making large spaces in the bread.
If yeast produces alcohol, why isn’t bread alcoholic?
All the alcohol that yeast produces evaporates during the baking process.
Is sugar an essential ingredient in the bread making process?
Yes!
Yeast gets its energy from sugar by breaking it down and producing Carbon Dioxide and Alcohol waste products.
Who is Anton van Leeuwenhoek?
He is known as the father of microbiology. However van Leeuwenhoek was not a scientist, he was a draper.
Anton learned how to make his own unique microscopes which offered unparallelled magnification (up to 270 times). Using these microscopes he made a number of crucially important scientific discoveries, including single-celled animals, plants and bacteria.
His microscopy methods were so finely tuned that after he discovered bacteria, this type of organism would not be observed again by any other scientist for over 100 years.
What are animalcules?
In 1674, aged 41, Leeuwenhoek made the first of his great discoveries: single-celled life forms. Nowadays these organisms are grouped with the protists – these are mainly single-celled plants and animals he called then ‘animalcules’.
How does yeast become active?
Warm water.
What is fermentation?
Yeast coverts sugar to carbon dioxide and alcohol.
How is gluten formed?
The proteins in the flour.
Why is gluten important in the bread making process?
It helps to trap the carbon dioxide.
Why isn’t bread alcoholic?
Because all the alcohol evaporates when the bread is cooked.
Name one of the Dutch father and son team who created the first microscopes?
Zacharias Janssen.
How powerful were Janssen’s lenses?
They could magnify things up to 9 times.
Who was the first english scientist to use a microscope?
Robert Hooke.
Why did Hooke call the tiny compartments in cork, cells?
They reminded him of Monks’ chambers.
What was the name of the Dutch cloth merchant who designed a hand held microscope?
Anton van Leeuwenhoek.
What was the magnification on the Leeuwenhoek’s microscopes?
270 times.
What did Anton van Leeuwenhoek call microbes?
Animalcules.
What other things did Leeuwenhoek discover?
Red blood cells, bacteria, nematodes and rotifers.
Why was bacteria only observed by other scientists 100 years after Leeuwenhoek discovered it?
No one else could make a lense as powerful.
Who is known as the father of microbiology?
Leeuwenhoek.
How powerful in a modern electron microscope?
10 000 000 times.
