3.1: The methods of studying cells Flashcards
The cell is the basic unit of life.
However, with a few exceptions, cells are not visible to the naked eye and their structure is only apparent when seen under a microscope.
What are microscopes?
Microscopes are instruments that produce a magnified image of an object
A simple what can act as a magnifying glass?
A simple convex glass lens can act as a magnifying glass
A simple convex glass lens can act as a magnifying glass, but such lenses work more effectively if they are what?
A simple convex glass lens can act as a magnifying glass, but such lenses work more effectively if they are used in pairs in a compound light microscope
A simple convex glass lens can act as a magnifying glass, but such lenses work more effectively if they are used in pairs in a compound light microscope.
The relatively long wavelength of light rays means that a light microscope can only do what?
The relatively long wavelength of light rays means that a light microscope can only distinguish between 2 objects if they are: 1. 0.2 μm Or, 2. Further apart
A simple convex glass lens can act as a magnifying glass, but such lenses work more effectively if they are used in pairs in a compound light microscope.
The relatively long wavelength of light rays means that a light microscope can only distinguish between 2 objects if they are 0.2 μm, or further, apart.
This limitation can be overcome by using beams of electrons rather than beams of light.
With their shorter wavelengths, the beam of electrons in the electron microscope can do what?
With their shorter wavelengths, the beam of electrons in the electron microscope can distinguish between 2 objects only 0.1 nm apart
The object
The object is the material that is put under a microscope
The object is the material that is put under a microscope.
The image is what?
The image is the appearance of this material when viewed under the microscope
The magnification of an object is what?
The magnification of an object is how many times bigger the image is when compared to the object
The equation for magnification
The equation for magnification is:
Magnification = Image size ÷ Real size
The important thing to remember when calculating the magnification is to ensure that what?
The important thing to remember when calculating the magnification is to ensure that the units of length are the same for both the:
- Object
- Image
The resolution, or resolving power, of a microscope
The: 1. Resolution Or, 2. Resolving power ,of a microscope is the minimum distance apart that 2 objects can be in order for them to appear as separate items
The resolution, or resolving power, of a microscope is the minimum distance apart that 2 objects can be in order for them to appear as separate items.
Whatever the type of microscope, the resolving power depends on what?
Whatever the type of microscope, the resolving power depends on the:
1. Wavelength
Or,
2. Form of radiation used
The resolution, or resolving power, of a microscope is the minimum distance apart that 2 objects can be in order for them to appear as separate items.
Whatever the type of microscope, the resolving power depends on the wavelength, or form of radiation used.
In a light microscope it is about 0.2 μm.
Greater resolution means what?
Greater resolution means greater clarity
The resolution, or resolving power, of a microscope is the minimum distance apart that 2 objects can be in order for them to appear as separate items.
Greater resolution means greater clarity.
This means that the image produced is what?
This means that the image produced is:
- Clearer
- More precise
The resolution, or resolving power, of a microscope is the minimum distance apart that 2 objects can be in order for them to appear as separate items.
Greater resolution means greater clarity.
This means that the image produced is clearer and more precise.
Increasing the magnification increases the size of an image, but does not always do what?
Increasing the magnification increases the size of an image, but does not always increase the resolution
The resolution, or resolving power, of a microscope is the minimum distance apart that 2 objects can be in order for them to appear as separate items.
Greater resolution means greater clarity.
This means that the image produced is clearer and more precise.
Increasing the magnification increases the size of an image, but does not always increase the resolution.
Every microscope has a what?
Every microscope has a limit of resolution
The resolution, or resolving power, of a microscope is the minimum distance apart that 2 objects can be in order for them to appear as separate items.
Greater resolution means greater clarity.
This means that the image produced is clearer and more precise.
Increasing the magnification increases the size of an image, but does not always increase the resolution.
Every microscope has a limit of resolution.
Up to this point increasing the magnification will reveal more detail, but beyond this point increasing the magnification will not do this.
The object, while appearing larger, will just be what?
The object, while appearing larger, will just be more blurred
In order to study the structure and function of the various organelles that make up cells, it is necessary to obtain large numbers of isolated organelles.
Cell fractionation is what?
Cell fractionation is the process where:
- Cells are broken up
- The different organelles they contain are separated out
In order to study the structure and function of the various organelles that make up cells, it is necessary to obtain large numbers of isolated organelles.
Cell fractionation is the process where cells are broken up and the different organelles they contain are separated out.
Before cell fractionation can begin, what happens?
Before cell fractionation can begin, the cut up tissue is placed in a cold, buffered solution of the same water potential as the tissue
In order to study the structure and function of the various organelles that make up cells, it is necessary to obtain large numbers of isolated organelles.
Cell fractionation is the process where cells are broken up and the different organelles they contain are separated out.
Before cell fractionation can begin, the cut up tissue is placed in a cold, buffered solution of the same water potential as the tissue.
The solution is cold to do what?
The solution is cold to reduce enzyme activity that might break down the organelles
In order to study the structure and function of the various organelles that make up cells, it is necessary to obtain large numbers of isolated organelles.
Cell fractionation is the process where cells are broken up and the different organelles they contain are separated out.
Before cell fractionation can begin, the cut up tissue is placed in a cold, buffered solution of the same water potential as the tissue.
The solution is of the same water potential as the tissue to prevent what?
The solution is of the same water potential as the tissue to prevent organelles:
1. Bursting
Or,
2. Shrinking
as a result of osmotic gain, or loss of water
In order to study the structure and function of the various organelles that make up cells, it is necessary to obtain large numbers of isolated organelles.
Cell fractionation is the process where cells are broken up and the different organelles they contain are separated out.
Before cell fractionation can begin, the cut up tissue is placed in a cold, buffered solution of the same water potential as the tissue.
The solution is buffered so that what?
The solution is buffered so that the pH does not fluctuate
In order to study the structure and function of the various organelles that make up cells, it is necessary to obtain large numbers of isolated organelles.
Cell fractionation is the process where cells are broken up and the different organelles they contain are separated out.
Before cell fractionation can begin, the cut up tissue is placed in a cold, buffered solution of the same water potential as the tissue.
The solution is buffered so that the pH does not fluctuate.
Any change in pH could do what?
Any change in pH could:
1. Alter the structure of the organelles
Or,
2. Affect the functioning of enzymes
In order to study the structure and function of the various organelles that make up cells, it is necessary to obtain large numbers of isolated organelles.
Cell fractionation is the process where cells are broken up and the different organelles they contain are separated out.
There are how many stages to cell fractionation?
There are 2 stages to cell fractionation:
- Homogenation
- Ultracentrifugation
Cell fractionation is the process where cells are broken up and the different organelles they contain are separated out.
There are 2 stages to cell fractionation, homogenation and ultracentrifugation.
Homogenation is when what?
Homogenation is when cells are broken up by a homogeniser (blender)
Cell fractionation is the process where cells are broken up and the different organelles they contain are separated out.
There are 2 stages to cell fractionation, homogenation and ultracentrifugation.
Homogenation is when cells are broken up by a homogeniser (blender).
This does what?
This releases the organelles from the cell
Cell fractionation is the process where cells are broken up and the different organelles they contain are separated out.
There are 2 stages to cell fractionation, homogenation and ultracentrifugation.
Homogenation is when cells are broken up by a homogeniser (blender).
This releases the organelles from the cell.
The resultant fluid, known as what, is then what?
The resultant fluid, known as homogenate, is then filtered
Cell fractionation is the process where cells are broken up and the different organelles they contain are separated out.
There are 2 stages to cell fractionation, homogenation and ultracentrifugation.
Homogenation is when cells are broken up by a homogeniser (blender).
This releases the organelles from the cell.
The resultant fluid, known as homogenate, is then filtered to do what?
The resultant fluid, known as homogenate, is then filtered to remove any:
- Complete cells
- Large pieces of debris
Cell fractionation is the process where cells are broken up and the different organelles they contain are separated out.
There are 2 stages to cell fractionation, homogenation and ultracentrifugation.
Homogenation is when cells are broken up by a homogeniser (blender).
Ultracentrifugation is the process by which what?
Ultracentrifugation is the process by which the fragments in the filtered homogenate are separated in a machine called a centrifuge
Cell fractionation is the process where cells are broken up and the different organelles they contain are separated out.
There are 2 stages to cell fractionation, homogenation and ultracentrifugation.
Ultracentrifugation is the process by which the fragments in the filtered homogenate are separated in a machine called a centrifuge.
This does what?
This spins tubes of homogenate at very high speed in order to create a centrifugal force
Cell fractionation is the process where cells are broken up and the different organelles they contain are separated out.
There are 2 stages to cell fractionation, homogenation and ultracentrifugation.
Ultracentrifugation is the process by which the fragments in the filtered homogenate are separated in a machine called a centrifuge.
This spins tubes of homogenate at very high speed in order to create a centrifugal force.
For animal cells, the process is as the tube of filtrate is what?
For animal cells, the process is as the tube of filtrate is:
- Placed in the centrifuge
- Spun at a slow speed
Cell fractionation is the process where cells are broken up and the different organelles they contain are separated out.
There are 2 stages to cell fractionation, homogenation and ultracentrifugation.
Ultracentrifugation is the process by which the fragments in the filtered homogenate are separated in a machine called a centrifuge.
This spins tubes of homogenate at very high speed in order to create a centrifugal force.
For animal cells, the process is as the tube of filtrate is placed in the centrifuge and spun at a slow speed.
The heaviest organelles, the nuclei, are what?
The heaviest organelles, the nuclei, are forced to the bottom of the tube
Cell fractionation is the process where cells are broken up and the different organelles they contain are separated out.
There are 2 stages to cell fractionation, homogenation and ultracentrifugation.
Ultracentrifugation is the process by which the fragments in the filtered homogenate are separated in a machine called a centrifuge.
This spins tubes of homogenate at very high speed in order to create a centrifugal force.
For animal cells, the process is as the tube of filtrate is placed in the centrifuge and spun at a slow speed.
The heaviest organelles, the nuclei, are forced to the bottom of the tube, where they do what?
The heaviest organelles, the nuclei, are forced to the bottom of the tube, where they form a thin:
1. Sediment
Or,
2. Pellet