Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
33 Cards in this Set
- Front
- Back
|
Resolution and magnification for light microscope
|
magnification= x1500
resolution= 200nm |
|
|
Resolution and magnification for transmission electron microscope
|
magnification= x500 000
resolution= 0.20mn |
|
|
Resolution and magnification for scanning electron microscope
|
magnification= x100 000
resolution= 0.20nm |
|
|
Magnification
|
How much larger the size of an image is larger than the object itself
|
|
|
Resolution
|
The degree to which it is possible to distinguish between two objects that are very close together
|
|
|
Why do we need to stain samples for light and electron microscopy?
|
A lot of biological material is not coloured, so you can't see the details. Also some material distorts when you cut it into thin sections
|
|
|
How do you calculate the linear magnification of an image?
|
magnification = image / actual
measure image size in mm and x by 1000 to convert to micro meters. Divide this by the actual size in microns |
|
|
Function of a nucleus
|
Houses nearly all of the cell's genetic material.
The chromatin consists of DNA and proteins some of these proteins regulate the cell's activities |
|
|
Function of a nucleolus
|
The nucleus makes RNA and ribosomes.these then pass into the cytoplasm and proteins are assembled at them
|
|
|
Function of a nuclear envelope
|
Lets relatively large molecules to pass through via nuclear pores
|
|
|
Function of rough and smooth endoplasmic reticulum
|
Rough ER: transports proteins that were made on the attached ribosomes. Some of these may be secreted from the cell. Some will be placed on the cell's surface membrane
Smooth ER: Makes the lipids that the cell needs |
|
|
Function of the golgi apparatus
|
Receives proteins from the ER and modifies them
it may add sugar molecules to them it then packages the modified proteins into vesicles that can be transported |
|
|
Function of ribosomes
|
Are the site of protein synthesis
they act as an assembly line where coded information from the nucleus is used to assemble proteins from amino acids |
|
|
Function of mitochondria
|
The site where ATP is produced during respiration
|
|
|
Function of lysosomes
|
Contain powerful digestive enzymes to break down materials
|
|
|
Function of cholroplasts
|
The site of photosynthesis in plant cells
carbohydrate molecules are made from carbon dioxide and water |
|
|
Function of the plasma cell surface
|
Controls the movement in and out of cells
separates the interior of cells from the outside environment |
|
|
Function of centrioles
|
They form fibres, known as the spindle, which move chromosomes during nuclear division
|
|
|
Function of flagella
|
Can move the cell about
|
|
|
Function of cillia
|
Can move liquid past the surface of the cell, such as mucus
|
|
|
Structure of the nucleus
|
Its is surrounded by the nuclear envelope
There is a nucleolus inside the nucleus |
|
|
Structure of the nucleolus
|
Dense and spherical
|
|
|
Structure of the nuclear envelope
|
A structure made of two membranes with a lot of holes called nuclear pores going right through.
|
|
|
Structure of the endoplasmic reticulum
|
flattened membrane sacs called cisternae.
they are continuous with the outer nuclear membrane Rough ER is studded with ribosomes |
|
|
Structure of the golgi apparatus
|
A stack of membrane bound flattened sacs
|
|
|
Structure of mitocondria
|
Two membranes separated by a fluid filled space.
The inner membrane is highly folded to form cristae. the central part is called the matrix |
|
|
Structure of choloroplasts
|
Two membranes separated by a fluid filled space
the inner membrane is continuous with an elaborate network of thylakoids chlorophyll molecules are present on the thylakoid membranes and in the intergranal membranes |
|
|
Structure of lysosomes
|
Spherical sacs surrounded by a single membrane
|
|
|
Structure of ribosomes
|
Ting organelles
some are in the cytoplasm and some are bound to the ER each ribosomes consists of two subunits |
|
|
Structure of centrioles
|
Small tubes of protein fibres
there is a pair of them next to the nucleus in animal cells and some protoctists |
|
|
What are the stages of protein synthesis within a cell?
|
1. mRNA copy the instructions from the nucleus
2. mRNA leaves the nucleus through a nuclear pore 3. mRNA attaches to a ribosome and this attaches to the Rough ER. Ribosomes reads the instructions to assemble the protein 4.Molecules are pinched off in vesicles 5.Vesicle fuses with the golgi apparatus 6. golgi apparatus processes and packages the molecule 7.molecules are pinched off in vesicles 8.vesicles fuse with the cell surface membrane 9. cell surface membrane opens to release molecules outside |
|
|
What is the importance of the cytoskeleton?
|
Contains a network of fibres
these fibres keep the cells shape stable by providing internal framework These fibres can also move against each other. these move organelles inside the cell and move white blood cells |
|
|
Structure of prokaryotic cells
|
only have one membrane
do not contain any membrane bound organelles surrounded by a cell wall usually peptidoglycan contains smaller ribosomes DNA is in the form of a single loop also contain plasmids DNA is not surrounded by a membrane the DNA lies in the nucleoid ATP takes place in infolded regions called mesosomes Some have flagella |
