2.1.1 Flashcards
What is staining?
- Coloured stains bind to chemicals on / in specimen
Why do we use staining?
- allows the specimen to become visible
- can see organelles
- improve contrast
What stains DNA dark red?
Acetic Orcein
What colour does eosin stain the cytoplasm?
pink
Why do we do sectioning?
to allow light to pass through
What is the difference between the uses of the electron microscopes?
TEM - looks at organelle detail
SEM - looks at cell surface
How do SEM’s work?
beam of electrons hits specimen and bounces off
How do TEM’s work?
beam of electrons passes through a specimen
Why can TEM images look different?
organelles have been cut at different planes/angles
What are light microscopes used for?
to look at whole cells and whole tissues
What does magnification mean?
Number of times larger an image is in comparison to the object
What does resolution mean?
ability to distinguish between very small structures that are closer together in detail
What is the magnification of a light microscope?
up to 1500X
What is he maginfication of SEM?
100,000X
What is the magnification of TEM?
up to 500,000
What is the maximum resolving power of a light microscope?
50-200nm
What is the maximum resolving power of SEM?
0.20nm
What is the maximum resolving power of TEM?
0.05 - 1nm
cm to mm?
*10
cm to micrometers?
*10000
cm to nm?
10 , 000, 000
nm to micrometers?
/1000
nm to mm?
/1, 000, 000
nm to cm?
/10, 000, 000
What is the nucleus?
- controls nearly all activities of cell
- contains DNA and contains genetic codes for proteins
What is the RER?
- flattened membrane bound sacs called cisternae
- continuous with nuclear envelope
- RER is studded with ribosomes
- protein synthesis occurs here
What is the SER?
- flattened membrane bound sacs called cisternae
- continuous with nuclear envelope
- SER has no ribosomes
- iipid and hormone production happens here
What is the golgi apparatus?
- stack of membrane-bound flattened sacs
- processes and packages proteins into vesicles
- some of these vesicles may be secreted out of the cell
What is the ribosome?
- tiny organelles
- in cytoplasm
- or bound to RER
- site of protein synthesis
What is the mitochondria?
- Spherical
- 2 membranes separated by fluid filled space
- membrane folded into cristae
- central part - matrix
- ATP made from areobic respirations
What is the lysosome?
- spherical sacs surrounded by a membrane
- contain powerful digestive enzymes
What is the chloroplast?
- 2 membranes separated by a fluid-filled space
- inner membrane is continuous with a network of flattened discs called thylakoids
- site of photosynthesis
What is the plasma cell surface membrane made of?
phospholipid bilayer
What controls what enters and leaves the cell?
plasma / cell surface membrane
What do centrioles do?
- take part in mitosis
- form spindle fibres
What is the cell wall?
- provides high tensile strength
- insoluble
- inert
- made of cellulose
- cell wall in a bacteria is made of peptidoglycan
What is the flagella?
9+2 arrangement inside
whole cell movemement
What is cilia?
hair - like
move substances
What is the vacuole?
membrane-bound
membrane surrounding is called tonoplast
filled with water and enzymes
helps remove unwanted substances from cell by becoming turgid or flaccid
What is the process for the production and secretion of proteins?
1) mRNA is made and leaves through a nuclear pore
2) mRNA attaches to a ribosome on RER / cytoplasm
3) ribosome makes proteins and is processed and packaged into a vesicle
4) golgi apparatus processe and packages proteins
5) vesicle fuses with cell surface membrane and releases proteins by exocytosis
What is the importance of the cytoskeleton?
- important in whole cell support / mechanicl strength
- movement of cilia / flagella
- changing cell shape
- moving organelles like a vesicle
- movement of chromosomes in mitosis
What are 3 components of the cytoskeleton?
Microfilaments
Microtubules
Intermediate filaments
What are microfilaments?
- contract and used in cytokinesis
- change cell shape
- made from actin
What are microtubules?
- forms spindle fibres to move chromosomes
- moves organelles around the cell using vesicles
- made of globular tubulin proteins to form tubes
What are intermediate filaments?
- made form actin and microtubules
- mechanical strength
- whole cell support
What structures are associated weith the cytoske;eton?
flagell and cilia
How does the cell propell forward with the flgellum?
by using ATP
What is a structure found in animal cells but not plant cells?
centriole/ glycogen granule
What is the size of a ribosome in a prokaryotic cell?
70S
What is a plasmid?
circular DNA
passed to other bacteria to exchange genetic information
What is pili?
used for lateral flow of DNA to other bacteria
Where is ATP produced in a bacterial cell?
mesosome
infolded regions of a cell membrane
Where in bacteria is resistance to antibiotics coded in?
plasmid DNA
