SPEC - P1 - M2: CELL STRUCTURE Flashcards
(a) the use of microscopy to observe and investigate
different types of cell and cell structure in a range
of eukaryotic organisms - image produced
Light Mainly used for whole cells or tissues
Transmission Electron 2D images Denser parts look darker, B+W
Scanning Electron 3D Shows the surface of the specimen, B+W
Scanning confocal 2D/3D Shows objects at different depths within the specimen, colour
(b) the preparation and examination of microscope
slides for use in light microscopy
Cut the specimen very thinly
Use forceps to put it in the middle of the glass slide.
Pipette two drops of water onto the specimen.
Add a stain, if necessary.
Place a cover slip on top
Being careful not to create any air bubble
(c) the use of staining in light microscopy
Provides contrast
Some cell components become more visible as they bind to the stain
Clearer image obtained
(d) the representation of cell structure as seen
under the light microscope using drawings and
annotated diagrams of whole cells or cells in
sections of tissue
Sharp pencil
One continuous line
Diagram fills at least half the page
Magnification stated
Xylem and phloem labelled
Label lines drawn with a ruler
(e) the use and manipulation of the magnification
formula + triangle
actual/object
image mag actual/object (diameter)
(f) the difference between magnification and
resolution + diff mag n res light, TEM, SEM can achieve
-magnification. (1)
How many times bigger a microscope image is compared to the original specimen.
-resolution. (1)
The shortest distance between two objects that are still seen as separate objects.
Microscope Magnification Resolution
Light X 1500 0.2µm
Transmission Electron X 1000000 0.2nm
Scanning Electron X 500000 2nm
(g) the ultrastructure of eukaryotic cells and the
functions of the different cellular components - 16
Nucleus Controls the cell’s activities Contains the DNA / chromosomes
Nucleolus Produces ribosomes
Nuclear envelope Double membrane around the nucleus Has pores that allow mRNA to leave the nucleus
Rough ER Processes and folds proteins
Smooth ER Synthesises and processes lipids
Golgi apparatus Processes and packages proteins into vesicles
Ribosomes Protein synthesis
Mitochondria Aerobic respiration / ATP production
Lysosomes Contains digestive enzymes
Chloroplast Photosynthesis
Plasma membrane Controls the movement of substances into and out of the cell Has receptor molecules used in cell signalling
Centrioles Pull the chromosomes / chromatids to opposite poles during cell division
Cell Wall Supports the plant cell
Flagella Allow movement of the cell
Cilia Cilia move to move substances along the cell surface
Vesicle Transports substances in and out of the cell
(i) the interrelationship between the organelles
involved in the production and secretion of
proteins
A complimentary copy of the DNA is made in the nucleus
The mRNA leaves the nucleus through a nuclear pore
mRNA attaches to a ribosome
Protein synthesis occurs
The proteins are folded and processed at the rough ER
The proteins are packaged into vesicles
Transported to the golgi apparatus
The vesicles fuse with the cis face of the Golgi apparatus and the proteins enter.
The proteins are structurally modified at the Golgi apparatus.
The proteins leave the Golgi apparatus on the trans side in a vesicle.
The vesicles are moved to the plasma membrane by the cytoskeleton
Proteins released by exocytosis
(j) the importance of the cytoskeleton
Provide mechanical strength to cells,
Aid transport within cells
Enables cell movement
(k) the similarities and differences in the structure
and ultrastructure of prokaryotic and eukaryotic
cells.
P E
Nucleus? No Yes
Shape of DNA? Circular Linear
Size of cells? Extremely small (less than 2µm) Larger (about 10 - 100µm)
Cell wall? Yes Cellulose in plant Chitin in fungi Not present in animal cells
Size of ribosomes Small (less than 20nm) Larger (over 20nm)
Membrane bound
organelles? No Yes
cilia crosssection diagram + function
plasma membrane with microtubule pairs
-allows substances to move along cell surface as microtubles allow cilia to move
largest to smallest of conversions and how to convert micro, nano, mili
milli
x1000 micro /1000
x1000 nano / 1000
calculating size of one division on eyepiece graticule
-how many divisions on stage micrometer is the same as eyepiece divided by eyepiece graticule
-multiply by how much in 1 divison is on stage micrometer
