magnification the number of times an image is greater than the actual size of
yi yi yi yi yi yi yi yi yi yi yi yi
the object
yi
resolution the ability to distinguish between two objects very close together;
yi yi yi yi yi yi yi yi yi
the higher the resolution, the greater the detail
yi yi yi yi yi yi yi
magnification = image size / actual size
yi yi yi yi yi yi
1 micrometer = 1000 millimetres
yi yi yi yi
1 nanometer = 1000 micrometers
yi yi yi yi
1
,AS-LEVEL BIOLOGY NOTES
yi yi BIANCA HIMAWAN yi
TYPICAL FEATURES OF PROKARYOTES (BACTERIA)
yi yi yi yi
always present yi sometimes present yi
cell wall
yi flagellum (for locomotion) yi yi
surface membrane
yi capsule (additional protection)
yi yi
cytoplasm infold of cell membrane
yi yi yi
circular DNA yi plasmid (small DNA circle)yi yi yi
ribosome pili (for attachment/sexual reproduction)
yi yi yi
LIGHT VS. ELECTRON MICROSCOPY
yi yi yi
no. feature light electron
1. source of radiation yi yi light electrons
2. wavelength 400nm 0.005nm
3. max. resolution yi 200nm 0.5nm
4. lenses glass condenser electromagnetic yi
5. specimen live/dead dead
6. stains coloured dyes yi heavy metals yi
7. image coloured black/white
STRUCTURES & FUNCTIONS OF ORGANELLES yi yi yi yi
name structure function
nucleus double membrane (nuclear yi yi pores allow control/exchange of
yi yi yi
yi envelope); outer membrane yi yi yi substances for protein yi yi
continuous with ER; has nuclear
yi yi yi yi yi yi synthesis; controls cell activities yi yi yi
pores
endoplasmic membrane extended as a yi yi yi small sacs called vesicles can
yi yi yi yi
reticulum
yi yi system of flattened sacs yi yi yi yi break off rough ER to join golgi
yi yi yi yi yi yi
yi interconnected to form yi yi yi body; smooth ER makes lipids
yi yi yi yi
yi reticulum; rough ER covered yi yi yi yi and steroidsyi
with ribosomes; smooth ER
yi yi yi yi
lacks ribosomes yi
ribosome has large and small units
yi yi yi yi for protein synthesis
yi yi
2
, AS-LEVEL BIOLOGY NOTES
yi yi BIANCA HIMAWAN yi
golgi stack of flattened sacs;
yi yi yi collects, processes, sorts yi yi
yi constantly being formed by ER; yi yi yi yi yi molecules from rough ER, ready yi yi yi yi
yi single membrane yi yi for transport to other parts of
yi yi yi yi yi
yi cell/out of cell (secretion); yi yi yi
vesicles also used for
yi yi yi yi
lysosomes
lysosomes spherical sacs; single yi yi breaks down unwanted yi yi
yi membrane; no internal structure; yi yi yi yi structures (old organelles); yi yi
yi contains digestive (hydrolytic) yi yi yi digests bacteria in WBC; yi yi yi
yi enzymes hydrolytic enzymes work in and
yi yi yi yi yi
out of cell
yi yi
mitochondria double membrane; inner yi yi aerobic respiration; lipid yi yi
yi membrane folded to form yi yi yi yi synthesis; produce ATP; porin yi yi yi
yi cristae; outer membrane yi yi yi forms aqueous channels; inner
yi yi yi
yi contains porin yi yi membrane controls entrance yi yi
of
yi
ions/molecules into matrix yi yi
surface membrane
yi extremely thin (7nm); double yi yi yi partially permeable; controls yi yi
membrane; 3 layers
yi yi yi exchange between cell and
yi yi yi yi
environment
microvilli finger-like extensions of the yi yi yi increase surface area of yi yi yi
surface membrane yi membrane for absorption yi yi
microtubules long, rigid, hollow tubes in
yi yi yi yi make up cytoskeleton
yi yi
cytoplasm; made up of tubulin yi yi yi yi
centrioles; hollow cylinder formed from a yi yi yi yi centrosome makes up spindle yi yi yi
centrosome
yi ring of short microtubules found
yi yi yi yi yi for cell division
yi yi
in centromeres
yi yi
chloroplast elongated shape; double yi yi photosynthesis; contains yi
membrane chlorophyll for green colour yi yi yi
cell wall
yi rigid; contains cellulose fibres
yi yi yi prevents cell from bursting; yi yi yi
gives cell definite shape
yi yi yi
plasmodesmata fine strands of cytoplasm
yi yi yi allow movement between cells;
yi yi yi
outside cell wall yi yi link cells together
yi yi
vacuole membrane-bound sacs within yi yi tonoplast controls exchange yi yi
yi cytoplasm yi between vacuole and yi yi
yi cytoplasm; contains fluid; yi yi
yi regulate osmotic properties of yi yi yi
cells
3
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