FULL REVISION GUIDE FOR AQA AS UNIT1

Add your own notes or revise from mine! GOOD LUCK

HideShow resource information
Preview of FULL REVISION GUIDE FOR AQA AS UNIT1

First 144 words of the document:

AMELIAS MINI
REVISION GUIDE
CELLS
MICROSCOPES:
There are two main types of microscopes: Light and Electron
Electron Micrographs- shown in colour
LIGHT ELECTRON
Uses beam of light Transmission Electron Scanning Electron
Magnification = x1500 Microscope (TEM) Microscope (SEM)
Resolution = 200 nm
Wide range of
specimens can be used
Samples are fairly quick
+ easy to prepare
Cheaper and safer
Limited resolution
Limited magnification
Uses electromagnets to focus Scan beam of electrons
beam of electrons across specimen
Denser parts of specimen absorb Beam bounces off surface
more electrons creating contrast of specimen
Can only be used on thin Produces 3D image
specimens Magnification = x100,000
Produces 2D image Resolution = 5 nm (lower)
Magnification = x500,000
Resolution = 0.2 nm
Advantages Di
sa
d

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

Can produce coloured
images M
Better resolution us
Better magnification t
b
e
us
e
d
in
a
v
ac
u
u
m
(n
o
ai
r)
-
el
e
ct
ro
ns
ar
e
a
b
s
or
b
e
d
b
y
m
ol…read more

Page 3

Preview of page 3

Here's a taster:

E
x
p
e
ns
iv
e
Tr
ai
ni
n
g
is
re
q
ui
re
d
N
at
ur
al
c
ol
o
ur
s
ca
n'
t
b
e
s
e
e
n…read more

Page 4

Preview of page 4

Here's a taster:

D
a
n
g
er
o
us
-
kil
ls
liv
in
g
c
el
ls
MEASUREMENTS:
MICROMETRE = µm
NANOMETRE = nm
1 cm 10, 000 µm
1 cm 10, 000, 000 nm
1 mm 1000 µm
1 mm 1, 000, 000 nm
1 µm 1000 nm
MAGNIFICATION: SIZE
The degree to which the size of an image is larger than the object itself
Magnification = Image size
Actual size
LIMITS OF RESOLUTION:
Human eye = 100 nm
Light microscope = 200 nm
Electron…read more

Page 5

Preview of page 5

Here's a taster:

Ribosome = 20 nm
Virus = 40 ­ 100 nm
RESOLUTION:
The ability to distinguish between two separate points
CELL ORGANELLES:
ORGANELLE STRUCTURE FUNCTION
Nucleus · Largest organelle with: · Chromatin made from protein and
· Chromatin DNA
· Nuclear envelope (double · Controls cell activities
membrane) · Nucleolus makes RNA and ribosomes
· Nuclear pore (holes) · Start process of cell division
· Nucleolus
Cell Wall · Made of cellulose · Supports cell
· Rigid, protective barrier · Protects against mechanical damage
Cell Surface…read more

Page 6

Preview of page 6

Here's a taster:

Mitochondrion · Double membrane · ATP produced during aerobic
· Cristae (folded) respiration
· Matrix (central part) · ATP is universal carrier energy
· Consist of two subunits · Protein synthesis occur
(large and small) · Coded information (mRNA) is used to
· Found in cytoplasm assemble protein from amino acid
· Attached to Rough ER
Ribosome
· Cisternae (flattened · Studded with ribosomes
membrane bound sacs) · Folds and processes proteins made
· Rough- ribosomes present at ribosome
on outer surfaces of · Provides…read more

Page 7

Preview of page 7

Here's a taster:

Golgi Apparatus · Stack of membrane bound · Receives and modifies proteins from
sacs ER
· Packages modified protein into
vesicles to be transported
· Makes lysosomes
· Produces secretory enzymes
Vesicle · Small fluid sac in cytoplasm · Transports substances in and out cell
with membrane · Formed at Golgi apparatus, ER, cell
surface membrane
· Round organelle · Contains digestive enzymes to break
surrounded by membrane down materials
· Can be used to digest invading cells
· Releases enzymes to outside of cell…read more

Page 8

Preview of page 8

Here's a taster:

Small, hair-like structures · Microtubules allow cilia to move
· Have ring of 9 pairs of · Movement is used by cell to move
protein microtubules substances along cell surface
inside
· Have 2 pairs of
microtubules in the middle
Cilia
Flagellum (undulipodia) · Like cilia, but longer · Microtubules contract to make
· Stick out from cell surface flagellum move
membrane · Used like outboard motors to propel
· Have 2 microtubules in cells forward (e.g.…read more

Page 9

Preview of page 9

Here's a taster:

Double membrane · Chlorophyll molecules present
· Thylakoid (flattened · Site for photosynthesis
membrane sac) · Grana- carries out light dependent
· Grana (stack of thylakoids) stage of photosynthesis
· Lamella (thin, flat pieces of
thylakoids)
Chloroplast
Vacuole · Filled with cell sap · Keeps plant supported, rigid and
turgid
· produces enzymes to destroy
bacteria
PROKARYOTIC AND EUKARYOTIC CELLS:
PROKARYOTES & DISEASE:
· Staphylococcus Auerus
· MRSA (Methicillin- resistance staphylococcus auerus)
· Resistance is coded on the plasmid and so bacteria can easily pass…read more

Page 10

Preview of page 10

Here's a taster:

Have true nucleus No nucleus ­ free in cytoplasm
DNA is linear DNA is circular (loop)- plasmid
Membrane bound organelles Only one cell surface membrane
No cell wall, cellulose (in plant cells) Cell wall made of "peptidoglycan"
Larger ribosomes Smaller ribosomes
Mitochondrion Mesosome
FUNCTIONS:
· To separate cell contents from outside the cell
· To separate cell components from the cytoplasm
· In cell recognition and signalling
· To hold some components of metabolic pathways in place
· In regulating the transport of materials in…read more

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all resources »