OCR Biology F211 complete revision notes

This is the complete OCR unit 1 biology revision note set. They took me a long time to complete. You are welcome to use them in your revision. If you could leave a comment saying thank you or how helpful they were, I would appreciate it. Good luck :)

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CELL STRUCTURES
a) state the resolution and magnification that can be achieved by a light microscope, TEM and
SEM.
T h e ma g n ific a ti
o n fo r a l
ig h t microscope i
s x1500 and t
h e
resolut
ion
in
200nm. The ma gni
fi
cati
on
fo r T E M is x 5 0 0 ,0 0 0 a n d fo r SE M i
t
is
x10 0,000.
The resol
uti
o n
is
0.2nm for
both TEM and
SE M.
b) explain the difference between resolution and magnification
R e so lu tio n is th e d e g re e to w hi
ch t
w o
o bj
ec t
s can
b e
dist
ingui
sh ed
in
an
imag e.
Ma gni
fi
cati
on i
s
th e d e g re e to w h ich th e ima ge
is
lar
ge r
t
ha n t
he actual
obj
ect i
tsel
f.
c) explain the need for staining samples for light and electron microscopy.
S ta in in g a llo w s th e s p e c i
me n
to
be
seen. Certai
n chemicals
bind t
o speci
fi
c cell
st
ruct
ures.
S o me o r g a n e l
le s o r s tru c tu res are
transparent
or di
ff
icul
t
to spot
.
d) calculate the linear magnification of an image
Ma g n ifica tio n = Ima g e s iz e /
Ac t
ual
size
e) describe and interpret drawings and photographs of eukaryotic cells as seen under a
microscope and be able to recognise: nucleus, nucleolus, nuclear envelope, RER and SER,
golgi body, ribosomes, mitochondria, lysosomes, chloroplasts, plasma membrane, centrioles,
flagella and cilia.
f) outline the functions of the organelles in e).
Nucleus: T h e la rg e s t o rg a n e l
l
e .
Surr
o unded by t
he nuclear
envelope which
con t
ains
pores t
o
a llo w mR N A a n d la rg e mo le cul
es t
o pass t
h r
ou gh.
Wh en st
ained t
he chroma t
in
can
be seen i
n
d a rk p a tc h e s . T h e n u c l
e u s c ontai
ns al
l
of t
h e
cell
's
gene t
ic
inf
orma t
ion.
It
has t
h e
inst
ructi
ons t
o
ma k e p ro te in s . T h e n u c l
e o lu s
ma kes RN A and r
ibosome s which
pass t
h r
oug h
the nucl
ear
e n v e lo p e i
n to th e c y to p la s m and assemb l
e s
p r
otei
n s.
Endoplasmic Reticulum (ER): C onsi
sts
o f
a ser
ies of
f
lat
tened me mbrane boun d
sacs.
R ER
h a s rib o s o me s o n it's su r fa ce ,
SER
do es
no t
.
F ound near
the nucl
eus.
R ER
tr
a nsport
s pr
otei
n s
th a t w e re ma d e in th e rib o so me s.
Some of
the
p r
otei
n s
are secr
eted,
some are
placed on
the
c e ll
s u rfa c e me mb ra n e . S E R ma kes
li
pids
that
the cel
l
ne eds.
Golgi Apparatus: A sta c k o f
me mbrane bo und
fl
a t
ten
sa cs.
I
t
receives
protei
ns f
rom the ER
a n d mo d ifie s th e m e .g . a d d ing
sugar molecules.
It
t
he n
packag es
protei
ns i
nto vesi
cles
to
be
tra n s p o rte d .
Mitochondria: S p h e ric a l/s a usage
sh aped.
T hey
h ave
two me mbranes.
T he i
nner memb rane i
s
fo ld e d to fo rm a c ris ta e . Mi to chondria
produ ce
A TP duri
ng aerobi
c r
e spi
rati
on.
Chloroplasts: F o u n d in p la nt
ce l
l
s. They
h ave t
w o
me mb ranes
sep ar
ated by
a
me mb r
ane
fi
ll
ed
s p a c e . T h e y a re th e s i
te o f p hotosynthesi
s in
plant
cell
s.
Lysosomes: S p h e r i
c a l s a c s sur
rounde d
by
a si
ngle memb rane.
The y
contain
pow erf
ul
digest
ive
e n z y me s w h ic h b re a k d o w n /remove
any unw anted
or f
oreign
ma ter
ial
.
1

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Regul
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Separ
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content
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out
side
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c) describe the fluid mosaic model of membrane structure
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