Summary AQA A-Level Biology – Cells (Unit 2) – Complete Revision Notes

, Cell Ultrastructure: Animal
Smooth Endoplasmic Reticulum
Rough Endoplasmic Reticulum
series of
interconnected , flattened sacs through the cytoplasm .


membranes form network of tubules & sacs Cisterne
a flattened




I
ten tubular continuous w/ the outer nuclear membrane
-




cks
more

ribosomes -




has ribosomes present outer surfaces
on
of
membranes
folding & processing of proteins by
↳
involved in made ribosomes
·

synthesises ,
stores , transports lipids & carbs
O

large SA- Synthesis of proteins & glycoproteins
-cells that store synthesise , ,
transport lots of lipids ·

pathway transport lipids & carbs
-



& carbs
#
↳ lots of
SER -

cells that make lots of proteins ,
secrete hormones, etc
↳ lots RER
of
Ribosomes F
-




80s in eukaryotes
y
- has two subunits Nucleus
↳
one large small
,
one
controls the cell's activities by controlling
↳
each contains ribosmal RNA transcription of DNA- protein synthesis&genes
& protein nucleolus makes ribosmal RNA and
#
assembles ribosomes
·
site
of protein synthesis nucleoplasm jelly-like
translate mRNA into
proteins nuclear envelope double membrane with
nuclear pores to allow
Centrioles
·
help chromosomes separate in
#

mitosis
F mRNA
↳ continuous
in and

w/rER
out


chromatin DNA round around proteins found in

Mitochondria chromosomes
aerobic respiration site ; has inner ·
& outer membrane

# Golgi Apparatus




I
cristae folds in inner membrane -



stack of flattened cisterne closely linked to RER ,


↳
large SA for attachment
1)
of enzymes & other proteins .



lipids produced SER transported in Vesicles passing through GA
proteins & in
,




respiration 2 ) GAmodigies these proteins by adding
non-protein components (EG carbs glycoproteins
:
in .
=




·
also labels' so can
accurately be sent to correct destination
matrix jelly-like with
enzymes 3) .




pinched off at end
of Golgi Listernae into Golgi Vesicles
for aerobic respiration
↳ lipids proteins ribosomes , Iso produces secretary like Pancreas & carbs like cellulose
-



A in
, ,
enzymes , , ,


DNA to allow mitochondria -




transports ,
stores modifies lipids
,



to control own protein
synthesis -forms lysosomes
ospherical sacs
containing enzyme lysozyme for breakdown of invading cells,
material worn down parts cells
foreign , of

, Cell Ultrastructure: Plant
Vacuole Chloroplasts
-fluid-filled sac bound by single -granum stacks of
disc-like
membrane tonoplast
of thy
structures made Kaloid
-
contains solution of mineral salts sugars, , membrane where chlorophy
acids wastes sometimes found
amino
, ,
pigments
firststep
↳
of photosynthesis
support herbaceous plants herbaceous ↳ connected w/ intergranal
·

,



parts of woody plants by making ,
lamella
cells turgid *
↳
Thykaloid membrane has a




sugar & amino acids temporary good high SA for attachment of
· =




stores chlorophyll ,
electron carriers &
pigment petals to
may colour firststage
·

enzymes for
attract pollinating insects photosynthesis to be attached
in an
orderlyfashion
-


stroma fluid-filled matrix where
of photosynthesis
second stage
occurs
↳
possesses all enzymes needed to
make sugars in second stage
-




Chloroplasts contain both DNA &
ribosomes they can quickly and
so


easily manufacture some of the proteins
needed for photosynthesis
-




has outer & inner membrane




#-

Cell Wall

-




has microfibrils of cellulose embedded in a matrix
Middle lamella thin layer , marks boundary between adjacent cell walls & cements
-




adjacent cells together
-provides mechanical strength
, so cell does not burst under pressure


-in fungi =
made from polysaccharide called Chitin
-in Algae =
made of cellulose glycoproteins ,
,
orboth