Transcript Cell Structures - Central Magnet School

Cell Structures
What are the functions of
the major cell structures?
Cell Wall
• Found in plants, algae, fungi and
nearly all prokaryotes
• Lie outside the cell membrane
• Made up of fibers of carbohydrate
and protein
– Plant cell walls made of cellulose
• MAIN FUNCTION: provide
support and protection for the cell
Image from:
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/
P/PlantCell.html
Plant Cell Wall Structure
Image from:
http://www.tvdsb.on.ca/westmin/science/sbi3a1/Cells/cellwall.htm
Bacterial cell walls
• Made up of
peptidoglycan
• Different
structures for
different types
of bacteria
Fungal and Algal cell walls
• Fungal cell
walls
–Composed of
chitin and
cellulose
• Algal Cell
Walls
– Composed of
polysaccharides
– Which
polysaccharides
depends on the
algae
Nucleus
• Controls most of the cell
processes and contains the
hereditary information (DNA)
• Parts of the nucleus
–Chromatin and chromosomes
–Nucleolus
–Nuclear envelope
Image from: http://sun.menloschool.org/~birchler/cells/animals/nucleus/
Image from: http://www.daviddarling.info/encyclopedia/N/nucleusc.html
Chromatin and
Chromosomes
• Chromatin
– The granular material visible within
the nucleus
– Consists of DNA bound to proteins
• Chromosomes
– Chromatin condenses into
chromosomes before cell division
– Contain genetic information
Nucleolus
• Assembly of ribosomes begins
here
Nuclear envelope
• Double membrane layer
surrounding the cell
• Has pores which allows
material into and out of the cell
Cytoskeleton
• Network of protein filaments
that help the cell maintain it’s
shape
• Involved in many forms of cell
movement
Parts of the Cytoskeleton
• Microtubules
–Hollow tubes of protein that maintain
shape
–Serve as “tracks” for moving organelles
–Important in cell division
–Make up centrioles in animal cells
–Also make up flagella and cilia in some
cells
Microtubules
Images from:
http://users.rcn.com/jkimball.ma.ultranet/BiologyPa
ges/C/Cytoskeleton.html
Parts of the Cytoskeleton
• Microfilaments
–Long, thin fibers that function
in the movement and support
of the cell
–Much smaller than
microtubules
Microfilaments
Ribosomes
• Small particles of RNA and
protein
• Function: assemble proteins
• Prokaryotic and Eukaryotic
ribosomes have different
structures
Ribosomes
consist of a
small
subunit
and a large
subunit
Image from:
http://cellbio.utmb
.edu/cellbio/ribos
ome.htm
Endoplasmic Reticulum
• Function: Components of the cell
membrane are assembled and some
proteins are modified
• Rough ER: Synthesis of proteins:
chemical modification; Studded
with ribosomes
• Smooth ER: synthesis of lipids
Image
from:
http://www
.winterwre
n.com/apbi
o/cellorgan
elles/er.htm
l
Image from: http://biology.about.com/library/weekly/aa041300a.htm
Golgi Apparatus
• Function: enzymes in the Golgi
attach carbohydrates and lipids
to proteins
• From Golgi proteins are
packaged and sent to their final
destinations
Image from: http://cellbio.utmb.edu/cellbio/GOLGI.HTM
Image from: http://cellbio.utmb.edu/cellbio/GOLGI.HTM
Lysosomes
• Small organelles filled with
enzymes
• Function: break down lipids,
carbohydrates and proteins from
food particles
• Break down old organelles and
other cellular debris
Image
from:
http://ce
llbio.ut
mb.edu/
cellbio/l
ysosom
e.htm
Vacuoles
• Function: Store materials such
as water, salts, proteins, and
carbohydrates
• In plants, a large central
vacuole filled with fluid is used
for support in the cell
Image
from:
http://mic
ro.magne
t.fsu.edu/
cells/plan
ts/images
/plantvac
uolesfigu
re1.jpg
Chloroplasts
• Function: use energy from the sun
to make energy-rich food
molecules in photosynthesis
• Bound by two envelope
membranes
• Stacks of photosynthetic
membranes contain chlorophyll
Image from:
http://www.davidda
rling.info/images/ch
loroplast.jpg
Mitochondria
• Function: use energy from food to
make high energy compounds
• Powerhouse of the cell
• Bound by two envelope
membranes
• Inner membrane is folded
Image
from:http://micro.
magnet.fsu.edu/ce
lls/mitochondria/i
mages/mitochondr
iafigure1.jpg
Organelle DNA
• Chloroplasts and mitochondria
contain their own DNA
• Endosymbiotic
theory:mitochondria and
chloroplasts the result of
endocytosis of bacteria and bluegreen algae whichbecame
symbiotic
Endosymbiotic theory
Image from:
http://www.ms
nucleus.org/m
embership/ht
ml/k6/lc/organ/5/i
mages/wpeA.
gif
Venn Diagram
• Use your notes and the venn
diagram handout to compare
and contrast prokaryotic and
eukaryotic cells and plant and
animal cells
Cell as a Factory
• See page 182