Organelle Presentations
Orange Block
October 2012
The Nucleus
Emma Suneby and Elizabeth Young
Orange Block
Structure
• What does it look like?
http://micro.magnet.fsu.edu/cells/nucleus/nucleus.html
• What is it made up of?
– Nuclear envelope, nucleolus, DNA,
nucleoplasm
Location
• Eukaryotic- inside both plant and animal
cells, not located in bacteria
• Located at the center of plant and animal
cells
•
http://www.animalport.com/animal-cells.html
» http://waynesword.palomar.edu/lmexer1a.htm
Function
• Localizes the cells DNA
• Tucks away DNA molecules making it easier for
parent cells to copy genetic instructions before
division
• Outer membrane forms boundary in which cells
control passages of substances and signals to and
from the cytoplasm
• Analogy: Nucleus is like the brain of the cell; it
sends instructions for the rest of the cell.
• Source: Biology Textbook The Unity and Diversity of Life
Nucleolus
Chloé Kolbet and Molly Micou
Structure/Location
• Inside the nucleus
• Only in eukaryotic cells
Function
• Where a large number of protein and RNA
molecules (chromatin) are constructed
• Houses the basic components of the cell
• Chromatin are Subunits of ribosomes that go out
of the nucleus’ pores to cytoplasm
• Factory of sweaters
•
Source: Biology: The Unity and Diversity of Life by Starr and Taggart
Ribosome
Structure
• Each ribosome organelle is made up of 2
subunits.
• These are assembled inside the nucleolus,
and the ribosome is therefore eukaryotic.
• The ribosome can travel inside of cells if it
is attached to the ER or float around the
cytoplasm.
• The ribosome is in animal, plant and
bacteria cells.
Analogy
• DNA is like an old book in a library that you
can’t check out.
• The mRNA is the copy of one specific recipe.
For example, delicious chocolate chip
cookies.
• The ribosome is the kitchen where these
cookies are made.
• The mRNA or recipe goes to this place
(ribosome or kitchen) and then attracts the
specific enzymes or ingredients.
• The end result is a chocolate chip cookie or
a protein!
• The two subunits (one large and one
small) are like the top and bottom of
a hamburger bun. They sandwich
the mRNA (or hamburger).
Function
• Polypeptide chains for proteins are
assembled on the surface of the
ribosome.
• Ribosomes make these polypeptide
chains by attracting specific enzymes.
• The place where the mRNA (the
instructions) binds to the surface.
The Rough Endoplasmic
Reticulum
• Function:
•
Part of Cytomembrane system; modifies
polypeptide chains into final protein product and
mRNA from nucleus
•
•
•
Newly forming chains with specific strings of amino
acids enter the space in the rough ER
There, enzymes attach oligosaccharides and other
side chains to the polypeptide, and modify the
polypeptide within the ER into the final protein
Sends out the new polypeptides in vesicles to the
Golgi Body
• Structure:
•
•
Arranged in stacks
Made of up space(inside the ER) and ribosomes
http://www.tutorvista.com/content/biology/biology-iii/cellorganization/membranous-cell-organelles.php
• Location:
– Only in eukaryotes
– Surrounds the nucleus
– It is in plant and animal cells.
• Analogy:
– Carpenter sanding and painting the final product.
http://sbaran.net/7scie
nce/cells/index.html
http://www.animalport.com/a
nimal-cells.html
Golgi Body
by: Ashton Chryssicas and Ellen Kitsos
Structure/location
• Layered, bean-like membranes
• Similar appearance to a series of flattened
pancakes
• Eukaryotic cells
• ribosomes are found in the pancake-like stacks.
• Found in plant and animal cell
• Floats in the cytoplasm
Function
• Modifies polypeptide chains into mature proteins
• Sorts, packages and distributes proteins and lipids
(macromolecules) for secretion outside of cell
• Absorbs vesicles from Rough ER
• Vesicles form as patches of the membrane bulge out, then
break away into cytoplasm.
– Nutrients enter through the cell membrane and into the cytoplasm
by Endocytosis
• Vesicles gravitate towards cell membranes and are released in
a process called exocytosis
Analogy: The function of a golgi body is similar to that of a
post office.
References
• http://www.johnkyrk.com/golgiAlone.swf
• Biology: The Unity and Diversity of Life
• http://www.biology4kids.com/files/cell_golg
i.html
Smooth E.R.
(Endoplasmic Reticulum)
Smooth ER
• FUNCTION: Lipid synthesis; Detoxifies certain
compounds; In sarcoplasmic reticulum:
located in skeletal muscle cells help in muscle
contractions.
• LOCATION:
In Eukaryotes; Its in both plants and animal cells;
It is a continuation of the rough ER; the
difference is that it lacks ribosomes.
Structure
It is Tubular
It is made up of
membranes.
Analogy
• Its is a kitchen because thats where food is
made and its sent out for people to eat it
afterwards.
Taylor Barnhill
Chloroplasts
• Location: photosynthetic eukaryotic
cells, all over the cell
• Disk shaped, encased by two
membranes
• Function: Sunlight energy  ATP
• ATP = chemical energy, used to make
sugars and organic compounds.
• Thylakoid membrane  has lighttrapping pigments, chlorophyll, enzymes,
and proteins which absorb energy and
store it in the form of ATP energy
• Grana = disks of thylakoid membrane
(folded and stacked)
• Stroma  the semi fluid interior where
ATP energy is used to make sugar,
starch, and other organic molecules
• Stromal lamellae = connect the grana
• Analogy: A chloroplast is like a factory with an
assembly line, each stage helps convert raw
materials into useful products.
• Sunlight  ATP  sugars, starch, organic materials.
http://hyperphysics.phy-astr.gsu.edu/hbase/biology/chloroplast.html
Mitochondria
By Peter and Liam
Structure
• The outermost membrane faces the
•
•
•
cytoplasm.
Inner membrane forms cristae, meaning it
folds back on itself.
The space between both membranes are
where hydrogen ions are stored
Resembles bacteria in biochemistry and
size
Location & Function
• Mitochondria exist only in eukaryotes, but are
•
•
•
•
in both animal and plant cells.
There are at least 1 in each cell
They exist anywhere in the cell membrane.
Mitochondria contain their own DNA
They aid cell respiration
Analogy
• Like the lungs of the cell
• Help the cell to breath
LYSOSOMES
• FUNCTION
– Used in intracellular digestion
• Contain enzymes that speed the breakdown of proteins, complex
carbohydrates, nucleic acids, and some lipids
– Apoptosis - programmed cell death
• Lysosomes release enzymes which break down cell components
• Cancer cells cannot go through apoptosis, so they can’t kill themselves
• LOCATION
– In eukaryotic cells
• All animals
• Some plants
• Some bacteria
– In the cytoplasm of the cell
LYSOSOME STRUCTURE
LYSOSOME IN A CELL
• Bag-like structures
• Different enzymes
contained by a
single membrane
– This membrane
protects from
apoptosis happening
when it shouldn’t
LYSOSOMES
• Pencil case
• Case – membrane
• Pens and pencils – enzymes
• Pens can explode - apoptosisis
•
•
•
•
http://www.ncbi.nlm.nih.gov/pubmed/18662570
http://www.buzzle.com/articles/lysosome-structure.html
http://www.proprofs.com/flashcards/cardshowall.php?title=human-anatomyphysiology
http://www.biology4kids.com/files/cell_lysosome.html
Central Vacuole
Function
• Increases cell surface area
• Storage for amino acids, sugars, ions
(similar to a battery: stores energy and
keeps everything running/moving)
• Gets rid of toxic waste (face wash: gets rid
of the bad parts of skin, keeps/ restores
nutrients and hydration)
• Causes fluid pressure in cell when
enlarges
Structure
• Made up of a fluid (cell “sap”) called
tonoplast that is released into the cell
when enlarges
• Fluid provides nutrients for cell
Location
• Eukaryotic
• Located in the cytoplasm (narrow area
between the central vacuole and the
plasma membrane)
http://www.cod.edu/people/faculty/fancher/cellstructure.htm
• Can take up to 50%-90% of the cell
interior
• Found mainly in plant cells
Cell Membrane
Cell Membrane
 Function: Controls the material exchanges and cell
environment in interactions, an example of an exchanges is
osmosis
 Location: the outermost layer of the cell for animal cells, in
plant and bacteria cells it is inside the cell wall
 The cell membrane is found in all three types of organisms
 Analogy: Security Guard
Composition of the Cell Membrane
Phospholipids Bi-layer
Proteins (ion channels and transmembrane
protein channels)
Nuclear Pores
Function of Cell Wall
The cell wall provides protection and
structural support in plant and bacteria
cells.
Structure of Cell Wall
•
•
•
•
•
Permeable to allow water and solutes to pass through
Middle Lamella-outermost layer, bonds with other cells
Primary Wall-made of gluey polysaccharides,
glycoproteins, and cellulose (in plants) and peptidoglycan
(in bacteria) which form into "rope-like strands" that are
sticky, and cement cells together, it's thin and pliable and
enlarges when water enters
Cuticle (a translucent, protective surface) forms when
cells are exposed to air, keeps water from escaping
Secondary Wall- rigid to reinforce cell shape
- in woody plants, made of lignin ( 3 carbon ring chain
and an oxygen atom attach to 6 carbon ring structure)
Location of Cell Wall
• Found in prokaryotes and some
•
•
eukaryotes
Wrapped around the plasma membrane
Found in plant and bacterial cells, NOT
animal cells
References
Starr, Cecie, and Ralph Taggart. Biology: The Unity and Diversity of Life. 9th ed.
USA: Thomson Learning, 2001. Print.
http://images.tutorvista.com/content/cell-organization/cell-wall-layers.jpeg
Cytoskeleton
By Ross Halpern & John Wilson
Cytoskeleton in Eukaryotic
Cells
The Structures and Functions of the Cytoskeleton
The cytoskeleton is an organized network of two to three primary protein filaments:
microtubules and micro/actin filaments which are present in Protista, Fungal, Plant, and
Animal cells. Intermediate filaments are found in some animal cells only. The Cytoskeleton is
a rope/ weblike structure found throughout the entirety of the cell that is responsible for
nearly all Eukaryotic cell movement.
Cytoskeleton of Animal
Fibroblast cells. The
microfilaments are tinted
green while the
microtubules are tinted
orange.
Function of Cytoskeleton in
Eukaryotic Cells
•
•
•
•
•
Establishes cell shape
Provides mechanical structure and internal organization
Intercellular transport of organelles
Gives cells capacity to move
Reinforces the plasma membrane
Microtubules: Long, hollow cylinders made
from monomers of the protein Tubulin. The
largest part of the cytoskeletal system. They
govern the division of cells as well as some
aspects of their shape and many cell
movements.
Microfilaments: The thinnest of cytoskeletal
elements. Made from 2 polypeptide chains of
monomers from the protein Actin that are
helically twisted together. Help with cell
movements especially on the surface of the cell
and the development of cellular shape in
Cytoskeleton in Prokaryotic
Cells
Recent advancements in Biology have led to the discovery of a Cytoskeleton within
Bacterial cells. Some of the many components that make up the Prokaryotic
Cytoskeleton are...
•
•
•
FtsZ, the first element discovered in the Prokaryotic Cytoskeleton; it forms a filamentous
ring in the middle of the cell and is essential for cell division as it forms the new cell wall
MreB, a bacterial protein which forms a helical network of protein filaments under the
cytoplasmic membrane. It determines the polarity of polar bacteria as well as the structure
CreS or Crescentin is the main element in determining structure. Forms a continuous
protein filament along the inner, concave side of a crescent shaped bacteria cell.