Organelle Presentations

Orange BlockOctober 2012

The Nucleus

Emma Suneby and Elizabeth YoungOrange 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/cell-organization/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://www.animalport.com/animal-cells.html

http://sbaran.net/7science/cells/index.html

Golgi Bodyby: 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 exocytosisAnalogy: 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.

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.

Taylor Barnhill

• Thylakoid membrane has light-trapping 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

MitochondriaBy 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

• Bag-like structures• Different enzymes

contained by a single membrane– This membrane

protects from apoptosis happening when it shouldn’t

LYSOSOME IN A CELL

LYSOSOMES

• 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

• Pencil case• Case – membrane• Pens and pencils – enzymes• Pens can explode - apoptosisis

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-layerProteins (ion channels and transmembrane

protein channels)Nuclear Pores

Function of Cell WallThe 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

ReferencesStarr, 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

CytoskeletonBy Ross Halpern & John Wilson

Cytoskeleton in Eukaryotic Cells

The Structures and Functions of the CytoskeletonThe 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 animal cells.Intermediate filaments: Most stable elements of cytoskeleton. Helps cells mechanically strengthen their parts and maintain their shape.

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.