cell type

Type of cells

Lab-5-
Sunday 3/1/2016

The cell

The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life.
Organisms can be classified as unicellular (consisting of a single cell; including most bacteria) or multicellular (including plants and animals). Humans contain about 10 trillion (1013) cells. Most plant and animal cells are between 1 and 100 µm and therefore are visible only under the microscope.
The cell was discovered by Robert Hooke in 1665. In 1835, before the final cell theory was developed.
The word cell comes from the Latin cellula, meaning "a small room". The descriptive term for the smallest living biological structure was coined by Robert Hooke in a book he published in 1665 when he compared the cork cells he saw through his microscope to the small rooms monks lived in.

Prokaryotic cells

Pro = “before”, karyon = “nucleus”
The first living organisms to evolve are primarily distinguished by the fact that they lack a membrane-bound nucleus. In fact, the only membrane in prokaryotic cells is the plasma membrane--the outer boundary of the cell itself.
Their genetic material is naked within the cytoplasm, ribosomes their only type of organelle.
Prokaryotes are most always single-celled, except when they exist in colonies. These ancestral cells, now represented by members of the domains Archaea and Bacteria, reproduce by means of binary fission, duplicating their genetic material and then essentially splitting to form two daughter cells identical to the parent.
Domain Archaea




Methanosarcina mazei, an archaeon

Domain Bacteria

E.coli, a bacterium

Features of Prokaryotes
Prokaryote cells are smaller and simpler
Commonly known as (bacteria), archaea, cyanobacteria.
1–10 µm in size.
Single-celled(unicellular) or
Filamentous (strings of single cells).

Prokaryotic cell

Diagram

Prokaryotic cell structure

Prokaryote cells are simply built (example: E. coli)
Capsule: slimy outer coating.
Cell wall: tougher middle layer.
Cell membrane: delicate inner skin.
Cytoplasm: inner liquid filling.


DNA in one big loop.
Pilli: for sticking to things.
Flagella: for swimming.
Ribosomes: for building proteins.

Prokaryote lifestyle

Unicellular: all alone.

Colony: forms a film.

Filamentous: forms a chain of cells.

Prokaryote Feeding
Photosynthetic: energy from sunlight.
Disease-causing: feed on living things.
Decomposers: feed on dead things.
Eukaryotic Cells
Eu = “true”, karyon = “nucleus”
The most noticeable feature that differentiates these more complex cells from prokaryotes is the presence of a nucleus, a double membrane-bound control center separating the genetic material, DNA (deoxyribonucleic acid), from the rest of the cell.
In addition to the plasma membrane, eukaryotic cells contain internal membrane-bound structures called organelles. Organelles, such as mitochondria and chloroplasts, are both believed to have evolved from prokaryotes that began living symbiotically within eukaryotic cells.
Eukaryotic cells can reproduce in one of several ways, including meiosis (sexual reproduction) and mitosis (cell division producing identical daughter cells).

Features of Eukaryotes

Eukaryotes are bigger and more complicated
Have organelles.
Have chromosomes.
Can be multicellular.
Include animal and plant cells, protists, slime molds, algae, fungi.

Domain Eukarya; Kingdom Protists

Paramecium, a unicellular protozoan

Domain Eukarya; Kingdom Fungi

Coprinus, a shaggy mane mushroom

Domain Eukarya; Kingdom Plants

Passiflora, passion flower, a flowering plant

Eukaryotic cell
Nerve cell

Eukaryotic cell

Muscle cell

Eukaryotic cell

Epithelial cell

Eukaryotic Cell

Diagram

Organelles are membrane-bound cell parts

Mini “organs” that have unique structures and functions.
Located in cytoplasm.

Cell Structures

Cell membrane
Delicate lipid and protein skin around cytoplasm.
Found in all cells.
Nucleus
A membrane-bound sac evolved to store the cell’s chromosomes (DNA).
Has pores: holes.


Nucleolus
Inside nucleus.
Location of ribosome factory.
Contains (RNA).
Mitochondrion
Makes the cell’s energy.
The more energy the cell needs, the more mitochondria it has.
Ribosomes
Build proteins from amino acids in cytoplasm.
May be free-floating, or May be attached to ER.
Made of RNA.
Endoplasmic Reticulum (ER)
May be smooth (SER): builds lipids and carbohydrates
May be rough (RER): stores proteins made by attached ribosomes.
Golgi Complex
Takes in sacs of raw material from ER.
Sends out sacs containing finished cell products.

Lysosomes

Sacs filled with digestive enzymes.
Digest worn out cell parts.
Digest food absorbed by cell.
Centrioles
Pair of bundled tubes.
Organize cell division.


Cytoskeleton
Made of microtubules.
Found throughout cytoplasm.
Gives shape to cell & moves organelles around inside.

Eukaryote cells can be multicellular

The whole cell can be specialized for one job.
Cells can work together as tissues.
Tissues can work together as organs.
Organs can work together as system.

Differences between Prokaryotic & Eukaryotic cells

Prokaryotic Cells
Eukaryotic cells
Small cells 1–10 µm
Larger cells 10–100 µm
Always unicellular
Often multicellular
No nucleus or any membrane-bound organelles
Always have nucleus and other membrane-bound organelles
DNA is circular, without proteins
DNA is linear and associated with proteins to form chromatin
Ribosomes are small (80S)
Ribosomes are large (100S)
No cytoskeleton
Always have a cytoskeleton
Cell division is by binary fission
Cell division is by mitosis or meiosis
Reproduction is always asexual
Reproduction is asexual or sexual


THANKS……
L.A. SURA SALAH