Prokaryotes Vs. Eukaryotes There are 2 main types of cells: Prokaryotes: - have no membrane- bound nucleus or organelles Prokaryotes: - have no membrane- bound nucleus or organelles –Usually very small – 0.001mm Eukaryotes: - have membrane-bound nucleus and organelles Eukaryotes: - have membrane-bound nucleus and organelles –Usually from 0.01 – 0.1mm –Often complex –Often specialised

Type of cell AnimalPlantFungusProtistBacteriumVirus P Vs. E EukaryoteProkaryote Not living. Must invade other cells to survive  not really a cell type. Cannot live on its own. NucleusYes No, nuceloid OrganellesYesNo Cell Wall NoYesYesSomeYes Cell Membrane Yes

Organelles Organelles are structures within the cell that are enclosed by a membrane Organelles are structures within the cell that are enclosed by a membrane They can be described as compartments within a cell They can be described as compartments within a cell They carry out specific functions They carry out specific functions Because they are enclosed by membranes, organelles can maintain conditions which are very different to other parts of the cell Because they are enclosed by membranes, organelles can maintain conditions which are very different to other parts of the cell

Nucleus The nucleus contains the DNA The nucleus contains the DNA It is enclosed by membrane sometimes called the nuclear envelope It is enclosed by membrane sometimes called the nuclear envelope This membrane has pores/spaces through which certain substances (such as mRNA) can pass in/out of This membrane has pores/spaces through which certain substances (such as mRNA) can pass in/out of The DNA inside forms a template for protein production The DNA inside forms a template for protein production

Nucleus The nucleus controls the functioning of the cell: The nucleus controls the functioning of the cell: –Cell division –Protein production –Apoptosis (programmed cell-death) Within the nucleus are many large clumps which appear as dark spots under the microscope. These are nucleoli (nucleolus sing.) Within the nucleus are many large clumps which appear as dark spots under the microscope. These are nucleoli (nucleolus sing.) The nucleoli are clumps of RNA molecules The nucleoli are clumps of RNA molecules

Nucleoli Nuclear Membrane Nuclear Pores

Ribosomes Produce protein for the cell by using DNA as a template Produce protein for the cell by using DNA as a template These are not membrane-bound  not true organelles These are not membrane-bound  not true organelles All cells have them (even prokaroytes) All cells have them (even prokaroytes) Cannot be seen without an electron microscope or specialised staining Cannot be seen without an electron microscope or specialised staining Made up of rRNA and other proteins Made up of rRNA and other proteins

Endoplasmic reticulum A series of membrane-bound channels. Its main function is transport of substances within the cell. A series of membrane-bound channels. Its main function is transport of substances within the cell. There are 2 types: There are 2 types: –Rough (RER): has ribosomes on the surface, found surrounding the nucleus –Function is to produce proteins and modify them for transportation –Smooth (SER): - also found surrounding nucleus, often joined to RER –Function is to remove toxins/de-activate them

Golgi Body Also called Golgi complex or Golgi apparatus Also called Golgi complex or Golgi apparatus Consists of stacks of membrane- bound sacks Consists of stacks of membrane- bound sacks Functions to package and transport proteins and lipids for export into secretory vesicles which can pass out of the cell membrane easily Functions to package and transport proteins and lipids for export into secretory vesicles which can pass out of the cell membrane easily

Secretory vesicles

Chloroplasts Produce energy for the cell Produce energy for the cell Contain chlorophyll in the grana Contain chlorophyll in the grana Chlorphylyll is an enzyme which traps the energy from sunlight for use in sugar productions (photosynthesis) Chlorphylyll is an enzyme which traps the energy from sunlight for use in sugar productions (photosynthesis) Chlorophyll is also a pigment which is green in colour Chlorophyll is also a pigment which is green in colour Plant cells (and some fungi) contain chloroplasts Plant cells (and some fungi) contain chloroplasts These organelles are often large enough to see with the light microscope and contain small amounts of DNA These organelles are often large enough to see with the light microscope and contain small amounts of DNA

External membrane Inner membrane Grana Stroma

Mitochondria Convert the energy obtained from food (glucose) to a form that the cell can use (ATP) using O 2 Convert the energy obtained from food (glucose) to a form that the cell can use (ATP) using O 2 This process is called cellular respiration This process is called cellular respiration Mitochondria also contain small amounts of DNA Mitochondria also contain small amounts of DNA All cells except Monera have these All cells except Monera have these

Vacuoles The main functions of vacuoles are to store substances such as food in an environment which is separate to the cytoplasm The main functions of vacuoles are to store substances such as food in an environment which is separate to the cytoplasm –Eg food Other specialised vacuoles store substances which may pose danger to the cell Other specialised vacuoles store substances which may pose danger to the cell

Lysosomes, Peroxisomes Lysosomes contain destructive enzymes which can break down damaged or old cell parts and molecules Lysosomes contain destructive enzymes which can break down damaged or old cell parts and molecules Peroxisomes contain enzymes which break down hydrogen peroxide (H 2 O 2 ) which is a product of many biochemical reactions and can be highly toxic and damaging to cells Peroxisomes contain enzymes which break down hydrogen peroxide (H 2 O 2 ) which is a product of many biochemical reactions and can be highly toxic and damaging to cells

Cytoplasm The fluid component of the cell The fluid component of the cell Also called the cytosol or cytogel Also called the cytosol or cytogel It contains dissolved minerals, proteins, enzymes, sugars, salts, lipids and the organelles It contains dissolved minerals, proteins, enzymes, sugars, salts, lipids and the organelles It provides the perfect environment for chemical reactions It provides the perfect environment for chemical reactions

Cytoskeleton This is an internal framework of proteins which supply structure and support to the cell and allow movement of the cell and the organelles within This is an internal framework of proteins which supply structure and support to the cell and allow movement of the cell and the organelles within

Cell Membrane Also called the Plasma Membrane or Plasmalemma Also called the Plasma Membrane or Plasmalemma Function is to control the movement of substances into and out of the cell Function is to control the movement of substances into and out of the cell All cells have one!! All cells have one!!

Cell Wall Not found in animal cells Not found in animal cells Plays an very important role in structural support of the cell Plays an very important role in structural support of the cell Prevents the cells from bursting due to water absorption Prevents the cells from bursting due to water absorption Found in bacteria, fungi, plants and some protists Found in bacteria, fungi, plants and some protists

Nucleus Mitochondrion Animal Cell Endoplasmic reticulum Golgi body Cell Membrane Cytoplasm