Today’s materials: Prokaryote and Eukaryote · 2.DNA as a blue print of life Prokaryote and Eukaryote Achadiah Rachmawati ... usually single-celled, ... Prokaryotes lack a nuclear

Prokaryote n Eukaryote

Biologi – Achadiah Rachmawati 1

Today’s materials:1. Prokaryote and Eukaryote2. DNA as a blue print of life Prokaryote and Eukaryote

Achadiah Rachmawati

Cell Structureand Function

What is a cell?

• All living things are made of cells–the basic units of structure and function



Cell Theory

Cell Theory is only about 150 years old.1) All living things are made up of one or more

cells.2) Cells are the basic living units of all living things.3) All cells come from preexisting cells. (Every living

thing begins as one cell than the cells divide andthe thing grows!)

Examples of Cells

Amoeba proteus

Plant Stem

Red Blood Cell

Nerve Cell

Bacteria

Types of Cells

Plant Cells Animal Cells

Eukaryotic Cells Prokaryotic Cells

Cell TypesCell Parts

Organelles



Surrounding the Cell

Cells• Cells have three basic components…a plasma membrane,

a central nuclear region, and cytoplasm.• Plasma membrane is the surface of the cell that protects

the cell and allows for food and waste exchanges.• Nuclear region is the area that controls all the cell’s

function and stores the DNA. (Some cells are missing thisarea, but don’t reproduce.)

• Cytoplasm is the gel-like substance filling the cell betweenthe plasma membrane and the nuclear region.



Cell Wall

• Main structural component of cell walls iscellulose.– Also contain matrix of hemicellulose, pectin, and

glycoproteins.

• Middle lamella is first produced when new cellwalls are formed.

• Secondary walls are derived from primary walls bythickening and inclusion of lignin.

Communication Between Cells

• Fluids and dissolved substances can pass throughprimary walls of adjacent cells via plasmodesmata.– Cytoplasmic strands extending between cells.– Symplast = supercell?



Cellular Components

• Plasma Membrane– Composed of phospholipids arranged in two layers,

with proteins interspersed throughout.• Some proteins extend across the entire width, while others

and embedded to the outer surface.

Inside the Cell

Nucleus

• Nucleus is bound by two membranes, whichtogether constitute the nuclear envelope.– Structurally complex pores occupy up to one-third of

the total surface area.

• Contains fluid nucleoplasm– Nucleolus composed primarily of RNA.– Chromatin Strands - Coil and become chromosomes.



Chromosomes

• In nucleus• Made of DNA• Contain instructions for

traits & characteristics

Endoplasmic Reticulum

• Endoplasmic Reticulum facilitates cellularcommunication and materials channeling.– Enclosed space consisting of a network of flattened

sacs and tubes forming channels throughout thecytoplasm.

• Ribosomes may be distributed on outer surface (Rough ER).– Associated with protein synthesis.

• Smooth ER is devoid of ribosomes and is associated with lipidsecretion.



Dictysomes

• Dictysomes (GolgiBodies in animals)are often bound bybranching tubulesthat originate fromthe ER.

Plastids

• Chloroplasts are the most conspicuous plastids.– Each bound by double membrane.

• Contain stroma - Enzyme-filled matrix.• Contain grana made up of thylakoids.

– Thylakoid membranes contain chlorophyll.

• Chromoplasts and Leucoplasts are additionalplastids found in many plants.

Mitochondria

• Site of cellularrespiration



Microbodies

• Microbodies are small, spherical bodies with asingle membrane, distributed throughout thecytoplasm which contain specialized enzymes.– Perixosomes - Serve in photorespiration.– Glyoxisomes - Aid in converting fat to carbohydrates.

Vacuoles

• In mature cells, 90% of volume may be taken up bycentral vacuoles bounded by vacuolar membrane(tonoplast).– Filled with cell sap which helps maintain pressure

within the cell.– Also frequently contains water-soluble pigments.

Cytoskeleton

• Cytoskeleton is an intricate network ofmicrotubules and microfilaments.– Microtubules control the addition of cellulose to the

cell wall.– Microfilaments play a major role in the contraction and

movement of cells in multicellular animals.• Appear to play a role in cytoplasmic streaming.



Special Parts: PLANT CELLS

• Chloroplasts• Cell Wall

Chloroplasts

Cell Wall

One of the most widely recognized andimportant characteristics of plants is theirability to conduct photosynthesis, in effect,to make their own food by converting lightenergy into chemical energy.

One of the most important distinguishing features ofplant cells is the presence of a cell wall. The relativerigidity of the cell wall renders plants sedentary,

Special Parts: ANIMAL CELLS

• Lysosome• Centrosomes

Lysosome

CentrosomesFound only in animal cells, these pairedorganelles are typically located togethernear the nucleus in the centrosome, agranular mass that serves as an organizingcenter for microtubules.

The main function of thesemicroscopic organelles is to serve asdigestion compartments for cellularmaterials that have exceeded theirlifetime or are otherwise no longeruseful.



37

Prokaryotes

• Unicellular• Reproduce asexually• Composition

– Protected interior (cytoplasm) that containsgenetic material (one circle of DNA) as well ascomplexes of protein enzymes to carry outnecessary functions of gathering energy,manufacturing proteins (ribosomes), etc.

38

Prokaryotes

• Size– 0.2-10 micrometer (µm)

• Composition– Phospholipid membrane, many contain cell wall

composed of peptidoglycan (positive for chemicalGram stain), those with little or no peptidoglycancalled Gram negative (like Coxiella).

39

Eukaryotes Prokaryotes

DNA linear strands within membrane-bound nucleus

single circle in “nucleoidregion

Size 5-100 µm 0.2-10 µm

Organization often multicellular, some have cellwalls (no peptidoglycan)

usually single-celled, somehave peptidoglycan cell walls

Metabolism usually need oxygen to exist may not need oxygen to exist

Organelles membrane bound organelles likemitochondria

no organelles, differentribosomes

Examples plants, animals, protists, fungi bacteria, archaea40

Eukaryotes• Uni- or multicellular.• Reproduce asexually &

sexually.• Composition:

– Genetic material (long linear strands of DNAchromosomes) especially isolated and enclosed inmembrane (nucleus)

– Some have cell walls (plants have cellulose, fungi ß-glucan)



41

Eukaryotes

• Size 10-100 (µm)• Composition:

– Phospholipid membrane outside, as well asinside.

– Interior membranes separate functionssuch as gathering and transforming cellularenergy and manufacturingmacromolecules.

42

Eukaryotic OrganellesAnimal Cell Plant Cell

43

Eukaryotic OrganellesMitochondrion

Chloroplast

NucleusEndoplasmic reticulum

Golgi

Eukaryote vs. Prokaryote

Biggest differences: Prokaryotes lack a nuclear membrane!Prokaryotes don't have intracellular organelles!Prokaryotes about 10X size of Eukaryotes.

eg. bacteriaeg. fungianimalsplantsunicellular organisms: yeast, Dictyostelium etc.



We continue to the next material….

DNA as a blue print of life

Documents

Today’s materials: Prokaryote and Eukaryote · 2.DNA as a blue print of life Prokaryote and Eukaryote Achadiah Rachmawati ... usually single-celled, ... Prokaryotes lack a nuclear