CELLS

subatomic particles atoms and molecules cells tissues organs

systems organisms

LEVELS OF ORGANIZATION

DISCOVERY OF CELLS

Robert Hooke discovered cells in 1665. Anton Van Leeuwenhoek perfected the

construction of the compound microscope in 1674.

Robert Brown discovered the nucleus of the cell in 1831 and observed the streaming movement of the cell’s cytoplasm (Brownian movement).

DISCOVERY OF CELLS

Felix Dujardin observed that cells are not empty but are filled with thick, jelly-like fluid in 1835.

Johannes Purkinje named the jelly-like fluid as protoplasm in 1839.

Matthias Schleiden formulated the plant cell theory in 1838.

Theodor Schwann formulated the animal cell theory in 1839.

Rudolf Virchow concluded that all cells must come from pre-existing cells in 1855.

PROTOPLASM

In biology, protoplasm is the viscid, translucent polyphasic colloid with water as the continuous phase that makes up the essential material of all plant and animal cells. Protoplasm is composed mainly of nucleic acids, proteins, lipids, carbohydrates, and inorganic salts. The protoplasm surrounding the nucleus is known as the cytoplasm and that composing the nucleus is the nucleoplasm (sometimes termed bioplasm).

DIFFERENCE BETWEEN THE CYTOPLASM AND PROTOPLASM

The main difference between the cytoplasm and protoplasm is its content and function. A protoplasm is the actual living substance that composes the inside of the cell. A part of it is the cytoplasm. The cytoplasm is the one that surrounds the nucleus.

MODERN CELL THEORIES

1. All organisms are made up of cells and cell is the basic structural unit of life.(Matthias Schleiden and Theodor Schwann)

2. All cells must have come from pre-existing cells.(Rudolf Virchow)

PROKARYOTIC CELL VS. EUKARYOTIC CELL

DEFINITION OF PROKARYOTES AND EUKARYOTES

Prokaryotes (from Old Greek pro- before + karyon nut or kernel, referring to the cell nucleus, + suffix -otos, pl. -otes; also spelled "procaryotes") are organisms without a cell nucleus or any other membrane-bound organelles. Most are unicellular, but some prokaryotes are multicellular.

Eukaryotes are organisms whose cells are organized into complex structures by internal membranes and a cytoskeleton. The most characteristic membrane bound structure is the nucleus. This feature gives them their name, (also spelled "eucaryote,") which comes from the Greek ευ, meaning good/true, and karyon meaning nut, refering to the nucleus. Animals, plants, fungi, and protists are eukaryotes.

ATTRIBUTES OFPROKARYOTIC CELL AND EUKARYOTIC

CELL

EUKARYOTIC CELL PROKARYOTIC CELL

Nucleus Present Absent

Number of chromosomes

More than oneOne--but not true

chromosome: Plasmids

Cell Type Usually multicellularUsually unicellular

(some cyanobacteria may be multicellular)

True Membrane

bound Nucleus

Present Absent

Example Animals and Plants Bacteria

CONTINUATION…

EUKARYOTIC CELL PROKARYOTIC CELL

Lysosomes Present Absent

Microtubules Present Absent or rare

Endoplasmic reticulum

Present Absent

Mitochondria Present Absent

Cytoskeleton Present May be absent

Ribosomes larger smaller

Vesicles Present Present

Golgi apparatus Present Absent

Chloroplasts Present (in plants)Absent; chlorophyll

scattered in the cytoplasm

Vacuoles Present Present

Cell size 10-100um 1-10um

A PROKARYOTIC CELL

AN ANIMAL CELL

A PLANT CELL

CELL PARTS AND THEIR FUNCTIONS

ORGANELLE LOCATION DESCRIPTION FUNCTION

cell wall plant *outer layer*rigid, strong, stiff*made of cellulose

*support (grow tall)*protection*allows H2O, O2, CO2

to pass into and out of cell

cell membrane both plant and animal

*plant - inside cell wall*animal - outer layer; cholesterol*selectively permeable *phospholipid bilayer

*support & protection*controls movement of materials in/out of cell*barrier between cell and its environment*maintains homeostasis

Cell WallCell

Membrane

CONTINUATION…

ORGANELLE LOCATION DESCRIPTION FUNCTION

nucleus both plant and animal

*large, oval *controls cell activities

nuclear membrane

both plant and animal

*surrounds nucleus*selectively permeable

*controls movement of materials in/out of nucleus

cytoplasm both plant and animal

*clear, thick, jellylike material and organelles found inside cell membrane

*supports/protects cell organelles

Nucleus Cytoplasm

CONTINUATION…

ORGANELLE LOCATION DESCRIPTION FUNCTION

ribosome both plant and animal

*small bodies free or attached to E.R.

*produces proteins

chloroplast plant *green, oval usually containing chlorophyll (green pigment)

*uses energy from sun to make food for the plant (photosynthesis)

vacuole plant - few/largeanimal - small

*fluid-filled sacs *store food, water, waste (plants need to store large amounts of food)

Vacuole

Chloroplast

Ribosome

CONTINUATION…

ORGANELLE LOCATION DESCRIPTION FUNCTION

lysosome plant - uncommon

animal - common

*small, round, with a membrane

*breaks down larger food molecules into smaller molecules*digests old cell parts

mitochondrion

both plant and animal

*bean-shaped with inner membranes

*breaks down sugar molecules into energy

endoplasmicreticulum

smooth ERrough ER

both plant and animal

*network of tubes or membranes

*carries materials through cell

*synthesizes lipids*synthesizes proteins

Endoplasmic Reticulum

Mitochondrion

Lysosome

CONTINUATION…

ORGANELLE LOCATION DESCRIPTION FUNCTION golgi

apparatusboth plant and animal

*membrane-bound vesicles of flattened sacs and stacks parallel to each other

*serves as storage modifications and packaging of secretory products in vesicles

centriole animal *cylindrical structure composed of microtubules located in the centrosome just outside the nucleus

*formation and anchoring of the spindle fibers during cell division

cytoskeleton both plant and animal

*complex network of tubules and filaments

*cell shape and movement of cell parts

Golgi Apparatus

Cytoskeleton

Centriole

ANIMAL CELL VS. PLANT CELL

Plant and animal cells have several differences and similarities. For example, animal cells do not have a cell wall or chloroplasts but plant cells do. Animal cells are round and irregular in shape while plant cells have fixed, rectangular shapes.

ATTRIBUTES OFANIMAL CELL AND PLANT CELL

ANIMAL CELL PLANT CELL

Cell wall AbsentPresent (formed of

cellulose)

Shape Round (irregular shape)Rectangular (fixed

shape)

VacuoleOne or more small

vacuoles (much smaller than plant cells).

One, large central vacuole taking up

90% of cell volume.

Centrioles Present in all animal cellsOnly present in lower

plant forms.

CONTINUATION…

ANIMAL CELL PLANT CELL

Mitochondria

Present Present

Plastids Absent Present

Golgi Apparatus

Present Present

Plasma Membrane

only cell membranecell wall and a cell

membrane

Nucleus Present Present

CONTINUATION…

ANIMAL CELL PLANT CELL

ChloroplastAnimal cells don't have

chloroplasts

Plant cells have chloroplasts because they make their own

food

Cytoplasm Present Present

Endoplasmic Reticulum

(Smooth and Rough)

Present Present

Ribosomes Present Present

CONTINUATION…

ANIMAL CELL PLANT CELL

Microtubules/ Microfilament

sPresent Present

FlagellaMay be found in some

cellsMay be found in

some cells

LysosomesLysosomes occur in

cytoplasm.Lysosomes usually

not evident.

Cilia Present It is very rare

THANK YOU…

MS. JSFLORES