BIO D

The Cell

ROBERT HOOKE

Devised one of the earliest microscopes

Came from a thin slice of cork from the bark of an oak

tree

Called these porous structures cellulae, using the Latin

word for “small room”

First to be credited with publishing the first

description of a cell in 1666

ANTONIE VAN

LEEUWENHOEK

Credited to be the first to study magnified cells

Devised his own microscope to study biological specimens

Invention was a simple microscope with only one lens

MATTHIAS JAOB

SCHLEIDEN

Botanist who focused his interests on the study of plant

cells

THEODOR

SCHWANN

Examined animal cells and found that all bodies of living

organisms are made up of cells

RUDOLF CARL

VIRCHOW

Proposed the third tenet in the cell theory, stating that

all cells come from other cells through the process of

cell division

Cell → Tissues → Organ → Organ System → Living

Organisms

PROKARYOTIC CELL

Pro meaning “before” and karyon meaning “nut,” which all mean “before the

nut”

It is the first kind of cell to develop, about 3.5 billion years ago

They are simple organisms possessing cells that are smaller in size with

simple internal structures

Reproduces very fast; thus, they can exist in great numbers in air,

bodies of water, soil, and even inside the bodies of living hosts

Examples are bacteria, blue-green algae, and archaeans

1.PLASMA MEMBRANE

semipermeable membrane responsible for allowing the

prokaryote to allow waste products to pass through while preventing the

diffusion of essential products to the external environment

2.CELL WALL ( PROKARYOTIC )

rigid wall responsible for maintaining its shape, especially

when the cell is exposed to water influx

3.CAPSULE

protective layer made up of polysaccharides lying outside the

cell wall

4.NUCLEOID REGION

lacks a distinct nucleus but possesses an irregular-

shaped region where it stores its genetic information in the form of DNA

5.CYTOPLASM ( PROKARYOTIC )

not organized into distinct interior compartments, and

organelles are spaced

6.RIBOSOME

small structure where proteins are made

7.PLASMID

independent circular DNA structure, apart from the chromosomal

DNA, and provides the bacteria with some genetic advantages such as

antibacterial resistance

8.FLAGELLUM

taillike appendage that allows locomotion. 360-degree

rotation of a whip-like tail moving back and forth can propel the

bacteria.

9.FIMBRIAE

smaller and bristle-like fibers that grow over the cell’s

surface. It helps bacteria attach themselves to surfaces such as objects

like doorknobs or even the nasal passages

10.CONJUGATION PILI

tubular structures present in the cell structure that

function for cell-to-cell communication, as well as to pass DNA from one

bacterium to the next. Particularly important because some bacteria are

very successful in developing drug resistance across bacterial

generations

2 Types of Cells

Prokaryotic Cell , Eukaryotic Cell

EUKARYOTIC CELL

Eu meaning true; karyon meaning nut, and evolved about 1.8 billion years ago.

Larger size and more complex structural components

Have their genetic material (DNA) encased within a distinct nucleus

Have many membrane-bound interior compartments, and their organelles are neatly

arranged

Examples are fungi, plants, animals, and protists

1.CELL/PLASMA MEMBRANE

thin barrier that forms a boundary, separating an individual

cell from the external environment. It acts as a gatekeeper for regulating the

passage of important molecules, ions, and gases

2.CELL WALL ( EUKARYOTIC )

rigid layer that gives protection, support, and shape to the cell. In

plants and algae, the cell wall is made up of the polysaccharide cellulose

3.CYTOPLASM ( EUKARYOTIC )

fills the space between the nucleus and the cell membrane.-

CYTOSOL

is the fluid portion consisting mainly of water and excluding the organelles

in it

4.NUCLEUS

storehouse of genetic information in the form of DNA and protects it from

damage

DNA

is a long chain of molecules, which can be segmented into portions called genes

that contain instructions for making proteins

Packaged by a special group of proteins called histones, forming a complex structure

called CHROMATIN

5.NUCLEUS ENVELOPE

encloses the DNA and is filled with holes called NUCLEAR PORES

that allow large molecules to pass between the nucleus and cytoplasm

6.NUCLEOLUS

dense region where small organelles essential for making proteins are

assembled

7.RIBOSOME

small organelles that make protein, and after they form, they pass

through the nuclear pores into the cytoplasm, where protein synthesis occurs

8.ENDOPLASMIC RETICULUM

interconnected network of thin and folded membranes which

fills much of the large portion of the cytoplasm. It is arranged like a maze of

enclosed spaces with many creases and folds

LUMEN

is the interior of the maze, which is a site for many processes such as the

production of proteins and lipids

ROUGH ER

has a bumpy look under the microscope and is either incorporated into the

cell membrane or secreted to areas where the body needs them

SMOOTH ER

is not studded with ribosomes and is responsible for the production of

lipids and other functions such as breaking down drugs and alcohol

9.GOLGI APPARATUS/BODIES/COMPLEX

layered stack of membrane-enclosed spaces where

proteins are processed, sorted, and delivered. It has enzymes that further modify

the protein

10.VESICLES

small membrane-bound sacs that transport proteins from the ER to the

Golgi apparatus. It is short lived and are formed and recycled as needed by the cell

11.VACUOLES

fluid-filled sacs for the storage of materials that store water, food

molecules, inorganic ions, and enzymes

12.LYSOSOMES

round-shaped, membrane-bound structures containing chemicals that can

break down materials

13.PEROXISOMES

surrounded by a single membrane, containing digestive enzymes for

breaking down toxic materials

CELL

is the basic biological unit of all known living organisms