THE PARTS OF A CELL

Biology 1 Textbook pp: 38-43

Robot Hooke (1635 - 1703)

inventor of the earliest microscope

Antonie van Leeuwenhoek (1632 - 1723)

keyed the terms animacules. studied pondwater, urine, feces and semen. first to study living cells

Matthias Jakob Schleiden (1804 - 1881)

botanist, found that plants are made up of cells

Theodor Schwann (1810 - 1862)

physiologist, animals are made up of cells

Rudolf Virchow (1821 - 1902)

German physician. all cells come from cells division (mitosis/memosis)

Eukaryotic

"eu" = true kayron = "nut". multi-cellular (animals, humans & plants). 1.8 b years ago

prokaryotic

pro = before, kayron = nut. single-celled. bacteria, 3.5 b years ago

Plasma Membrane

semipermeable membrane responsible for the prokaryote to allow waste products to pass through while preventing the diffusion of essential products to the external environment.

Cell Wall

A rigid wall responsible for maintaining its shape, especially when the cell is exposed to high water influx.

Capsule

Acts as a protective layer made up of polysaccharides lying outside the cell wall.

Nucleoid Region

a prokaryotic cell lacks a distinct nucleus, it still possesses an irregular

Cytoplasm

Not organized into distinct interior compartments.

Ribosomes

Small structures where proteins are made.

Plasmid

An independent circular DNA structure, apart from the chromosomal DNA. Provides the bacteria with some genetic advantages such as antibacterial resistance.

Flagellum

A tail like appendage for locomotion. Propels bacteria in 360 degrees rotation moving back and forth (whiplike). Seen at the end part of the prokaryotic cell or randomly scattered over its surface.

Fimbriae

Additional smaller and bristle like fibers that grow over the cell’s surface. Help the bacteria to attach themselves to surfaces such as in objects like door knobs or even the nasal passages.

Conjugation Pili

Tubular structures present in the cell surface. 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

Cell Membrane

Also called Plasma Membrane, A thin barrier that forms a boundary, separating an individual cell from the external environment. A living system that controls the passage of important molecules, ions, and gases between outside and inside the cell.

Cell Wall

In plants and algae, the cell wall is made up of polysaccharide cellulose In fungi, cell walls are made of chitin In bacteria, they are composed of peptidoglycan

Cytoplasm

Fills the space between the nucleus and the cell membrane Cytosol is the fluid portion consisting mainly of water (necessary for maintaining cell structure)

Nucleus

The storehouse of genetic information in the form of DNA, protects the DNA from damage

Nucleolus

A dense region where small organelles essential for making proteins are assembled

DNA

a long chain of molecule, 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

Nuclear Envelope

Encloses the DNA, Filled with holes called nuclear pores that allow large molecules to pass between the nucleus and the cytoplasm

Ribosomes

Small organelles that make proteins. After these are formed in the nucleolus, they pass through the nuclear pores into the cytoplasm, where protein synthesis occurs.

Endoplasmic Reticulum

An interconnected network of thin and folded membranes which fills much of the large portion of the cytoplasm. The composition is much similar to that of the cell membrane and nuclear membrane.

Endoplasmic Reticulum

Arranged like a maze of enclosed spaces with many creases and folds

Lumen

the interior of this maze which is site for many processes such as production of proteins and lipids

Endoplasmic Reticulum (Rough Endoplasmic Reticulum)

dotted with ribosomes that join amino acids together to form proteins

Endoplasmic Reticulum (Smooth Endoplasmic Reticulum)

not studded with ribosomes. responsible for production of lipids and perform other specialized functions, such as breaking down drugs and alcohol

Golgi Apparatus (Golgi Complex)

Layered stacks of membrane enclosed spaces where proteins are transported from the ER Where proteins are processed, sorted, and delivered. Have membranes that further modify the proteins. Finished products are packaged here.

Vesicles

Small membrane bound sacs that pinches off from the ER which encloses the protein. Transports the protein from ER to Golgi apparatus. Generally short lived and are formed and recycled as needed by the cells. Some may develop into lysosomes and vacuoles

Vacuoles

A fluid filled sac for the storage of materials needed by the cell. Stores water, food molecules, inorganic ions, and enzymes

Lysosomes

Round shaped membrane bound structures containing chemicals that can break down materials in the cell. Contain powerful enzymes, known as lysozyme, which can defend a cell from invading bacteria or viruses. Break down damaged or worn out cell parts

Peroxisomes

Hydrogen peroxide (H2O2) is a by product of digestion. Surrounded by a single membrane, containing digestive enzymes. Carry oxidative enzymes that require oxygen. Absorb nutrients that had been acquired by the cell. Break down complex molecules into smaller molecules. Helps break down alcohol in the body

Mitochondria

Supply energy to the cell

Plastids

help a plant convert solar energy to chemical energy

Thylakoids

contain chlorophyll, a light absorbing pigment that gives plants their green color and plays a role in photosynthesis

Centrosome

a small dense region of cytoplasm that serves the main microtubule organizing center, where microtubules are organized and assembled.

Cilia and Flagella

Two locomotory projections in eukaryotes. for single cells, the movement results in swimming For cells anchored in tissue, ciliary motion. sweeps liquid across the cell surface. Allow the cell to move like an oar or a whip

Cilia

look like little hairs with much shorter length, move in coordinated fashion

Flagella

looks and moves like a whip or a tail

Cytoskeleton

A flexible network of framework. Made up of a small protein subunit, forming a long threads or fibers that can crisscross the entire cell. Help the cell to organize its contents and to direct the cell’s movement in response to the cell’s changing needs and signals from its external environment.

Microtubules

filaments characterized to be lengthy and the thickest among the filaments. Stiff hollow tubes that gives cell shape and serves as anchorage for the membrane bound organelles and other cell parts. Act as tracks for the movement of vesicles. During cell division, they form spindle fibers that pull each sister chromatid into each daughter cell

Intermediate Filaments

smaller than microtubules and rope like in appearance. Give tensile strength or the ability to stretch without breaking apart. Prominently present in skin cells or other body sites subject to mechanical stress. Important in ensuring the strength of claws, hairs, and feathers of animals

Microfilaments

thinnest among the cytoskeletons. Also known as actin filaments. Tiny flexible filaments that provide protective meshwork under the plasma membrane. Actin filaments are important particularly in cell movement, as that allow muscles to contract and relax

Plasmodesmata

are tiny channels that pass through the cell walls of plant cells and connect the cytoplasm of neighboring cells. help neighboring cells communicate and transport materials, allowing plant tissues to function in a coordinated manner.