Biology (Chapter 4)

The study of cells

• The cell is the basic functional unit of life
• All cells come from pre existing cells
• All living things are composed of cells 

Cell Membrane/Cytoplasm require that cells remains small

• Simpler and smaller than eukaryotes and lack many of the internal features
• Evolutionary beginnings are 3.6 billion years ago

• Sized 10-100 Microns
• Membrane-Bound Nucleus

Encloses the cell, separating it from its environment and regulating the molecular traffic that enters and exits the cell. 

An area of dense cytoplasm that contains the hereditary information (DNA)

A semifluid solution composed mostly of water, dissolved molecules, including a large number of enzymes

• Roughly spherical strucutres suspended in the cytoplasm that function to manufacture proteins.
• A bacterial cell contains thousands of ribosomes, which are smaller than eukaryotic ribosomes.

located outside of the plasma membrane, provides rigidity and support to the cell and determines it's shape 

A polymer of amino sugars 

Encloses the cell wall of some bacteria, compsed mostly of polysaccharide; they are well organized, compact, and not easily washed off

gelatinous sheath, which can allow bacteria to stick to slick surfces; more diffuse, and readily removed

Flat membranous disk that contain light sensitive pigments; only found in photosynthetic bacteria

Project from the surface of some bacteria, shorter than flagellaand more threadlike, they help bacteria to adhere to one another, as well as to animal cells 

Longer, hollow tubes that allow bacteria to pass DNA from cell to cell

Many Bacteria contain tiny, circular, extrachromosomal DNA, which often confer protective traits like antibiotic resistance or toxin and enzyme production

Appendages that make some bacteria motile (capable of movement)

A protein that makes up flagella, it spins on its axis like a propeller, driving the cell along.

1000 micrometers (um)= 1 millimeter

A light source illuminates the object to be seen. That source can be a mirror, or the instrument can be self-illuminating. As light passes through the object, the lens nearest the object, called the objective lens, produces an enlarged image of the object in the primary image angle. The lens that you look into, the eyepiece, acts as a magnifier and produces an enlarged image of the image produced by the objective lens.

Reveals cell surface features; Specimens are not sectioned and electrons do not pass through them, rather the whole specimen is bombarded with electrons. Resolving power is no better than 10 nm.

contain centrioles, which are not found in plant cells 

Cell wall and chloroplasts, and central vacuoles

Little organs found within the cytoplasm

Double membrane that surrounds the nucleus; it has numerous pores that connect the interior of the nucleus with the cytoplasm. 

DNA+ protein that forms a fibrous complex (threads), found within the nucleus

When a cell undergoes division, the chromatin super coils and condenses, to form these; each one contains one long molecule of DNA

Water and dissolved substances found surrounding the chromatin within the nucleus, much like cytoplasm, but more protein rich 

Singular nucleolus, usually one or more dense, spherical shaped bodies found in the nucleus; ribosomes are made here

The site of protein synthesis in both eukaryotes and prokaryotes, the most numerous organelle found within the cell

• "The Powerhouse of the Cell"
• Convert potential energy (chemical bond energy) in the form of food molecules into a form the cell can use, ATP.

Typically small, about the size of many bacteria, they are composed of two membranes, an outer membrane, and an inner membrane that is quite extensive (shelf like) in animal cells

The energy rich molecule of the cell

Organelles that are found only in plant cells and certain protists; photosynthesize or store materials

Contains chlorophyll and is the site of photosynthesis found in plants and algae.

A green pigment, present in all green plants and in cyanobacteria, responsible for the absorption of light to provide energy for photosynthesis.

Contain red, orange, or yellow carotenoids and are found in ripe tomatoes, carrots, peppers, etc

Any of a class of mainly yellow, orange, or red fat-soluble pigments, including carotene, which give color to plant parts such as ripe tomatoes and autumn leaves.

colorless, storage depot for starch in plant cells 

Proposed in the early 1980's, suggests that mitochondria and chloroplasts chould have been free living prokaryotes that took up residence within another cell

A network of membranes or channels flowing from the nuclear envelope, found throughout the cytoplasm, involved in modifying and transporting proteins

Covered with Ribosomes; produces proteins that are exported outside of the cell

Areas that lack ribosomes; the site of phospholipid, steroid, and fatty acid synthesis (lipids)

• Consists of flattened membraneous sacs resembling a stack of pancakes, called cisterne and small membrane enclosed vesicles
• Storage, chemical modification, and packaging of proteins for delivery outside of the cell

• Fluid filled, membrane bound vesicles, produced by the Golgi Apparatus
• Contain digestive enzymes that breakdown proteins, carbohydrates, nucleic acids, and lipids
• "Suicide Sacs"

Small organelles with granular interior that breaks down toxic peroxides, such as hydrogen peroxide, with the aid of a catalase enztme

• Membrane enclosed organelles, specific for the function they carry out
• Most prominent feature in many plant cells

Act as tiny pumps, used in protist to remove excess water

Used for digestion

Protein components found in the cytoplasm that maintain cell shape and support, and provide for various types of cell movement ; it extends from the nucleus to the plasma membrane. 

Long, thin, flexible, protein threads made from the protein actin

A protein that makes up microfilaments

Intermediate in diameter found only in multicellular organisms, stabilizing cell structure and resisting tension

• A fibrous protein forming the main structural constituent of hair, feathers, hoofs, claws, horns, etc
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Receptors that mediate attachment between a cell and the tissues surrounding it

Hollow protein tubes, having the largest diameter, made of tubulin

A protein that is the main constituent of the microtubules of living cells

Usually found singly or in pairs

• Shorter appendages, usually present in great numbers
• They beat stiffly in one direction and recover flexibility in the other direction

9 fused pairs of microtubules-called doublets forming an outer cylinder, and one pair of unfused microtubules running up the center

• Contains a pair of centrioles at right angle to each other
• Major microtubule organizating centers (MTOC) for the cell

Barrel-Shaped organelles, composed of microtubules function during cell division

In plant cells, numerous membrane-lined channels, serve as openings between cell walls and plasma membranes allowing the exchange of water, plant hormones, ions, etc

• Connect the plasma membranes of adjacent animal cells in a sheet.
• Specialized proteins link adjacent epithelial cells lining the intestines of the digestive tract. 

In animal cells, are made up of specialized protein channels (connexons), which facilitate communication between cells.

Mechanically attach the cytoskeletons of adjacent cells, acting like "spot welds" or "rivets."