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Prokaryotes Characteristics

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1. Their DNA is not enclosed within a membrane.
2. Their DNA is not associatedd w/ histones other proteins are associated w/the DNA
3. They lack membrane-enclosed organelles.
4. Thier cell walls almost always contain the complez polysaccharide peptidoglycan
5. The usually divide by binarry fission.

OR

-one circular chromosome NOT in a membrane
- no histones
-no organelles
-Peptidoglycan cell walls if bacteria
- Psedomurien cell walls if archaea

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Binary Fission-

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DNA is copied and the cell splits into 2 cells. Involved fewer structures and processes than eukaryotic cell division.

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Eukaryotes Characteristics

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1. Their DNA is found in the cell's nucleaus, which is seperated from the cytoplasm by a nuclear membrane and the DNA is found in multiple chromosomes.
2. Their DNA is associated w/ chromosomal proteins called histones.
3. They have a number of membrane enclosed organelles.
4. Their cell walls are simple, chemically.
5. Cell division usually involves mitosis, in which chromosomes replicate and an i dentical set is distributed in each nuclei.

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Diplococci

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cocci that remain in pairs

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Streptococci

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Cocci that remain in a chainlike pattern

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Tetrads

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Cocci that divide in two planes and remain in groups of 4

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Sarcinae

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Cocci that divide in 3 planes and reamin attached in cubelike groups of eight.

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Diplobacilli

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Bacilli that appears in pairs after division

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Streptobacilli

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Baccilli that occurs in chains.

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Vibrios

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Bacteria that look like curved rods.

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Spirilla

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have a helical shape, like a corkscrew and fairly rigid bodies.

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Monomorphic

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bacteria that maintains a single shape

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pleomorphic

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Bacteria that has many shapes

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Glycocalyx

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a general term used for substances that surround cells
- sugar coating outside of the cell wall

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Capsule

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if the substance surrounding a cell is organized and firmly attached to the cell wall,it is ...

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Slime layer

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if the substance is unorganized and only loosely attached to the cell wall, it is known as...

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Flagella

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long filamentous appendages that propel bacteria.

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Atirchous

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bacteria that lack flagella

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Peritrichous

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flagella is distributed all over the cell

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Polar

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Flagella that is at one or both poles or ends of the cell. Flagella will also be monotrichous (one pole)

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Average size of prokaryotic cells

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.2- 1.0 micrometer x 2-8

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Basal bodie

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anchors the flagella to the cell wall and plasma membrane, composed of 2 small central rod inserted into a serie of rings

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Gram- Negative Bacteria....

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contains 2 pairs of rings, the outer pair of rings is anchored to various portions of the cells wall.. The inner pair of rings is anchored to the plasma membrane.

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Gram- Positive Bacteria-

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only the inner pair of rings are present.

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Gram- Positive Bacteria-

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only the inner pair of rings are present.

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Taxis

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The movement of bacterium toward and away from a particular stimulus

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H-antigen

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a flagellar protein, useful for distinguishing among serovars, or variations within a species, of gram-negative bacteria.

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Axial Filaments or endoflagella

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bundles of fibrils that arise at the ends of the cell beneath an outer sheath and spiral around the cell.

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Pili

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involved in motility and DNA transfer.

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Gliding Motility

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smooth gliding movement of myxobacteria

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Twitching motility

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a pilus extends by the addition of subunits of pilin, makes contact with another cells and then retracts.

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The Cell wall

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...of the bacterial cell is a complex, semirigid structure responsible for the shape of the cell.

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Peptidoglycan

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the bacterial cell wall is composed of a macromolecular network.

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lysis

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destruction caused by the rupture of the plsma membrand and the loss of cytoplasm

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Describe gram-positive bacteria walls

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the cell wall consist of many layers of peptidoglycan, forming thick rigid structures

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Describe gram-negative walls

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contain only a thin layer of peptioglycan, consist of lipopolysaccarides (LPS) lipoproteins, and phospholipids.

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Porins

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part of the permability of the outer membrame is due to proteins in the membrane.
- they also permit the passage of molecules such as nucleotides, disaccharides, peptides, amino acids, b12 and iron.

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Lipopolysaccharide (LPS)

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the outer membrane is a large complex that contains lipids and carbohydrates and consists of 3 components:
1. Lipid A
2. Core Polysaccliaride
3. O Polysaccaharide.

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Lipid A

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A lipid portion of the LPS and is embedded in the top layer of the outer membrane.
_____ is released when the gram negative bacteria dies.

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mycolic acid

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hydrophobic waxy lipid in their cell wall that prevents uptake of dyes .

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Protoplast

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wall-less cell, spherical and still capable of carrying on metabolism

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L Forms

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Proteus, as well as other genera, can lose their cell walls and swell into irregularly shaped cells.

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Osmotic Lysis

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Protoplasts and spheroplasts burst in pure water or dilute sugar or salt solutions becuase the water molecules from the surrounding fluid rapidly move into and enlarge the cell. This rupturing is called ------

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Plasma (cytoplasmic) Membrane

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a thin structure lying inside the cell wall and enclosing the cytoplasm of the cell.
- consist primarily of phospholipids (most abundant chemicals in the membrane, and proteins)
- Phospholipid Bi layer
-peripheral proteins
- intergral proteins
-Transmembrane
-Proteins

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glycoproteins

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proteins attached to carbohydrates

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glcolipids

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lipids attached to carbohydrates

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spheroplast

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a wall less gram positive cell. susceptible to osmotic lysis

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Fluid mosaic model

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-Membrane is as viscous as olive oil
-Proteins move to function
-Phospholipids rotate and move laterally

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Selectively Permeability

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Allows passage of some molecules.
- Indicates that certain molecules and ions pass through but that others are prevented from passing through.

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Chromatophores

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Membrane structures that are in some bacteria, pigemnts and enzymes involved in photosynthesis are found in infoldings of the plasma membrane that extend into the cytoplasm

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Simple Diffusion

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the movement of molecules or ions from an area of HIGH concentration to an area of LOW Concentration. Movement continues until molecules or ions are evenly distributed.

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Facilitated Diffusion

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integral membrane proteins function as channels or carriers that facilitate movement of ions or large molecules across the plasma membrane.

- Solute combines with a transporter protein in the membrane.

It is similar to simple diffusion however the cell does NOT expend enrgy.

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Osmosis

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The movement of water across a selectively permeable membrane from an area of high water to an area of lower water concentration.

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Osmotic Pressure

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the pressure required to prevent the movement of pure water (water with no solutes) into a solution containing some solutes.

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Isotonic Solution

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a medium in which the overall concentration of solutes equals that found inside a cell.

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Water leaves and

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enters the cell at the same rate (no net change)

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Hypotonic solution

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outside the cell is a medium whose concentration of solutes is lower than that inside the cell

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hypertonic solution

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a medium having a higher concentration of solutes than inside the cell has.

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active transport

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the cell usues energy in the form of ATP to move substances across the plasma membrane

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group translocation

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a special form of active transport that occurs exclusivley in prokaryotes, the substance is chemicalled altered during trnasport across the membrane

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cytoplasm

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the substance of the cell inside the plasma membrane

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Plasmids

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bacteria often contains small usually circular double stranded DNA molecules

They are not connected to the main bacterial chromosomes and they replicate independently of chromosomal DNA.

Contain 5-100 genes that are not crucial for the surviaval of the bacterium .

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Ribosomes

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Are contained in all eukaryotic and prokaryotic cells. Functions at the sites of protein synthesis.

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Name for Prokaryotic Ribosomes

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70S (smaller and less dense)

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Name for Eukaryotic Ribosomes

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80S

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What does the S in 70S and 80S refer to?

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The Letter S refers to Svedberg units, which indicate the relative rate of sedimentation during ultra-high-speed centrifugration ( Rate at which Ribosomes will settle)

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Inconclusions

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Within the cytoplasm of prokaryotic cells are several kinds of reserve deposits called...

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Endospores

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When essential nutrients are depleted, certain gram-positive bacteria, such as those of the genera form specialized "resting" cells.

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Germination

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An endospore returns to its vergetative state by a process called _____. It is triggered by physical or chemical damage to the endospore's coat.

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Flagella

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projections are few and are long in relation to the size of the cell

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Cilia

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projections are numberous and short they are called ____

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Microtubles

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_______ are long hollow tubes made up of a protein.

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glycocalyx

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In eukaryotic cells, including animal cells, the plasma membrane is covered by _______, a layer of material containing substantial amounts of sticky carbohydrates.

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cytoplasm membrane

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substance inside plasma and outside nucleaus

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Cytosol

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Fluid portion of cytoplasm

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Cytoskeleton

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provides support and shape and assists in transporting substances therough the cell.

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Cytoplasmic streaming

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the movement of eukaryotic cytoplasm from one part of the cell to another, which helps distribute nutrients and move the cell over a surface.

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