microbiology ch:4 obj

identify the basic shapes and arrangements of bacterial cells.

-Most bacteria are 0.2 to 2.0 Um in diameter and 2-8 Um in length. -The three basic bacterial shapes are: 1. Coccus (spherical) 2. Bacillus (rod-shaped) 3. Spiral (twisted)

Describe the structure and functions of the prokaryotic cell membrane.

Prokaryotic cell- are unicellular organisms that lack organelles or other internal membrane bound structures. They do not have a nucleus but instead have a single chromosome. A piece of circular, double stranded DNA located in an area of the cell called the nucleoid.

identify the functions of four types of inclusions

- Inclusions are reserve deposits found in prokaryotic and eukaryotic cells. 1. Sulfur granules- derive energy by oxidizing sulfur and sulfur containing compounds. - energy reserve. 2. Magnetosomes- iron oxide inclusions. - use magnetosomes to move downward until they reach a suitable attachment site. - may protect cell against hydrogen peroxide accumulation. 3. Lipid- common lipid storage. 4. Metachromatic granules- volutin that represents are serve of inorganic phoshate, that can be used in the synthesis of ATP.

define organelle

-any of a number of organized or specialized structures within a living cell. -specialized membrane-enclosed structure in the cytoplasm of eukaryotic cells.

describe the functions of endospores and differentiate between sporulation and endospore germination.

1. Endospores- are resting structures formed by some bacteria; they allow survival during adverse environmental conditions. - the process of endospore formation is called sporulation; the return of an endospore to its vegetative state is called germination.

discuss evidence that supports the endosymbiotic theory of eukaryotic evolution.

1. Eukaryotic cells evolved from symbiotic prokaryotes living inside other prokaryotic cells. 2. Arrangement evolved into a symbiotic relationship in which the host nucleoplasm supplied nutrients and the endosymbiotic bacterium produced energy that could be used by the nucleoplasm. 3. Eukaryotic flagella and cilia are believed to have originated from symbiotic associations between plasma membrane of early eukaryotes and motile spiral bacteria called spirochetes.

differentiate flagella, axial filaments, fimbriae, and pili.

1. Flagella- are relatively long filamentous appendages consisting of a filament, hook, and basal body. -Prokayotic flagella rotate to push cell. -Motile bacteria exhibit taxis; positive taxis is movement toward an attractant, and negative taxis is movement away from a repellent. -Flagellar (H) protein is an antigen. 2. Axial filament- are spiral cells that move by means of an axial filament (endoflagellum) are called spirochete. -Axial filaments are similar to flagella, except that they wrap around the cell. 3. Fimbriae- help cells adhere to surfaces. 4. Pili- are involved in twitching motility and DNA transfer.

compare and contrast the cell walls of gram-positive bacteria, gram-negative bacteria, acid-fast bacteria, archaea, and mycoplasmas.

1. Gram positive bacteria- have many layers of peptidoglycan formin a thick, rigid structure. -The crystal violet iodine complex combines with peptidoglycan. 2. Gram negative bacteria- have a thin layer of peptidoglycan. -The decolorizer removes the lipid outer membrane of this G-NEG. bacteria and washes out the crystal violet. 3. Acid-fast bacteria- Identify all bacteria of the genus Mycobacerium and pathogenic species of Nocardia. AFB contain high concentration of a hydrophobic waxy lipid in their cell wall that prevent the uptake of dyes, including those used in the Gram stain. 4. Archaea- semi rigid cell wall that protects them from the environment. The cell wall of archaea is composed of S-layers and lack peptidoglycan molecules with exception of methanobacteria who have pseudpeptidoglycan in their cell wall. 5. Mycoplasmas- are a bacteria that lack a cell wall around their cell membranes. With out cell wall they are unaffected by many common antibiotics like penicillin.

compare and contrast Archaea and mycoplasmas.

1. Mycoplasma- is a bacterial genus that naturally lacks cell walls. 2. Arcaea- have pseudomurein; they lack peptidoglycan.

identify the functions of the nucleoid and ribosomes.

1. Nucleoid- the nucleoid contains the DNA of the bacterial chromosome. - Bacteria can also contain plasmids, which are circular, extrachromosomal DNA molecule. 2. Ribosomes- The cytoplasm of prokaryote contains 70S ribosome; ribosomes consist of rRNA and protein. - Protein synthesis occurs at ribosomes; it can be inhibited by certain antibiotics. - repairs damage or directing chemical processes. - structure that makes protein.

define the terms pleomorphic and monomorphic.

1. Pleomorphic-means bacteria can have many shapes. (Ex: Rhizobium and Coryrebacterium) 2. Monomorphic- means bacteria maintain a single shape. (most bacteria are this shape)

compare and contrast overall cell structure of prokaryotic and eukaryotic cells.

1. Prokaryotic and eukaryotic cells are similar in their chemical composition and chemical reactions. 2. Prokaryotic cells lack membrane-enclosed organelles (including a nucleus). 3. Peptidoglycan is found in prokaryotic cell walls but NOT in eukaryotic cell walls. 4. Eukaryotic cells have a membrane-bound nucleus and other organelles.

compare prokaryotic and eukaryotic flagella.

1. Prokaryotic flagella- rotates and its projections are few and are long in relation to the size of the cell. 2. Eukaryotic flagella- moves in a wave-like manner and its projections are numerous and short (cilia).

compare the structure and function of prokaryotic and eukaryotic ribosomes.

1. Prokaryotic ribosomes- present in bacterium, mitchondrion, and chloroplast. - consists of 2 subunits, 50S and 30S. -70S ribosomes are composed of 60% RNA and 40% proteins. - the 50S subunit contains two rRNA's (23S and 5S) complexed with 34 proteins. -30S subunit contains 16S rRNA's complexed with 21 proteins. 2. Eukaryotic ribosomes- present in all higher organisms. - consist of 2 subunits , 60S and 40S. - the 80S ribosomes are composed of 40% RNA and 60% proteins. - 60S subunit contains three rRNA (28S, 5.8S, and 5S) complexed with 33 proteins.

differentiate protoplast, spheroplast, and L-form.

1. Protoplast- In the presence of lysozome, gram pos. cell walls are destroyed, and the remaining cellular content are a protoplast. 2. Spheroplast- In the presence of lysozyme, gram-neg. cell walls are not completely destroyed, and the remaining cellular contents are spheroplasts. 3. L-form- are gram-pos. or gram-neg. bacteria that do not make a cell wall.

compare and contrast prokaryotic and eukaryotic cell walls and glycocalyxes.

1. The cell walls of many algae and some fungi contain cellulose. 2. The main material of fungal cell wall is chitin. 3. Yeast cell walls consist of glucan and mannan. 4. animal cells are surrounded by a glycocalyx, which strengthens the cell and provides a means of attachment to other cells.

describe the structure and function of the glycocalyx, including distinguishing between a capsule and a slime layer.

1. The glycocalyx capsule, slime layer, or extracellular polysaccharide is a gelatinous polysaccharide and/or polypeptide covering. 2. Function of glycocalyx capsule: may protect pathogens from phagocytosis. 3. Capsules enable adherence to surfaces, prevent desiccation, and may provide nutrients. 4. The difference between a capsule and a slime layer is that in a capsule polysaccharides are firmly attached to the cell wall, while in a slime layer the glycoproteins are loosely attached to the cell wall.

describe the functions of the eukaryotic cell nucleus, endoplasmic reticulum, golgi complex, lysosomes, vacuoles, mitochondria, chloroplasts, peroxisomes, and centrosomes.

1. eukaryotic cell nucelus- contains DNA in the form of chomosomes. Direct synthesis of ribosomes and proteins. Stores chromatin (DNA proteins). 2. endoplasmic reticulum- the nuclear envelope is connected to a system of membranes in the cytoplasm, transport of synthesized proteins in vesicles to the golgi apparatus. 3. golgi complex- modifying, sorting, and packing of proteins for secretion. 4. lysosome- removes wastes; key organelle that involves digestion and wastes removal. Gets rid of worn out organelles, food particles, viruses or bacteria. 5. vacuoles- in plant cell; maintains proper pressure within plant cells to provide structure and support for the growing plants. 6. mitochondria- to produce the energy currency of cell ATP through respiration and to regulate cellular metabolism. 7. chloroplasts- convert light energy of the sun into sugars that can be used by cells (photosynthesis). 8. peroxisomes- is the breakdown of very long chain fatty acids through beta-oxidation. 9. centrosomes- in mitosis the nuclear membrane breaks down and the centrosome nucleated microtubles can interact with chromosome to build mitotic spindle.

compare and contrast prokaryotic and eukaryotic plasma membranes.

1. like the prokaryotic plasma membrane the eukaryotic plasma membrane is a phospholipid bilayer containing proteins. 2. Eukaryotic plasma membranes contain carbohydrates attached to the proteins and sterols not found in prokaryotic cells. 3. Eukarotic cells can move by materials across the plasma membrane by the passive process used by prokaryotes and by active transport and endocytosis (phagocytosis and pinocytosis).

define simple diffusion, facilitated diffusion, osmosis, active transport, and group translocation.

1. simple diffusion- molecule and ions that move until equilibrium is reached. 2. facilitated diffusion- substances are transported by transporter proteins across membranes from areas of high to low concentration. 3. osmosis- is the movement of water from areas of high to low concentration across a selectively permeable membrane until equilibrium is reached. 4. active transport- materials from areas of low to high concentration by transporter proteins and the cell must expend energy. 5. group translocation- energy is expended to modify chemical and transport them across the membrane.

compare and contrast prokaryotic and eukaryotic cytoplasms.

1. the cytoplasm of eukaryotic cells includes everything inside the plasma membrane and external to the nucleus. 2. the chemical characteristics of the cytoplasm of eukaryotic cells resemble those of the cytoplasm of prokayrotic cells. 3. eukaryotic cytoplasm has a cytoskeleton and exhibits cytoplasmic streaming .