Lesson 4 - Chapter 4 Notes

spiral

(helical) shape

Compare and contrast the overall cell structure of prokaryotes and eukaryotes.

Both contain nucleic acids, proteins, lipids and carbohydrates. They use the same kinds of chemical reactions to metabolize food, build proteins, and store energy. However the structure of cells walls and membranes and the absence of organelles is what makes them different.

Compare and contrast prokaryotic and eukaryotic cell walls and glycocalyxes.

Eukaryotic cell walls are much simpler relative to prokaryotic cells. The cell walls of many algae and some fungi contain cellulose, where the main material of fungal cell walls is chitin. Yeast cells typically consist of glucan and mannan (polysaccharides). Animal cells, on the other hand, are surrounded by a glycocalyx (layer of "sticky" carbohydrates) that strengthens the cell and provides a means of attachment to other cells.

endosymbiotic theory

Eukaryotic cells evolved from symbiotic prokaryotes living inside other prokaryotic cells

Discuss evidence that supports the endosymbiotic theory of eukaryotic evolution.

Evidence for Endosymbiotic theory: mitochondria and chloroplasts resemble bacteria in size and shape. These organelles contain circular DNA, which is typical of prokaryotes and the organelles can reproduce independently of their host cell. their ribosomes resemble those of prokaryotes and their mechanism of protein synthesis is more similar to that found in bacteria than Eukaryotes.

Compare and contrast prokaryotic and eukaryotic plasma membranes.

Like the prokaryotic plasma membrane, the eukaryotic membrane is a phospholipid bilayer containing proteins. However, there are differences in the types of proteins found in eukaryotic membranes. Eukaryotic plasma membranes also contain carbohydrates attached to the proteins and sterols not found in prokaryotic cells (except the Mycoplasma bacteria mentioned earlier). Sterols are believed to help resist lysis. Eukaryotic cells can move materials across the plasma membrane by the passive processes previously described in the prokaryotic section of the lesson, in addition to active transport and endocytosis (phagocytosis and pinocytosis - the enclosure of material to transport it).

Compare and contrast prokaryotic and eukaryotic cytoplasms.

The cytoplasm of eukaryotic cells includes everything inside the plasma membrane and external to the nucleus. The chemical characteristics of the cytoplasm of eukaryotic cells resemble those of the cytoplasm of prokaryotic cells; however, eukaryotic cells have an internal network structure called a cytoskeleton, and the cytoplasm exhibits cytoplasmic streaming (moving materials within the cytoplasm).

nucleoid

The nucleoid (meaning nucleus-like) is an irregularly shaped region within the cell of a prokaryote that contains all or most of the genetic material, called genophore. In contrast to the nucleus of a eukaryotic cell, it is not surrounded by a nuclear membrane.

spirilla

a bacterium with a rigid spiral structure; like a corkscrew

cell wall

a complex, semi-rigid structure responsible for the shape of the cell. the major function is to prevent bacterial cells from rupturing when the water pressure inside the cell is greater than that of outside cell

endospores

a dormant, tough, non-reproductive structure produced by a small number of bacteria "resting cells"

fluid mosaic model

a dynamic arrangement of phospholipids and proteins

crista (pl: cristae)

a fold in the inner membrane of a mitochondrion. Latin for crest. providing a larger surface area for chemical reactions to occur.

plasmids

a genetic structure in a cell that can replicate independently of the chromosomes, typically a small circular DNA strand in the cytoplasm of a bacterium or protozoan.

vibrios

a genus of Gram-negative bacteria, possessing a curved-rod shape

hypertonic solution

a medium having a higher concentration of solutes than inside the cell has (hyper means above or more)

chloroplast

a membrane enclosed structure that contains chlorophyll and enzymes for photosynthesis

cytoskeleton

a microscopic network of protein filaments and tubules in the cytoplasm of many living cells, giving them shape and coherence.

prokaryotes

a microscopic single-celled organism that has neither a distinct nucleus with a membrane nor other specialized organelles. include the bacteria and archaea

microtubules

a microscopic tubular structure present in numbers in the cytoplasm of cells, sometimes aggregating to form more complex structures.

ribosomes

a minute particle consisting of RNA and associated proteins. found in the cytoplasm or attached to the rough endoplasmic reticulum

bacillus (pl: bacilli)

a rod-shaped bacterium

matrix

a semifluid substance found within a mitochondrion.

cilia

a short, microscopic, hairlike vibrating structure. causing currents in the surrounding fluid, or, in some protozoans and other small organisms, providing propulsion.

nucleus

a single rounded structure bounded by a double membrane, containing the genetic material.

nucleolus

a small dense spherical structure in the nucleus of a cell during interphase.

peroxisomes

a small organelle that is present in the cytoplasm of many cells and that contains the reducing enzyme catalase and usually some oxidases.

Describe the structure, chemistry, and functions of the prokaryotic plasma membrane.

a thin structure lying inside the cell wall and enclosing the cytoplasm of the cell; consists of phospholipids and proteins. less rigid than eurkaryotic membranes. contains a lipid bilayer. the most important function is the selective permeability of allowing certain things in and keeping others out.

chromosomes

a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.

peptidoglycan

aka murein; consists of a repeating disaccharide attached by polypeptides to form a lattice that surrounds and protects the entire cell

centrosome

an organelle near the nucleus of a cell that contains the centrioles. involved in formation of the mitotic spindle and microtubules

eukaryotes

an organism consisting of a cell or cells in which the genetic material is DNA in the form of chromosomes contained within a distinct nucleus. include all living organisms

organelles

any of a number of organized or specialized membrane-enclosed structures within a living cell.

coccus (pl: cocci)

any spherical or roughly spherical bacterium. (berries)

lysosomes

are formed from Golgi complexes. they store digestive enzymes

axial filaments

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

rough ER

called rough because it has ribosomes attached to its surface. protein synthesis and transport occurs here

fimbria (pl: fimbriae)

can occur at the poles of the bacterial cell, or they can be evenly distributed over the entire surface of the cell. they enable the cell to adhere to surfaces

Identify the three basic shapes of bacteria.

coccus, (berry) bacillus, (rod like) spiral, (corkscrew)

nuclear envelope

connected to a system of membranes in the cytoplasm called the endoplasmic reticulum.

gram-positive

consist of many layers of peptidoglycan which forms a thick rigid structure. contain teichoic acids. retain crystal violet dye and stain dark violet or purple.

gram-negative

consist of one or a very few layers of peptidoglycan and an outer membrane. they lose the crystal violet stain (and take the color of the red counterstain). do not contain teichoic acids. more susceptible to mechanical breakage.

golgi complex

consists of flattened sacs called cisterns. it functions in membrane formation and protein secretion.

thylakoids

each of a number of flattened sacs inside a chloroplast, bounded by pigmented membranes on which the light reactions of photosynthesis take place, and arranged in stacks or grana.

Describe the functions of endospores, sporulation, and endospore germination.

endospores: resting structures formed by some bacteria, they allow survival during adverse environmental conditions. sporulation: the process of endospore formation. endospore germination: the return of an endospore to its vegetative state

EPS

extracellular polysaccharide; a glycocalyx made of sugars, enables a bacterium to survive by attaching to various surfaces in its natural environment in order to survive.

Describe the structure and function of the glycocalyx, flagella, axial filaments, fimbriae, and pili.

glycocalyx: sugar coat that surrounds the cells. flagella: filamentous appendage to give motility. axial filaments: bundles of fibrils that arise at the ends of the cell beneath an outer sheath and spiral around the cell; produces a movement for spirochetes. fimbriae: they allow a cell to adhere to surfaces pili: longer than fimbriae and help with DNA transfer

Compare and contrast the cell walls of gram-positive bacteria, gram-negative bacteria, archaea, and mycoplasmas.

gram-positive bacteria: retain crystal violet dye, thick peptidoglycan layer, contains teichoic acids, can be disrupted by lysozymes and penicillin. gram-negative bacteria: can be decolorized to accept counterstain, thin peptidoglycan, has outer membrane and lipopolysaccharide. archaea: can lack cell walls but if they do have them they contain pseudomurein and cannot be gram-stained. mycoplasmas: no cell walls, their plasma membranes have sterols to protect them from lysis.

staphylo-

grape-like clusters or broad sheets

spirochetes

group of spirals are helical and flexible

sarcinae

having a cuboidal cell arrangement

monomorphic

having or existing in only one form

slime layer

if the glycocalyx is unorganized and only loosely attached to the cell wall

isotonic solution

is a medium in which the overall concentration of solutes equals that found inside a cell. (iso meaning equal)

taxis

is the movement of an organism in response to a stimulus

simple diffusion

is the net movement of molecules or ions from an area of high concentration to an area of low concentration. it continues to do so until it reaches equilibrium

osmosis

is the net movement of solvent molecules across a selectively permeable membrane from an area with a high concentration of solvent molecules (low concentration of solute molecules) to an area of low concentration of solvent molecules (high concentration of solute molecules)

osmotic pressure

is the pressure required to prevent the movement of pure water into a solution containing some solutes.

flagella

long filamentous appendages that propel bacteria

glycocalyx

meaning sugar coat; is the general term used for substances that surround cells

diplo-

means double, for example a bacteria that remains in pairs following cell division

vacuole

membrane-enclosed cavities derived from the Golgi complex or endocytosis. They are usually found in plant cells that store various substances, help bring food into the cell, increase cell size, and provide rigidity to leaves and stems.

chemotaxis

movement of a motile cell or organism, or part of one, in a direction corresponding to a gradient of increasing or decreasing concentration of a particular substance (chemicals)

Identify the functions of the nuclear area, ribosomes, and inclusions.

nuclear area: contains the DNA of the bacterial chromosome. ribosomes: protein synthesis occurs here. inclusions: are reserve deposits found in prokaryotic and eukaryotic cells

Describe the functions of the nucleus, endoplasmic reticulum, ribosomes, Golgi complex, lysosomes, vacuoles, mitochondria, chloroplasts, peroxisomes, and centrosomes.

nucleus: contains DNA endoplasmic reticulum: provides a surface for chemical reactions, transporting network and synthesized molecules ribosomes: protein synthesis Golgi complex: functions in membrane formation and protein secretion lysosomes: store digestive enzymes vaculoes: membrane enclosed cavities mitochondria: makes ATP chloroplasts: contain chlorophyll and enzymes for photosynthesis peroxisomes: oxidize various organic substances centrosomes: involved in formation of mitotic spindle and microtubules

hypotonic solution

outside the cell is a medium whose concentration of solutes is lower than that inside the cell. (hypo meaning under or less)

mitochondria

primary sites of ATP production. They multiply by binary fission.

Differentiate between prokaryotic and eukaryotic flagella.

prokaryotic flagella: consist of two protein building blocks ( rotates ) eukaryotic flagella: complex; consist of multiple microtubules ( moves in a wave-like manner )

Differentiate between protoplast, spheroplast, and L form.

protoplast: a wall-less cell, typically spherical and is still capable of carrying on metabolism L forms: lost their cell walls and swell into irregular shaped cells. can happen spontaneously or due to penicillin or lysozyme Spheroplast: a bacterium or plant cell bound by its plasma membrane, the cell wall being deficient or lacking and the whole having a spherical form.

ER

provides surface for chemical reactions, serves as a transporting network, and stores synthesized molecules. Protein synthesis and transport occur on Rough ER; lipid synthesis occurs on smooth ER.

cytoplasm

refers to the substance of the cell inside the plasma membrane. thick, aqueous, semitransparent and elastic

smooth ER

regulates and releases calcium ions and processes toxins. lipid synthesis

tetrads

remain in groups of four

inclusions

reserve deposits found in prokaryotic and eykaryotic cells. (Nonliving material in the protoplasm of a cell, such as pigment granules, fat droplets, or nutritive substances.)

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

simple diffusion: a process whereby a substance passes through a membrane without the aid of an intermediary osmosis: a process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one, thus equalizing the concentrations on each side of the membrane. facilitated diffusion: active transport: the movement of ions or molecules across a cell membrane into a region of higher concentration, assisted by enzymes and requiring energy. group translocation: a special form of active transport that occurs exclusively in prokaryotes, the substance is chemically altered during transport across the membrane.

selective permeability

sometimes called semipermeability. indicates that certain molecules and ions pass through the membrane but others are prevented from passing through it.

Define organelle.

specialized membrane-enclosed structures in the cytoplasm of eukaryotic cells.

pleomorphic

the ability of some bacteria to alter their shape or size in response to environmental conditions in more than just one way.

cystol

the aqueous component of the cytoplasm of a cell, within which various organelles and particles are suspended.

phototaxis

the bodily movement of a motile organism in response to light, either toward the source of light (positive phototaxis) or away from it (negative phototaxis).

active transport

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

plasma membrane

the inner membrane; is a thin structure lying inside the cell wall and enclosing the cytoplasm of the cell. contains phospholipids and proteins

endocytosis

the plasma membrane surrounds a particle or large molecule, encloses it, and brings it into the cell. done by phagocytosis or pinocytosis

facilitated diffusion

the substance (glucose for example) to be transported combines with a plasma membrane protein called a "transporter" then moves to other side

nuclear pores

tiny channels within the nuclear envelope that allow the nucleus to communicate with the cytoplasm

strepto-

twisted; in the form of a twisted chain.

pilus (pl: pili)

usually longer than fimbriae and number only one or two per cell. join bacterial cells in preparation for the transfer of DNA from one cell to another

capsule

when the glycocalyx is organized and is firmly attached to the cell wall