Chapter 4

Define active transport

Movement across cell membrane--from low to high concentration--requires energy

Define Phagocytosis

the ingestion of bacteria or other material by phagocytes and amoeboid protozoans.

Define exocytosis

a process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell membrane.

Define Diffusion

movement of molecules from high concentration to low concentration

Compare/contrast protoplast vs spheroplast vs L forms

- Protoplast is a wall-less cell - Spheroplast is a wall-less gram-negative cell - Protoplasts and spheroplasts are susceptible to osmotic lysis - L forms are wall-less cells that swell into irregular shapes

Define concentration gradient

difference in the concentration of a substance from one location to another

Define osmosis

diffusion of water across a selectively permeable membrane

Be able to thoroughly describe the structure of the bacterial cell wall, include the following terms: • Peptidoglycan, N-acetlyglucosamine (NAG), N-acetlymuramic acid (NAM) • Amino acid cross bridge

A cell wall is a layer located outside the cell membrane found in plants, fungi, bacteria, algae, and archaea. A peptidoglycan cell wall composed of disaccharides and amino acids gives bacteria structural support. In both E. coli and B. subtilis, the dibasic amino acid of the stem peptide, which allows the formation of the peptide cross bridge

Give a brief description and function of chloroplasts

Chloroplasts work to convert light energy of the Sun into sugars that can be used by cells

define the following: • Coccus, Bacillus, Spiral, tetrad, Vibrio, pleomorphic

Coccus = Spherical Bacillus = Rod-shaped Tetrad = a group or set of four Vibrio = comma shape Pleomorphic = the ability of some micro-organisms to alter their shape or size in response to environmental conditions.

compare the chemical components of the cell walls of Gram (+) versus Gram (-).

Gram + bacteria have a thick, multi-layered peptidoglycan layer; Gram - bacteria have a thin, single layer one. Gram + have techoic acids in the cell wall; Gram - do not. Gram + do not have a periplasmic space; Gram - do. Gram + bacteria have no outer membrane; Gram - have this feature. Lipopolysaccharides are in high concentration only in Gram - bacteria. lipid concentration is higher in Gram - than in Gram +. Gram + stains as purple in the Gram Stain procedure, even after rinsing and counter-stain. Gram - will stain as pink due to the counter-stain, but cannot retain the purple dye well.

Define endospores

Heat-stable forms of bacteria which are formed during the life-cycle of certain bacteria

define the terms prokaryotic and Eukaryotic

Prokaryotes are 1-celled organisms that do not have a nucleus or any other membrane-bound organelles inside them. The name prokaryote itself actually lets you know that there isn't a nucleus, since pro means before and karyo refers to nucleus. Eukaryotes (/juːˈkærioʊt, -ət/) are organisms whose cells have a nucleus enclosed within membranes, unlike prokaryotes (Bacteria and Archaea), which have no membrane-bound organelles. Eukaryotes belong to the domain Eukaryota or Eukarya.

Give a brief description and function of ribosomes (compare 70s with 80s)

Ribosomes are a cell structure that makes protein

Give a brief description and function of the nucleus endoplasmic reticulum

The endoplasmic reticulum is a very large organelle, seen via high resolution as a series of sacs and tubular folds. Within a eukaryotic cell, this organelle is found outside of the nucleus within the cell's cytosol. Its functions include producing and processing proteins and lipids.

list 4 differences between prokaryotic and eukaryotic cells

The main difference between prokaryotes and eukaryotes is this: eukaryotic cells contain membrane-bound organelles, such as the nucleus, while prokaryotic cells do not.

Give a brief description and function of mitochondria

The main job of mitochondria is to perform cellular respiration. This means it takes in nutrients from the cell, breaks it down, and turns it into energy.

describe the structure and composition of plasma membranes.

The primary function of the plasma membrane is to protect the cell from its surroundings. Composed of a phospholipid bilayer with embedded proteins, the plasma membrane is selectively permeable to ions and organic molecules and regulates the movement of substances in and out of cells.

Define endocytosis

A process when a cell surrounds and takes in large materials or large amounts of materials from the environment

Give a brief description and function of the cell wall

A major function of the cell wall is to give the cell strength and structure, and to filter molecules that pass in and out of the cell.

explain the action of lysozyme

breaking the chemical bonds in the outer cell wall of the bacteria

Give examples of types of prokaryotes with a-typical cell walls

Bacteria and Archaea

describe cell components that differentiate eukaryotic cells from prokaryotic.

Eukaryotic cells contain membrane-bound organelles, including a nucleus. Prokaryotic cells do not contain a nucleus or any other membrane-bound organelle.

Define chromosome

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

Define semipermeable membrane

a type of biological or synthetic, polymeric membrane that will allow certain molecules or ions to pass through it by diffusion

list cell features used to differentiate species of bacteria, and which are observable with the light microscope.

bacteria shape and arrangement

Define facilitated diffusion

facilitated diffusion is the net movement of dissolved particles down their concentration gradient with the help of carrier molecules

describe the structure and function of the following: • capsule (glycocalyx) flagella pili axial filaments

Capsule (glycocalyx) = a carbohydrate-enriched coating that covers the outside of many eukaryotic cells and prokaryotic cells, particularly bacteria Flagella = whip-like structure that allows a cell to move. Pili = A pilus is a thin, rigid fiber made of protein that protrudes from the cell surface. The primary function of pili are to attach a bacterial cell to specific surfaces or to other cells. Axial filament = structure composed of rotating endo-flagella that allows a spirochete to "corkscrew" through its medium.

Define cytoplasm

Cytoplasm is a thick solution that fills each cell and is enclosed by the cell membrane. The cytoplasm functions to support and suspend organelles and cellular molecules.

Know the following prefixes: diplo, strepto, staphylo

Diplo = two cells Strepto = twisted Staphylo = bunch of grapes

describe the purpose and circumstances for endospore formation, and briefly describe the processes of sporulation (sporogenesis) and germination.

Endospore formation is usually triggered by a lack of nutrients, and usually occurs in gram-positive bacteria. In endospore formation, the bacterium divides within its cell wall, and one side then engulfs the other. Endospores enable bacteria to lie dormant for extended periods, even centuries. The one vegetative cell forms a single spore, which, after germination, develops into a new cell.

describe the structure of Gram (-) outer cell wall membranes with LPS.

In the Gram-negative Bacteria the cell wall is composed of a single layer of peptidoglycan surrounded by a membranous structure called the outer membrane. The LPS molecule is toxic and is classified as an endotoxin that elicits a strong immune response when the bacteria infect animals.

Give a brief description and function of the golgi complex

It acts to process and package the macromolecules such as proteins and lipids that are synthesized by the cell.

Give a brief description and function of lysosomes

Lysosomes are organelles that contain digestive enzymes. They digest excess or worn out organelles, food particles, and engulfed viruses or bacteria.

Define passive transport

Movement across cell membrane--high to low--does NOT require energy

Define osmotic lysis

the bursting of a cell

explain why most scientists believe prokaryotic cells evolved first, and how prokaryotic evolved into Eukaryotic cells.

the first eukaryotic cells evolved from a symbiotic relationship between two or more prokaryotic cells. Smaller prokaryotic cells were engulfed by (or invaded) larger prokaryotic cells.

Define pinocytosis

the ingestion of liquid into a cell by the budding of small vesicles from the cell membrane.

Define osmotic pressure

the pressure needed to stop the movement of water across the membrane

Define inclusions

Granules of glycogen or pigments, lipid droplets, vacuoles, and crystals

Give a brief description and function of centrosome (centrioles)

The main purpose of a centrosome is to organize microtubules and provide structure for the cell, as well as work to pull chromatids apart during cell division.