Prokaryotes

What 4 things do all living things possess?

Growth, reproduction, responsiveness, metabolism

What is Growth?

an increase in size

What is Reproduction?

an increase in number

What is Metabolism?

controlled chemical reactions

What do all living organisms have that viruses don’t have?

A cellular structure and depend on a host cell’s metabolism for reproduction

Prokaryotic cells

bacteria and archaea, lacks a nucleus and membrane-bound organelles

Eukaryotic cells

such as animals, plants, algae, fungi, and protozoa which have internal membrane bound organelles including true nuclei

What are the common structural features between Prokaryotes and Eukaryotes?

external structures, cell walls, cytoplasmic membrane, and cytoplasm

Glycocalyx

sticky substance that surrounds the outside of some cells

Capsule

when the glycocalyx of a bacterium is composed of organized repeating units of organic molecules firmly attached to the cell surface

Slime Layer

a diffuse, unorganized, and loosely attached layer of extracellular material that surrounds bacterial cells

What are the advantages to capsules and slime layers?

protects the cell from desiccation and increases the cell’s ability to survive and cause disease

What do capsules protect cells from?

phagocytosis

What do slime layers enable?

enables cells to adhere to each other and to environmental surfaces

Flagella

located beyond the cell surface and glycocalyx and controls cell motility

Peritrichous flagella

flagella covering the cell

Polar flagella

found at the ends of cells

Endoflagella

special flagella of some spirochetes that spiral tightly around the cell instead of protruding into the environment

What do Endoflagella form?

axial filament

Axial filament

wraps around the cell and rotates enabling it to “corkscrew” through its medium

Taxis

flagella move the cell toward or away from stimuli such as chemicals or light

Fimbriae

short, sticky, proteinaceous extensions of some bacteria that help cells adhere to one another and to substances in the environment

Biolfilms

slimy masses of bacteria adhering to a surface, adhesion and signaling between cells

Pili (conjugation pili)

special type of fimbriae with 1 or 2 per cell and functions to transfer DNA from one cell to another

Conjugation

transferring of DNA from one cell to another

What are bacterial cell walls composed of?

peptidoglycan

What is peptidoglycan made of?

2 alternating sugars called NAG and NAM and are attached to each other by chains of crossbridges of 4 amino acids

Gram positive cell walls have

thick peptidoglycan layers that contain Teichoic acids

Gram negative cell walls have

thin layers of peptidoglycan and has a lipopolysaccharides

Periplasmic Space

between the cytoplasmic and outer membranes that contains peptidoglycan

Which bacteria lacks cell walls entirely and have prokaryotic ribosomes instead?

Mycoplasma pneumoniae

Phospholipid bilayer

double layered structure composed of molecules with hydrophobic lipid tails and hydrophilic phosphate heads

Fluid mosaic model

describes the structure of cell membranes as a dynamic flexible barrier

Selectively permeable

allows some substances to cross while preventing the crossing of others

How do proteins act in selectively permeable membranes?

as pores, channels, or carriers to facilitate the transport of substances

Concentration Gradient

difference in the amount of a dissolved substances between the inside and outside a microbes cell

Electrical Gradients

the difference in electrical charge between the inside and outside of a cell

What do concentration and electrical gradients both create?

creates an electrochemical gradient across the membrane

What does the cytoplasmic membrane use energy from the electrochemical gradient for?

transporting substances into or out of the cell

Passive Processes

requires no cellular energy expenditure to move chemicals across the cytoplasmic membrane

Simple Diffusion

movement of chemicals down their concentration gradient from a higher concentration to a lower concentration

Facilitated Diffusion

proteins act as channels or carriers to allow certain molecules to diffuse into or out of the cell along their electrochemical gradient

Osmosis

diffusion of water molecules across a semipermeable membrane in response to differing concentrations of solutes

Hypertonic solutions

higher concentration of solutes

Hypotonic Solutions

lower concentration of solutes

Isotonic solutions

the same concentration of solutes

Active Transport

require cells to expand energy in the form of ATP to move materials across the cytoplasmic membrane against their electrochemical gradient

Symports

2 substances moving in the same direction

Antiports

moves substances in opposite directions

Group Translocation

causes chemical changes to the substance being transported causing the membrane to be impermeable to the altered substance which becomes trapped inside the cell

Cytoplasm

the gelatinous, elastic material inside a cell

What is Cytoplasm composed of?

cytosol, inclusions, ribosomes, and cytoskeletons

Cytosol

the liquid portion of the cytoplasm and contains the nucleoid

Inclusions

reserve deposits of lipids, starch, or other chemicals

Gas Vesicle Inclusions

stores gases

Ribosomes

are the sites of protein synthesis in cells and are composed of protein and rRNA

Cytoskeleton

internal scaffolding of fibers that play a role in forming a cell’s basic shape, division of one into 2 cells, and sometimes motility

What are the 2 nonmembranous organelles?

ribosomes and cytoskeletons

What are the structural similarities between Archaeal cells and bacteria?

glycocalyces, flagella, fimbriae and some have hamus

What are Archaeal glycocalyces composed of

polysaccharides, polypeptides, or both

What is the function of Archaeal glycocalyces

adheres and biofilm formation

What are Archaeal Flagella powered by?

ATP

Differences between Archaeal flagella and bacteria

smaller, made of different proteins, and has sugar molecules attached

Hamus

helical filament with prickles and a terminus that drives into 3 curved hooks

What does bacteria and hami have in common?

they attach to surfaces