CELLULAR STRUCTURE & FUNCTION CH.3

what are the characteristics of life

growth

reproduction

responsiveness

metabolism

cellular structure

what are the cell theory statements

all living things are made of cells

cells are the basic units of life

every new cell comes from pre-existing cells

what is the cell membrane composition

phospholipid bilayer with hydrophilic heads facing water and hydrophobic tails forming the core. there are embedded integral proteins that span the membrane while peripheral proteins cling to the surface.

what is the phospholipid structure

[head]

a choline/serine labelled as R

phosphate group

a glycerol molecule

[tail]

2 fatty chains that can be either saturated or unsaturated

which list describes prokaryotic cells

lack nucleus

can read DNA and make protein simultaneously

lack internal membrane bound organelles

are less than 1.0 um in diameter

include bacteria and archaea

what list describes eukaryotic cells

have nucleus

have internal membrane bound organelles

are larger : 10-100 um in diameter

have more complex structure

composed of algae , protozoa, fungi, animals, and plants

what are the common cellular components

an enclosing plasma membrane which separates the cells inter from the environment

cytoplasm made of cytosol in which other components of the cell are found

DNA being the genetic material of the cell

ribosomes which synthesize proteins

what is the glycocalyx (BACTERIAL)

a sticky gelatinous coating surrounding the outside of the cell

what is the structure of the glycocalyx

polysaccharides and polypeptides

what is the function of glycocalyx

provides protection and helps the cell adhere to surfaces

what is the structure of the flagella (PROPERTIES OF BACTERIA)

filament - long visible tail

hook - a curved connector

basal body - anchors the flagellum to the cell all and membrane

what is the function of the flagella

responsible for movement in many bacteria

what are the arrangements of flagella

monotrichous

lophortrichous

amphitrichous and polar

peritrichous flagella

describe how flagella “run”

rotating counterclockwise

describe how flagella “tumble”

rotate clockwise, causing reorientation

what is the structure of fimbriae

subunits of the protein pillin that are sticky bristle like projections

what is fimbriae

sticky surface structures that build biofilms

what is the function of fimbriae

used by bacteria to adhere to one another and to substances in environment . serve as important function in biofilms

what is pili

a special type of fimbriae that are the molecular grappling hooks of bacteria

what is the function of pili

transfer DNA from one cell to another (conjugation)

what is the structure of the cell wall (bacterial)

build from peptidoglycan

what are gram positive cell walls composed of

thick peptidoglycan , no outer membrane. cells stain purple

what are gram negative cell walls composed of

thin peptidoglycan, plus an outer membrane . cells stain pink

what is the gram staining principle

fixation — crystal violet — iodine treatment — decolorization — counterstain safinin

what is an endospore

unique structures formed by some gram-positive bacteria . they are defensive survival capsules triggered by harsh conditions

what is passive membrane transport

molecules move from high to low concentration. no energy input. three types - simple diffusion, facilitated diffusion , osmosis (move down the concentration gradient)

what is active transport

molecules move from low to high concentration. energy is required. (against the concentration gradient)

what is tonicity

how an extracellular solution can change the volume of a cell by affecting osmosis

what is group translocation

a type of active transport where the substance is chemically modified as it crosses the membrane ( ex; phosphotransferase system & phosphoenolpyruvate)