an introduction to cell structure and function

theodor schwann, matthias schleiden

two people who developed the cell theory

cell theory

states that all living things are composed of cells

both

characteristic: growth

2 multiple choice options

both

characteristic: reproduction

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both

characteristic: responsiveness

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both

characteristic: metabolism

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both

characteristic: cellular structure

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before nucleus

meaning of prokaryote

prokaryotes

their distinctive structural feature is not what they have, but what they lack

prokaryotes

cells that lack internal membrane-bound structures

1.0 micrometer

approximate diameter of prokaryotes

10-100 micrometer

approximate diameter of eukaryotes

true nucleus

meaning of eukaryote

eukaryotes

cells that have membrane surrounding their DNA, forming a nucleus

eukaryotes

cells that have a true nucleus with membrane-bound compartments

glycocalyces

these are gelatinous, sticky substances surrounding outside prokaryotic cells

glycocalyx

singular for glycocalyces

glycocalyces

"sugar cup"

glycocalyces

these are composed of polysaccharides or polypeptides or both

capsule

a glycocalyx which is composed of repeating units of organic chemicals firmly attached to the cell surface

slime layer

a loose, water soluble glycocalyx

slime layer

an often viscous glycocalyx, providing attachments to surfaces

flagella

in prokaryotes, are long whip-like structures that extend beyond the surface of the cell and the glycocalyx

flagella

in prokaryotes, these propel the cell

flagellum

singular for flagella

fimbriae

in prokaryotes, are non-motile extensions

fimbriae

in prokaryotes, these are sticky proteinaceous, bristle-like projections used to adhere to one another and to substances

fimbriae

these are shorter than flagella, and there may be 100 per cell

fimbriae

in prokaryotes, these serve an important function in biofilms

biofilms

are slimy masses of bacteria adhering to a substrate

pili

in prokaryotes, are tubules composed of a protein

pilin

protein in pili

pilus

singular for pili

pili

in prokaryotes, these are longer than fimbriae but shorter than flagella

1-10

there are these many pili in a cell

pili

in prokaryotes, these are used by bacteria to move across a substrate or towards another bacterium

pili

in prokaryotes, these mediate the transfer of DNA from one cell to the other

attachment pili

pili used to move across a substrate

conjugation pili

pili used in DNA transfer

prokaryotic cell walls

in prokaryotes, these provide structure and shape to the cell and protects it from osmotic forces

prokaryotic cell walls

in prokaryotes, these assist some cells in attaching to other cells or in eluding antimicrobial drugs

bacterial cell walls

these are composed of peptidoglycan

peptidoglycan

a complex polysaccharide which is composed of two regularly alternating sugars

N-acetylglucosamine, N-acetylmuramic acid

two regularly alternating sugars in peptidoglycan

glycan

these portions of peptidoglycan are where NAG alternates with NAM

tetrapeptides

a chain of alternating NAGs and NAMs is connected to another chain via _____

peptido

the portion of peptidoglycan where NAG and NAM are attached to other chains by cross-bridges

Gram Positive Cell Walls, Gram Negative Cell Walls

two basic types of bacterial cell walls

purple

color of gram positive cell walls

gram positive cell walls

bacterial cell walls with thick layer of peptidoglycan and unique polysaccharides which are covalently linked to lipids that anchor the peptidoglycan to the cell membrane

teichoic acids

polysaccharides in cell walls of gram-positive bacteria

lipotechoic acids

acids that anchor the peptidoglycan to the cell membrane that involve teichoic acid and lipids linking covalently

pink

color of gram negative cell walls

gram negative cell walls

these bacterial cell walls have a thin layer of peptidoglycan

phospholipids, channel proteins, lipopolysaccharides

outside the peptidoglycan layer of gram negative cell walls, there is a bilayer membrane composed of (3):

porins

channel proteins

lipopolysaccharides (LPS)

is a union of lipid and sugar

lipid a

the lipid portion of LPS

endotoxin

lipid a

lipopolysaccharides (LPS)

is released from dead cells when the cell walls disintegrate, and it may trigger fever, inflammation, shock, and blood clotting in humans

periplasmic space

found between the cell membrane and outer membrane in bacteria

periplasmic space

this contains the peptidoglycan and periplasm

periplasm

the gel between membranes of gram-negative cells

archaeal cell walls

these contain a variety of specialized polysaccharides and proteins, but NO peptidoglycan

gram positive archaeal walls

in archaea, these have thick walls and stain purple

gram negative archaeal walls

in archaea, these have a layer of protein covering the wall, rather than a lipid membrane; they stain pink

prokaryotic cytoplasmic membranes

in prokaryotes, these are found beneath the glycocalyx and cell wall, composed of lipids and associated proteins

prokaryotic cytoplasmic membranes

in prokaryotes, these are also referred to as cell membranes or plasma membranes

bacterial membranes

in prokaryotes, these contain phospholipids, and some have sterol-like molecules

hopanoids

sterol-like molecules in bacterial membranes

archaeal membranes

in prokaryotes, these are composed of lipids that lack phosphate groups and have branched hydrocarbons linked to glycerol

ether linkages

archaea membranes use these instead of ester linkages

passive transport processes

processes require no use of energy by the cell

electrochemical gradient

provides energy for passive transport process

diffusion

molecules move down their electrochemical gradient through the phospholipid bilayer of the membrane

oxygen, carbon dioxide, lipid-soluble chemicals

substances transported in diffusion

facilitated diffusion

molecules move down their electrochemical gradient through channels or carrier proteins

glucose, fructose, urea, some vitamins

substances transported in facilitated diffusion

osmosis

water molecules move down their concentration gradient across a selectively permeable membrane

water

substances transported in osmosis

active transport processes

cell expends energy in the form of ATP to move a substance against its electrochemical gradient

active transport

atp-dependent carrier proteins bring substances into cell

na+, k+, ca2+, h+, cl-

substances transported by active transport

group translocation

the substance is chemically altered during transport, found only in prokaryotes

glucose, mannose, fructose

substances transported in group translocation

endocytosis

substances are surrounded by pseudopodia and brought into the cell

phagocytosis

endocytosis that involves solid substances

pinocytosis

endocytosis that involves liquids

exocytosis

vesicles containing substances are fused with the cytoplasmic membrane, dumping their contents to the outside

cytoplasm

the general term used to describe the semi-liquid, gelatinous material inside a cell

cytosol

in prokaryotes, it contains the cell's DNA

nucleoid

the region of the cytoplasm of prokaryotes that are not surrounded by a membrane, but contains the cell's DNA

inclusions

prokaryotes; are deposits found within the cytosol

inclusions

prokaryotes; may include reserve deposits of lipids, starch, or compounds containing nitrogen, phosphate, and sulfur

inclusions

prokaryotes; serve as a diagnostic tool for pathogenic bacteria

ribosomes

prokaryotes; sites of protein synthesis

1000

prokaryotic cells have about this many ribosomes which give the cytoplasm a grainy appearance

svedbergs

the approximate size of ribosomes is expressed in _______________

sedimentation rate

svedberg units are determined by their _________________

70s

svedberg units of prokaryotic ribosomes