Chapters 2 & 3 Flashcards
Eukaryote
“true nucleus”
Membrane bound organelles and membrane systems
Prokaryote
“pre-nucleus”
No nucleus or other internal membrane bound organelles
3 Main shape of Bacteria
Coccus (Cocci)
Bacillus (Bacilli)
Spirillus (Spirilli)
Coccus (Cocci)
Spherical
Bacillus (Bacilli)
Rods
Spirillus (Spirilli)
Spirals
Vibrio
Comma shaped cells
Spirochete
More tightly coiled spirals
Pleomorphic
Irregular shaped
Di
prefix
Two
Strep
prefix
long chain
Staph
prefix
Irregular clusters
Coccus
1 singles sphere shaped cell
Diplococcus
2 sphere shaped cells connected
Tetrad
clusters of four cocci together
Streptococcus
long chains of cocci
staphylococcus
irregular clusters of cocci
Sarcina
Clusters of 8, 18, 32 or more cocci cells in a perfect cube shape
Bacillus
single rod shaped cell
Diplobacillus
2 rod shaped bacilli connected
Streptobacillus
Chains of rod shaped bacilli
Palisades
side-by-side arrangement of bacilli
4 biochemisty groups
Proteins
Carbs
Lipids
Nucleic Acids
Proteins
amino acids joined by peptide bonds, often with complex foldings
Ex. enzymes, most hormones, collagen
Carbohydrates
basic structure CH2O simple sugars Glucose (C6H12O6) Comples carbs (polysaccharides like cellulose and chitin)
Lipids
hydrophobic
- triglycerides and phospholipids contain glycerol and fatty acids
- steroids (cholestrol and sex hormones) are variations of 4 carbon ring structure
Cell Membrane
Prokarya
Phospholipid bilayer (40%) embedded with proteins (60%) Fluid mosaic model
3 layers of the cell envelope
Prokarya
Cell membrane
Cell wall
Glycocalyx
Phospholipid Bilayer
Prokarya
One phospholipid molecule has:
Two hydrophobic tails
Hydrophilic head of glycerol and phosphate
Phospholipid comparisons
-Bacteria and Eucarya - fatty acid tails
- Archaea - tails made of isoprene with branches
Also differences in glycerol and how glycerol links to hydrophobic tails
Prokaryote membrane functions
Transport
Enzymes
Transport
Prokaryote membrane functions
Selectively permeable
(Osmosis, Facilitated diffusion, active transport, secretion)
Integral Proteins (Carrier Proteins, Channel proteins -aqua proteins for faster water transport)
Enzymes
Prokaryote Membrane functions
Metabolic Pathways
- Synthesis of extracellular structures
- Electron transport and ATP synthesis
Difference between Animal and Fungal cell membranes
Animal - cholesterol
Fungal - ergosterol
Eucarya Cell Membrane
Receptor proteins - cell communication can recognize foreign cells
Sterols - give strength to cell membranes
Lipid Rafts - groups of proteins and lipids
Cell Wall
- Lacking in animal cells and some protists(protozoa)
- Found in most bacteria and Archaea
- Bacteria genus Mycoplasma has NO CELL WALL (sterols for strength)
Cell Wall function
Maintain Shape
Protection from environment
Protection from osmotic pressure
Bacteria normally live in what kind of solution
Hypotonic
Peptidoglycan composition
Only found in bacteria
Two major subunits: Alternating glycan molecules and tetrapeptide chains
Glyan Molecules
simple sugar + amino acid (amino sugars)
Two types of glycans
NAM - N-acetylmuramic acid
NAG - N-aceytlglcosamine
alternating chains NAG_NAM_NAG_NAM
Tetrapeptide chains
String of 4 amino acids
Link together the glycan chains
- peptide interbridges (Gram +)
- direct connection (Gram - )
Gram Stain
Hans Christian Joachim Gram in 1882
Gram Positive Cell Wall
One thick peptidoglycan layer (upto 30 layers)
Teichoic Acid
Periplasm
Teichoic Acid
Amino acids, sugars, glycerol, phosphate - from cell membrane through cell wall
Present only in Gram +
Periplasm
Gel like substance in between membrane and peptidoglycan
Gram Negative Cell Wall
2 parts outter and inner 1. thin Peptidoglycan + Periplasm = periplasmic space 2. Phospholipids Lipopolysaccharides (LPS) Lipoproteins Porin
Penicillin
interferes with synthesis of peptide inter-bridges in Gram positive
Lysozyme
an enzyme that digests glycan (NAG NAM)
Why are gram - bacteria less sensitive to antimicrobial medication
because of its outer membrane
Glycocalyx
Outside cell wall
Usually made of polysaccharides
2 kinds: Capsule or Slime layer
Glycocalyx function
- Protect from dehydration
- Attachment to tissue (biofims and teeth)
- Protection from white blood cells (phagocytosis)
Bacteria Flagella
- long, thin - special flagella stain
- Rigid, hair-like - made of FLAGELLIN
- Rotate 360
- Used to enter host cell
Structure of Bacteria Flagella
Filament
Hook
Basal body
Filament
spiral chains of protein form a hollow tube
Hook
curved protein structure, connects filament to cell structure
Basal body
ringed protein structure, anchors to cell membrane and cell wall, “motor”of flagella
-Trichous
hair
Mono
one
Amphi
both
Lopho-
tuft
Peri-
Around
Flagella arrangement found in….
ALL spirilla
half of bacilli
few cocci
Eucarya flagella
- covered with plasma membrane
- groupings of mictotubule proteins
- Basal body - anchor, different arrangement of microtubules than flagellum
- Whip like motion
Axial fibrils
found in spirochetes
used to burrow into host cell
Gliding
polysaccharide slime or surface proteins used for movement
Pili
- Shorter and thinner than flagella
- long hollow filament of PILIN proteins
- Adhesive tip for attachment
2 Types of Pili
Fimbriae and sex pili
Fimbriae
Usually many found on a bacteria cell
Stick to surfaces and other fimbriae
Allow for invasion of host tissue
Example: E.Coli
Sex Pili
- longer than fimbriae, less numerous (usually 1 or 2)
- In Gram - bacteria and some Gram +
- Used in conjugation
Conjugation in Sex pili
Sex pilus directly links the cytoplasm of one cell to another, plasmid DNA travels through the sex pilus
Nucleic Acids
DNA and RNA
Monomer
nucleotide = pentose sugar, nucleobase (A,G,C,T,U) and phosphate
DNA
double helix, sugar-phosphate backbone
RNA
shorter, single stranded
rRNA, mRNA, tRNA involved in protein systhesis
Bacterial Chromosome
- Single, circular, double stranded DNA
- contains genes that code for cell maintenance and growth
- Contains 3000 - 4000 genes
- Area where DNA is found is called NUCLEOID
- DNA is supercoiled with various proteins (histones only in Archaea and Eucarya)
Area where DNA is found in a bacteria chromosome
Nucleoid
Plasmids
Very small, circular pieces of DNA
- Free floating in cell
- contain few genes to 1000 genes
- supercoiled
Plasmids, are they essential
Not essential but helpful
drug resistance
enzyme and toxin production
What domain are Plasmids found
Bacteria, Archaea and SOME Eucarya
Ribosomes
Bacterial cell contains 15,000
Protein synthesis
60% rRNA and 40% proteins
Ribosome subunits
2 (small and large)
Bacteria and Archaea subunits
30S and 50S = 70S total
Eucharya subunits
40S and 60S = 80S
Mitochondria and chloroplast Sunits
70S ribosomes
S units
Svedberg units - measure size of ribosome and subunits
Higher S = heavier RNA
Endosymbiotic theory
Engulfs the cell and uses it instead of digesting it
Cytoplasmic Inclusions/Granules
- Storage of organic energy (glycogen and PHB)
- gases for floatation in aquatic systems
- storage of essential elements as inorganic crystals (sulfer granules & volutin)
- Some enclosed by membranes (storage particles)
Volutin
phosphate storage (metachromatic)
What are Endospores
- Small, protected, dormant bacteria
- Cannot divide, degrade or synthesize while dormant
- Genetically identical to original cell
When are Endospores formed
- in unfavorable conditions (starvation, desiccation)
- Germinates under favorable conditions to become a vegetative cell
- For survival, not reproduction
- Energetically very costly to produce
Endospores - WHO
- Only some Gram-positive rods
- Bacillus and Clostridium species
- Diseases from endospore forming bacteria - botulism, tetanus
A normal cell when not dormant is called a
vegetative cell
Endospores How they form
- One spore formed from one bacteria cell
- DNA duplcates, septum forms in cell
- “mother cell” engulfs “forespore”
- Peptidoglycan material added to forespore
- Mother cell degrades
Endospore layers
Spore coat
Cortex
Core
Spore coat (endospore)
outer layer - protein - protection from chemicals and enzymes
sometimes EXOSPORIUM is present
Cortex
endospore
middle layer - peptidoglycan - keeps spore dry, helps to resist heat and radiation
Extreme Resistance of Endospores
- high temperatures, desiccation, freezing, radiation, and many chemicals of toxins
- Endospores 1000s of years old can still germinate
- Can quickly return to vegetative state
- preventing endospore contamination: moist heat of pressurized steam using an autoclave
Core
endospore
inner part - contains and protects bacteria’s DNA
Core also contains calcium salts and dipicolinic acid
Ecoli facts
Gram -
Normal microbiota or possibly virulent
single bacillus with flagella and fimbriae
Many different strains ex. Shiga toxin producing E.Coli
Element
Matter made of one type of atom
How many naturally occurring elements
92
Which 4 elements are most common in organisms***
Oxygen, Carbon, Hydrogen, Nitrogen, Phosphorus
Atoms
the smallest part of an element that still has the properties of that element
3 subatomic particles that compose atoms
Protons
Neutrons
Electrons
Protons
location and charge
Nucleus
+
Neutrons
Neutral
Nucleus
Electrons
Location and charge
Negative
Shells, Orbitals
Atomic Number
the number of protons
atomic weight
the total number of protons and neutrons
What is an isotope
Atoms for the same element with different numbers of neutrons
What is a molecule
two or more atoms (ions) chemically bonded
Chemical bond
energy that holds atoms (ions) together
Covalent bond
form by equal sharing of a pair of electrons between two atoms
Polar (unequal sharing)
Nonpolar (equal sharing)
Ionic Bond
formed because of the transfer of electrons between two atoms
Hydrogen bond
the attraction of the positive hydrogen end of a polar molecule to the negative nitrogen or oxygen end of another polar molecule.
THE WEAKEST BOND
What is an Ion
an electrically charged atoms: an atom either gains or looses an electron
anion
an atom that gains an electron and becomes -
cation
an atom that loses an electron and becomes +
pH
measurement of hydronium H+ ions in a solution
0-14
buffer
reacts with a strong acid/base to for a weak acid/base; resists pH change
Diffusion
movement of molecule or ions from an area of high concentration to an area of low concentration of that molecule achieving equilibrium
Osmosis
movement of water molecules from an area of high concentration of H20 to an area of lower concentration through a selectively permeable membrane
Hypertonic
Higher concentration of solutes outside the cell
Hypotonic
lower concentration of stuff outside the cell
Isotonic
same osmotic pressure as body fluids
What happens if a cell is placed in a hypertonic or hypotonic solution
hypertonic - cell will shrink
hypotonic - cell will expand and possibly explode
Mitochondria
function
ATP production
Chloroplast
function
Use photosynthesis to make ATP for energy
Ribosome
function
Protein synthesis
Golgi apparatus
refines processes and packages proteins from ribosomes into packages
Rough Endoplasmic Reticulum
function
molecular transport of protein
Three organelles which have a double membrane and contain DNA
Mitochondria
Chloroplast
Nucleus