LEC EXAM #1 CHP. 3 Flashcards
How does bacteria move?
By changing the rotation of their flagella
What is chemotaxis:
- Causes spinning of flagella to move towards the attractant
- Chemical attractants cause more runs
Run vs. tumble:
RUN:
- Flagella rotates in a counterclockwise direction
- Flagella bundled
TUMBLE:
- Flagella rotates in a clockwise direction
- Not bundled
Brownian motion vs directed movement:
Brownian motion:
the random movement of microscopic particles suspended in a gas or liquid due to collision of these particles in the fluid
Directed movement:
directed movement of cells up a conc. gradient
How does the presence of a capsule help bacteria survive?
- Encapsulates them for more protection
- Prevents WBC’s from phagocytosis
- Hinders abx functions
- Allows slime layer to adhere to a smooth surface, allowing it to stay for a longer amount of time
What is a pathogen?
- Agent that causes diseases or illness to its host
- 4 types: bacteria, viruses, fungi, and parasites
What types of molecules can move through the membrane freely (simple diffusion) or diffuse across a membrane?
- Small, uncharged molecules
- Hydrophobic molecules
- O2, CO2, lipids, water
What types of molecules require a carrier protein transporter for facilitative diffusion?
- Large and charged molecules
- Hydrophilic molecules
- Glucose, carbs, amino acids, ions
What types of molecules require active transport?
Glucose, ions, amino acids
Simple diffusion:
Molecules move DOWN their conc. gradient (high->low)
-Does not use energy to do this
Active transport?
- Pumps molecules against their conc. gradient using ATP (low-> high)
- Uses ATP as energy to do this
Facilitated diffusion:
- Molecules move down their conc. gradient using the help of a carrier/transport protein (high->low)
- Does not use energy to do this
How does osmosis work in prokaryotic cells? *
In prokaryotic cells, the cell wall provides some protection against changes in osmotic pressure, allowing it
to maintain its shape
The key morphological innovations of eukaryotic cells:
- Has a nucleus that contains DNA
- Has membrane bound organelles
- Has a cytoskeleton that provides structure, keeps organelles in place, and helps with cellular transport
- Has 80s proteins ribosomes
How do prokaryotic cells (7) differ from eukaryotic cells (6)?
Prokaryotic cells:
- unicellular
- smaller
- more basic
- came first
- found in bacteria and archaea
- no nucleus
- no membrane bound organelles
Eukaryotic cells:
- unicellular or multicellular
- bigger
- more complex
- found in protists, plants fungi, and animals
- has nucleus
- has membrane bound organelles
What do prokaryotic and eukaryotic cells have in common?
Both have:
- DNA
- Cell/plasma membrane
- Cell wall (besides animal cells in eukaryotic cells)
- Ribosomes
What is endomembrane trafficking?
- Group of membrane organelles that produce and modify proteins and lipids
- Starts in nuclear envelope goes to RER for protein synthesis or SER for lipid synthesis-> golgi apparatus-> packages it to plasma membrane or other parts of the cell
How does the RER differ from the smooth ER?
RER surrounds nuclear membrane and is bound by ribosomes-> makes proteins
Smooth ER makes lipids not proteins
Peroxisomes:
Membrane bound organelle that has lipid bilayer that breaks down peroxides to keep free radicals from forming
Cytoskeleton:
Provides structure and support
-Network/highway for transportation
3 cytoskeleton elements:
- Microtubules
- Microfilaments
- Intermediate filaments
Golgi apparatus:
Site where proteins are modified by placing sugar on proteins and ships them out to their final destination
Lysosome:
Garbage disposal of cell, breaks down the waste
Nuclear lamina:
Intermediate filaments that support the nuclear membrane/gives it structure
Centrosome:
Spindle fibers that segregate chromosomes in mitosis or meiosis
Ribosomes:
Synthesize RNA into protein in the RER
Microtubules:
- Highway of cell
- Responsible for movement of cilia and flagella
- Maintains shape of eukaryotic cells
How do we get things in and out of the nucleus?
DNA goes through nuclear pores that selectively allows you take things inside and outside the nucleus
Prokaryotic ribosomes:
70s
Eukaryotic ribosomes:
80s
60S + 40S=
80S ribosomal subunits
When vesicle pinches off from the RER, where does it go?
Cys side of golgi apparatus
Mitochondria:
5
- Powerhouse of cell, makes ATP for cell
- Comes from prokaryotic cells
- Has 70S ribosomes, like bacteria
- Has their own DNA
- Creates cristae to increase surface volume
Plasma membrane:
4
- Mobile, not static
- Composed of lipid bayer and embedded proteins
- Contains cholesterol that maintains membrane (IN EUKARYOTIC ONLY)
- Contains glycoproteins and glycolipids that recognize other cells or pathogens
Prokaryotic and eukaryotic cells have the same:
PHOSPHOLIPID BILAYER
Eukaryotic plasma membrane performs:
Simple, facilitated, and active transport
3 processes that are SPECIFIC to eukaryotic cells:
Phagocytosis, pinocytosis, and receptor-mediated endocytosis
Extracellular matrix:
- Allows for external stress to be reduced on cells
- Acts as anchor for the cell
Microfilaments:
-Responsible for amoeboid movement, contractile ring formation, and pinching off ring
Intermediate filaments:
- Permeable
- Composed of various proteins
- Cell-to-cell contact
Subunit of microfilaments:
Actin
Subunit of microtubules:
Tubulin
Subunit of intermediate filaments:
Composed of various proteins such as keratin
Vesicular transport:
Membrane bound packets of protein made by the RER that are picked up by the golgi apparatus
Cilia:
Captures particules entering the airway and moves upwards out of airway
Dynein:
2
- Protein in tubule that walks along microtubules using ATP
- Takes mitochondria in cell where ATP is needed
Cilia is made up of:
Microtubules
Flagella movement in prokaryotic cells?
Run and tumble
Flagella movement in eukaryotic cells?
Whipping
3 domains and which types of bacteria in each?
- Archaea- prokaryotic
- Bacteria- prokaryotic
- Eukarya- eukaryotic
Endocytosis:
Selective of what we bring inside the cell
Phagocytosis:
Brings in food particles via ameboid movement
Pinocytosis:
Pulls in extracellular fluid for osmotic pressure
What happens to a cell in a hypertonic soln?
A soln that has a HIGHER solute conc. -> cell crenates
What happens to a cell in a hypotonic soln?
A soln that has a LOWER solute conc. -> cell lyses/swells
What happens to a cell in a isotonic soln?
No net movement of water particles-> overall conc. on both sides of cell membrane remains constant
Define tonicity:
Describes amount of particles in soln compared to the cell
Slime layer made of:
Glycocalyx and proteins
Osmosis:
Movement of water from HIGH-> LOW concentration
NAP:
DNA in prokaryotic cells interacts with NAPS (nucleoid associated proteins) which helps organize the DNA
Nucleoid:
Dense region of DNA in prokaryotic cell
3 variants of the cell wall:
- Gram negative
- Gram positive
- Acid-fast
Gram negative:
inner to outer
- Inner membrane
- Periplasmic space
- Thin peptidoglycan cell wall
- Lipoprotein
- Outer membrane
- LPS endotoxin
- Harder to treat with abx
Acid fast:
Absorbed by mycolic acid which acts as a waxy coat
Gram positive:
inner to outer
- Inner plasma membrane
- Thick peptidoglycan cell wall
- Teichoic acid: gives rigidity and allows to bind to host cells glycoproteins
- Acid fast stain on outside
- Easier to treat with abx
Gram negative structure:
- 5 proteins horizontally and 4 proteins vertically
- Peptidoglycan crosslink
What membrane bound organelles do eukaryotes have?
Nucleus, mitochondria, golgi, ER
How does osmosis work in cells that do not have a cell wall?
In cells that lack a cell wall, changes in osmotic pressure can lead to crenation in hypertonic environments or cell lysis in hypotonic environment
ALL gram negative have:
LPS that sticks out on outer membrane
Gram positive structure:
- 4 proteins vertically only
- Direct link from tetra to tetra
- No peptidoglycan cross link
