LEC EXAM #1 CHP. 3 Flashcards
(70 cards)
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
