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(3.4-3.6)
(3.4)
What is the structure and function of the prokaryotic chromosome?
They’re SINGLE, CIRCULAR DOUBLE-STRANDED DNA molecule that CONTAINS ALL GENETIC INFORMATION NEEDED BY A CELL (or other information that’s not need
It REPLICATES WITH THE GENOME
A genome is the complete set of DNA
PASSED DOWN DURING CELL DIVISION
They’re the MAIN DNA FOR REPLICATION, GROWTH, AND SURVIVAL
What is a nucleoid?
A REGION OF A PROKARYOTIC CELL THAT CONTAINS THE DNA
What are plasmids? What role do plasmids play in bacterial antibiotic resistance?
They’re EXTRA DNA MOLECULES that REPLICATES INDEPENDENTLY OF THE CHROMOSOME
DOESN’T CARRY GENETIC INFORMATION
HELPS WITH RESISTANCE AND DEFENCE (and gene transfer)
They help create enzymes that destroy some antibiotics (which allows them to resist medication)
How can plasmids spread between bacterial cells, and what implications does this have for antibiotic resistance?
It TRANSFERS A COPY OF A PLASMID TO ANOTHER CELL (CONJUGATION) which iNCREASES ANTIBIOTIC-RESISTANT BACTERIA
What are ribosomes? What is the structure of prokaryotic ribosomes, and how do they differ from eukaryotic ribosomes?
These are INVOLVED IN PROTEIN SYNTHESIS
They’re like the FACTORIES THAT MAKES PROTEINS
They’re REFERRED TO AS 70S (For PROKARYOTIC RIBOSOMES)
Why is the difference between prokaryotic and eukaryotic ribosomes medically significant?
ANTIBIOTICS THAT IMPACT THE 70S RIBOSOME DON’T EFFECT 80S (the eukaryotic ribosomes) AND VICE VERSA
Antibiotics that impact 70S don’t affect 80S
Antibiotics that impact 80S don’t affect the 70S ribosomes
What are cytoskeletons?
The INTERIOR PROTEIN THAT PROVIDES STRUCTURE AND SUPPORT
**Relate and define the cell membrane, cell wall, and cytoskeleton and how does each relate to each other
What are endospores, and what makes them so resilient to extreme conditions?
Endospores are DORMANT CELLS MADE BY CERTAIN BACTERIAS TO HELP IT SURVIVE HARSH ENVIRONMENTS
Endospores STOP METABOLIC PROCESSES which makes it DORMANT, allowing it to SURVIVE LONGER
What is a vegetative cell?
It’s a cell that AFTER SURVIVING HARSH CONDITIONS, it EXITS from its DORMANT STATE and BECOMES A TYPICAL MULTIPLYING CELL
What is sporulation? What triggers the process of sporulation in endospore-forming bacteria?
Sporulation is ENDOSPORE FORMATION
It’s triggered when ENDOSPORE-FORMING BACTERIA EXPERIENCE LIMITING AMOUNTS OF CARBON OR NITROGEN
Describe the steps involved in sporulation, including the formation of the septum and the roles of the two compartments.
When it starts, the CELL STOPS GROWING AND DUPLICATES DNA
Then a SEPTUM FORMS — this will DIVIDE THE CELL ASYMMETRICALLY
LARGER compartment (the “mother cell”) ENGUFS SMALL COMPARTMENT which FORMS DOUBLE MEMBRANE (they each have their own roles in creating endospore)
The SMALL compartment BECOMES A FORE-SPORE (which becomes the core of the endospore)
MOTHER CELL DEGRADES, ENDOSPORE IS RELEASED
How do the various layers of the endospore protect it from damage?
The CORTEX of the endospore PROTECTS IT FROM EFFECTS OF HEAT
The core of the endospore has a PROTEIN that BINDS TO DNA and PROTECTS FROM DAMAGE
What is germination? How is the process of germination triggered, and what are the key steps involved?
It’s when an ENDOSPORE EXITS DORMANT STATE and BECOMES A VEGETATIVE CELL
It starts to germinate when it’s EXPOSED TO CERTAIN CHEMICALS
When it becomes exposed, the endospore absorbs water and it swells, then the vegetative cell grows out
How does the core wall transform during the process of germination?
The core wall BECOMES A PEPTIDOGLYCAN LAYER of the VEGETATIVE CELL
(3.5)
What are organelles? What is the function of it?
A CELL STRUCTURE that has ONE OR MORE SPECIFIC JOBS in the cell
There are different kinds of organelles in the eukaryotic cell (NOT PROKARYOTES cause those don’t have membrane-bound organelles)
It allows the cell to PERFORM COMPLEX FUNCTIONS IN SEPARATED AREAS
Which organelle contains the cell's genetic information?
The NUCLEUS
How do protozoa and animal cells differ from fungi and plant cells in terms of their structural features?
Animal cells and Protozoa DON’T HAVE CELL WALLS
Fungi and Plant cells HAVE CELL WALLS
How is the structure of the eukaryotic cytoplasmic membrane similar to that of prokaryotic cells?
It has a CYTOPLASMIC MEMBRANE
What role do membrane proteins play in cellular processes?
It could be INVOLVED IN TRANSPORT or MAINTAIN CELL INTEGRITY
What is a receptor and ligand? How do receptor-ligand interactions contribute to cell communication?
Receptors: PROTEINS on CELL SURFACE that BINDS TO LIGANDS TO TRIGGER RESPONSES
Ligand: Thing that BINDS TO RECEPTORS
Contributes to cell communication through SIGNALING
The ligands are the “messages” that CONNECT to the receptors and tells them what to do so that they could execute the action
What are aquaporins?
They are PROTEINS that acts as a WATER CHANNEL IN CELL MEMBRANES
helps MAINTAIN WATER BALANCE IN CELLS, tissues, and organs
What are channels?
PROTEINS that ALLOWS SPECIFIC IONS OR SMALL MOLECULES TO EXIT/ENTER the cell
It can open or close based on the environment that it’s it
If there’s too much of something, it might not allow that certain ion/molecule to pass through (which means that it would be closed)
Notice how the channel proteins can just let certain molecules in/out FREELY
What are carriers?
PROTEINS that BIND TO SPECIFIC MOLECULES and ACTIVELY TRANSPORT THEM THROUGH THE CELL MEMBRANES
These bind to a molecule/ions, change it’s shape, then transports it through the cell membrane
What are the different types of transport proteins in eukaryotic cells, and how do they facilitate movement across the cytoplasmic membrane?
It’s AQUAPORINS, CHANNELS, OR CARRIERS
Aquaporins allow water to pass through
Channels allow small molecules/ions to let them IN/OUT of the cell membrane FREELY
Carrier take a SPECIFIC MOLECULE/ION, change its shape, then transport it
Does some kind of modification
⭐️ How does facilitated diffusion differ in multicellular organisms compared to unicellular organisms? (Look at bio notebook)
For PROKARYOTES, it RARELY USES FACILITATED DIFFUSION because the inside has high concentration of solutes, making facilitated diffusion useless
For EUKARYOTES, on the other hand, it MUST USE FACILITATED DIFFUSION because of their LARGER SIZE and how it ALLOWS HARDER-TO-PASS MOLECULES to MOVE ACROSS THE MEMBRANE
It’s much more complex to move nutrients in/out of a eukaryote, that’s why they use facilitated diffusion
What is the role of endocytosis in the cell? What are different types of endocytosis (3 — PRP)?
Endocytosis is a process where a CELL ENGULFS LARGE SUBSTANCES (that won’t pass through a transport protein) BY SURROUNDING THEM WITH ITS MEMBRANE, which creates a VESICLE TO BRING INSIDE
There’s pinocytosis
Receptor-mediated endocytosis
Phagocytosis
What is pinocytosis?
It’s a type of endocytosis that TAKES IN LIQUIDS AND ANY DISSOLVED SUBSTANCES
It’s like it’s DRINKING and taking in the liquids
What is receptor-mediated endocytosis?
it’s a type of endocytosis where SPECIFIC MOLECULES BIND to RECEPTORS and TRIGGERS FORMATION OF VESICLE AND GETS ENGULFED (and it’s surrounded by membrane, forming a vesicle)
What is phagocytosis?
Type of endocytosis where a CELL ENGULFS LARGE PARTICLES (like bacteria) TO DIGEST THEM AND BREAK IT DOWN
ETC: white blood cells eats and destroys harmful bacteria
When looking at the photo, we can see that after eating the large particles, it breaks it up and lets it go
PHAGOCYTES (cell type of the body’s defense system)USE THIS
What is exocytosis? How is it different from endocytosis?
Exocytosis is when CELLS “THROW UP” MATERIALS
instead of swallowing small molecules or ions (endocytosis), exocytosis is throwing it up
When thinking about “EXO” you want to THROW UP because of how hot the members are
They EXPEL THINGS TO REMOVE WASTE AND RELEASE IMPORTANT MOLECULES
(3.6)
What are ribosomes?
Ribosomes CREATE PROTEINS by ASSEMBLING AMINO ACIDS DURING TRANSLATION
Ribosomes are created my the NUCLEOLUS
What’s the difference between eukaryotic and prokaryotic ribosomes? Why’s it medically relevant?
Eukaryotic ribosomes are made of 80S (made of 60S and 40S subunits) while the prokaryotic ribosomes are 70S
It’s medically important because scientists can create an antibiotic that can kill a bacteria (the prok) without harming the animal cells (the Euk)
So basically, things that affect the prok ribosomes STRUCTURALLY WONT AFFECT EUK RIBOSOMES
What is a cytoskeleton? What are the THREE main compartments of the sky cytoskeleton? (“MIA”)
Cytoskeleton is the INTERNAL STRUCTURE that ACTS AS SOMETHING THAT GIVES IT SHAPE AND STRUCUTRE
There are:
Microtubules
Intermediate filaments
Actin filaments
What is a microtubules? Why are microtubules essential for cell division?
Microtubules are like the TRAIN TRACKS WHICH ALLOWS MOLECULES TO TRAVEL TO DIFFERENT AREAS WITHIN THE CELL with the help of motor proteins
it HELPS KEEP SHAPE AND DIVIDE PROPERLY
MOTOR PROTEINS HELP FACILITATE THIS TRAVEL
They are essential for cell division because microtubules CREATE MITOTIC SPINDLES WHICH DIVIDES DUPLICATED CHROMOSOMES
No mitotic spindles → no cell reproduction
What are intermediate filaments? What function do intermediate filaments serve in a cell?
Intermediate filaments are structures in eukaryotic cell that STRENGTHEN THE CELL MECHANICALLY.
It gives MECHANICAL SUPPORT which ALLOWS CELLS TO RESIST PHYSICAL STRESS
What are actin filaments? How do actin filaments contribute to cell movement?
CYTOSKELETAL STRUCTURES (of euk cells) that ALLOW MOVEMENT WITHIN CELL and SHAPE CHANGES
The actin ASSEMBLE AND DISASSEMBLE QUICKLY TO CREATE FORCE TO DRIVE MOTION
What is a cilia?
SHORT, HAIR-LIKE STRUCTURES that MOVE TO HELP WITH MOVEMENT
How is the structure of a eukaryotic flagellum different from its prokaryotic counterpart?
Eukaryotic flagellum USES ATP AS A SOURCE OF ENERGY while Prokaryotic flagellum uses PMF (proton motive force)
Unlike PF where the flagella ROTATES (acting like a helicopter propeller) to go to a different direction, EF MOVES USING A WHIP-LIKE MOTION (smooth, blinding motion)
When looking at the photo, the PF looks more like a slump dick (which could be rotated around) while the EF looks like a hard boner (it moves like a whipping motion)
The flagella for EUKARYOTES ARE 9+2 ARRANGEMENT
9 pairs of microtubules surrounded by 2 individual microtubules
What is the difference between the protein structures of a eukaryotic cell and prokaryotic cell?
Eukaryotes have:
CYTOSKELETON - it's more well developed
FLAGELLA (that are more like a hard dick than a limp one — this allows for the flagella to move in a “whip” motion
CILIA
80S ribosome
