ASU MIC 205 PENTON EXAM 1 2024-2025 WITH
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Endocytosis and Exocytosis:
In endocytosis, the cell membrane engulfs material to bring it inside the cell, while exocytosis involves
vesicles fusing with the membrane to release materials outside the cell.
Endocytosis example
Phagocytosis, where immune cells like macrophages engulf bacteria or debris by wrapping the cell
membrane around them and forming a vesicle.
Exocytosis
Neurotransmitters are released from nerve cells into the synaptic cleft when vesicles containing these
signaling molecules fuse with the plasma membrane.
why do bacteria have to move molecules across the membrane
Nutrient uptake, waste removal, signal reception, Homeostasis, Energy production
What are the different transport proteins?
Channel Proteins, Carrier Proteins:, Pump Proteins, Symporters, Antiporters
How do channel proteins operate?
They form water-filled pores that allow specific ions or small molecules to pass through.
What determines whether channel proteins are open or closed?
They can be open all the time or gated, it opens or closes when it gets a signal like a physical pressure or
electrical voltage
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,What is the function of open channel proteins?
When open, they allow rapid movement of substances down their concentration gradient through
facilitated diffusion.
How do carrier proteins operate?
Carrier proteins bind to specific molecules then they change shape to fit through the channel and gets
dropped off inside
What happens to carrier proteins after binding a molecule?
The protein changes shape (conformational change), allowing the molecule to be released on the other
side of the membrane.
What are the two types of processes involving carrier proteins?
The process can be passive (facilitated diffusion) or active (requiring energy).
How do pump proteins operate?
Pump proteins actively transport ions or molecules against their concentration gradient.
What provides energy for pump proteins to function?
Pump proteins use energy from ATP hydrolysis to transport ions or molecules.
Can you give an example of a pump protein?
An example is the sodium-potassium pump, which moves Na⁺ out and K⁺ in.
how do Symporters operate
type of carrier protein (for example you drive 2 different friends (glucose, and sodium) to the store. It
takes 2 different things at once to the same place at the cell time (into the cell)
how do Antiporters: operate
Type of carrier protein (for example its like a se saw when one friend goes up the other goes down
against their concentration gradient) Uses energy to keep everything balanced
What is the main function of the plasma membrane?
The plasma membrane regulates the movement of substances into and out of the cell.
How does the plasma membrane maintain homeostasis?
by controlling what enters and exits the cell, using both passive and active transport.
How do bacteria reproduce? How is the cytoskeleton involved in this process?
Bacteria reproduce primarily through binary fission, where one cell divides into two identical cells. The
cytoskeleton aids in this process by helping to organize the cell's structure, ensuring proper division and
separation of genetic material.
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,What is the implication of bacteria not having a nucleus while eukaryotes do, in terms of transcription
and translation?
Bacteria don't have a nucleus, so they can make RNA and proteins right next to each other in the
cytoplasm at the same time
since eukaryotes have a nucleus they need to first make RNA in the nucleus, then move it to the
cytoplasm for protein production.
Bacteria can respond quicker to changes
Understand osmosis and tonicity (isotonic, hypertonic, hypotonic).
Osmosis is the movement of water across a semi-permeable membrane.
isotonic solutions: water movement is balanced
Hypertonic solutions: water moves out of the cell, causing it to shrink
hypotonic solutions water moves into the cell, causing it to swell.
What are the key structural parts of a prokaryote?
Plasma membrane, cell wall, ribosomes, genetic material
What is the function of the plasma membrane in a prokaryote?
Regulates transport
What is the function of the cell wall in a prokaryote?
Provides shape and protection
What is the function of ribosomes in a prokaryote?
ribosomes read MRNA to build amino acid chains that then later fold into proteins
What is the function of genetic material in a prokaryote?
Circular DNA
(INSTRUCTIONS FOR LIFE)
(helps in cell division, produces proteins, and allows for adaptation to new challenges!)
What are some additional structures that may be found in a prokaryote?
Flagella (movement) or pili (attachment)
What is the fluid mosaic model? Describe the composition of the cell membrane.
a flexible structure made up of a phospholipid bilayer, with proteins, carbohydrates, and cholesterol
embedded in it.
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, allows the membrane to be dynamic and functional, supporting various cellular processes.
What are the characteristics of staphylococcus versus streptococcus?
Staphylococcus is typically spherical (cocci), forms clusters, and is catalase-positive. Streptococcus is also
spherical but forms chains and is catalase-negative. Their arrangements influence pathogenicity and
identification.
What is the role of peptidoglycan and composition?
Peptidoglycan provides structural support to bacterial cell walls, preventing lysis. It consists of a polymer
of sugars (Nag and nam).
What are the two types of glycocalyxes?
Capsules and slime layers
What is the advantage of capsules in glycocalyxes?
Capsules help bacteria evade the immune system by masking antigens
They cover the bacteria serving as a protective layer to the bacteria
What is the advantage of slime layers in glycocalyxes?
Slime layers aid in adhesion and biofilm formation, enhancing survival and resistance to antibiotics
What are the characteristics of a microbial flagella?
long, whip-like structures made of proteins that enable motility by rotating or waving,
allowing bacteria to move toward or away from stimuli in their environment.
How does the flagella move and howdo the bacteria move? Compare to flagella in eukaryotes.
Bacterial Flagella: Rotate like a propeller, using proton gradients for energy, allowing bacteria to swim in
liquid environments.
Eukaryotic Flagella: Move in a wave-like manner, powered by ATP, found in cells like sperm.
What is an endoflagella? What movement characteristics are induced by an endoflagella?
between the cell membrane and outer membrane
endoflagella are internal flagella that help certain bacteria move in a corkscrew fashion, making it easier
for them to move through dense environments.
How does the shape of a bacteria possibly help in infection?
The shape of bacteria, such as rods or spirals, can enhance their ability to invade host tissues and evade
immune responses. For example, spiral-shaped bacteria can burrow into tissues more effectively.
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