Biology Chapter: Transport Mechanisms

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Questions and Answers

What is the primary energy source utilized in active transport mechanisms?

FADH2

ATP (correct)

NADH

Glucose

Which statement accurately describes a concentration gradient?

It is unaffected by changes in temperature.

It signifies the difference in concentration across a space. (correct)

It drives the movement of molecules from low to high concentration.

It represents equal distribution of molecules throughout a space.

How do phagocytosis and pinocytosis differ?

Phagocytosis involves liquid intake, while pinocytosis involves solid particles.

Both processes involve the same mechanism of transport.

Phagocytosis engulfs large particles, whereas pinocytosis engulfs small particles and fluids. (correct)

Phagocytosis is carried out by all cells, while pinocytosis is limited to specific cells.

What effect does a hypertonic solution have on a cell?

Water leaves the cell, leading to shrinkage. Signup and view all the answers

What is the significance of osmosis in cellular processes?

It maintains cell volume and nutrient uptake. Signup and view all the answers

What fundamental difference exists between prokaryotic and eukaryotic cells?

Prokaryotic cells lack membrane-bound organelles unlike eukaryotic cells. Signup and view all the answers

What role do ribosomes play in a cell?

They translate genetic codes into proteins. Signup and view all the answers

What does the endosymbiont theory propose?

Mitochondria and chloroplasts originated as free-living prokaryotic cells. Signup and view all the answers

What is the main role of the Golgi apparatus in eukaryotic cells?

Modification and packaging of proteins Signup and view all the answers

Which component of the cytoskeleton is primarily involved in cell division?

Microtubules Signup and view all the answers

What process describes the uptake of large particles by a cell?

Phagocytosis Signup and view all the answers

Which of the following is a characteristic feature of eukaryotic cells?

Containment of a nucleus Signup and view all the answers

What happens to a cell in a hypotonic solution?

The cell bursts due to water influx Signup and view all the answers

What is the primary function of ribosomes in a cell?

Synthesis of proteins Signup and view all the answers

Which type of junction is responsible for direct communication between neighboring cells?

Gap junctions Signup and view all the answers

What is the significance of glycosylation in protein processing?

Adds carbohydrates to proteins for identification and signaling Signup and view all the answers

What role do integrins play in cellular function?

They facilitate cell-ECM adhesion and signaling Signup and view all the answers

What defines action potential in neurons?

An electrical signal traveling along a neuron's membrane Signup and view all the answers

Which of the following best describes the extracellular matrix (ECM)?

A complex network of proteins and carbohydrates providing support Signup and view all the answers

What is a primary function of the endoplasmic reticulum (ER)?

Protein and lipid synthesis Signup and view all the answers

How do microfilaments contribute to cell function?

They facilitate muscle contraction and cell motility Signup and view all the answers

What distinguishes a prokaryotic cell from a eukaryotic cell?

Eukaryotic cells possess membrane-bound organelles Signup and view all the answers

Study Notes

Active vs. Passive Transport

Active transport moves molecules against their concentration gradient, requiring energy (ATP). Example: sodium-potassium pump.
Passive transport moves molecules along their concentration gradient, without energy input. Example: oxygen diffusion across cell membranes.

Concentration Gradient & Diffusion

A concentration gradient is the difference in concentration of a substance across a space.
This difference drives diffusion, which is the natural movement of molecules from high to low concentration until equilibrium is reached.

Phagocytosis vs. Pinocytosis

Phagocytosis ("cell eating") involves engulfing large particles, like bacteria by white blood cells.
Pinocytosis ("cell drinking") involves taking in small particles and fluids, such as nutrient absorption by intestinal cells.

Hypertonic Solution Effects

A hypertonic solution has a higher solute concentration than the cell.
This causes water to leave the cell through osmosis, leading to cell shrinkage (crenation).

Osmosis

Osmosis is the diffusion of water across a selectively permeable membrane from a region of low solute concentration to a region of high solute concentration.
It is crucial for maintaining cell volume, nutrient uptake, and waste removal.

Prokaryotic vs. Eukaryotic Cells

Prokaryotic cells lack a nucleus and membrane-bound organelles.
Eukaryotic cells possess a nucleus and membrane-bound organelles , and are generally larger and more complex.

Ribosomes

Ribosomes are essential for protein synthesis.
They translate genetic code from mRNA into amino acid sequences to build proteins.

Endosymbiont Theory

The endosymbiont theory proposes that mitochondria and chloroplasts originated as free-living prokaryotic cells that were engulfed by ancestral eukaryotic cells.
Supporting evidence includes their double membranes, unique circular DNA, and ribosomes similar to prokaryotes.

Golgi Apparatus

The Golgi apparatus modifies, sorts, and packages proteins and lipids received from the endoplasmic reticulum.
It adds carbohydrates to proteins (glycosylation), and sorts them for transport to other organelles or secretion outside the cell.

Cytoskeleton Components

The cytoskeleton is composed of microfilaments (actin filaments) responsible for muscle contraction and cell motility.
Intermediate filaments provide structural support and maintain cell shape.
Microtubules are involved in cell division and intracellular transport.

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Description

Explore the key concepts of active and passive transport, as well as phagocytosis and pinocytosis in this quiz. Understand how concentration gradients influence diffusion and the effects of hypertonic solutions on cells. Test your knowledge on these fundamental biological processes!