Cell membranes and Physiology

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Questions and Answers

What is the function of microfilaments in a muscle cell?

To form a cellular scaffolding

To generate lots of force (correct)

To crawl and explore the environment

To sense important stimuli

Which protein monomer forms microtubules?

Dynein

Actin

Myosin

Tubulin (correct)

What is the primary cilium's function?

To form a cellular scaffolding

To crawl and explore the environment

To generate force

To sense important stimuli (correct)

Which protein can 'walk' and advance along microfilaments?

Myosin Signup and view all the answers

What is the function of intermediate filaments?

To confer stability to cells Signup and view all the answers

Which intermediate filament is found in muscle cells and some epithelial cells?

Desmin Signup and view all the answers

Where are keratins primarily found?

In epithelial cells, hair, and nails Signup and view all the answers

Which intermediate filament confers stability and structure to glial cells?

Vimentin Signup and view all the answers

What is the function of neurofilaments?

To provide strength across the cell Signup and view all the answers

What is responsible for the shape of microvilli?

Actin filaments Signup and view all the answers

Which of the following is NOT a function of membrane proteins?

Cellular movement Signup and view all the answers

What is the purpose of tight junctions in cells?

To regulate movement across membranes Signup and view all the answers

Which of the following is NOT a component of an anchoring junction?

Microfilaments Signup and view all the answers

What is the function of microfilaments in the cytoskeleton?

Structural organization of the plasma membrane Signup and view all the answers

What factors contribute to the stability of F-actin in microfilaments?

Capping proteins Signup and view all the answers

Which type of lipid has a sphingosine backbone instead of a glycerol backbone?

Sphingolipids Signup and view all the answers

Which type of lipid is a type of steroid and can intercalate between phospholipids?

Cholesterol Signup and view all the answers

Which type of lipid impacts membrane fluidity depending on its amount?

Cholesterol Signup and view all the answers

Which type of lipid has sugar residues and can contribute to the glycocalyx?

Sphingolipids Signup and view all the answers

Which type of lipid has a phosphate 'head' linked to another molecule?

Glycerophospholipids Signup and view all the answers

Which type of transport requires the hydrolysis of ATP?

Active transport Signup and view all the answers

What is the main function of aquaporins in the plasma membrane?

To allow water molecules to traverse the membrane Signup and view all the answers

What is the role of the Na+/K+ ATPase in preventing cell swelling?

All of the above Signup and view all the answers

What is the diffusional force that drives sodium into the cell?

The high concentration of sodium in the extracellular fluid Signup and view all the answers

What is the main function of the membrane surrounding organelles in the cell?

To control the environment needed for its specific function Signup and view all the answers

Which of the following is true about the formation of micelles and bilayers in the cell membrane?

Bilayers are more thermodynamically favorable than micelles Signup and view all the answers

What is the main function of the phospholipid bilayer in the cell membrane?

Serving as a barrier to the movement of molecules Signup and view all the answers

Which of the following is true about the integrity of the plasma membrane?

It is important for cellular movement and shape Signup and view all the answers

Which membrane-bound components might have more cholesterol and/or sphingolipids?

Golgi and ER Signup and view all the answers

Study Notes

Muscle Cell Microfilaments

Microfilaments provide structural support and facilitate muscle contraction through interaction with myosin.

Microtubule Formation

Tubulin is the protein monomer that forms microtubules.

Primary Cilium Function

The primary cilium acts as a sensory organelle, playing a key role in signal transduction for the cell.

Protein Movement Along Microfilaments

Myosin can 'walk' and advance along microfilaments, crucial for muscle contraction and other cellular movements.

Intermediate Filaments Functions

Intermediate filaments provide mechanical strength and help maintain the integrity of cell structure.

Muscle Cell Intermediate Filament

Desmin is the intermediate filament found in muscle cells and some epithelial cells, important for maintaining muscle integrity.

Keratin Location

Keratins are primarily found in epithelial tissues, providing resilience and protection.

Intermediate Filament in Glial Cells

GFAP (Glial Fibrillary Acidic Protein) confers stability and structure to glial cells in the nervous system.

Neurofilament Function

Neurofilaments provide structural support specifically to neurons, playing a critical role in maintaining axonal diameter.

Microvilli Structure

Actin filaments are responsible for the shape and structure of microvilli, increasing the surface area for absorption.

Membrane Protein Functions

Functions of membrane proteins include transport, signaling, and structural support; however, not all proteins directly contribute to intercellular communication.

Tight Junctions Purpose

Tight junctions prevent the passage of materials between cells, maintaining a selective barrier and controlling the paracellular pathway.

Anchoring Junction Components

Components of anchoring junctions typically include cadherins and cytoskeletal connections; not all elements categorized under this junction contribute directly to mechanical support.

Microfilaments in Cytoskeleton

Microfilaments in the cytoskeleton help maintain cell shape, facilitate movement, and enable cell division.

F-actin Stability Factors

The stability of F-actin in microfilaments is influenced by nucleotide binding, regulatory proteins, and cross-linking with other proteins.

Sphingosine Backed Lipids

Sphingolipids have a sphingosine backbone instead of a glycerol backbone, playing significant roles in membrane stability and signaling.

Steroid Lipid Type

Cholesterol is a type of steroid lipid that can intercalate between phospholipids, influencing membrane fluidity.

Lipid Impact on Membrane Fluidity

Phospholipids, particularly when saturated or unsaturated, impact the fluidity of membranes depending on their concentration.

Glycocalyx Contribution

Glycolipids have sugar residues and contribute to the glycocalyx, which plays a role in cell recognition and protection.

Phospholipid Structure

Phospholipids consist of a phosphate 'head' linked to fatty acid tails, forming a fundamental component of cell membranes.

ATP Hydrolysis Transport

Active transport requires the hydrolysis of ATP to move substances against their concentration gradient.

Aquaporin Function

Aquaporins facilitate the rapid transport of water across the plasma membrane, crucial for maintaining osmotic balance in cells.

Na+/K+ ATPase Role

The Na+/K+ ATPase prevents cell swelling by actively transporting sodium out of the cell and potassium into the cell, maintaining osmotic balance.

Sodium Diffusional Force

The electrochemical gradient acts as the diffusional force that drives sodium into the cell.

Organelle Membrane Function

The membrane surrounding organelles helps compartmentalize cellular processes, providing distinct environments for biochemical reactions.

Micelle and Bilayer Formation

Micelles and bilayers form due to the amphipathic nature of lipids, where hydrophobic tails cluster together away from water while hydrophilic heads face outward.

Phospholipid Bilayer Function

The main function of the phospholipid bilayer is to create a barrier that separates the interior of the cell from the external environment, enabling selective permeability.

Plasma Membrane Integrity

The integrity of the plasma membrane is maintained through lipid bilayer structure and membrane-bound proteins working cooperatively to resist hydrophilic and hydrophobic forces.

Cholesterol and Sphingolipid Presence

Membrane-bound components such as lipid rafts might have higher concentrations of cholesterol and/or sphingolipids, impacting fluidity and signaling.

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Description

Test your knowledge on membrane proteins and their wide range of functions in this quiz. Explore their role in signaling, transport, homeostasis, protection, and cell structure. Get ready to dive into the fascinating world of anatomy and physiology!