introduction to cells part 1

Question 1

Cell membrane

structure
function
importance

Answer 1

Cell Membrane (Plasma Membrane)
Structure: Composed of a phospholipid bilayer with embedded proteins, cholesterol, and carbohydrates.

Function: Acts as a semi-permeable barrier, controlling the entry and exit of substances, which is essential for maintaining the cell’s internal environment.

Relevance in Pharmacy: The cell membrane’s structure allows selective drug targeting. For example, some drugs are designed to bind to membrane receptors (like G-protein coupled receptors) to activate or inhibit specific cellular responses.

Question 2

nucleus

structure
function
importance in pharmacy

Answer 2

Structure: Enclosed by a double membrane (nuclear envelope) with nuclear pores that regulate molecule exchange. Contains chromatin (DNA + proteins) and a nucleolus, where ribosomal RNA is produced.

Function: The nucleus houses genetic material (DNA) and controls gene expression, cell division, and protein synthesis.

Relevance in Pharmacy: Some drugs (like certain cancer therapies) target DNA or gene expression processes within the nucleus to inhibit cell growth or promote cell death.

Question 3

ribosome

Answer 3

Ribosomes
Structure: Composed of RNA and proteins, either free-floating in the cytoplasm or attached to the rough ER.

Function: Sites of protein synthesis, where mRNA is translated into amino acid chains.

Relevance in Pharmacy: Some antibiotics specifically target bacterial ribosomes to inhibit protein synthesis, leveraging differences between bacterial and human ribosomes to avoid harming human cells.

Question 4

endoplasmic recticulum
RER
SER

Answer 4

(RER)

Structure: Covered with ribosomes, giving it a “rough” appearance.

Function: Synthesizes proteins that are either secreted from the cell, inserted into the cell membrane, or shipped to specific cell compartments.

Smooth ER (SER):
Structure: Lacks ribosomes, appears smooth.

Function: Synthesizes lipids, detoxifies certain chemicals, and stores calcium ions.

Relevance in Pharmacy: The ER plays a crucial role in drug detoxification and lipid synthesis. Drugs that affect protein synthesis (like antibiotics in bacteria) often target processes similar to those in the RER.

Question 5

Golgi Apparatus

Answer 5

Structure: A stack of flattened, membrane-bound sacs called cisternae.

Function: Modifies, sorts, and packages proteins and lipids for secretion or for use within the cell.

Relevance in Pharmacy: The Golgi is involved in the final steps of protein modification, affecting how drugs are processed, activated, or transported within cells.

cis faces the rer and trans face is towards the membrane

Question 6

mitochondria

Answer 6

Outer Membrane: A semi-permeable barrier with porins, allowing selective passage of small molecules and ions into the mitochondrion.

Intermembrane Space: The space between the outer and inner membranes, where protons are stored to create an electrochemical gradient for ATP production.

Inner Membrane: Impermeable and folded into cristae, it houses the electron transport chain (ETC) and ATP synthase for efficient ATP production.
Cristae: Folds of the inner membrane that increase surface area, maximizing the space for respiratory enzymes essential to ATP synthesis.

Matrix: Contains enzymes for the citric acid cycle, mitochondrial DNA (mtDNA), and ribosomes; critical for energy production and independent protein synthesis.

Mitochondrial DNA (mtDNA): Circular DNA in the matrix that encodes essential mitochondrial proteins and is susceptible to mutations linked to diseases.

Pharmacological Relevance: Mitochondria are targets in drug development for energy disorders, cancer, and mitochondrial toxicity, as they regulate ATP production and apoptosis (programmed cell death).

Question 7

cytoplasm

Answer 7

Structure: The jelly-like fluid (cytosol) within the cell that holds all organelles in place.

Function: Provides a medium for biochemical reactions and helps in transporting molecules within the cell.

Relevance in Pharmacy: The cytoplasm is the site for many cellular processes affected by drugs, including those impacting enzymes and ion channels.

Question 8

lysosome

Answer 8

Lysosomes
Structure: Small, membrane-bound organelles containing hydrolytic enzymes.

Function: Break down cellular waste, old organelles, and foreign particles via enzyme action.

Relevance in Pharmacy: Lysosomal storage disorders are caused by enzyme deficiencies, which some drugs are designed to treat. Additionally, certain drug delivery systems are engineered to release drugs within lysosomes.

Question 9

cytoskeleton

Answer 9

Cytoskeleton
Structure: Composed of microfilaments (actin), intermediate filaments, and microtubules.

Function: Provides structural support, facilitates cell movement, and plays a role in intracellular transport.

Relevance in Pharmacy: The cytoskeleton is a target for certain drugs, such as anticancer agents that interfere with microtubules to inhibit cell division (e.g., paclitaxel).