Cell Structure and Function Flashcards
(27 cards)
What are the three main components of a cell?
Plasma membrane, cytoplasm, nucleus.
What is the function of the plasma membrane?
Separates the intra and extracellular environments, regulates molecule movement, facilitates communication, and provides structural support.
What is cytoplasm composed of?
Cytosol (intracellular fluid) and organelles.
What is the function of the nucleus?
Controls cellular processes and contains DNA.
What is the structure of the plasma membrane?
A phospholipid bilayer with embedded proteins, cholesterol, and receptors.
What are the hydrophobic and hydrophilic parts of the membrane?
- Hydrophilic head (faces extracellular/intracellular fluids).
Hydrophobic/lipophilic tail (faces inward, away from water).
What are cellular receptors?
Proteins on the cell surface or inside the cell that receive signals and trigger physiological responses.
What is the function of the mitochondria?
Produces ATP (energy); known as the “powerhouse of the cell.”
What is the function of the rough endoplasmic reticulum (RER)?
Synthesizes and folds proteins; associated with ribosomes.
What is the function of the smooth endoplasmic reticulum (SER)?
Synthesizes lipids, steroids, and detoxifies drugs/alcohol.
What is the function of the Golgi apparatus?
Modifies, stores, and packages proteins for transport.
What is the function of lysosomes?
Contain digestive enzymes that break down cellular waste and pathogens.
What is the function of ribosomes?
Translate mRNA into proteins; can be free-floating or attached to the RER.
What is the function of the cytoskeleton?
Provides structural support and helps in cell movement.
What are the three types of cytoskeletal filaments?
Microtubules, intermediate filaments, microfilaments.
What are cilia and microvilli?
- Cilia: Hair-like projections that move substances across cell surfaces.
- Microvilli: Membrane extensions that increase surface area for absorption.
What is a ligand?
A chemical messenger that binds to a receptor to produce a cellular response.
What are the four main types of receptors?
Ion channels, G-protein coupled receptors (GPCRs), enzyme-linked receptors, intracellular receptors.
How do ion channel receptors function?
They open or close to regulate ion movement across the membrane, influencing processes like neurotransmission and muscle contraction.
How do G-protein coupled receptors (GPCRs) work?
Ligand binding activates a G-protein, which triggers intracellular signaling pathways.
How do receptor tyrosine kinases (RTKs) initiate a response when the receptor is acted upon?
Ligand binding causes dimerization and phosphorylation, leading to cell signaling cascades (e.g., insulin receptor).
How do intracellular receptors work?
Located in the cytoplasm or nucleus; when bound by a ligand, they influence gene transcription.
Why do cells have different structures?
Their structure is specialized for their function in the body.
How is a fibroblast specialized?
Produces collagen for connective tissues; has abundant RER and Golgi.
