Structure & Functions of the Cell Flashcards
What is the main function of the Golgi apparatus?
Protein modification, sorting, and secretion or degradation via the lysosomal pathway.
What are the components of the Golgi apparatus?
Membrane-bound compartments (flattened cisternae) interconnected in the perinuclear area.
What is the ER lumen?
The cisternal space of the endoplasmic reticulum.
What differentiates rough ER from smooth ER?
Rough ER is covered with ribosomes; smooth ER is not.
What are vesicles used for?
Transport molecules between different cellular compartments.
List the types of vesicles mentioned.
- Clathrin-coated
- Coat protein complex-I-coated
- Endocytotic
What are the functions of the cytoskeleton?
- Cellular transport
- Cell growth and division
- Cell differentiation
- Signal transduction
- Gene transcription
- Cell and organelle motility
- Cell shape maintenance
What are septin filaments?
Rod-like filaments formed by the polymerization of GTP-binding proteins.
What are microtubules?
Dynamic polar hollow cylinders involved in transport, structural support, and chromosome separation during cell division.
What are microfilaments composed of?
Solid polar rods made up of globular proteins called actin.
What role do intermediate filaments play in the cytoskeleton?
They confer mechanical strength to the cell.
What is the structure of the endoplasmic reticulum (ER)?
Dynamic membrane-bound organelle made up of flattened sacs and branching tubules.
What is cytosol?
The fluid portion of the cytoplasm.
What is the bilipid layer model?
A continuous spherical lipid bilayer formed by molecular forces.
Define the fluid mosaic model.
A model describing membranes as fluids with proteins embedded in or attached to the bilipid layer.
What are lipid translocators?
Proteins that facilitate the movement of lipids between the inner and outer leaflets of the membrane.
What is the dynamic fluid-mosaic model?
A model that emphasizes the nonrandom distribution of membrane proteins and lipids forming microdomains.
What are centrioles?
Barrel-shaped cylindrical organelles essential for chromosome movement during cell division.
What is the primary function of lysosomes?
Mediating the degradation of extracellular and intracellular particles.
What causes lysosomal storage diseases?
Mutations of the gene that codes for lysosomal enzymes.
What is the function of peroxisomes?
Perform degradative reactions, including beta oxidation of fatty acids and detoxification of reactive oxygen species.
What is the main function of mitochondria?
Converting oxygen and nutrients into energy (ATP synthesis).
What is the role of the nucleus?
Houses genetic material and is involved in intermediary metabolism, protein synthesis, and RNA synthesis.
What is the nucleolus?
The site of ribosome synthesis within the nucleus.
What genetic materials are found in the nucleus?
Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
What is transitional ER?
A region of the ER where secretory proteins are exported to the Golgi complex.
What are the functions of the ER?
- Quality control of secretory cargo proteins
- Protein processing
- Lipid metabolism
- Intracellular Ca2+ reservoir
What is the transitional ER?
A region of the ER where secretory proteins are exported to the Golgi complex.
What are the functions of the endoplasmic reticulum (ER)?
- Quality control sites in secretory cargo proteins (transitional ER)
- Site of protein processing (rough ER)
- Site of lipid metabolism (smooth ER)
- Intracellular Ca2+ reservoir.
Who introduced the Bilipid Layer Model?
Evert Gorter and François Grendel.
What is the orientation of phospholipids in a fluid medium?
The head (polar hydrophilic) is directed towards the fluid medium, while the tail (nonpolar hydrophobic) extends in the opposite direction.
What is the glycocalyx?
A carbohydrate-rich layer on the extracellular face of the plasma membrane, comprising glycoproteins, collagen proteins, proteoglycans, and mucopolysaccharides.
Define lipidome.
The entire lipid composition of the cells of an organism.
What are the three main groups of lipids in the plasma membrane?
- Phospholipids
- Glycolipids
- Cholesterol.
What are lipid rafts?
Small, heterogeneous, highly dynamic domains rich in sterols and sphingolipids that compartmentalize cellular processes.
What is the structure of a phospholipid molecule?
Composed of a hydrophilic head with attached hydrophobic acyl chains.
What are caveolae?
Flask-shaped membrane invaginations composed of integral and adaptor proteins.
What are peripheral membrane proteins?
Proteins associated with one leaflet of the bilayer, involved in signal transduction and anchoring the plasma membrane to the cytoskeleton.
True or False: Integral proteins span the membrane and are embedded in the lipid bilayer.
True.
What is the role of membrane proteins in signaling?
They translate extra- and intra-cellular cues into meaningful signals.
What does the term glycomics refer to?
The study of carbohydrates as information-encoding biological macromolecules.
Fill in the blank: The plasma membrane is composed of _______.
[phospholipids, proteins, cholesterol, carbohydrates]
What is the function of glycoproteins?
They are proteins conjugated to carbohydrate residues that can play roles in recognition and signaling.
What are the functions of membrane lipids?
- Vesicle budding and fusion
- Cellular transport
- Cell attachment and support
- Cellular signaling
- Regulation of cellular homeostasis.
What is the role of cavins in the plasma membrane?
Involved in membrane remodeling.
What is the function of lipid rafts in cellular signaling?
They form scaffolds for signaling molecules and receptors that relay information from the extracellular environment.
What are clathrin-coated pits?
Membrane invaginations lined by clathrin protein, involved in the initial processes of endocytosis.
What are the main functions of membrane carbohydrates?
They play roles in cell recognition, signaling, and forming the glycocalyx.
What are the two types of proteins based on their solubility in membrane fluids?
- Soluble proteins
- Insoluble proteins.
What are the two structural forms of membrane proteins?
- Fibrous proteins
- Globular proteins.
