Cell Flashcards
What is the structure of the cell membrane?
The cell membrane is a phospholipid bilayer with embedded proteins, cholesterol, and carbohydrates. It is selectively permeable and forms the outer boundary of the cell.
What are the types of cell membrane proteins?
- Integral (Intrinsic) proteins
- Peripheral (Extrinsic) proteins
What are the functions of membrane proteins?
- Transport (channels, carriers)
- Enzymatic activity
- Signal transduction
- Cell-cell recognition
- Intercellular joining
- Attachment to cytoskeleton and ECM
What is the glycocalyx and its functions?
The glycocalyx is a carbohydrate-rich layer on the cell surface made of glycoproteins and glycolipids.
Functions:
- Protection
- Immunity to infection
- Cell recognition
- Adhesion
What are the membranous organelles?
- Endoplasmic reticulum (Rough & Smooth)
- Golgi apparatus
- Lysosomes
- Peroxisomes
- Mitochondria
- Vesicles
What are the non-membranous organelles?
- Ribosomes
- Centrosomes (Centrioles)
- Cytoskeleton
- Nucleolus
Which organelles are self-replicative?
- Mitochondria
- Peroxisomes
- Centrioles (partially)
What are the differences between Smooth and Rough ER?
- Rough ER: Has ribosomes; involved in protein synthesis and folding
- Smooth ER: No ribosomes; involved in lipid synthesis, detoxification, and calcium storage
What are the functions of the Golgi apparatus?
- Modifies, sorts, and packages proteins and lipids
- Forms lysosomes
- Secretes substances via vesicles
- Glycosylation of proteins
What are the enzymes found in lysosomes?
Hydrolytic enzymes, e.g.:
- Proteases
- Lipases
- Nucleases
- Phosphatases
What are the functions of lysosomes?
- Intracellular digestion
- Autophagy (self-digestion of organelles)
- Defense against pathogens
- Recycling cellular materials
What are the enzymes found in peroxisomes?
- Oxidases
- Catalase
What are the functions of peroxisomes?
- Detoxification of harmful substances (e.g., alcohol)
- Breakdown of fatty acids
- Neutralization of hydrogen peroxide (via catalase)
What are the components of the cytoskeleton?
- Microfilaments (actin)
- Intermediate filaments
- Microtubules
What are the functions of the cytoskeleton?
- Maintains cell shape
- Facilitates cell movement
- Assists in intracellular transport
- Organizes organelles
- Aids in cell division (mitotic spindle)
What is endocytosis? What are its types?
Endocytosis is the process of cellular uptake of materials via vesicles.
Types:
- Phagocytosis (cell eating)
- Pinocytosis (cell drinking)
- Receptor-mediated endocytosis
What is the mechanism of pinocytosis?
In pinocytosis, the cell membrane invaginates to form small vesicles that engulf extracellular fluid and solutes, which are then internalized into the cytoplasm.
