Lecture 8 Flashcards
Nucleus
Synthesizes mRNA
Enclosed by double membrane
Chromatin: complex of DNA and Proteins that make up chromosomes
Chromosomes: structures that organize DNA to carry genetic info
Nucleolus: Synthesis of rRNA and ribosomes
Nuclear pores: composed of nucleoporin and mediate transport in and out of nucleus
Ribosomes
Synthesizes proteins
Composed of rRNA combined with cytosolic proteins
Made of two subunits (1 large one small)
Two Types:
Free Ribosome: synthesize cytosolic proteins, suspended in cytosol
Bound Ribosomes (to rER): synthesize integral membrane proteins and secreted proteins
Endomembrane System
Collection of membranes inside and surrounding eukaryotic cell, including:
Nuclear Envelope
Endoplasmic Reticulum
Golgi Apparatus
Lysosomes
Various vesicles and vacuoles
Plasma Membrane
Endoplasmic Reticulum (general)
Continuous with nuclear envelope
Smooth ER
Ribosome free
Functions: synthesis of lipids, metabolism of carbs, detoxification of drugs and poisons, and storage of calcium
Rough ER
Processing of proteins synthesized by ER-bound ribosomes
Processes and folds proteins
Membrane Factory:
- Synthesizes phospholipids
- Membrane transferred in vesicles to other organelles or cell membrane
Golgi Apparatus
Flattened membranous sacs
“Sorts, packages, and tags” lipids and proteins in transport vesicles
Modifies the proteins and lipids and ships them on microtubules
Cisternae: internal space
Cis face: receiving side
Trans face: shipping (transport) side
Lysosome
Synthesized in rER and processed in Golgi (bud from trans face)
Fuse and digest vacuoles, phagosomes (food vacuoles), and damaged organelles (autophagy - recycling of no-longer-functional intracellular elements)
Hydrolyzes (breaks down) proteins, fats, polysaccharides, and nucleic acids
Phagocytosis - recycling of external material brought into cell by endocytosis
Proton pumps in lysosomal membrane maintain low pH (works best at low pH)
Lysosomal storage disorders (LSDs)
Inherited disorders resulting from a lack of specific enzymes that break down lipids or carbs in lysosomes
