Lecture 5 Flashcards
Endosymbiotic Hypothesis
Origin of mitochondria and chloroplast, arose from a primitive bacteria living inside a primitive eukaryote
Endomembrane System
Membrane bound organelles that arose from infolding of membrane and are connected via vesicles
Nucleus
Not technically part of endomembrane system, stores DNA as multiple linear chromosomes
Inner Nuclear Membrane
Inner membrane of the nucleus
Outer Nuclear Membrane
Outer membrane of the nucleus, continuous with the endoplasmic reticulum
Nuclear Pore Complex
Transmembrane protein that spans both inner and outer nuclear membrane, provides a non-selective pore for most small molecules
Nucleolus
Site of rRNA transcription and ribosomal unit assembly
Ribosomal Subunit
Associated with unique rRNA’s, packaged with rRNA at nucleolus
Nuclear Envelope
Created to protect nucleus from Oxygen, consists of both nuclear membranes
Chromatin
A complex of DNA and proteins that forms a chromosome, organizes and protects DNA
Nucleosome
A section of DNA wrapped around a histone octomer, attached by positive-negative interactions
Histone Octomer
Composed of several positively charged proteins, 2 of each H2A, H2B, H3 and H4
Solenoid/30 nm fibre
Nucleosomes stack with help of histones (H1)
Looped Domains
30 nm fibre loops off non-histone scaffolding proteins
Mitotic Chromosome
DNA in its fully condensed form
Ribosomes
Enzymes of translation (catalyze peptide bonds)
Rough Endoplasmic Reticulum
Where proteins destined for within the endomembrane system or secretion are translated on bound ribosomes, also responsible for protein quality control (chaperones are found here)
Bound Ribosomes
Ribosomes bound to the rough endoplasmic reticulum, responsible for translating proteins destined for secretion or use within the endomembrane system
Smooth Endoplasmic Reticulum
Responsible for ion storage (Ca2+), phospholipid synthesis, steroid synthesis, detoxification of drugs and alcohol
Cis Golgi
Receives cargo from endoplasmic reticulum in vesicles
Medial Golgi
Sorts and modifies cargo
Trans Golgi
Sorts cargo into various destinations within endomembrane system, mostly the lysosome or plasma membrane
Golgi Apparatus
Processes/packages lipid and protein molecules, made up of approximately 20 cisternae
Vesicle Trafficking
Within golgi, cargo is transported between cisternae in vesicles
Cisternae
Flattened, membrane bound sacs
Cisternal Maturation
Within golgi, cargo is transported as cisternae mature, i.e. new vesicles form a new cis golgi, the old cis golgi becomes a new medial golgi, the old medial golgi becomes a new trans golgi, and the old trans golgi vesiculates
Lysosome
Organelle responsible for digestion of molecules received from endocytosis
Hydrolytic Enzymes
Enzymes found within lysosome and that function only at a pH of 5
Autophagy
Self-eating, can be a response to extensive cell damage
Cytoskeleton
Network of fibres extending through cytoplasm, responsible for cell support, motility and shape
Microtubules
Responsible for compression resistance and movement within the cell, composed of tubulin dimers which form protofilaments and are then bundled into microtubules
Motor Proteins
Change shape with ATP hydrolysis and generate force
Eukaryotic Flagellum
Whiplike movement, powered by ATP hydrolysis, membrane bound, force generated by dynein
Kinesin
Positive end directed motor protein, hand over hand (monkey bar) movement
Dynein
Negative end directed motor protein
Microfilaments (Actin Filaments)
Polymer of actin monomers forming a twisted rope, responsible for tension resistance and movement
Sarcomere
Contractile unit of muscle
Myosin
Motor molecule, has 2 actin binding heads and moves using a hopping motion
Nuclear Lamina
Maintains structure of nucleus, found on inside of inner membrane
Intermediate Filaments
Rope-like polymers formed by many different monomers, not very dynamic (no motor proteins associated), used for tension resistance
Laminin
Forms the nuclear lamina, provides shape to nucleus, sits on inner face of inner nuclear membrane
