Lecture 6: Cell structure and function Flashcards
What are the 3 components that make up the cytoskeleton: in order from smallest to biggest
Microfilaments, Intermediate filaments and microtubules
Microfilaments : materials made from, function and location, permanence
made of actin and myosin. Anchors the cytoskeleton to plasma membrane proteins, therefore found lining the periphery of the cell. Assembled and disassembled as required
Intermediate filaments : materials made from, function and location, permanence
made of keratin mostly. Bears tension and weight throughout the cell, stabilising position of organalles therefore found in cytoplasm. Most permanent of cytoskeleton
Microtubules: materials made from, function and location, permanence
made from alpha and beta tubulin dimers. They guide the movement of organelles and chromosomes. Support the movement of cillia and flagella. They extend from the centre of cell.
List the functions of membrane proteins
Transport, Enzymatic activity, signal transduction, cell to cell recognition, intercellular joining and attachment of the Cytoskeleton and ECM.
What is an integral protein
one that is embedded partially or fully into the membrane but doesn’t span it.
Describe the levels of DNA packaging in the Nucleus from smallest to biggest
DNA, the double helix < wrapped around 8 histones = nucleosome < nucleosomes linked together = chromatin < 3 or more chromatin strands = chromatin fiber < looped domains of chromatin fibre < chromosome
What is the nucleolus
this is the middle of the nucleus which is the site of synthesis and assembly of ribosomes.
Where is DNA housed in the nucleus
Between the nuclear lamina (lining of the nuclear envelope) and the nucleolus.
Which form of DNA is the most inaccessible but easiest to organise
chromosomes
Which form of DNA is the most accessible but hardest to organise
chromatin
What is the smooth ER: where is it and function
Part of the RER that lacks ribosomes so doesn’t make proteins but stores cell specific proteins and enzymes and synthesises lipids (steroids and phospholipids).
What is the structure and function of the Golgi apparatus
3-20 flattened membranous sacs called cisternae. It makes combinations of glyco, lipid, proteins. and modifies proteins, packaging them for transport to their destination.
is the mitochondria part of the endomembrane system ?
no
What are the 4 things that prokaryote and eukaryote cells have in common
plasma membrane, ribosomes, cytosol, (DNA,RNA and protein)
What are the differences between prokaryote and eukaryote cells
prokaryote cells are smaller and lack membrane bound organelles (no nucleus) compared to eukaryotes which have membrane bound organelles.
What are peripheral membrane proteins
proteins associated with the membrane but not actually embedded in it.
What is the intercellular joining function of transmembrane proteins
Linkers anchoring proteins in the other cells plasma membrane together with or to protein filaments inside or outside the cell
What is cell to cell recognition function of transmembrane
Glycoprotein dots are cell identity markers allowing cells to recognise same cells during tissue formation and also recognise foreign cells that are dangerous
What is attachment function of transmembrane proteins
Microfilaments of the cytoskeleton or fibres of the ECM may be attached to the transmembrane proteins to maintain structure shape and fixed location of membrane proteins. Proteins adhered to the ECM can also coordinate extra and intracellular change.
What is an attachment transmembrane protein
fibronectin
