DEV2011 Study Guide - Midterm Guide: Rudolf Virchow, Robert Hooke, Cell Theory
25 May 2018
School
Department
Course
Professor
DEV2011 Mid Semester Notes
Lecture 2 – Cells: Organelles and Functional Compartments
Mammalian Cell
• Robert Hooke (17th century)
o Discovered piece of cork was composed of cells
Cell Theory (Rudolf Virchow 1859)
• 3 basic components
o All organisms are composed of cells
o Cell is basic unit of life
o Cells are produced by the division of pre-existing cells
• Modern Cell Theory
o Cells contain hereditary information ! passed on
o All cells are comprised of the same chemical mix
o Cells carry out all basic chemical and physiological processes within
themselves
o Cellular activity depends on activities of subcellular structures
Why are we Made up of Individual Cells
• Efficiency
o Surface area increases
o Nutrient/oxygen supply and waste disposal
• Specialisation
o Numerous small cells allow for specialisation
" Different cells have different functions
• *Average human composed of ~100 trillion cells
Subcellular Compartments
Organelle
Function
Cell (plasma)
membrane
• Fluid mosaic model
• Separates living cells from nonliving surroundings
• Selectively permeable
o Transport selected molecules
• Incorporates receptors that allows the cell to respond to signals from outside
o Communication between cells drives development
o Critical for cell-cell communication
o Continuously receiving signals from external sources
o Extra signals ! cells grow + divide or differentiate (change gene expression
pattern and structure ! function)
o If cell receives no signals ! cell dies (apoptotic cell)
o Extracellular signal molecule never enters pathway ! alters receptor protein
to activate signalling pathway within the cell ! pass signal down the cell
• Structure
o Phospholipids, proteins and other macromolecules
Mitochondria
• Site of cellular respiration
• Cellular metabolism – Krebs cycle (production of ATP)
• Function
o Cell differentiation, cell death (apoptosis)
o Some control over cell cycle and growth
• Theory of origin
o Formed by endosymbiosis
• Passed down maternally only
o Sperm head can’t fit in mitochondria
• Second location of DNA in a cell
o Genes code for many proteins requires for mitochondrial function
• Mitochondria rich cell types
o Skeletal and cardiac muscle
o Sperm (tail)
o Renal tubular cells
• Defects – exercise intolerance (minor)
• Serious: Leber hereditary optic neuropathy (LHON)
o Loss of vision
o Caused by mutation in I NADH dehydrogenase subunit 4 of mitochondrial
respiratory chain
o Three person in vitra fertilisation
" Person will have 2 mothers and 1 father
" Remove nucleus so replaced with mitochondria from second women
Nucleus
• Contains
o Nucleoplasm
o Nuclear envelope – protective membrane
o Nuclear pores – protein trafficking
o Nucleolus – site of ribosome assembly
• Contains majority of DNA
• DNA wrapped around histone proteins – chromatin
• Non dividing cells
o Chromatin is not formed into chromosomes (only occurs during mitosis or
meiosis) – dispersed throughout nucleus in two major forms
" Heterochromatin (dark regions)
• Tightly packed DNA
• Transcriptionally inactive regions of DNA
" Euchromatin (light regions)
• Loose, open chromatin
• Allows Active transcription (gene expression)
• Disruptions to development / mutations to DNA ! RNA
Endoplasmic
Reticulum –
Rough and
Smooth
• Interconnecting channels associated with storage, synthesis and transport within the
cell
• Rough ER
o Translation of mRNA into proteins by ribosomal complexes
o Production and processing of specific proteins
• Smooth ER
o No ribosomes
o Site of carbohydrate metabolism, ion regulation, synthesis
• Defects – neurological disorders
o Decrease in normal protein folding ! disease states
Golgi
• Large cellular component
• After ER complex, sent to golgi
• Function
o Sorts, modifies and packages these products before exporting them into or
out of cell
Cytoplasm
• Location of many cellular organelles
• Many complex cellular chemical reactions take place there
o Glycolysis
o Gluconeogenesis
o Biosynthesis of sugars, fatty acids and amino acids
o RNA modification
o Protein synthesis
• Many cellular organelles are located
Cilia
• Protrusions from the cell surface
o Motile
" Respiratory surfaces, fallopian tubes
o Immotile
" Involved in cellular signalling
• Number of development disorders to issues of the cilia ‘ciliopathies’
o E.g. Oral facial digital (OFD) syndrome type I aka Papillon-League-Psaume
syndrome – X linked (predominantly in females)
Document Summary
Lecture 2 cells: organelles and functional compartments. Mammalian cell: robert hooke (17th century, discovered piece of cork was composed of cells. Why are we made up of individual cells: efficiency, surface area increases, nutrient/oxygen supply and waste disposal, specialisation, numerous small cells allow for specialisation. Different cells have different functions: *average human composed of ~100 trillion cells. Cell (plasma) membrane: fluid mosaic model, separates living cells from nonliving surroundings, selectively permeable, transport selected molecules. Person will have 2 mothers and 1 father. Remove nucleus so replaced with mitochondria from second women. Heterochromatin (dark regions: tightly packed dna, transcriptionally inactive regions of dna. Euchromatin (light regions: loose, open chromatin, allows active transcription (gene expression, disruptions to development / mutations to dna rna. Golgi: large cellular component, after er complex, sent to golgi, function, sorts, modifies and packages these products before exporting them into or out of cell.
