2010 Foundations - Cells, organelles and cell boundaries

From CellBiology

Introduction

Cells

2010 Lecture Slides: 3 slides/22 pages PDF | 4 slides/17 pages PDF

Note - This current page is not yet completed see also the earlier 2008/2009 Lecture

The 2 major classes of cells are defined by the presence or absence of a nucleus; Eukaryotic (with nucleus) and Prokaryotic (without nucleus).

Eukaryotes can be further divided into unicellular (only one cell, like prokaryotes) and multicellular (like us) organisms.

A major difference between eukayotes and prokaryotes is the presence of physical compartments (membrane bound) and organelles within the cell. These compartments allow the separation/specialization of processes within the cell.

About Human Body

Human Cells

  • 210+ cell types in body
  • total number of estimated cells in the body - 1013 (American Ten trillion/British Ten billion)

Flora

  • bacteria, fungi and archaea
  • found on all surfaces exposed to the environment
    • skin and eyes, in the mouth, nose, small intestine
  • most bacteria live in the large intestine
  • 500 to 1000 species of bacteria live in the human gut
  • total number of estimated flora ten times as many bacteria 1014 (American One hundred trillion/British One hundred billion)

Divisions of Life

Prokaryotic

Eukaryotic

  • plants
  • animals
  • fungi
  • protists

Begin

RobertHookeMicrographia1665.jpg Cork-cells-sem.jpg

Genomes - Figure 2.1 Cells of eukaryotes (left) and prokaryotes (right)

MBoC - Figure 1-12 Procaryote sizes and structures (Note image scale should be microns mot millimetres)


Escherichia coli.jpg CDCherpes.jpg

Prokaryote cell.jpg

Plant cell structure.png

Cell Membranes

Membrane evolution.jpg

Phospholipid bilayer.jpg

Cell membrane.png

Membrane compartments.jpg

Proteintransport.gif

Exo endo cytosis.jpg

Exocytosis types.jpg

Endocytosis types.png

Cell Nucleus

DNA (gene): storage, gene regulation, gene expression, messenger RNA processing.

Humans have cells both with a single nucleus, with several nuclei and without a nucleus. Are still considered eukaryotic cells?

In general these fully differentiated (adult) cells started out quite differently, always with a nucleus, as they developed (differentiated) this changed.

Red blood cells which as they develop in the bone marrow had a nucleus, that is lost as they mature, and exist in the circulation without a nucleus.
Heart cardiomyocytes may have 2 nuclei, bone osteoclasts may have several nuclei and a single skeletal muscle fiber may have several hundred nuclei.

Cell Cytoplasm

Metabolism: absorbtion (endocytosis), secretion (exocytosis), messenger RNA translation (ribosomes), protein processing (rough endoplasmic reticulum, Golgi appraratus), transport (transport vesicles), energy production (Mitochondria), digestion (lysosomes), lipid synthesis and detoxification (smooth endoplasmic reticulum).

Is this all these organelles do?

The list above is very generalised, as many organelles have many different functions, and interact with other organelles and structures.

Do all these organelles just "float" in the cytoplasm?

The cytoskeleton, which are 3 separate filament systems (microfilament, intermediate filament, microtubules), regulate cell shape, motility and the position of organelles within the cytoplasm.


Eukaryote Organelles

Within eukaryotic cells exist physical compartments (separated by membranes) and functional compartments where specific processes may occur or are restricted too. This lecture is also an introduction to compartments within the cell and membranes. The key components are: cell compartments, membrane structure. The lecture slides and textbook alone contain enough information as an introduction to the subject for this level of study. If you are interested in further reading, I have also included below links to more detailed textbooks with further information and images.

Nucleus

Nucleus cartoon3.jpg

Tem nucleus rer2.jpg

Endoplasmic-types.jpg


Mitochondria

08lungtem.jpg

Heart papillary muscle.jpeg

Mitochondrion structure cartoon.jpg

Golgi Apparatus

Tem golgi1.jpg

Lysosome

Lysosome primary secondary tem.jpg