Discovery of the cell

The Cell

How was the cell discovered?  The discovery of the cell was credited to a microscopist, Robert Hooke. He attempted to ask a simple question as to why cork stopper ( which were made from the wood of a tree)  that were used to bottle toppers was suitable to maintain air in the bottle. He took a sample of the cork and examined it under a microscope which revealed that it contained pores. In his assessment he compared the porous material to that of the structure of a honeycomb and thus named the pores “cells” due to their memory of the cells that monks lived in the monastery.  Hooke was also able to further his findings when he noted that the cork cells which as we know it today are plant cell, they had cell walls. This revelation about cells led to the further discovery of microscopic organisms such as bacteria by Leeuwenhoek. His findings were confirmed by Robert Hooke in 1678.

Image 25  of Robert Hook and the discovery of cells from a cork stopper.

Cell Theory?

Following the discovery of the cell that is the basic unit that is characteristic of  all life.  A botanist by the name Robert Brown observed the plant cell and noted the presence of the nucleus. Following the publication of Brown’s findings another botanists, Matthias Schleiden proposed the ideas that cells made the basis of plants and that the nucleus was an important part of the functionality of the cell.  Then later on Theoder Schwann a biologist related the ideas of Schleiden to animals. In that both plants and animals were made of cells and they both had the nucleus present.

References of picture

Reflection on Pathophysiology – Tay- Sachs Disease!!!


This is generally the study of how a particular disease came about within the cells of a specific organ in the body due to the improper functioning of a certain structure, located within that specific organ.


Tay- Sachs disease is a condition that affects the brain. Dangerous amounts of a certain type of fatty substance, known as gangliosides, continuously builds up in tissue and nerve cells of the brain. Gangliosides, are created and “suppose” to be broken down at a fast rate at “baby stage” of a human’s life that is when the brain is now starting to develop.




Well, in an area of the brain there is something called enzymes and there is one in particular whose job it is to break down the gangliosides. This enzyme is called, beta- hexosominidase A, if this enzyme is “lazy”, that is it not active enough, then, the result is Tay- Sachs disease.


Babies who are born with this disease, they seem to be growing and developing as any other normal baby for the first few months, “the super cute, adorable stage”. Then……….. the nerve cells become occupied by this fatty material, which results in the weakening of the mental abilities, which, in turn affects the physical. The child may become deaf, blind or may not be able to swallow, the muscles can degenerate, bringing with it paralysis.

Not only the innocent, adorable babies are affected by this Tay- Sachs Devil, sorry I mean Disease. There is also a rare form of it that occurs in patients in their prime of adulthood, twenties to early thirties. It can be determined by an unsteady posture and progressive neurological depletion.

This disease is higher among the Eastern European people and Askhenazi Jews descendants.


THE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!  A blood test, obviously. This blood tells measures beta- hexosaminidaseA activity. Wait!!!!!!!!!!!!!!! We do not need to panic and run to the doctor if we suspect that we or someone we know has the disease. To have Tay- Sachs disease, both your parents must carry the mutated gene in order to bring forth an affected child.


  • Dementia
  • Seizures
  • An increased startle reflex to noise
  • “Cherry red” spots in the eyes.
  • Paralysis or loss of motor function
  • Slow growth or development



At present, there is no known cure for the disease, probably because I am still at the University level but I’ll get to that when I’m done. Only ways and means, to help people accept and live comfortable- “ish” lives with the disease. The treatment involves: preventing breathing problems, relieving a term known as dysphagia: which is feeding or swallowing difficulties and therapy for patients who suffered loss of motor skills or paralysis.



References for pictures

Cytoplasmic Streaming



Do you know what is Cytoplasmic Streaming??????????????     

  Also known as Protoplasmic streaming, involves the movement of cytoplasm throughout the cell facilitating diffusion at a quick rate. This allows the cell to grow larger than the expected surface area to volume ratio without being harmed. Recall that as the surface area increases the volume increases thus restricting the size of a cell. Cytoplasmic streaming allows cells to jump this hurdle. The movement of the cytoplasm causes the movement of materials and organelle around the cell therefore allowing for diffusion to occur at a fast rate even with a large surface area to volume ratio. This is done by motor proteins which are responsible for the movement of proteins and vesicles. Myosin motors, a family of motor proteins acts on actin filaments to generate contractions in the cell. Other motor proteins like kinesin allow movement of organelles and vesicles around the cell.



References for pictures



Reflection #1 The Cell

In this week’s lecture we gained some additional information about the cell…… as well as were refreshed about some of the things we have  forgotten. 

    IMAGE 2

     The Cell

the cell

Wordle For Cells


Discovered by Robert Hooke .It is the fundamental unit of all living things. There is even a theory for the cell that is The Cell Theory which states that all living organisms are made up of cells. This was formulated by Schleiden and Schwann . Organisms can either be prokaryotic or eukaryotic. Prokaryotic cells have no nucleus so there DNA is in the cytoplasm, no membrane bound organelles and their DNA are circular. Eukaryotic cells, however, have a nucleus, have membrane bound organelles and their DNA are linear.


Functions of the Organelles of the Cell
Nucleus or control centre contains the DNA that controls the activities of the cell. Within the nucleus is the Nucleolus which makes ribosomal RNA (rRNA).


Proteasome are located in the nucleus and in the cytoplasm. Its purpose is to degrade proteins.

Mitochondria are where cellular respiration occurs by the manufacture of ATP used as energy for the cell, much like a power station just without ATP.


Cytoskeleton -or structure of the cell is really like the framework of the cell since it gives the cell its shape and moves organelles around the cell. Reminds me of the skeletal system. The cytoskeleton is made up of the microtubules, microfilaments and intermediate filaments. Microtubules are made of tubulin and are  responsible for locomotion. Microfilaments are mostly made up of actin and are responsible for gliding, cytokinesis and contraction. Intermediate filaments are responsible for tensile strength.


Ribosomes are the sites of protein synthesis. these can be found free in the cytoplasm or attached to the endoplasmic reticulum.

                                                                                                 IMAGE 7          

Endoplasmic Reticulum is a network of tubes, vesicles and cisternae which are sac-like structures extending from the nucleus. It is  subdivided into rough ER and smooth ER. Rough ER has ribosomes attached while smooth ER doesn’t. Rough ER synthesizes proteins while smooth ER synthesizes lipids.


Golgi apparatus like a post office can modify, package and distribute the proteins and lipid that were synthesized by the endoplasmic reticulum and ribosomes.


Lysosomes are vesicles that break down any phagocytized food. Lysosomes bind to these vesicles releasing the enzymes to break down the food particles. They also break down waste .
Peroxisome degrades amino and fatty acids.


                                                                                                               IMAGE 10

Choloroplast-  are the site of photosynthesis. Contains the green pigment chlorophyll which absorbs light and converts it to glucose and oxygen.





Cell membrane controls what enters the cell.


Cell wall prevents the cell from bursting.



Plasmodesmata narrow bridges to allow transport of materials between cells.


There are two types of cells, the plant and animal cell.The plant cell is easily distinguished by a cell wall, plasmodesmata, chloroplast and a large vacuole. The plant cell does not have centrioles, but the animal cell does.

Can you figure out from the diagram above which is the plant and which is the animal cell???


What is the Endosymbiont Theory??


Lyn Margulis proposed that the mitochondria and chloroplast existed as aerobic bacteria and photosynthetic bacteria respectively which were ingested by anaerobic bacteria. Instead of the bacteria being completely digested the bacteria remained part of the bacteria resulting in a mutual relationship between both bacteria.

Evidence which supports this theory is:
1) Both have their own circular DNA and ribosomes as bacteria
2) Both are similar in size to that of bacteria.
3) They both reproduce by binary fission as bacteria.
4) The ribosomes are similar in size to those in bacteria.




References for pictures view=detail&id=4B335B5486BA90F9B5474ECA586F95793BA0B379&selectedIndex=14