Home Study Cytology Course

Cell biology is an introductory course designed for everyone wanting to learn more about biology. This is a foundation course for those wishing to have a career in health sciences, biology and biochemistry. Upon completion of this course students should have a sound understanding of cell structure and processes.

Duration: 100 hrs

Extract from course:

"The word cell is derived from the Latin “cella” which means “small room”. Cells are the units from which all living organisms are built. Some organisms (e.g. bacteria) have only one cell in the entire organism. Others are multicellular. A human body can contain an estimated 100,000 billion cells.

Each cell is a self-contained and partially self-sufficient compartment designed to carry out a limited series of functions. While the structure and function of cells is extremely variable, their basic structure is similar. All cells are bound by an outer membrane and contain cytoplasm and DNA."

Course Content

This course contains 10 lessons as follows:

1.Introduction to Cells and Their Structure

Including: what is a cell, history of cell biology; prokaryotic and eukaryotic cells; cell shape and size; cell structure; the nucleus; the nucleolus; euchromatin and heterochromatin; the animal cell; the plant cell; human cells.

2. Cell Chemistry

Including: cell chemical composition; carbohydrates; lipids; nucleic acids; proteins; enzymes; cell membranes; golgi apparatus.

3. DNA, Chromosomes and Genes

Including: what is DNA, Chromosomes, Genes; DNA replication; telomeres and telomerase; genetics; case study in genetic inheritance; phenotype and genotype; gene mutations.

4. Cell Division: Meiosis and Mitosis

Including: Mitosis and meiosis overview; mitosis; meiosis.

5. Cell Membranes

Including: membranes; structure of cell membranes; movement of molecules through cell membranes; endocytosis; osmosis and filtration; hydrostatic pressure; active transport; electro-chemical gradient; nutrient and waste exchange in animal cells; mediated and non-mediated transport.

6. Protein Structure and Function

Including: protein structure; fibrous proteins; globular proteins; protein organisation; primary to quaternary structure; protein function.

7. Protein Synthesis

Including: overview; the function of ribonucleic acid in protein synthesis; transcription and translation; initiation; elongation; termination.

8. Food, Energy, Catalysis and Biosynthesis

Including: sources of energy; metabolism within the cell; catabolic metabolism; anabolic metabolism; ATP movement; Kreb's cycle; production and storage of energy; energy production pathways from different foods; biosynthesis of cell molecules; mitochondria; chloroplasts.

9. Intracellular Compartments, Transport and Cell Communication

Including: Cell communication; endocrine signalling; paracrine signalling; autocrine signalling; cytoskeleton; actin filaments; intermediate filaments; microtubules.

10. The Cell Cycle and Tissue Formation

Including: the cell cycle; phases of the cell cycle; cell cycle regulation; cell death; cells to bodies; stem cells; animal tissues including muscle, connective, epithelial, nerve; blood.

Aims

• Review basic cell structure and discuss the scope and nature of cell biology.
• Describe the chemical components and processes of cells.
• Describe the storage of genetic information within cells and how this information is passed on to the next generation.
• Describe key concepts in molecular biology.
• Discuss membrane structure and transport across cell membranes.
• Discuss protein structure and function.
• Describe and discuss protein synthesis.
• Describe the significant processes involved in transfer and storage of energy in a cell.
• Describe the significant processes that occur in cell communication and intracellular transport
• Describe the life cycle of cells and how they combine to create different types of tissues.

Duration:   100 hours

THE BREAKDOWN OF FOOD MOLECULES IN AN AEROBIC SYSTEM

The food we eat must be broken down into smaller molecules before they are available to cells.  Obviously we do not want to break down our own cells, therefore it must occur outside the cells in a process called digestion which occurs in our intestines or in specialised organelles called lysosomes. Both of these processes are involved in breaking down large molecules into their base constituents such as proteins are broken down into amino acids and polysaccharides into sugars.  When broken down these molecules may enter the cell where oxidation of the molecules can occur in the cytosol. 
 
In the cytosol the molecules undergo oxidation, whereby glycolysis further breaks down glucose into two molecules of pyruvate.  Other sugars are also broken down into pyruvate however they must first be altered to fit into the glycolytic pathway.  As a result, three energy carrying molecules are formed, they are 2 ATP and NADH.  

Formation of Acetyl CoA
The pyruvate formed can then enter the mitochondria.  In the mitochondria the pyruvate is converted into two acetyl groups and CO2.  An acetyl group is attached to Coenzyme A to form Acetyl CoA (remember this is another energy carrying molecule). 

Lipids also form large amounts of Acetyl CoA. Hydrolysis involves splitting three fatty acid molecules from a glycerol molecule. (NB: Fatty acids are simply long carbon chains with hydrogen ions.) When this happens Acetyl CoA can be produced.

Mitochondrial Processes
As mentioned above Acetyl CoA if formed by the breakdown of glucose, lipids and amino acids, Acetyl CoA is an easily transferable high energy chemical group.    In the mitochondria this group is transferred to oxaloacetate, after this the acetyl group can enter the Citric Acid Cycle (also known as the Krebs Cycle).

The Krebs Cycle
It is named after Hans Krebs, one of the first scientists to study this process. This is a very important cycle in the cell and it accounts for the major portion of carbohydrate, fatty acid and amino acid oxidation and it is also the source of numerous biosynthetic precursors. It is therefore an amphibolic (both anabolic and catabolic) pathway and one that the cell has to regulate very carefully.