Cell Biology

Study Cell Biology by Distance Learning

An essential foundation course for all people interested in human health, animal care and animal studies. The cell is the basic unit of life. Its knowledge is most essential to understand how life works for higher animals and plants. 

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.

Student Comment:

"The course was better than I expected" "I am studying a Bachelor of Health Science next year at university. I gained far more knowledge from this course than I expected." J.McEwanWhat is a Cell?

"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."

Lesson Structure

There are 10 lessons in this course:

1. Introduction to Cells and Their Structure
   • 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
   • Cell chemical composition; carbohydrates; lipids; nucleic acids; proteins; enzymes; cell membranes; golgi apparatus.
3. DNA, Chromosomes and Genes
   • 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
   • Mitosis and meiosis overview; mitosis; meiosis.
5. Cell Membranes
   • 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
   • Protein structure; fibrous proteins; globular proteins; protein organisation; primary to quaternary structure; protein function.
7. Protein Synthesis
   • Overview; the function of ribonucleic acid in protein synthesis; transcription and translation; initiation; elongation; termination.
8. Food, Energy, Catalysis and Biosynthesis
   • 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; mitochrondria; chloroplasts.
9. Intracellular Compartments, Transport and Cell Communication
   • Cell communication; endocrine signalling; paracrine signalling; autocrine signalling; cytoskeleton; actin filaments; intermediate filaments; microtubules.
10. The Cell Cycle and Tissue Formation
    • 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.

Each lesson culminates in an assignment which is submitted to the school, marked by the school's tutors and returned to you with any relevant suggestions, comments, and if necessary, extra reading.

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.

What are the Different Types of Cells?

Cell Theory

The following are the key points of Cell Theory:

1. All known living organisms are composed of one or more cells.

2. All cells are derived from previously existing parent cells.

3. Cells contain genetic information that controls the cell’s functions.

4. Genetic information is duplicated and transmitted from parent cells into any new cells.

PROKARYOTIC AND EUKARYOTIC CELLS

There are two main types of cells:

Prokaryotes

Prokaryotes or prokaryotic cells do not have a nucleus, or membranes surrounding their organelles. Their DNA is not organised into chromosomes, but is a single molecule, most often circular. Prokaryotes include bacteria and other organisms known as archae.

Eukaryotes

Eukaryotes or eukaryotic cells have membranes surrounding the nucleus and organelles. This effectively divides the cell into distinct compartments that perform distinct functions. Their DNA is organised into linear chromosomes. The cells that make up the human body, other animals and also plants are eukaryotic.

CELL SIZE ans SHAPE

The size of a cell can vary considerably. Some of the smallest recorded living things are single cell organisms with cell sizes as small as 250 nm (nanometre), while a nerve cell in a giraffe may stretch to several meters. The importance of cell size matters due to simple geometry. Basically a cell must transport materials in and out through a membrane.

• The larger the cell, the smaller the surface area to volume ratio.

• The smaller the cell, the larger the surface area to volume ratio.

When a cell reaches a certain size, the surface area will not be able to keep up with the needs of the cell and growth will cease.

So how does nature compensate for cells which need to be large such as the giraffe’s nerve cell? There a few different ways to achieve this, the first is to change the shape. Not all cells are spherical in shape, a nerve cell is very long and very thin. This increases the surface area to volume ratio dramatically. Another other way of sustaining a large cell is by including food within the cell. This is common in cells that are going to divide, giving rise to multicellular organisms. As a cell grows it divides into two, then four so on, giving a much larger surface area to ratio.