The Chemical Nature of the Cell

This material starts you on your journey through Unit 3 Biology - Studying the Signatures of Life - A world measured in nanometres - The molecular world of the cell.

Biomacromolecules: Lipids, Complex Carbohydrates

Biomacromolecules are made by the cell from smaller molecules. Your course looks at four classes of biomacromolecules that are essential to life processes. These G-Casts explain how smaller molecules are linked together in the condensation reaction and we talk about the structure and function of lipids and complex carbohydrates.

Biomacromolecules: Nucleic acids and Proteins

Biomacromolecules are made by the cell from smaller molecules. Your course looks at four classes of biomacromolecules that are essential to life processes. These G-Casts explain how smaller molecules are linked together in the condensation reaction. In Part A we talk about the structure and function of lipids and complex carbohydrates.

In this G-Cast, we talk about the structure and function of nucleic acids and proteins. The slide material visualises the main concepts presented in the audio casts.

Crossing the Plasma Membrane

This material explains the structure of the plasma membrane, the processes by which hydrophilic and hydrophobic substances cross over the lipid bilayer and how large macromolecules like proteins are secreted from the cell.

Enzyme Action

This material explains the role of enzymes in the cell and how they work. Factors that influence the activity of enzymes are examined.

Photosynthesis

The focus of this material is to describe in simple steps the two stages of photosynthesis in terms of inputs and outputs.

Cellular Respiration

This material summarises the main stages of the biochemical pathways in cellular respiration, in terms of their inputs and outputs.

Chemical Signalling

This audio cast outlines the types of chemical signals that are received by cells and how the stimulus response model is applied at the cellular level.

Pathogenic Organisms

This audio cast outlines the various types of pathogens that can cause disease and the types of barriers that are employed to keep them out or used to inhibit their growth.

Immune Response

This audio cast outlines the major components and characteristics of both the innate and adaptive immune responses. The role of antigens as the initiator of the immune response and the interrelationship between the innate and adaptive responses is highlighted.

The Cell Cycle and Cell Division

The audio cast details binary fission in prokaryotic cells, the division of the nucleus in eukaryotic cells (mitosis) and the key events in meiosis that produce a haploid cell from a diploid cells. The importance of DNA replication in the cell cycle is stressed.

Genes in Action: Expression & Regulation

This audio cast details key aspects of gene structure, gene expression (transcription & translation) and the role of regulatory genes.

Mutations

This audio cast outlines the importance of mutations as a cause of variation and explores the types of mutations including point mutations, translocations, aneuploidy and polyploidy.

Changing Allele Frequencies

The concept of the gene pool is outlined. Students are asked to consider various change agents that impact and change the frequencies of alleles within a population. The importance of environmental factors as selection pressures is stressed. Concepts such as Natural Selection, Gene Flow and Genetic Drift are summarised. Students are advised to consider change and then to ask the question what is the biological consequence, both for the individual organism and the species.

Speciation

The main steps in Allopatric Speciation are outlined.

The Evidence For Biological Evolution

Various types of evidence for biological evolution over time are outlined including the fossil record, biogeography, comparative anatomy and molecular homology. The distinction between homology and analogy is stressed.

This audio cast outlines the use of relative and absolute dating techniques, the use of index fossils in stratigraphic correlation, rock types and plate tectonics. The meaning of “mass extinction” is explained.

A History of Ideas

This audio cast outlines the development of ideas to explain the diversity of species. The ideas of Lamarck and Darwin are summarised and what is meant by Neo-Darwinism is explained.

Patterns of Evolution

This audio cast outlines the differences between divergent and convergent patterns of biological evolution. The difference between gradualism and punctuated equilibrium is explained. Students are reminded of the importance of molecular homology in determining relatedness and the use of cladograms in depicting evolutionary relationships.

Cultural Evolution

This audio cast outlines what is meant by cultural evolution, the impact of technology and the interrelationship with our biological evolution.