The food and energy requirements for organisms on Earth are extremely varied. All organisms need energy to survive, some of these organisms get their energy from the sun (like plants with photosynthesis) and others are able to get their energy from consuming other organisms. Organisms living in a particular area and any non-living conditions within …
Introduction All the organisms in a species have an equal number of chromosomes in their cells that are present in the form of pairs. Each pair is homologous containing two identical chromosomes except the sex chromosomes that are different in males and females. In organisms that reproduce through sexual reproduction, the new organism is developed …
Summary Oxidative Phosphorylation is the fourth and final step in cellular respiration and is the main producer of ATP in the process. Oxidative phosphorylation is an aerobic process, meaning it only occurs in the presence of oxygen. Oxidative phosphorylation consists of two elements: the electron transport chain and chemiosmosis. In the electron transport chain, electrons …
Summary Evolution begins with the inheritance of new genetic variation. Variation describes differences in the genetic make-up between individuals within a species. Variation can exist in all cells of the body but is only passed on to the next generation when it is present in the gametes. In this way, genetic variation can influence future …
Summary of Lipid Structures and Functions Lipids are composed of the elements carbon, hydrogen and oxygen, similar to carbohydrates, but contain less water. In fact, lipids are insoluble in water. Fats are an example of a type of lipid. Lipids play a variety of important functions in the cells. The most common type of lipids …
Introduction Water is an inorganic compound essential for sustenance of all forms of life. It is the predominant compound present in all living systems. It is present in all living cells in different proportions ranging from 70% to 95%. The human body is made up of 70% water that is distributed differently among different types …
Summary Enzymes describe a class of proteins that are biological catalysts. That is, they accelerate biological reactions without being used up during the reaction. Enzymes are essential for almost all biochemical reactions in living organisms, and they act by lowering the activation energy required for the reaction to proceed. Enzymes are essential because without them, …
Summary Proteins are the building blocks of cells. They perform a variety of functions, and are the key executers of the instructions held within the DNA. Enzymes are examples of proteins, and are crucial in catalysing reactions within the cell and allowing cells to carry out their jobs. Proteins also regulate the transport of molecules …
Summary The cell cycle describes a sequence of reactions that results in the growth of the cell and replication of the genetic material to make two identical daughter cells. These events are tightly regulated and precisely timed, and can be grouped into two phases: interphase and the mitotic (M) phase. During interphase, the cell grows …
Summary Cells have various mechanisms of transporting particles within and outside the cell. Some of these are passive and do not require energy (such as diffusion, facilitated diffusion, and osmosis), and some are active processes requiring energy (such as endocytosis and exocytosis). Diffusion Diffusion is the movement of molecules from a higher concentration to a …
