BIO 1140 - Introduction to Biology

• Cellular Structure • Growth • Development • Reproduction • Metabolism • Response to stimuli • Adaptation • Homeostasis • Evolution • Limited lifespan

Biology is the scientific study of living things (organisms) both alive and dead (fossils)

discovering and understanding the underlying unity and diversity of the complex processes that make up life

• Similarity in chemical composition, cell structure, cell functions, genetic codes • composed of a common set of chemical compounds (carbohydrates, fatty acids, nucleic acids, and amino acids) • contain genetic information which always flows from DNA to RNA and from RNA to protein • use a universal molecular code to build proteins from their genomic information • Use the same amino acids to produce proteins

Almost all biological molecules are composed of only six types of elements: - hydrogen, carbon, nitrogen, oxygen, phosphorus, sulfur and similar chemical groups: - methyl, hydroxyl, carboxyl, carbonyl, phosphoryl, amino and thiol

Organisms have common characteristics due to the three domains: - Eubacteria - Archaea - Eukarya

Earth was formed around 4.6 billion years ago

Life appeared around 4 billion years ago

The critical step for the evolution of life was the appearance of nucleic acids The enclosure of biological molecules by membranes composed of fatty acids was an important step in the evolution of life

Nucleic acids could reproduce themselves and serve as templates for the synthesis of proteins

Fatty acids make spherical structures called liposomes

Allowed membranous structures to envelop complex biological molecules

Photosynthesis allows some organisms to capture energy from the Sun

Aerobic metabolism is far more efficient than anaerobic metabolism in extracting energy from nutrient molecules With the accumulation of oxygen, life began to move to land

Eukaryotes arose with contributions from both bacteria and archaea - the endosymbiotic theory of the origin of eukaryotic cells

• Living organisms obtain nutrients from their environment • Biochemical reactions break down nutrient molecules

Chemical breakdown produces building blocks for structures and energy for cell works (mechanical, biochemical and electrical)

Maintenance of a constant internal environment is called homeostasis - Homeostasis requires cell activity regulation - Regulation requires internal and external information

Sensory, effector and signaling mechanisms help integrate information

The major information systems of animals are the nervous, hormonal, and immune systems • They use chemical and electric signals to process information

The populations of all the species that live and interact in a defined area are called a community Communities together with their abiotic, or physical, environment constitute an ecosystem

The study of genes

Mendel showed that discrete units (genes) are responsible for trait inheritance

DNA molecules are composed of four different subunits called nucleotides