Characteristics of Life & Microbial Cell Lecture PDF

Characteristics of Life A thing can be classified as either biotic or abiotic. Abiotic things are non-living, meaning they are missing one or more of the 8 characteristics of life, while biotic things are living, which means they have all 8 of these characteristics. These 8 characteristics are: 1....

Characteristics of Life A thing can be classified as either biotic or abiotic. Abiotic things are non-living, meaning they are missing one or more of the 8 characteristics of life, while biotic things are living, which means they have all 8 of these characteristics. These 8 characteristics are: 1. Reproduction - For something to be considered 5. Adaptation Through Evolution - Every alive, it must be able to reproduce and create living thing has evolved at some point in time offspring. and continues to do so to adapt to an ever- changing environment. 2. Heredity - Heredity is the ability to pass on genetic material (DNA) from parent to offspring. 6. Response to Stimuli - Living things respond This can be in the form of phenotypic traits (how a to environmental stimuli. living thing looks on the outside) 7. Homeostasis is a living thing's ability to and genotypic traits (the actual genetic code that maintain stable internal factors, such as blood determines how something behaves and looks). pressure, body temperature (thermoregulation), and water balance within 3. Cellular Organization - All living things are cells. composed of one or more cells. 8. Metabolism - An organism must use 4. Growth and Development - All organisms chemical reactions to process and/or use develop over time to become more physically and environmental resources to continue mentally mature. functioning. 1.1 Microbiology and Microorganisms The science of microbiology revolves around two themes: Understanding basic life processes (basic biological science). Microbes are excellent models for understanding cellular processes in unicellular and multicellular organisms Applying that knowledge to the benefit of humans (applied biological science) Microbes play important roles in medicine, agriculture, and industry 1.1 Microbiology and Microorganisms The importance of microorganisms Oldest and smallest form of life Largest mass of living material on Earth Carry out major processes for biogeochemical cycles Can live in places unsuitable for other organisms Other life forms require microbes to survive 1.2 Microbial cell Characteristics of living systems 1- Compartmentalization and metabolism: A cell is a compartment that takes up nutrients Cell from the environment, transforms them, and releases wastes into the environment. Environment The cell is thus an open system. 2-Growth Chemicals from the environment are turned into new cells under the genetic direction of preexisting cells. 1.2 Microbial cell Characteristics of living systems 3- Differentiation Spore Some cells can form new cell structures such as a spore, usually as part of a cellular life cycle. 4- Communication Many cells communicate or interact by means of chemicals that are released or taken up. 1.2 Microbial cell Characteristics of living systems 5- Motility Some cells are capable of self- propulsion Distinct Ancestral cell species 6- Evolution Cells contain genes and evolve to display new biological properties. Distinct species Phylogenetic trees show the evolutionary relationships between cells. 1.2 Microbial cell Cells as Catalysts and as Coding Devices 1. Cells carry out chemical reactions Enzymes: protein catalysts of the cell that accelerate chemical reactions 2. Cells store and process information that is eventually passed on to offspring during reproduction through DNA (deoxyribonucleic acid) and evolution. Transcription: DNA produces RNA Translation: RNA makes protein  Genetic Catalytic functions functions DNA Energy conservation: ADP + Pi ATP Metabolism: generation Replication Transcription of precursors of macro- molecules (sugars, amino acids, fatty acids, etc.) RNA Enzymes: metabolic catalysts Translation Proteins Growth © 2012 Pearson Education, Inc.