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Oct 19, 2024 · Life: Defining Life. The basic constituents of life are also the most common elements in the universe: carbon, oxygen, hydrogen, nitrogen. Many biochemists therefore regard the emergence of life as inevitable wherever the right chemical and environmental conditions exist.
- Cells and Organization
- Metabolism
- Environmental Adaptation
- Homeostasis
- Growth and Development
- Reproduction
- Evolution
- Reference
Cells are the basic unit of life. The smallest organism consists of one cell. Within that cell is the cellular equivalent of organs, called organelles. Organelles are made of molecules or macromolecules such as carbohydrates, lipids, proteins, and nucleic acids. These organelles serve different functions including transferring ribonucleic acid (RNA...
Organisms must acquire and use energy in order to maintain their complex, living systems. Cells metabolize molecules, such as nutrients, to produce energy and use it for other processes, like replicating deoxyribonucleic acid (DNA). Some organisms, including plants and some bacteria, can convert light energy to produce nutrients. This is called pho...
Organisms must be able to adapt to their changing environments. For example, during the season when the sun is directly overhead, plants will grow upward, but they will grow more toward the side during those seasons when the sun is lower in the sky. Horses shed their coats in the spring and summer to allow for easier cooling during the warmer weath...
Organisms must maintain an internal environment that is conducive to cell metabolism. For example, humans must maintain a specific body temperature. When they are cold, they will shiver, a response that causes the muscles to produce more heat. When they are too warm, the body will produce sweat which carries heat away from the body when it evaporat...
All organisms undergo a process of growth and development. Single-celled organisms start as smaller cells that grow. The contents of the cell may become more diverse and complex. More complex organisms, such as humans, start out as a single cell that divides to create more cells. These new cells differentiate to develop into specialized cells that ...
All living organisms have DNA, which is genetic material containing the information and instructions for forming an organism. All organisms die and must be able to pass this genetic material on to create more organisms. This is done through reproduction. Single-celled organisms may divide in half and grow. Other organisms reproduce sexually, a proc...
The book, Biology, by Robert J. Brooker, et al., defines biological evolution as “the phenomenon that populations of organisms change over the course of many generations.” This can include the beak length and shape of a particular species of bird that is better suited to acquiring certain kinds of food in a particular environment. The characteristi...
Brooker, Robert J., Widmaier, Eric P., Graham, Linda E., and Stiling, Peter D. Biology. New York: McGraw-Hill, 2008.
Cell theory states that all living things are composed of cells, that cells are the basic unit of life, and that cells come from pre- existing cells. All cells have the same basic structure of a gel-like cytoplasm enclosed by a double layer of lipid molecules called the plasma membrane.
- Katherine Mattaini
- 2020
Oct 31, 2023 · A cell is the smallest unit of a living thing. A living thing, whether made of one cell (like bacteria) or many cells (like a human), is called an organism. Thus, cells are the basic building blocks of all organisms.
The following outline is provided as an overview of and topical guide to life forms: A life form (also spelled life-form or lifeform) is an entity that is living, [1] [2] such as plants , animals , and fungi .
DNA and RNA are nucleic acids; alongside proteins and complex carbohydrates, they are one of the three major types of macromolecule that are essential for all known forms of life. Most DNA molecules consist of two biopolymer strands coiled around each other to form a double helix .
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A cell is the basic unit of life as we know it. It is the smallest unit capable of independent reproduction. Robert Hooke suggested the name ‘cell’ in 1665, from the Latin cella meaning storeroom or chamber, after using a very early microscope to look at a piece of cork.
