In Episode 6, Melanie recaps elements of life and shares two mnemonics - OSHMERG (1:03) and CHNOPS (4:00).
In Episode 6, Melanie recaps elements of life and shares two mnemonics - OSHMERG (1:03) and CHNOPS (4:00). She begins with the definition of matter and reviews its role in growth. Can you describe the atomic structure (2:09) and its role in bonding? Metabolism misconceptions are debunked (2:38) - even though students can eat an entire pizza. What do you think of when you hear the word organic? (3:20) The six most common elements of life are reviewed and distinctly associated with the four biological molecules. (4:12)
The Question of the Day (5:28) asks “How is the periodic table organized?”
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Hi and welcome to the APsolute RecAP: Biology Edition. Today’s episode will recap Elements of Life.
Lets Zoom out:
Unit 1 - Chemistry of Life
Topic - 1.2 Elements of life
Big ideas - Energy
Remember – Structure influences function, and this will hold true for atoms as well. Let's review some basic concepts of atoms before diving into common elements
Lets Zoom in:
The CED states that organisms must exchange matter with the environment to grow, reproduce and maintain organization. As an aside, are you having trouble remembering the characteristics that all living things share? Remember the acronym OSHMERG. All living things have organization, respond to stimuli, maintain homeostasis, metabolize, use energy, reproduce, and grow.
Ok, now back to matter. Matter is made up of atoms, has mass and takes up space. For example, rocks, trees, and people are made of matter while energy is not. We just said that living things grow, and - spoiler alert - they have to accumulate more matter to do so. Once they have this matter, they can use the raw materials to build useful molecules for biological processes. For example, taking in glucose as a reactant for cellular respiration or carbon dioxide for photosynthesis.
Atoms contain three subatomic particles. Protons are positively charged, found in the nucleus and are represented as the atomic number found in the periodic table. Neutrons have no charge and are also found in the nucleus. Electrons have a negative charge and are found surrounding the nucleus. They are often described as an electron cloud or arranged in rings. Because electrons are the most peripheral of the three subatomic particles, they will be involved in bonding with other atoms.
The making and breaking of bonds is the foundation of metabolism. Too often, metabolism is miss-defined and only thought of as how well someone can digest their food. Like “Wow, high school students must have great metabolism. They can eat an entire pizza and never gain any weight!” If living things were only completing reactions of digestion, we would break bonds continuously until nothing was left of us! In contrast, metabolism is the sum of all chemical reactions that take place within an organism - those that are bond breaking, or catabolic, and those that are bond forming, or anabolic. We have to do both to be biologically successful.
What do you think of when you hear the word organic? Images might come to mind of apples grown without pesticides or grass fed cows. But in science, it is much simpler. Not all atoms are equally valued by living things. There is one element that reigns supreme - CARBON. Organic molecules contain carbon. Because carbon has 4 valence or outer ring electrons, it forms 4 covalent bonds with other elements. These bonds can be single, double, or triple – causing molecular shapes of straight chains, branched chains and rings. Often times carbon (and sometimes hydrogen) is omitted from molecular ring diagrams because their presence is always assumed at a corner.
In order of appearance, the 6 most common elements found in living things – CHNOPS. Carbon, hydrogen and oxygen are frequently linked and are represented in all biological molecules. Nitrogen will never be found in carbs and lipids but is always a component of nucleic acids and proteins (think nitrogenous base and amino group). Even though nitrogen is the most abundant gas in the atmosphere, it will need to be taken in through food – this is true for plants too and is the primary component in products like Miracle grow. The final two elements make infrequent appearances. Phosphorous will always be in nucleic acids as a component of the backbone of DNA and will appear in only lipids that are phospholipids. The presence of a phosphate group gives DNA is negative charge and phospholipid heads their polarity and subsequent hydrophilic affinity. Sulfur makes its only appearance in some R groups of proteins. This influences protein folding through the formation of disulfide bridges.
To recap….
Organic molecules are made of carbon and form a variety of structures through bonding patterns with other elements (CHNOPS). Organisms obtain these elements from their environment and through metabolism, build up and break down polymers to grow, reproduce and maintain organization.
Today’s Question of the day is about elements.
Question: How is the periodic table organized?