EONS LEARNING

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      • Study Skills
      • Periodic Table
      • Common Ion Sheet
      • The Scientific Method
      • Doing Background Research
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    • Unit 1: Beginning Chemistry >
      • Lesson 1: The Atom >
        • What is an Atom?
        • The Structure of Atoms
        • The Periodic Table
        • Modeling Atoms
      • Lesson 2: Chemical Bonding >
        • Why Do Atoms Form Bonds?
        • Ionic Bonding
        • Covalent Bonding
        • Intermolecular Attraction
      • Lesson 3: Chemical Nomenclature >
        • Octet Rule
        • Ionic Compounds
        • Covalent Molecules
      • Lesson 4: Molecular Molecules >
        • Modeling Ionic Compounds
        • Modeling Covalent Molecules
      • Lesson 5: States of Matter >
        • States of Matter
        • Phase Changes
      • Lesson 6: Density >
        • What is Density?
        • Calculating Density
      • Lesson 7: Thermodynamics >
        • Temperature
        • Heat
        • Gas Laws
      • Lesson 8: Solution Chemistry >
        • Diffusion
        • Solutions and Molarity
        • Semi-Permeable Membranes
      • Lesson 9: Thermal Expansion >
        • Thermal Expansion
    • Unit 2: Earth Science >
      • Lesson 10: Earth at a Glance >
        • Perspective
        • Maps
      • Lesson 11: Layers of the Earth >
        • Layers of the Earth
      • Lesson 12: Plate Tectonics >
        • Plate Tectonics
      • Lesson 13: Rocks and Minerals >
        • Rocks and Minerals
      • Lesson 14: Particle Sorting >
        • Differentiation
        • Deposition of Sediment
      • Lesson 15: The Atmosphere >
        • Composition of the Atmosphere
        • Layers of the Atmosphere
        • Change Over Time
        • Atmospheric Disruption
    • Unit 3: The Cell >
      • Lesson 16: Life >
        • What is Life?
        • Structural Hierarchy of Living Things
      • Lesson 17: Biochemistry >
        • Intro to Biochemistry
        • Water
        • Micromolecules
        • Energy, Carbohydrates, Lipids
        • Protein and Nucleic Acid
      • Lesson 18: Cells >
        • What are Cells?
        • Microscopy
        • Plant and Animal Cells
      • Lesson 19: Membrane Transport >
        • A Special Environment
        • The Structure of Membranes
        • Membrane Transport
      • Lesson 20: Energy and Cell Respiration >
        • Energy in Biology
        • Energy Diagrams
        • Glycolysis and Anaerobic Respiration
        • Aerobic Cellular Respiration
      • Lesson 21: Photosynthesis >
        • Plants Get Energy From The Sun
        • Photosynthesis Process
        • Energy, Ecosystems, and the Environment
    • Unit 4: Anatomy and Physiology >
      • Lesson 22: The Human Body >
        • What Are Bodies Made Of?
        • What Do Bodies Do?
      • Lesson 23: The Nervous System >
        • The Nervous System
        • Neuronal Communication
        • The Central Nervous System
      • Lesson 24: The Endocrine System >
        • The Endocrine System
        • Hormones
        • Hormones, Puberty, and Reproduction
      • Lesson 25: The Integumentary System >
        • The Integumentary System
      • Lesson 26: The Musculoskeletal System >
        • The Skeletal System
        • The Muscular System
        • Anatomy Of The Musculoskeletal System
      • Lesson 27: The Cardiovascular System >
        • Blood and Blood Vessels
        • The Heart
      • Lesson 28: The Respiratory System >
        • The Respiratory System
      • Lesson 29: The Digestive System >
        • The Digestive System
        • Nutrition
      • Lesson 30: The Excretory System >
        • The Excretory System
      • Lesson 31: The Immune System >
        • Disease and Infection
        • Immunity
    • Units 5-6 Coming Soon
  • Workbench
    • Unit 1 >
      • EIS >
        • Lesson 1: Atoms
        • Lesson 2: Chemical Bonding
        • Lesson 3: Chemical Nomenclature
        • Lesson 4: Molecular Models
        • Lesson 5: States of Matter
        • Lesson 6: Density
        • Lesson 7: Thermodynamics
        • Lesson 8: Solution Chemistry
        • Lesson 9: Thermal Expansion
      • Unit 1: Project
      • Unit 1: Exam Review
      • Unit 1: Exam
    • Unit 2 >
      • EIS >
        • Lesson 10: Earth at a Glance
        • Lesson 11: Layers of the Earth
        • Lesson 12: Plate Tectonics
        • Lesson 13: Rocks and Minerals
        • Lesson 14: Particle Sorting
        • Lesson 15: The Atmosphere
      • Unit 2: Project
      • Unit 2: Exam Review
      • Unit 2: Exam
    • Unit 3 >
      • EIS >
        • Lesson 16: Life
        • Lesson 17: Biochemsitry
        • Lesson 18: Cells
        • Lesson 19: Membrane Transport
        • Lesson 20: Energy and Cell Respiration
        • Lesson 21: Photosynthesis
      • Unit 3: Project
      • Unit 3: Exam Review
      • Unit 3: Exam
    • Unit 4 >
      • EIS >
        • 22: The Human Body
        • 23: The Nervous System
        • 24: The Endocrine System
        • 25: The Integumentary System
        • 26: The Musculoskeletal System
        • 27: The Cardiovascular System
        • 28: The Respiratory System
        • 29: The Digestive System
        • 30: The Excretory System
        • 31: The Immune System
      • Unit 4 Project
      • Unit 4 Exam Review
      • Unit 4 Exam
    • Units 5-6 Coming Soon
  • Donate
  • Home
  • About Us
  • Classroom
    • Resources >
      • Study Skills
      • Periodic Table
      • Common Ion Sheet
      • The Scientific Method
      • Doing Background Research
    • Introduction and Course Philosophy
    • Unit 1: Beginning Chemistry >
      • Lesson 1: The Atom >
        • What is an Atom?
        • The Structure of Atoms
        • The Periodic Table
        • Modeling Atoms
      • Lesson 2: Chemical Bonding >
        • Why Do Atoms Form Bonds?
        • Ionic Bonding
        • Covalent Bonding
        • Intermolecular Attraction
      • Lesson 3: Chemical Nomenclature >
        • Octet Rule
        • Ionic Compounds
        • Covalent Molecules
      • Lesson 4: Molecular Molecules >
        • Modeling Ionic Compounds
        • Modeling Covalent Molecules
      • Lesson 5: States of Matter >
        • States of Matter
        • Phase Changes
      • Lesson 6: Density >
        • What is Density?
        • Calculating Density
      • Lesson 7: Thermodynamics >
        • Temperature
        • Heat
        • Gas Laws
      • Lesson 8: Solution Chemistry >
        • Diffusion
        • Solutions and Molarity
        • Semi-Permeable Membranes
      • Lesson 9: Thermal Expansion >
        • Thermal Expansion
    • Unit 2: Earth Science >
      • Lesson 10: Earth at a Glance >
        • Perspective
        • Maps
      • Lesson 11: Layers of the Earth >
        • Layers of the Earth
      • Lesson 12: Plate Tectonics >
        • Plate Tectonics
      • Lesson 13: Rocks and Minerals >
        • Rocks and Minerals
      • Lesson 14: Particle Sorting >
        • Differentiation
        • Deposition of Sediment
      • Lesson 15: The Atmosphere >
        • Composition of the Atmosphere
        • Layers of the Atmosphere
        • Change Over Time
        • Atmospheric Disruption
    • Unit 3: The Cell >
      • Lesson 16: Life >
        • What is Life?
        • Structural Hierarchy of Living Things
      • Lesson 17: Biochemistry >
        • Intro to Biochemistry
        • Water
        • Micromolecules
        • Energy, Carbohydrates, Lipids
        • Protein and Nucleic Acid
      • Lesson 18: Cells >
        • What are Cells?
        • Microscopy
        • Plant and Animal Cells
      • Lesson 19: Membrane Transport >
        • A Special Environment
        • The Structure of Membranes
        • Membrane Transport
      • Lesson 20: Energy and Cell Respiration >
        • Energy in Biology
        • Energy Diagrams
        • Glycolysis and Anaerobic Respiration
        • Aerobic Cellular Respiration
      • Lesson 21: Photosynthesis >
        • Plants Get Energy From The Sun
        • Photosynthesis Process
        • Energy, Ecosystems, and the Environment
    • Unit 4: Anatomy and Physiology >
      • Lesson 22: The Human Body >
        • What Are Bodies Made Of?
        • What Do Bodies Do?
      • Lesson 23: The Nervous System >
        • The Nervous System
        • Neuronal Communication
        • The Central Nervous System
      • Lesson 24: The Endocrine System >
        • The Endocrine System
        • Hormones
        • Hormones, Puberty, and Reproduction
      • Lesson 25: The Integumentary System >
        • The Integumentary System
      • Lesson 26: The Musculoskeletal System >
        • The Skeletal System
        • The Muscular System
        • Anatomy Of The Musculoskeletal System
      • Lesson 27: The Cardiovascular System >
        • Blood and Blood Vessels
        • The Heart
      • Lesson 28: The Respiratory System >
        • The Respiratory System
      • Lesson 29: The Digestive System >
        • The Digestive System
        • Nutrition
      • Lesson 30: The Excretory System >
        • The Excretory System
      • Lesson 31: The Immune System >
        • Disease and Infection
        • Immunity
    • Units 5-6 Coming Soon
  • Workbench
    • Unit 1 >
      • EIS >
        • Lesson 1: Atoms
        • Lesson 2: Chemical Bonding
        • Lesson 3: Chemical Nomenclature
        • Lesson 4: Molecular Models
        • Lesson 5: States of Matter
        • Lesson 6: Density
        • Lesson 7: Thermodynamics
        • Lesson 8: Solution Chemistry
        • Lesson 9: Thermal Expansion
      • Unit 1: Project
      • Unit 1: Exam Review
      • Unit 1: Exam
    • Unit 2 >
      • EIS >
        • Lesson 10: Earth at a Glance
        • Lesson 11: Layers of the Earth
        • Lesson 12: Plate Tectonics
        • Lesson 13: Rocks and Minerals
        • Lesson 14: Particle Sorting
        • Lesson 15: The Atmosphere
      • Unit 2: Project
      • Unit 2: Exam Review
      • Unit 2: Exam
    • Unit 3 >
      • EIS >
        • Lesson 16: Life
        • Lesson 17: Biochemsitry
        • Lesson 18: Cells
        • Lesson 19: Membrane Transport
        • Lesson 20: Energy and Cell Respiration
        • Lesson 21: Photosynthesis
      • Unit 3: Project
      • Unit 3: Exam Review
      • Unit 3: Exam
    • Unit 4 >
      • EIS >
        • 22: The Human Body
        • 23: The Nervous System
        • 24: The Endocrine System
        • 25: The Integumentary System
        • 26: The Musculoskeletal System
        • 27: The Cardiovascular System
        • 28: The Respiratory System
        • 29: The Digestive System
        • 30: The Excretory System
        • 31: The Immune System
      • Unit 4 Project
      • Unit 4 Exam Review
      • Unit 4 Exam
    • Units 5-6 Coming Soon
  • Donate

Macromolecules for Doing Things: Proteins and Nucleic Acids

What Do Cells Do?

Cells do a lot of things that keep you alive. Mainly, they do chemical reactions that are catalyzed, or made faster (in this case, fast enough to be possible), by special proteins called enzymes. Basically, just about every useful thing that your cell does is made possible by a protein. They’re kind of a big deal.

Many basic cell processes involve making it possible for proteins to do stuff. These reactions also involve a lot of proteins doing stuff. For example, cell respiration, a chemical reaction catalyzed by enzymes (proteins) provides energy for proteins to do stuff. Another reaction, protein synthesis, a chemical reaction catalyzed by enzymes (including proteins), makes proteins based on instructions for DNA. Another reaction, DNA replication, which occurs before mitosis (cell replication), involves making new DNA so that all cells will have the instructions to make protein. And, you guessed it, DNA replication and mitosis are both chemical reactions that rely on enzymes, which are proteins. We’ll talk about a couple of these processes in a little more details in this class.

For a little more on the topic of what cells do, check out this quick overview of cell biology:

How Do Cells Do Things?: Protein

So, proteins do stuff. Let’s get into more of the details of the types of things proteins do and what they’re made of.

​Enzymes are the “Workhorse” of the Cell

The first type of protein in living things is called an enzyme. Enzymes are often called “the workhorse of the cell” because they make a lot of the chemical reactions in our bodies possible. Now, technically, every reaction in our body could occur at some point without an enzyme. But, “at some point” in chemistry might be a really, really long time.

Life doesn’t have the luxury of waiting around for molecules to just randomly bump into each other and, even then, only maybe carry out a chemical reaction. Chemical reactions, especially the elaborate ones involved in life, take a lot of energy to make them happen. This energy is called activation energy. When molecules are just randomly floating around in solution, like in a test tube, they have to—just by chance—bump into each other at just the right angle, with enough kinetic energy to react, in a chemical environment that allows that reaction to occur (like high or low pH).

Picture
Enzymes fix all of these problems. Enzymes lower activation energy by taking a lot of the chance out of how molecules interact with each other. Enzymes bring the right molecules for a reaction together in just the right orientation, and provide just the right surrounding environment, to make it a lot easier—and so, so, so much faster—for biochemistry to occur. Thanks, enzymes!
Picture
This video provides a helpful overview of enzymes (don’t worry about inhibitors for this class, but it’s good for you to know that they exist):
Structural Proteins Provide Structure
​

​The next type of protein in living things is called a structural protein. Much as the name implies, these proteins provide structure.

In humans, the most common structural protein is called collagen. Collagen basically forms a giant net that suspends all of your cells, keeping them in just the right place in your tissues and organs to carry out their jobs. Here’s a video of collagen at work:

​Oh, oops, that was Spiderman. But, collagen works in basically the same way as Spiderman’s webshooters: It’s really strong, pretty stretchy, and is great at holding stuff together. Here’s an actual video of collagen:
​


Nope, Spiderman again, my bad....
​

Aced it.

​
Carrier Proteins Carry Stuff

The third type of protein in living things is the carrier protein. Like the name implies, these proteins carry other things, especially things that are very small or are hard to dissolve in water. One major example in animals (including humans) is hemoglobin, which carries oxygen through your blood and drops it off at the cells that need it most. Carrier proteins are also involved in transporting substances across the cell membrane, which we’ll learn more about when we talk about membrane transport.

Here’s a sneak peak:
Picture

​Or, for more detail:


​Signalling Proteins Are For Cellular Communication

The last major group of proteins is made up of signalling proteins. Signalling proteins are involved in signalling pathways. Signalling pathways are how cells in our body talk to each other to perform complex functions.

Basically, when one cell recognizes that something needs to be done (because of some other chemistry that happened to cause it to realize that), it releases a signalling molecule. That signalling molecule is then recognized by other cells, which somehow change their function to make that thing that needs to be done happen. This process typically involves a protein interacting with another protein, which then interacts with another protein, which then interacts with another protein, and so on, until the protein or proteins that do the thing that needs to be done are turned “on”.
Picture
The nuances of how this all works are a bit more complicated than we’ll go into in this class, but you should know that cells communicate with each other through biochemistry involving proteins. Here’s an example of a signalling pathway:
Talk about a game of telephone….

What Are Proteins Made Of?: Amino Acids

So, now we know that proteins either make chemical reactions happen, hold stuff together, move stuff, or tell cells to do stuff. So… basically, they do all the things. But, what are these über important structures made of? Well, as macromolecules, they are polymers. Their monomers are called amino acids.

An amino acid consists of a “--COOH” group, an “amino” group, and an “R” group. The “R” isn’t actually a chemical structure, we just use it as a placeholder to describe the general structure.
Picture
If you’ve been scratching your head, looking at your Periodic Table, trying to figure out what the heck kind of element is “R,” don’t! It’s not actually an element: we just use it as a placeholder to tell us that an amino acid could have any one of about 20 different sidechains, or functional groups. There are many different amino acids, all of which have a different chemical structure in place of the “R.” These different chemical structures and the different order that the amino acids are found in different proteins are what give each protein its unique structural and functional features. You don’t need to know the details of what the R groups look like or what kinds of things they do for this class, but you should know that they’re what make proteins unique and useful.
Picture
Amino acids have different sidechains, or R groups, that give the protein unique
structural and ​functional properties. Click to enlarge.

How Are Proteins Made?: Nucleic Acids

At this point, you may be asking, “If proteins are so important, where do they come from?” The short answer is that they are made with the help of nucleic acids.

Of the different kind of macromolecules, I suspect you may not be as familiar with the term nucleic acid. So, what is a nucleic acid? I’ll give you a hint: DNA stands for DeoxyriboNucleic Acid.

DNA is a term that a lot of people know but not enough people really understand. You probably know that DNA makes you you, and you may also know it as your genes or your genome. It is found in every cell of your body (well, expect for your red blood cells…. They’re weird). It stores your genetic information. You get half of it from your mom and half from your dad. It is a permanent fixture of your cells and will never go away. And, fun fact, if you stretched out all the DNA in your body, it would stretch to the sun and back about 4 times. But what is DNA? What does it do?
Picture
DNA is a double-helix: a popular icon of science and biology that you should
​really understand as more than just a popular icon of science and biology.

Well, through a process that we won’t get into in this class, DNA is transcribed into another, more temporary nucleic acid called RNA, or ribonucleic acid. This RNA is then translated into protein. You don’t have to know any of the details of this process for this class, but this video explains it, and it will probably help you to understand the purpose of DNA much better:
​


​The short version of this video: DNA does not
become protein, but it sure makes protein possible. Basically, DNA is the recipe for all of the proteins in your body. Since proteins are basically everything you are and do on a cellular level, that makes DNA the recipe for you! Thanks, DNA!

Summary

So, that’s biochemistry in a nutshell. Energy in the form of carbohydrates and fat, the stuff proteins do with that energy, and the DNA (and RNA) that form the recipe for those proteins. Just about everything you are and do distilled down to 4 major types of molecules. It’s absolutely amazing, and understanding the general purpose of these molecules will provide you with the background you need to understand what makes life possible.

Here’s a helpful recap of the four different types of macromolecules:

You should understand:
  • That proteins do most of the jobs of a cell:
    • Enzymes: make the chemical reactions of life possible by putting substrates (the things reacting) in the right orientation to react with each other, lowering the activation energy of that reaction.
    • Structural proteins like collagen provide shape and support to cells. They also bind cells together in tissues.
    • Carrier proteins transport substrates in a very specific manner. One application of this is deciding what can go in and out of a cell.
    • Signalling proteins allow cells to communicate with each other.
  • That proteins are made up of amino acids. There are many different types of amino acids, each of which gives the protein unique structural and functional abilities.
  • That protein is made using the genetic instructions from the nucleic acid DNA, with the help of a nucleic acid called RNA.

Learning Activity

Picture
Lesson 18: Cells
Lesson 17: biochemistry eis

Contributors: Allan Wu and Emma Moulton
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