Biology Basics For Pre-Medical Students

Learner Series:

Biology Basics for the Pre-Medical Student

Table of Contents

Biology is the fundamental pre-medical class. Not because it's the easiest. Rather it's the class that ties together all of your other pre-medical classes and applies what you learn to the study of life.

The Fundamental Medical Class

Biology is, quite simply, the most fundamental of pre-medical classes you’ll take. That doesn’t mean it’s easy! It also doesn’t mean that if you have trouble with biology your medical career is doomed. By the time that most of you take biology in college, you’ve probably had it in high school. If you’re reading this article as a high school student, bravo! Work hard now and it’ll help later! If you’re reading this article as a college student, you’re probably thinking – it’s so much harder now! You’re right it is. That’s because college biology tends to be broader, faster paced, and less forgiving then high school biology. Just remember, biology is the fundamental pre-medical class. Not because it’s the easiest. Rather it’s the class that ties together all of your other pre-medical classes and applies what you learn to the study of life. Do well in biology and you’ll be setting yourself up for future success and understanding. 

Biology Basics For Pre-Medical Students

This post is only meant to serve as a brief review of biology concepts you’ll encounter during an undergrad biology course. We’re only going to review some biology basics for pre-medical students here. Since you’ll be taking 2 semesters of biology, there’s a lot to cover. There’s also some flexibility in what your professors will be covering. However, the core material usually stays the same from class to class. With that being said, let’s get to work!

Now let us say that this is only 1% of the topics you’ll cover. (We need to say that before our biology teachers email us and scold us for leaving out the other 99% of biology.) However, we felt these topics were important to briefly present for the pre-medical undergrad. Learn this, apply the tips we share, and you’ll be off to a good start in your class. However, you’ll also need to learn many more topics on subjects like taxonomy, physiology, mycology, gene expression, mitosis, meiosis, multicellularity, macroevolution, cell communication, population genetics, research methods… ah the list is LONG! Be diligent and you’ll never look at the word again the same way. 

General Biology Tips

Here’s some tips that will help you do well in General Biology in college. These should be especially useful if you are a Freshman and this is one of the first classes that you’re taking!

  • Maintain a Life Schedule: All the freedom of being at college is fun, but it can also be insidious. Make yourself wake up, go to go to bed at a good time, study every day, eat dinner and breakfast, and generally stay organized!
  • Attend EVERY class. Make your face known to the teacher. 
  • Develop a Reputation to your teacher as a hard worker. 
  • Study Every Day. Even if class just started. Even if the first exam is a month away.
  • Pay Attention and Ask Questions!
  • Go to Tutoring! Even if you don’t think you need it.
  • Do Not Wait to get help if you need it.
  • Maintain a Study Schedule! Read your Syllabus and organize your schedule around it.
  • Take Good Notes. You’ll need them for the MCAT!
  • Create Keyword Lists. Starting day 1 make a word document. Start each line with a keywork follow it with a 1 sentence definition. Your text books may bold words. Use these bolded words to formulate your keyword list. Study this list every day until your test!
  • Study the Syllabus’ Learning Objectives. Create a word document, like your keyword document, and answer every learning objective as completely as possible. Continue to study this document until your test. 

Biology, The Study of Life... and Some Other Stuff.

Biology is really about learning how things in the world relate to themselves and other things. It’s pretty heavy on memorization, learning systems, taxonomy, principles, research, and well pretty much everything else on this planet! Don’t worry though, your class will be just a basic overview. 

I’ll show you some key concepts you need to know presented in a keyword list format. The same format I recommend using above. DO NOT USE THIS LIST BY ITSELF TO STUDY FOR CLASS! CREATE YOUR OWN LIST! If you only read my list, it’s no better then just reading a chapter of the book. 

Notice that in the example of a keyword list below… a lot of work went into it. It takes time to create, it takes time to study, and it takes time to learn. You will not be able to cram the creation and learning of keyword documents into a single night. 

Read over this content and lightly and try to learn a few things from it. Be patient though, you can’t do everything in a day!

12 Principles of Biology Keyword Review

*I created documents just like this for my General Biology classes as a Pre-Medical Student. Notice that this is memorization heavy and reflects the structure of most biology exams. For the Record, creating, studying, and organizing documents like this helped me get a 100+ on all of my exams. The highest grades in the class by far. *

Chapter 1: Principles of Biology.

Principles of Biology: 12 Broad and Unifying Principles Unify the Fields of Biology.
(Notice that there are 12 principles of biology here. You better believe all 12 are going to show up on an exam!)

Principle 1:
Cells are the simplest units of life.
Organism: Term which can be applied to all living things. They maintain an internal order separate from the environment.
Cell: Simplest unit of an organism’s organization.
Cell Theory: 1. All organisms are comprised of cells. 2. Cells are the smallest units of life. 3. New cells come from pre-existing cells via cell division.

Principle 2
: Living organisms use energy.
Respiration: When a cell breaks down nutrients to release energy. This energy can be / is used in processes such as Metabolism.
Metabolism: Chemical reactions that are involved with the breakdown and synthesis of cellular molecules.
Photosynthesis: When plants, certain bacteria, and algae use light to produce their own nutrients.

Principle 3: Living organisms interact with, and respond to, their environment.
Principle 4: Living organisms maintain homeostasis.
: When cells and bodies maintain a relatively stable internal environment.

Principle 5: Living organisms grow and develop.
Growth: Produces more and larger cells.
Development: A series of changes in the state of a cell, tissue, organ, or organism.

Principle 6: Genetic material provides a blueprint for reproduction.
Reproduce: Generating offspring to continue life which resembles the parent(s).
DNA (Deoxyribonucleic Acid): What genetic material is comprised of. Provides the blueprint for the development, organization, and function of living things.
Heritable: DNA is passed onto offspring.
Genes: Segments of DNA which govern characteristics or traits of organisms. They include proteins.
mRNA (Messenger Ribonucleic Acid): What genes are transcribed into. A type of RNA
Polypeptide: What the mRNA becomes, with a specific amino acid sequence.
Protein: Composed of one or more polypeptides. The structure and function or proteins are largely responsible for the traits of living organisms.

Principle 7: Populations of organisms evolve from one generation to the next.
Biological Evolution / Evolution:
A heritable change in the population of organisms from generation to generation.

Principle 8: All species (past and present) are related by an evolutionary history.
Genome: Refers to complete genetic composition of an organism or species.
Proteome: The complete protein composition of a cell or organism. Evolution often effects the genome which then alters the proteome.

Principle 9: Structure Determines Function. (This principle was more important to medicine then I realized at the time!)

Principle 10: New Properties of Life Emerge from Complex Interactions.
Emergent Properties:
When individual components interact with one another or the environment to create novel structures and functions.
Systems Biology: The study of how new properties of life arise by complex interactions of is components.

Principle 11: Biology is an Experimental Science.

Principle 12: Biology Affects our Society.

Let's Review SOME of the Principles

First of all recognize that’s just 1 chapter – and only half of the chapter so far! The other half is below. Expect your biology midterms to be long, multi-chapter exams. You need to maintain high A’s on these exams, and if the exam is 60 questions long… You can only get about 3 wrong. Now let’s talk about the content. 

These principles are critical to understanding the study of General Biology and Biology as a discipline. There are many, many medically related concepts that come from those principles. Let’s talk about a few. 

  1. Cells are the simplest units of life.
    1. Here is where you’ll be introduced to the discipline of cellular biology. This is critically important to understand for your Bio exams and for medical school.
  2. Living organisms use energy.
    1. I thought this was a silly principle at first, duh of course living things use energy. What do we have to think about zombies or something? But actually, this principle is frighteningly deep.
    2. Almost the entire class of Biochemistry is built on understanding how living organisms achieve this principle
  3. Living Organisms Interact with and respond to their environment. Living Organisms maintain homeostasis.
    1. These two principles are related and some very bad diseases are the result of the body trying to maintain homeostasis when it shouldn’t. 
    2. The principle of homeostasis also has implications with aging!

  4. Structure Determines Function and Novel Properties Emerge from Complex Interactions.
    1. These two principles are important because the complexity of life builds upon itself. 
    2. Think of a bat’s wing. Each bone, all the tendons, the skin when put together allows that bat to fly.
      1. Structure determined function and a novel property emerged from their interaction!

Basic Principles of Biology Keywords


10 Levels of Biological Organization Exist: 1) Atoms, 2) Molecules & Macromolecules, 3) Cells, 4) Tissues, 5) Organs, 6) Organisms, 7) Population, 8) Community, 9) Ecosystem, 10) Biosphere.
Atom: Smallest unit of an element that retains the element’s characteristics.
Molecules: Atoms bound together.
Many Molecules!
Cell: Surrounded by a membrane and contains a variety of molecules and macromolecules.
Tissues: Made of many cells of the same type.
Organs: Composed of two or more types of tissue.
Organisms: All living things, made up of many organs.
Species: Classifications of organisms into unique and particular groups.
Population: Groups of organisms that occupy the same environment.
Community: An assemblage of populations of different species.
Ecosystem: The interaction between communities and their environment.
Biosphere: All places on Earth where life exists.

Lineage: Studying evolution from a progression of changes in a series of ancestors.
Vertical Evolution: Evolution that occurs in a lineage.
Mutations: The mechanism in vertical evolution. Occurs by the accumulation of mutations.
Natural Selection: When a beneficial mutation increases the chances of survival of an organism.

Taxonomy: The grouping of species.
3 Domains of Life: Archaea, Bacteria, and Eukarya.
Prokaryotic: Bacteria & Archaea. Simple.
Eukaryotic: Larger cells with internal compartments that serve various functions.
Cell Nucleus: Only exists in eukaryotic cells and contain the genetic material.
Binomial Nomenclature: A two-part name used to provide each species with a unique scientific name.

Genomics: The ability to analyze the DNA sequence of genomes.
Proteomes: All of the proteins that a cell or organism makes.
Science: The observation, identification, experimental investigation, and theoretical explanation of natural phenomena.
Model Organisms: Organisms studied by many different researches in order to compare them.
Scientific Method: O.H.E.T. (Observe, Hypothesis, Experiment, Theory)
Ecology: The study of organisms in their natural environment.
Anatomy and Physiology: The study of the form and function or an organism.
Cell Biology: The study of cells.
Molecular Biology: The study of individual molecules in cells.
Systems Biology: Research aimed at studying how emergent properties arise.
Hypothesis: A proposed explanation for a natural phenomenon.
Predictions: Expected outcomes that can be shown to be correct or incorrect.
Falsifiable: Can be shown to be correct by additional observations or experimentation.
Theory: A broad explanation of some aspect of the natural world that is substantiated by a large body of evidence.
Discovery-Based Science: The collection and analysis of data without the need for a preconceived hypothesis. Often leads to hypothesis testing and is good for exploring new branches.
Hypothesis Testing: OHET (Observe, Hypothesis, Experiment, Theory)
Control Group & Experiment Group: Used in hypothesis testing.
Repeatable: Valid experiments are repeatable.

See how we went from principles to a ton of terms and concepts? Get used to this. Expect at least 3 – 6 chapters from just like this on your first midterm. We’ll look at a few more chapters!

The Elements of Life Keywords

Chapter 2: The Chemical Basis of Life

(I told you biology ties together all your other pre-med science classes right? Expect to get a solid introduction to chemistry early on in Biology. You’ll need it to understand how cells work!)


2.1 – Atoms

Matter: Anything that has mass and occupies space.
Atoms: Elementary unit of matter which cannot be broken down into smaller pieces by ordinary chemical means.
Molecules: Two or more atoms bonded together.
Element: A pure substance of only one kind of element.
Protons: Positive charge.
Electrons: Negative Charge. Very little mass.
Neutron: In the nucleus, has mass.
Atomic Nucleus: The center of the atom where the neutrons and protons are found.
Energy: The capacity to do work. In biology common energy types are chemical, light, and mechanical.
Atomic Number: Number of protons in an atom.
Isotope: Atoms which have varying number of protons in their nucleus.
Elements that are Essential For Life (Mass % / Atom %): Oxygen (.65 / .25), Carbon (.18 / 9.5),
Hydrogen (.09 / .63), Nitrogen (.03 / .014) 

So we start our discussion in this chapter with what the most basic building blocks of nature are. Don’t worry too much if you don’t know the atomic mass of Carbon, or any other details. You’ll get this all later.  


2.2 – Chemical Bonds and Molecules

Compound: A molecule of two or more different elements.
Covalent Bonds: Atoms which share a pair of electrons. Sigma bond
Double Bond: Occurs when atoms share two pairs of electrons. Sigma + Pi bond.
Ion: Created when an atom gains or loses an electron.
Cations: Positively charged ions, readily created by Row I, II, III elements.
Anion: Negatively charged ions, created by Row VI, VII, VIII elements.
Ionic Bonds: Occurs when a cation bonds to an anion.
Free Radical: A molecule containing an atom with a single unpaired electron in its outer shell. Highly reactive, can steal electrons from other atoms / molecules. Can be created via toxins and radiation. Antioxidants help to protect against them.
Chemical Reaction: Occurs when one or more substances change into other substances.
Catalyst: Speeds up a reaction.
Reactants: Starting materials.
Products: Ending materials.

Now you see how these elements are interacting with each other on the atomic level. This will be important as we expand our knowledge of how cells work. We’ll next look at the properties of water, the literal building block of life. 

2.3 – Properties of Water

Solutes: Substances dissolved in liquids.
Solvents: The liquid in which solutes are dissolved.
Solution: The combined solute / solvent mix.
Hydrophilic: “Water” loving molecules. These are molecules with ionic or polar bonds.
Hydrophobic: “Water fearing” molecules. These molecules have no partial positive or negative regions.
Specific Heat: Water has a high SH.
Surface Tension: Surface attraction of a liquid. High for water.
Strong Acid: Fully ionizes – 7 Strong acids.
Weak Acid: Partially ionizes.
Base: Absorbs hydrogen ions.
pH: The negative logarithm to the base 10 of the H+ concentration.
Acidic: pH Balances under 7
Alkaline (Basic): pH balances over 7
Buffer: A compound that minimizes pH fluctuations in the fluids of living organisms.

Water is a big deal. It’s an amazing compound. You need to understand its chemistry in order to understand biology. The terms above are the very basics for understanding the building block of life. 

Carbon and Macromolecules Keywords


Now let’s take everything you learned in the last chapter and builds additional principles upon it. Now we’re starting to look at macromolecules, organic molecules, and the most incredible element of life: carbon.
You’ll also be learning about functional groups. These are very important in biology and organic chemistry. 

Organic Molecules: Carbon-containing molecules.
Macromolecules: Large complex molecules which include lipids, carbohydrates, proteins, and nucleic acids.


3-1 The Carbon Atom and the Study of Organic Molecules

Organic Chemistry: The science of carbon-containing molecules. (Oh you’ll get super friendly with orgo soon!)
Carbon Forms Four Covalent Bonds with Other Atoms: Commonly with Carbon, Nitrogen, Oxygen, Hydrogen and Sulfur. These bonds can be polar or non-polar (Important!)
Hydrocarbons: Molecules with mainly carbon / hydrogen bonds. They are hydrophobic and poorly soluble in water. They are hydrophobic because the Carbon and Hydrogen have similar polarities and form non-polar bonds (remember like dissolves like!).
Carbon Atoms Can Bond to Several Biologically Important Functional Groups: Memorize Table 3.1
Functional Groups
: Groups of atoms with characteristic functions and properties.
Amino: -NH2, Found in Amino Acids; Weakly basic, polar, forms part of peptide bonds.
Carbonyl: -CO (double bonded oxygen at the end of a chain), Found in Steroids, waxes, and proteins; Polar, highly chemically reactive, forms hydrogen bonds.
Ketone: -CO (double bonded Oxygen at the middle of a chain), Found in Steroids, waxes, and proteins; Polar, highly chemically reactive, forms hydrogen bonds.
Aldehyde: -COH (The Carbon and Oxygen are double bonded), Found in Linear forms of sugars and some odor molecules; Polar, highly chemically reactive, forms hydrogen bonds.
Carboxyl: -COOH, Found in Amino acids, fatty acids; Acidic; forms part of peptide bonds.
Hydroxyl: -OH. Found in steroids, alcohol, carbohydrates, some amino acids; Polar, forms hydrogen bonds with water.
Methyl: -CH3. May be attached to DNA, proteins, and carbohydrates; Nonpolar.
Enzymes: Molecules that catalyze, speed up, the rates of many biologically important chemical reactions. Enantiomers of enzymes typically do not recognize one another.


Organic Molecules are awesome! Make sure you understand the differences between carbohydrates, lipids, proteins, and nucleic acids! You’ll go into much more detail in your real class. 


3.2 Formation of Organic Molecules
4 Categories of Organic Molecules that All Life Has: 1) Carbohydrates, 2) Lipids, 3) Proteins, 4) Nucleic Acids
(Important concept for nutrition in medicine!)

3.3 Carbohydrates
Carbohydrates: Composed of carbon, hydrogen and oxygen atoms (Cn(H2O)n). Remember the root of the name – Carbon-containing compounds that are hydrated. 
Glucose: Water soluble, very important to energy. Can exist as two enantiomers, which change the position of the –OH (hydroxyl) group attached to the carbon atom.
Polysaccharides: Many monosaccharides are linked together.

3.4 Lipids
Lipids: Hydrophobic molecules composed mostly of hydrogen and carbon atoms, and some oxygen. They are non-polar / insoluble and account for about 40% of the organic matter in a human body. 
Triglycerides: “Fats”.
Triglycerides: Created by bonding glycerol to three fatty acids via an Ester Bond. 
Saturated Fatty Acid: A Fatty Acid in which all the carbon bonds are single covalent bound. High melting point and solid at room temp. Think animal fats.
Unsaturated Fatty Acid: Mono- (1 double bond) or Poly- (More than 1 double bond). Called ‘Oils’. 
Role of Fats: Important for storing energy. Hydrolysis of triglycerides releases the fatty acids from the glycerol, and these products can then be metabolized to provide energy to make ATP. Also plays a role in structuring / cushioning the organs and with providing insulation.
Steroids: Distinct chemical structure. Four fused carbon rings of carbon atoms form the skeleton of all steroids. 
Cholesterol: A type of steroid from which all other steroid hormones are developed. 


Understand Carbohydrates and Lipids. Many health problems come from over-consumption of these two categories of organic molecules. You’ll spend a lot of time in medical school learning about their impact on health and how they are related to disease like hyperlipidemia and diabetes. 

3.5 Proteins
Proteins: Polymers found in all cells and play critical roles in nearly all life processes. Account for about 50% of the organic material in an animal’s body. 
Amino Acids: The building blocks of proteins. Made up of a carbon linked to a carboxyl group and an amino group. Called amino acids because there is an amino group and the carboxyl group acts as an acid.
7 Major Protein Functions: Gene Expression & Regulation, Motor, Defense, Metabolic, Cell Signaling, Structural, and Transporters. 

Remember the principle that structure determines function? Understanding protein level structure is essential to really understanding that principle. This may take some time to grasp so start studying early and try to watch as many videos as possible, if you are a visual learner. 

4 Progressive Levels of Protein Structure.


  1. Primary Structure: Its amino acid sequence from beginning to end. Determined by genes. Average size – 300 to 500 amino acids in length.
  2. Secondary Structure: Repeated patterns which define shape. Two basic patterns are beta folded sheets and alpha helices.
  3. Tertiary Structure: The three dimensional shape of the polypeptide. This includes the secondary structures plus interactions amongst the amino acid side-chains. For some polypeptides, this is the final level of complexity.
  4. Quaternary Structure: Two or more polypeptides bound to one another to form a functional protein. Also known as multimeric proteins.

Cellular Structure

Here is where you really start to learn how all those building blocks come together to make the most basic structure of life – a cell. It’s frankly amazing how a cell works. Make sure you have a firm understanding of cellular biology and cell theory. It is a topic that is heavily tested on your MCAT!

Cell Theory: 1. All living things are comprised of one or more cells. 2. Cells are the smallest unit of life.
3. New Cells come only from pre-existing cells from cell division.

Overview of the Cell Structure
Cell Structure Determined By: 1) Matter. 2) Energy. 3) Organization. 4) Information
Genome: The entire compliment of a organisms genetic material.
Genes: Contains information to produce cells with particular structures and functions.
Prokaryotic Cells: Protean. Bacteria and Archea. Very small. 
Eukaryotes: Protists, fungi, plants, and animals.
Organelle: A membrane-bound compartment with its own unique structure and function. 

Keep in mind that biology teaches you a lot about plant, bacteria, and fungi too! You may not want to study these topics, but to get to medical school you need to get A’s in biology class, so don’t neglect them!


4-3 The Cytosol
Cytosol: The region that is outside the membrane bound organelles but inside the plasma membrane. 
Synthesis and Breakdown of Molecules occur in the Cytosol.
Metabolism: The sum of the chemical reactions by which cells produce the materials and utilize the energy necessary to sustain life.
Enzyme: An enzyme that accelerates a chemical reaction. 
Catabolism: Some pathways which involve the breakdown of a molecule into smaller components.
Anabolism: Pathways involved in the synthesis of molecules and macromolecules. 
Cytoskeleton: A network of three different types of protein filaments: microtubules, intermediate filaments, and actin filaments. 

General Structure of an Animal Cell:

Centrosome: Site where microtubules grow and centrioles are found.
Rough ER: Site of protein sorting and secretion.
Smooth ER: Site of detoxification and lipid synthesis.
Mitochondrion: Site of ATP Synthesis.
Cytoskeleton: Protein filaments that provide shape and aid in movement.
Peroxisome: Site where hydrogen peroxide and other harmful molecules are broken down.
Golgi Apparatus: Site of modification, sorting, and secretion of lipids and proteins.
Cytosol: Site of many metabolic pathways.
Plasma Membrane: Membrane that controls movement of substances into and out of the cell; site of cell signaling.
Ribosome: Site of polypeptide synthesis.
Lysosome: Site where macromolecules are degraded.
Nuclear Envelope: Double membrane that encloses the nucleus.
Nucleus: Area where most of the genetic material is organized and expressed.
Nuclear Pore: Passageway for molecules into and out of the nucleus.
Nucleolus: Site for ribosome subunit assembly.
Chromatin: A complex of protein and DNA.

General Structure of a Plant Cell:

Central Vacuole: Site that provides storage; regulation of cell volume.
Cytosol: Site of many metabolic pathways.
Mitochondrion: Site of ATP synthesis.
Chloroplast: Site of photosynthesis.
Cytoskeleton: Protein filaments that provide shape and aid in movement.
Golgi Apparatus: Site of modification, sorting, and secretion of lipids and proteins.
Peroxisome: Site here hydrogen peroxide and other harmful molecules are broken down.
Cell Wall: Structure that provides cell support.
Plasma Membrane: Membrane that controls movement of substances into and out of the cell; site of cell signaling.
Rough ER: Site of protein sorting and secretion.
Smooth ER: Site of detoxification of lipid synthesis.
Ribosome: Site of polypeptide synthesis.
Nuclear Pore: Passageway for molecules into and out of the nucleus.
Nucleus: Area where most of the genetic material is organized and expressed.
Nucleolus: Site for ribosome subunit assembly.
Chromatic: A complex of protein and DNA.

Let’s skip forward a few sections bit and look at something called cellular respiration and fermentation. Those are fancy words for making energy! Our cells don’t run on hamburgers and salads. They run on ATP. Your body needs a way to turn your lunch into ATP and that’s where cellular respiration and fermentation come in.

Cellular Respiration and Fermentation

Cellular Respiration: The metabolic reactions that a cell uses to get energy from food molecules and release waste products.

This topic comes up again and again. First as a pre-med and then later as a medical student early in your education. Many metabolic diseases are related to cellular respiration, so you at least need a basic familiarity with the subject. For your Bio exam you want to know this really well!

5-1 An Overview of Cellular Respiration
Aerobic Respiration:
The process of making ATP using oxygen as a fuel and producing CO2 as a waste.
Glycolysis: Occurs in Cytosol. Using 2 ATP, Glucose (6 Carbons) is broken into two pyruvate molecules (3 carbons each) producing 4 ATP and 2 NADH (2 ATP and 1 NADH per pyruvate).
Citric Acid Cycle: Occurs in the Mitochondrial Matrix. Each acetyl group (actually acetyl CoA) enters into the Krebs cycle, starting with oxaloacetate. Each produces two CO2, one ATP, three NADH, and one FADH2. All made via substrate level phosphorylation.

5-2 Glycolysis
The breaking down of a glucose molecule into two molecules of pyruvate. 10 Steps.
Biochemistry: The study of the chemistry of living organisms.

5-3 Breakdown of Pyruvate
Breakdown of Pyruvate: Creates a molecule of Acetyl COA

5-4 Citric Acid Cycle
Citric Acid Cycle: The Metabolic cycle seen in the mitochondria that we’re studying here. Starts with acetyl CoA and oxaloacetate reacting with one another.


5-5 Oxidative Phosphorylation
Oxidative Phosphorylation:
When NADH and FADH2 have electrons removed and become oxidized. In the process making ATP by the phosphorylation of ADP.
Electron Transport Chain (ETC): A group of small organic molecules and protein complexes embedded in the inner mitochondrial matrix.
ATP Synthase: The enzyme that synthesizes ATP at the end of the ETC and uses the H+ Electrochemical gradient to do so. A rotary machine.
H+ Acts as the water in a watermill, spinning the ATP Synthase and ‘grinding’ together ADP and Pi.

(The watermill action to make ATP is a favorite test topic! Know it well!)



5-6 Anaerobic Respiration and Fermentation 
Anaerobic: An environment that lacks oxygen.
Fermentation is the Breakdown of Organic Molecules without Net Oxidation

The 4 Metabolic Pathways of Cellular Respiration

1) Glycolysis
2) Pyruvate to Acetyl CoA
3) Citric Acid Cycle
4) Oxidative Phosphorylation

Take a deep breath, you’re done! 

The Path to Medical School Can Feel Long And Unclear

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