BIO 111 Lecture Notes

BIO 111 Lecture Notes

Thu Apr 2

Unit 1 Module 1: Connection Between Diet and Energy

  • Why do we need to eat?

  • Everything your body does requires energy

    • Moving

    • Thinking 

    • Staying Warm

  • We are Heterotrophs: We obtain energy by eating food

Energy: The ability to do work (transfers energy between forms)

  • Without an energy source, all life on earth would stop

Types of Energy: Solar Energy

  • Energy in the form of light from the sun

  • Every single organism on earth depends on solar energy for life 

Types of Energy: Mechanical Energy

  • Kinetic Energy 

    • Energy of movement

    • Examples: Flapping wings, heat energy

  • Potential Energy

    • Stored energy

    • Examples: Water behind a dam, concentration gradient 

Types of Energy: Chemical

  • Energy stored in chemical bonds

Food Is a Form of Chemical Energy

  • Foods contain organized nutrient molecules with chemical energy stored in bonds between atoms

  • When you digest food, you break bonds and harvest the energy to run your cellular processes

First Law of Thermodynamics

  • Energy cannot be created or destroyed, but it can change forms

  • Photosynthesis is not creating energy, it is converting light energy from the sun to chemical energy in the plant

  • All energy in the universe existed when its first began

Second Law of Thermodynamics 

  • Energy conversations are inefficient and some energy will ALWAYS be lost

    • Example: heat loss 

Third Law of Thermodynamics

  • Energy flows from higher (more ordered or efficient) forms to lower (less ordered or efficient) energy forms

  • Disorder, or entropy increases over time 

  • Entropy: disorder or randomness in a system

    • Low entropy -> organized (ordered)

    • High entropy -> messy (disorganized)

Energy Conversions

  • Solar Energy is converted into chemical energy by plants (plant sugars)

  • Animals eat plants (or other animals) to convert plant sugar into ATP (energy for now) and is stored energy (saved for later)

How do Cells Fuel Chemical Reactions?

  • Adenosine Triphosphate (ATP)

  • Adenosine Diphosphate (ADP)

ATP: can be used and recycled thousands of times

  1. Energy is released as a phosphate group is ejected from ATP

  2. An input of energy from the breakdown of food attaches ADP to Pi

  3. Cells store energy in the bonds of ATP


Organic Nutrients

  • AKA Biological Macromolecules

  • Hydrogen and other elements covalently bonded to Carbon

  • Carbon is the backbone of organic molecules necessary for life - forming long chain of hydrogens and carbons

    • Hydrocarbons

Carbon

  • Most versatile element on earth

  • Four valence electrons means many covalent bonds 

Functional Groups

  • Functional groups are attached to hydrocarbon chains to provide chemical reactivity to organic molecules 

  • Different functional group means the molecules has a different job

Dehydration Synthesis

  • Joining monomers to form a polymer by removing a water molecule 

Hydrolytic Reaction (Hydrolysis)

  • Breaking polymers down into monomers by adding a water molecule 

Types of Organic Nutrients: Carbohydrates

  • Chains of sugar molecules (carbon rings with 3-7 carbons)

  • Quickly accessed as an energy source (preferred energy source)

  • Can form long polymers that are easily broken down by digestive enzymes 

  • Energy storage molecule found in roots and seeds of plants

  • Energy storage molecule found in muscles and the liver of animals

Types of Organic Nutrients: Lipids

  • Non-polar molecules that do not dissolve in water

  • Stores in fatty tissue; used for long-term energy storage

  • Hydrophobic

  • Insulation

  • Helps protect vital organs

  • Three types:

    • Fats: long term energy storage and insulation

      • Saturated fats raise bad cholesterol in the blood stream which can create blockages and heart disease

      • Trans Fats: manmade fats, one of the worst things you can eat

        • Physically changing chemical structure 

    • Sterols: Regulate growth and development

      • Carbon arranged in four rings instead of chains

      • Cholesterol: component of animal cell membranes

        • In blood, can attach to vessel walls, causing blockage 

      • Steroid Hormones

        • Regulate sexual development, maturations, and sex cell production

        • Estrogen: Memory/Mood

        • Testosterone: Muscle growth

    • Phospholipids

      • Compose the membrane of all living cells

Types of Organic Nutrients: Proteins

  • Amino groups and carboxyl group bound to a chain of amino acids

  • Order, identity and number of amino acids determine protein function

  • Wide range of functions: enzymes and signaling molecules

  • Supplies organisms with energy if carbohydrates and fat are not available 

Nucleic Acids

  • Not a source of energy in organisms’ diet

  • Storage and processing of genetic information 


Food = chemical energy -> converted into ATP -> powers life