Chapter 6: Energy Flows Through Life

Cell Membranes

barrier between the cell and the environment, they act as filters for the cell with their selective permeability

Metabolism

the sum of all the chemical reactions in the body, it speeds up or slows down when needed

Catabolic Reactions

A metabolic reaction that breaks larger molecules into smaller ones, releasing energy

Anabolic Reactions

A. metabolic reaction that builds larger molecules out of smaller ones, requiring an input of energy

Phospholipid Bilayer

Builds the cell membrane, 2 layers, made of phosphate and lipids where the phosphate head is hydrophilic and outward facing and the lipid tail is hydrophobic and faces inward towards each other

Plasma Membrane

the cell membrane, refers to the fluidity of the membrane because of lipid movement

Selective Permeability

The property of membranes that lets certain substances pass while blocking others, this is due to the hydrophobic interior of the membrane

Electrolytes

Includes minerals that all carry a charge and easily dissolve in water

Membrane Potential

A measure of the electrical charge difference between the inside and the outside of the cell, measured in millivolts(mV)

Cellular Transport

The movement of substances across membranes

Concentration Gradient

The differences in the amounts of a substance across a space

Electrical Gradient

The difference in charge on each side of a membrane

Electrochemical Gradient

When there is both a chemical gradient and an electric gradient

Diffusion

The spontaneous movement of a substance down its concentration gradient, requires energy

Solvent

A substance that dissolves an other chemical

Solute

A chemical that is dissolved by an other substance

Osmosis

Diffusion of water

Water potential

the potential energy of water, its ability to move from one area to another

Tonicity

the ability of water to move in and out of a cell by osmosis depending on the relative concentrations of solutes and the membranes permeability to these solutes

Hypertonic Solutions

Lower water potential outside the cell due to higher concentration of solutes

Hypotonic Solutions

Higher water potential outside the cell due to lower concentration of solutes

Isotonic Solutions

The concentration of solutes and water potential is the same inside and outside of the cell

Facilitated Diffusion

Uses membrane proteins enabling solutes to diffuse into or out of a cell

Active Transport

Uses energy and proteins to pump substances across their membranes, moving them against their concentration gradient

Energy

The ability to do work

System

A set of components interacting as part of a whole within a boundary

First Law of Thermodynamics

Energy cannot be created nor destroyed

Second Law of Thermodynamics

Every time energy is used, some of it becomes less available to do work because entropy increases

Entropy

Measure of disorder in a system

Kinetic Energy

Energy of motion

Potential Energy

Stored energy

Temperature

Measures the average thermal energy in a system

Chemical Reactions

They make and break chemical bonds

Activation Energy

The energy required to break covalent bonds

Exergonic/Endergonic Chemical Reactions

They release energy/they take in energy

Electronegativity

The measurement of how well an element attracts electrons