Nature of Life
Define science
Science is a particular way of knowing about the world.
Covalent vs. Hydrogen
Stronger covalent bonds hold the water molecule together internally
Weaker hydrogen bonds hold different water molecules together externally
What is considered the universal solvent and why?
Water's polarity makes it really good for dissolving things making it the universal solvent, it dissolves more substances than any other liquid.
List the investigative process
Ask a question
Conduct background research
Construct a hypothesis
Test your hypothesis in an experiment
Analyze data
Draw conclusions and communicate them
List the Properties of water
Cohesion
Adhesion
High Specific Heat
Less dense as a solid
Water is a terrific solvent
What are macromolecules made of?
Structurally, most macromolecules are polymers made out of monomers
Division of electron cloud
The electron cloud of an atom is divided into energy
levels, or shells
The inner most level holds up to 2 e-
Most of the others hold up to 8 e-
The electrons in the outermost energy level are
called valence electrons
Define Adhesion
The type of attraction that happens between two different molecules
Glass, soil, plant tissue, cotton, etc
Forms stronger bonds than cohesion
Example: Meniscus forming on graduated cylinder
Capillary action, seen in plants, trees and with straws
too!
Phospholipids structure and bilayer
2 fatty acids + 1 phosphate
Hydrophilic head = phosphate group
Hydrophobic tail = fatty acids
Bilayer: 2 layers make up the plasma membrane of our cells
Makes membrane selectively permeable
Water
molecule made of 2 atoms of hydrogen covalently bonded to 1 atom of oxygen
Critical for all of life’s processes!!
Has special properties, mostly due to the fact that water is a polar molecule
Define Cohesion
The attraction between molecules of the same substance
Water sticking to water
Tendency of molecules of the
SAME “kind” to stick together
Causes HIGH surface tension
Dictates Function
Form dictates function
Hydrogen Bonds
Polar water molecules can be attracted to each other
The partially positive hydrogen atom is attracted to the partially negative
Define High Specific Heat
The temperature of water does not change easily.
Water has to absorb more heat energy to increase overall temperature compared to other compounds
This helps to regulate cell temperatures in organisms.
Its temperature does NOT fluctuate very much 🡪 allows life to live in water
What's the difference between covalent and ionic bonds
Electron Sharing vs. Donation: In covalent bonds, electrons are shared equally or unequally between atoms, while in ionic bonds, one atom donates electrons to another.