Natural Selection
What is the term for traits that help organisms survive?
Adaptations
Is water polar or nonpolar?
polar
What is the monomer of proteins?
Amino acids
Are lipids hydrophobic or hydrophilic?
Hydrophobic
What is electronegativity?
The ability of an atom to attract electrons in a bond
What is genetic drift?
Random change in allele frequencies
Why don’t oil and water mix?
Oil is nonpolar, water is polar
What type of reaction links monomers?
Dehydration synthesis
What type of lipid makes up cell membranes?
phopholipids
Which element has the highest electronegativity?
Fluorine
What are the four key components of natural selection?
Variation, competition, adaptation, reproduction
What part of a phospholipid is hydrophilic?
The head
What type of bond holds amino acids together?
Peptide bond
What type of fat is solid at room temperature?
Saturated fat
How does electronegativity affect polarity?
A larger difference creates a more polar bond.
How does natural selection lead to adaptation?
Over generations, individuals with traits that increase survival and reproduction become more common. Populations then become better adapted to their environment.
What type of bond causes polarity?
Covalent bond with unequal sharing of electrons
What is the name for the breakdown of polymers?
hydrolysis
What lipid-based molecule is a key part of hormones?
Steroids
How does electronegativity affect bond type?
Large difference = ionic, small difference = polar covalent, no difference = nonpolar covalent
What is the process called when humans breed organisms for traits?
Artificial selection
How does soap allow polar and nonpolar substances to mix?
It has amphipathic molecules that trap nonpolar substances in micelles.
What polymer makes up plant cell walls?
cellulose
What is the difference between unsaturated and saturated fats?
Unsaturated has double bonds, saturated has none
How does electronegativity affect partial charges in polar molecules?
The more electronegative atom gets a partial negative charge, the less electronegative gets a partial positive charge.