Biology Exam 1

All living organisms share these traits

membrane bound cells, ability to replicate/ reproduce, undergo evolution, process hereditary info and use energy

Unity

shared evolutionary history displaying a common

set of traits

diversity

varied forms adapted to distinct environments

Cell Theory

all organisms are made of cells

Theory of Evolution by Natural Selection

explains how species change over time and where they come from

Chromosome Theory of Inheritance

details how hereditary data is transmitted across generations

Process of Science

hypothesis are tested via Scientific Method

Scientific Method

aking

observations, forming testable predictions (hypotheses), conducting controlled experiments, analyzing data, and drawing conclusions

Elements of Life

Carbon, Hydrogen, Oxygen, and Nitrogen

Oxygen and Nitrogen

make up approximately 95% of all living matter

Electron configuration

electrons occupy shell energy levels surrounding the nucleus

Valence Shell

dictates an atoms reactivity and capacity to bond

Covalent Bonds

formed when atoms share electron pairs to maximize stability

Polar vs. Nonpolar bonds

driven by electronegativity

Polar Covalent Bonds

Unequal sharing of atoms of diff. electronegativities, ex. O-H in water

Nonpolar Covalent

equal sharing of atoms, ex. C-H

Ionic Bonds

electrostatically attract oppositely charged ions result from loss or gain of electrons

Hydrogen Bonds

weak, easily broken lectrical attractions between a partially positive

hydrogen atom in a polar molecule and a highly electronegative atom in another

molecule. Collectively, they provide immense structural stability, such as holding DNA

strands together

Adhesion

attraction of different molecule types, ex. water clings to other charged or polar surfaces

Cohesion

molecules of the same substance bind to each other, water and hydrogen bonds

Properties of Water

Due to its unique geometric arrangement, hydrogen bonds form a crystal lattice when freezing, pushing molecules apart; thus, ice expands, is less dense than liquid water, and floats.

Water

universal solvent

Hydrophilic

polar or ionic molecules and dissolve readily

Hydrophobic

nonpolar carbon-hydrogen that are insoluble

Amphipathic

molecules possess both distinct polar and nonpolar zones, organizing into structures like micelles or bilayers in water

Acidic and basic solutions

acidic is pH<7, basic is pH>7

Carbohydrates