Study Guide - Bio 101 Exam 1

Life

The condition distinguishing living organisms from inorganic matter, characterized by growth, reproduction, and response to stimuli

Common Characteristics of Living Things

Traits shared by all living organisms, including cellular organization, metabolism, homeostasis, growth, reproduction, and adaptation

Genetic Relatedness

All living things share a common genetic heritage, indicating evolutionary connections among species

Atomic Number

The number of protons in an atom's nucleus, which determines the element's identity and electron configuration

Isotopes

Variants of a chemical element that have the same number of protons but different numbers of neutrons; radioisotopes are unstable isotopes that emit radiation

Polar Covalent Bonds

Bonds formed when electrons are shared unequally between atoms, resulting in partial charges; non-polar covalent bonds involve equal sharing of electrons

Ionic Bonds

Formed when one atom donates an electron to another, creating charged ions that attract each other

Ion

An atom or molecule with a net electric charge due to the loss or gain of one or more electrons; cation:positively charged ion; anion:negatively charged ion

How ionic bonds are formed

When one atom transfers one or more of its electrons to another atom, this typically happens between metals and non-metals

How an ion is formed from a neutral
atom

A neutral atom either loses or gains electrons, leading to an imbalance between the number of protons (positive charges) and electrons (negative charges)

Cation

Positively-charged ions (atoms or groups of atoms that have more protons than electrons due to having lost one or more electrons)

Anion

Negatively-charged ions (meaning they have more electrons than protons due to having gained one or more electrons)

Salt Dissolution

Salt dissolves in water due to the attraction between water molecules and the charged ions of the salt

Hydrogen Bonds

Weak attractions between a hydrogen atom covalently bonded to an electronegative atom and another electronegative atom

Strength of Bonds

Covalent bonds > ionic attractions > hydrogen bonds > van der Waals forces

Hydrophilic

Molecules that are attracted to water; hydrophobic:molecules that repel water

Hydrophilic

water-loving

Hydrophobic

water-fearing

Examples of hydrophilic and hydrophobic molecules:

Hydrophylic

• glucose

• sodium chloride

• ethanol

• amino acids

• proteins

Hydrophobic

• lipids

• cholesterol

• methane

• benzene

• fatty acids

Hydrophobic Interactions

Nonpolar molecules clustering together in an aqueous environment to minimize contact with water

Properties of Water

High specific heat, cohesion, adhesion, and solvent capabilities due to hydrogen bonding

Ice Floats

Ice is less dense than liquid water due to the formation of a crystalline structure in freezing

High Heat Capacity

Water's ability to absorb and retain heat helps regulate temperature in living organisms

How water’s high heat capacity (related to high specific heat) and heat of vaporization is beneficial to living organisms

High heat capacity

• temperature regulation

• climate moderation

• protection of aquatic life

Heat of vaporization

• cooling mechanism (evaporative cooling)

• sweating

• panting

• water cycle and climate

Acids

Substances that donate hydrogen ions (H+) or protons in solution, pH less than 7

Bases

Substances that accept hydrogen ions (H+) or protons in solution, pH greater than 7

pH Scale

Measures the acidity or basicity of a solution, ranging from 0 (acidic) to 14 (basic).

Macromolecules

Four types found in cells:proteins, carbohydrates, lipids, and nucleic acids, constructed from specific monomers.

Functional Groups

Specific groups of atoms that confer particular chemical properties to organic molecules.

Structural Isomers

Molecules with the same molecular formula but different structural arrangements; optical isomers are non-superimposable mirror images.

Condensation Reactions

Chemical reactions that link monomers together, releasing water as a byproduct

Hydrolysis Reaction

A reaction that breaks down polymers into monomers by adding water

Functions of Macromolecules

Proteins (catalysis, structure), carbohydrates (energy storage, structure), lipids (membranes, energy), nucleic acids (genetic information)

Amino Acid Structure

Composed of an amino group, carboxyl group, and R group (side chain)

Amino Acid Properties

Determined by the characteristics of their side chains, affecting polarity and charge

Disulfide Bonds

Covalent bonds formed between the sulfur atoms of cysteine residues, stabilizing protein structure

Peptide Linkages

Bonds formed between amino acids, linking the N terminus to the C terminus of a polypeptide

Protein Shape

The three-dimensional structure of a protein is crucial for its biological function

Protein Structures

Primary (sequence), secondary (α-helix, β-sheet), tertiary (3D folding), and quaternary (multiple polypeptides)

Denaturation

The process where a protein loses its functional shape due to environmental changes, affecting its activity

Environmental Factors

Temperature, pH, and ionic strength can influence protein structure and function

Quaternary Structure

The arrangement of multiple polypeptide chains in a protein, stabilized by various interactions

Chaperone Proteins

Assist in the proper folding of proteins and prevent aggregation

Carbohydrate Structure

Composed of carbon, hydrogen, and oxygen, typically in a 1:2:1 ratio

Monosaccharide

The simplest form of carbohydrates, consisting of single sugar units

Glucose Forms

Exists in both chain and ring forms, with α and β configurations

Glycosidic Linkages

Bonds between monosaccharides; α-glycosidic linkages are found in maltose, while β-glycosidic linkages are in cellobiose

Important functional groups…

…

Functional group: hydroxyl R-OH

Class of compounds: alcohols (ethanol) OH

Properties: polar, forms hydrogen bonds with water to help dissolve molecules, enables linkage to other molecules by condensation

Functional group aldehyde H-C=O

Class of comnpounds: aldehydes (acetaldehyde) H-C=O

Properties: polar, C=O group is very reactive, important in building molecules and in energy-releasing reactions

Functional group: keto C=O

Class of compounds: ketones (acetone) C=O

Properties: Polar, C=O group is important in carbohydrates and energy reactions

Functional Group: carboxyl OH-C=O

Class of compounds: carboxylic acids (acetic acid) OH-C=O

Properties: charged; acidic, ionizes in living tissues to form

-COO- and H+, enters into condensation reactions by giving up

-OH, some carboxylic acids important in energy-releasing reactions

Functional group: amino R-H-N-H

Class of compounds: amines (methylamine) H-N-H

Properties: charged; basic, accepts H+ in living tissues to form -NH3+, enters into condensation reactions by giving up H+

Functional Group: phosphate R-O-P=O-O-O

Class of compounds: organic phosphate (3-phosphogylcerate) O-P=O-O-O

Properties: charged; acidic, enters into condensation reactions by giving up -OH

Functional Group: sulfhydryl R-SH

Class of compounds: thiols (mercaptoethenal) SH

Properties: by giving up H, 2 -SH groups can react to form a disulfide bridge, stabilizing protein structure

Functional Group: methyl CH3

Class of compounds: alkyl (alkaline) CH3

Properties: nonpolar, important in interacting with other nonpolar molecules and in energy transfer