General Biology - Exam 1 (ChatGPT)
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350 Terms
Matter
Anything that has mass and occupies space.
Element
A substance that cannot be broken down into simpler substances by chemical reactions.
Atom
The smallest unit of an element that retains the element's properties.
What are the three major subatomic particles?
Protons, neutrons, and electrons.
What charge does a proton have?
Positive (+).
What charge does a neutron have?
No charge (neutral).
What charge does an electron have?
Negative (−).
Where are protons and neutrons found?
In the nucleus.
Where are electrons found?
Outside the nucleus in electron shells/clouds.
What determines which element an atom is?
Its number of protons.
What is the atomic number?
The number of protons in an atom.
What is the mass number?
The total number of protons + neutrons.
What is an isotope?
An atom of an element with a different number of neutrons.
Do isotopes of the same element have the same number of protons?
Yes.
What primarily determines an atom's chemical behavior?
Its electrons, especially outer-shell electrons.
Why are electrons important in chemical reactions?
They participate in forming and breaking chemical bonds.
What is a compound?
A substance consisting of two or more different elements chemically combined.
What is a chemical bond?
An attraction that holds atoms together.
What is an ionic bond?
An attraction between oppositely charged ions.
How are ions formed?
Atoms gain or lose electrons.
What is a cation?
A positively charged ion.
What is an anion?
A negatively charged ion.
What is a covalent bond?
A bond formed when atoms share electrons.
What is a molecule?
Two or more atoms held together by covalent bonds.
What is a nonpolar covalent bond?
Electrons are shared relatively equally.
What is a polar covalent bond?
Electrons are shared unequally.
Why is water a polar molecule?
Oxygen attracts the shared electrons more strongly than hydrogen does, creating partial charges.
What is a hydrogen bond?
A weak attraction between a partially positive hydrogen and an electronegative atom, such as oxygen.
Why can water form hydrogen bonds?
Water is polar.
Why does ice float on liquid water?
Hydrogen bonds create an open structure in ice, making it less dense than liquid water.
What is cohesion?
Attraction between molecules of the same substance.
What is adhesion?
Attraction between molecules of different substances.
What is a solvent?
The substance that dissolves another substance.
What is a solute?
The substance dissolved in a solvent.
What is an aqueous solution?
A solution in which water is the solvent.
Why is water an excellent solvent?
Its polarity allows it to interact with and dissolve many charged or polar substances.
What is an acid?
A substance that increases H⁺ concentration in a solution.
What is a base?
A substance that decreases H⁺ concentration or increases OH⁻ concentration.
What does the pH scale measure?
Hydrogen ion concentration.
What does a low pH mean?
High H⁺ concentration; acidic.
What does a high pH mean?
Low H⁺ concentration; basic.
What is neutral pH?
Approximately 7.
What is a buffer?
A substance that resists changes in pH.
How does a buffer resist pH changes?
It can accept excess H⁺ or donate H⁺ when needed.
Why is pH important to living organisms?
Many biological processes and enzymes function properly only within particular pH ranges.
What makes a molecule organic?
It generally contains carbon bonded to hydrogen.
Why is carbon especially important in biology?
Carbon can form four covalent bonds, allowing enormous molecular diversity.
What are the four major classes of biological molecules?
Carbohydrates, lipids, proteins, and nucleic acids.
What is a macromolecule?
A large biological molecule.
What is a monomer?
A smaller molecular subunit used to build a polymer.
What is a polymer?
A large molecule made from repeating smaller subunits.
What reaction joins monomers together?
Dehydration synthesis.
What happens during dehydration synthesis?
Water is removed as a bond forms.
What reaction breaks polymers apart?
Hydrolysis.
What happens during hydrolysis?
Water is added to break a bond.
What are carbohydrates primarily used for?
Energy and structural materials.
What is a monosaccharide?
A single sugar molecule.
Give two examples of monosaccharides.
Glucose and fructose.
What is glucose?
A major cellular fuel.
What is a disaccharide?
A sugar composed of two monosaccharides.
What is sucrose made of?
Glucose + fructose.
What is a polysaccharide?
A carbohydrate composed of many sugar units.
What is starch?
A plant storage polysaccharide.
What is glycogen?
An animal storage polysaccharide.
What is cellulose?
A structural polysaccharide found in plant cell walls.
Why can't humans digest cellulose effectively?
Humans lack the enzyme needed to break its particular bonds.
What is a major characteristic of lipids?
They are largely hydrophobic.
Name three major types of lipids.
Fats, phospholipids, and steroids.
What are triglycerides made from?
Glycerol + three fatty acids.
What is a saturated fat?
A fat whose fatty acid chains contain no carbon-carbon double bonds.
What is an unsaturated fat?
A fat whose fatty acid chains contain one or more carbon-carbon double bonds.
Why are unsaturated fats often bent?
Double bonds can create bends in the fatty acid chains.
What is a phospholipid made of?
Glycerol, fatty acids, and a phosphate-containing group.
What is special about a phospholipid?
It has a hydrophilic head and hydrophobic tails.
Why are phospholipids important to cells?
They form the basic structure of cell membranes.
What are steroids?
Lipids with a characteristic structure of four fused carbon rings.
What are proteins made from?
Amino acids.
How many standard amino acids are used to build proteins?
20.
What bond connects amino acids?
A peptide bond.
What is a polypeptide?
A chain of amino acids.
What determines a protein's specific function?
Its three-dimensional structure.
What are some functions of proteins?
Enzymes, transport, structure, signaling, defense, and movement.
What is protein denaturation?
Loss of a protein's normal shape and function.
What can cause protein denaturation?
Changes in temperature, pH, or chemical environment.
What are nucleic acids?
DNA and RNA.
What are nucleic acids made from?
Nucleotides.
What are the three parts of a nucleotide?
Sugar, phosphate group, and nitrogenous base.
What is DNA's primary role?
Storing genetic information.
What is RNA involved in?
Using genetic information to help make proteins.
What is the basic difference between DNA and RNA?
DNA stores genetic information; RNA helps use that information.
What are the two major categories of cells?
Prokaryotic and eukaryotic.
What defines a prokaryotic cell?
It lacks a membrane-bound nucleus.
What defines a eukaryotic cell?
It has a membrane-bound nucleus.
Where is DNA located in a prokaryotic cell?
In the nucleoid region.
Where is most eukaryotic DNA located?
Inside the nucleus.
What is the nucleoid?
The region of a prokaryotic cell containing its chromosome.
Which cells are generally smaller?
Prokaryotic cells.
What is one major difference between prokaryotic and eukaryotic cells?
Eukaryotes have a nucleus and membrane-bound organelles; prokaryotes generally do not.
What is the nucleus?
The organelle containing most of a eukaryotic cell's genetic information.
What surrounds the nucleus?
The nuclear envelope.