Biology 101 Test #1

What is matter?

anything that occupies space and has mass

Characteristics of living things

reproduce, grow, respond, cells, DNA, energy

Levels of organization

atom, molecule, macromolecule, organelle, cell, tissue, organ, organ system, organism

Name the three domains of life.

Bacteria archea eukarya

Important common elements of living

Carbon, hydrogen, oxygen, nitrogen

What are trace elements?

chemical elements present in extremely small quantities

what is an element ?

pure substance that consists entirely of one type of atom

What is a compound?

2 or more elements chemically combined

What is a molecule?

A group of atoms bonded together

what is the atomic number of an atom ?

number of protons in the nucleus

What is the mass number of an atom?

the total number of protons and neutrons in a nucleus.

What is an isotope?

Atoms of the same element that have different numbers of neutrons

What is a radioactive isotope?

Atom whose nucleus undergoes degeneration and in the process gives off radiation

what is an organic compound?

any molecule that is made mostly of carbon with no metals in it

What is the octet rule?

atoms prefer to have 8 electrons in their outer shell to become stable

What is a valence electron?

Electrons in the outermost shell of an atom.

What is a hydrocarbon?

a compound made of hydrogen and carbon atoms

what are the 4 main organic compounds in living organisms?

carbohydrates, lipids, proteins, and nucleic acids

What is an ionic bond?

A chemical bond that's formed when an atom transfers and electron to another Atom

What is a covalent bond?

A chemical bond formed when two or atoms share electrons.

what is a non polar covalent bond ?

equal sharing of electrons

What is a polar covalent bond?

unequal sharing of electrons

what is unique about a water molecule?

hydrogen bonding

What is a solute?

A substance that is dissolved in a solution.

What is a solvent?

substance that does the dissolving

What is a solution?

A homogeneous mixture of two or more substances

what is a hydrophilic molecule?

A molecule that is attracted to water

what is a hydrophobic molecule?

water fearing molecule

What is an acid?

An acid is a source of hydrogen ions, H⁺

What is a base?

Substance with pH greater than 7: proton acceptor

What is the pH of a solution?

a measure of its hydrogen ion concentration

What is a buffer?

weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in pH

What are monomers?

Smaller units from which larger molecules are made

What are polymers?

Molecules made from a large number of monomers joined together

What are carbohydrates?

sugars and polymers of sugars

What are proteins?

Proteins are found in living things and are made up of amino acid chains.

what're lipids and fats?

Lipids are a broad group of natural molecules that do not dissolve in water, and fats are a specific type of lipid that stay solid at room temperature.

What is a peptide bond?

covalent bond between two amino acids

how do plants store carbohydrates ?

As starch or sucrose

How do animals store carbohydrates?

in the form of glycogen

what's the difference between saturated and unsaturated fats ?

Saturated fats have a straight chemical structure with single carbon bonds and are solid at room temperature, while unsaturated fats have flexible structures with at least one double carbon bond and are liquid at room temperature

how can we convert an oil into a solid at room temperature ?

add hydrogen

what are the the different structures of a protein?

Protein structure has four distinct levels of organization—primary, secondary, tertiary, and quaternary—that determine the final three-dimensional shape and function of the protein. [1, 2]

what are nucleotides?

monomers of nucleic acids

what is the composition of a nucleotide ?

phosphate group, pentose sugar, nitrogenous base