Biology 204 Test 1

The atomic number of an atom is the number of protons it has, which determines its chemical properties and its place in the periodic table. It does not refer to the mass, number of electrons, or atomic weight of the atom.

The atomic mass is determined by the combined mass of the protons and neutrons in the nucleus, not the electrons in the atom or the number of valence electrons.

Protons have a positive charge, unlike electrons which have a negative charge and neutrons which have no charge.

Neutrons are subatomic particles that have no charge, unlike protons which have a positive charge and electrons which have a negative charge.

Electrons are subatomic particles that carry a negative electrical charge and are found in the outer regions of an atom. Protons carry a positive electrical charge, neutrons carry no electrical charge, and positrons are the antimatter counterparts of electrons and carry a positive charge.

The majority of the mass of an atom is located in the nucleus, which contains protons and neutrons. Electrons are much smaller in mass and are located in the electron cloud surrounding the nucleus.

In a covalent bond, atoms share pairs of electrons which hold the atoms together. This type of bond is commonly found in nonmetal elements like chlorine. Ionic bonds involve transfer of electrons between atoms, metallic bonds occur in metals, and hydrogen bonds are weaker compared to covalent bonds.

Ionic bonds involve the transfer of electrons from one atom to another, resulting in the formation of positive and negative ions that are then attracted to each other. This attraction creates a strong bond like the one found in sodium chloride (table salt), where sodium donates an electron to chlorine.

A polar covalent bond has unequal sharing of electrons, leading to partial positive and negative charges at opposite ends of the molecule. Water is a common example where oxygen's higher electronegativity causes it to tug on the shared electrons more than hydrogen, resulting in a polar molecule.

A hydrogen bond is a type of intermolecular bond, not intramolecular. It does not involve metal atoms, and it specifically involves a hydrogen atom that is covalently bound to an electronegative atom forming a bond with another electronegative atom, not between two hydrogen atoms in different molecules.

Monosaccharides join together through condensation reactions to form disaccharides and polysaccharides.

A disaccharide is a type of sugar made up of two smaller sugar molecules (monosaccharides) combined together.

Triglycerides consist of a glycerol molecule and three fatty acid chains, not any of the other options provided.

Understanding the concepts of hydrophilic and hydrophobic is crucial in understanding how substances interact with water and the composition of cell membranes.

Estrogen, testosterone, and cholesterol belong to the group of lipids known as the steroid nucleus, characterized by a four-ring structure. Phospholipids, triglycerides, and waxes are different types of lipids with distinct structures and functions.

Proteins are made up of amino acids, which are organic compounds containing amine and carboxyl functional groups. Sugars, fatty acids, and nucleotides are not the basic building blocks of proteins.

Peptide bonds are specific types of bonds that are formed between amino acids in proteins. They play a crucial role in protein structure and function.

Enzymes are proteins that act as biological catalysts accelerating chemical reactions within cells. They play a crucial role in various metabolic processes.

Protein function is primarily dictated by its three-dimensional shape, as the structure enables specific interactions with other molecules.

Nucleic acids are complex organic substances composed of nucleotides, not to be confused with proteins, carbohydrates, or lipids.

The correct answer includes the pairs of nitrogen bases that form complementary base pairs in DNA: adenine + thymine and guanine + cytosine. In RNA, thymine is replaced by uracil.

The genetic code carried by DNA is transcribed into mRNA which then carries the code to the ribosomes for protein synthesis. tRNA brings amino acids to the ribosomes, rRNA is a component of ribosomes, and cDNA is a synthesized DNA copy of a messenger RNA molecule.

Chromosomes are the structures that contain genetic information in the form of DNA and associated proteins, not specialized cells, protein building blocks, or carbohydrates.

Watson & Crick are known for their groundbreaking discovery of the structure of DNA, which revolutionized the field of genetics and molecular biology.

Rosalind Franklin was a British biophysicist who made significant contributions to the understanding of the molecular structures of DNA, RNA, viruses, coal, and graphite.