Biology Test 3 Notes
• What are the differences between RNA and DNA?
➢ DNA: deoxyribonucleic acid, an organisms genetic information
➢ RNA: ribonucleic acid, a spiral helix strand that reads DNA instructions to
• How do the bases pair in a DNA strand?
➢ Adenine and thymine, guanine and cytosine
• What is a mutation? What can cause a mutation?
➢ Mutation: any change in the nucleotide sequence of DNA
➢ Mutations may result from:
o Errors in DNA replication
o Physical or chemical agents called mutagens
• What are the four nucleotide bases for DNA and RNA?
➢ DNA: adenine, cytosine, guanine, and thymine
➢ RNA: adenine, cytosine, guanine, and uracil
• What is the full name for DNA? RNA?
➢ DNA: deoxyribonucleic acid
➢ RNA: ribonucleic acid
• Where are the sugar, phosphates, and nucleotides located on the double
➢ The double helix consists of chemical units called nucleotides. These
nucleotides are joined by sugar-phosphate backbone.
• How can a mutation be good, bad, or cause no obvious difference?
➢ The result of a mutagen depends on:
o The type of change
o Where the change in DNA occurs
o If the change is detected and fixed before replication
o How it affects the organism and its survival
• Who won the Nobel Prize for the structure of DNA?
➢ James Watson and Francis Crick
• What is replication?
➢ The process of copying the DNA molecule
➢ When a cell or whole organism reproduces, a complete set of genetic
instructions must pass from one generation to the next.
➢ Fast and quite accurate process • What is transcription?
➢ The synthesis of RNA on a DNA template
➢ Occurs in the nucleus of eukaryotic cells
• What is translation?
➢ The synthesis of a polypeptide using the genetic information encoded in
an mRNA molecule. There is a change in the “language” from nucleotides
to amino acids.
➢ Occurs in the cytoplasm of eukaryotic cells
• Where does replication, transcription, and translation take place?
➢ Replication: begins at specific sites on a double helix and then proceeds in
➢ Transcription: the nucleus of eukaryotic cells
➢ Translation: the cytoplasm of eukaryotic cells
• How can mutations in the DNA result in a protein not functioning correctly?
➢ Mutations are the basis of cancer, many genetic diseases, and evolution
• What is a mutagen? Know some examples of mutagens?
➢ A chemical or physical agent that interacts with DNA and causes a
➢ Radioactive substances, x-rays, ultraviolent radiation, and certain
• What is a gene?
➢ Inheritance unit
• What are homologous chromosomes?
➢ Have genes at specific loci
➢ Have alleles of a gene at the same locus
• What is a zygote?
➢ A fertilized egg cell that results from the union of a female gamete with a
• Who is Gregor Mendel?
➢ The first person to analyze patterns of inheritance
➢ Deduced the fundamental principles of genetics
• Why did he use the garden pea?
➢ These plants are easily manipulated and can self-fertilize • What is the P generation?
➢ The parent individuals from which offspring are derived in studies of
inheritance. P stands for parental
• How do you produce an F1 generation?
➢ The offspring of two parental (P generation) individuals. F1 stands for
• How do you produce an F2 generation?
➢ The offspring of the F2 generation. F2 stands for second filial.
• What are Mendel’s 4 hypotheses and what does each mean?
➢ There are alternative forms of genes, the units that determine heritable
➢ For each inherited character, an organism inherits to alleles, one from
➢ If the two alleles of an inherited pair differ, then one determines the
organism’s appearance and is called the dominant allele, the other has no
noticeable effect on the organism’s appearance and is called the recessive
➢ A sperm or egg carries only one allele for each inherited character
because the two members of an allele pair separate from each inherited
character because the two members of an allele pair separate from each
other during the production of gametes.
• What is the difference between codominance and incomplete dominance?
➢ Codominance: when alleles are expressed in the phenotype as they share
o Blood types A and B
➢ Incomplete dominance: F1 generation hybrids have an appearance that is
in between the phenotypes of the two parents
• What is pleiotropy? Know an example.
➢ Plieotropy is the impact of a single gene on more than one c