Biology Practice Flashcards - Chapters 8, 9, and 10

Vocabulary flashcards covering human genetics, gene therapy, DNA structure, replication, and the central dogma of biology (transcription and translation).

Genetic disorder

A disease caused by a defective gene(s), or an abnormality in chromosome number or structure; it may be inherited or occur spontaneously.

Gene therapy

A technique for correcting abnormal genes responsible for disease development by removing or replacing mutated DNA to slow or stop disease.

Genetic engineering

The permanent introduction of one or more new or altered genes into a cell, tissue, or organism.

Stem cells

Unique, unspecialized cells that can make identical copies of themselves for long periods of time.

Virus vector

An inactivated virus used by scientists to transport a healthy gene into a cell’s nucleus during gene therapy.

Mutation

A change to the sequence of nucleotides in an organism’s DNA, or a change to chromosome number or structure.

Homologous chromosomes

Pairs of chromosomes that are similar in size and shape; humans have 23 pairs, or 46 total.

Chromosomal abnormality

Any change in the chromosome number or structure, compared to what is typical for a species.

CRISPR

A genome-editing tool composed of a protein and two single-stranded molecules of RNA that acts like a "molecular scalpel" to add or delete genes.

Xenotransplantation

The process of transplanting organs from nonhuman animals into humans.

Porcine endogenous retroviruses (PERVs)

Viruses found in pig cells that historically stalled xenotransplantation efforts due to fear of human infection.

Nucleotides

The repeating units that build DNA, each composed of the sugar deoxyribose, a phosphate group, and one of four bases ($Adenine$, $Cytosine$, $Guanine$, or $Thymine$).

Covalent bonds

Strong chemical bonds that connect the nucleotides within a single strand of DNA.

Hydrogen bonds

Weak bonds that link the bases of one DNA strand to the bases of another, allowing the strands to be pulled apart for replication.

Base-pairing rules

The biochemical principle that $Adenine$ (A) can pair only with $Thymine$ (T), and $Cytosine$ (C) can pair only with $Guanine$ (G).

DNA replication

The duplication of a DNA molecule that occurs before a cell enters mitosis.

DNA polymerase

An enzyme that "proofreads" complementary base pairs as they form and corrects almost all mistakes during DNA replication.

Point mutation

The change of one nucleotide in a single base pair of DNA.

Substitution

A type of point mutation where one nucleotide is replaced by another in a DNA sequence.

Insertion

A type of point mutation where one nucleotide is added to a DNA sequence.

Deletion

A type of point mutation where one nucleotide is removed from a DNA sequence.

Transcription

The process that creates a segment of RNA based on a DNA template.

RNA polymerase

The enzyme that binds to a promoter, unzips the DNA double helix, and constructs a messenger RNA (mRNA) strand.

Promoter

A segment of DNA near the beginning of a gene where RNA polymerase binds to start transcription.

Terminator

A special sequence of bases that signals RNA polymerase to stop transcription.

Uracil (U)

The nitrogenous base found in RNA that replaces $Thymine$ (T) and pairs with $Adenine$ (A).

Translation

The process by which ribosomes convert the information in mRNA into proteins.

Ribosomes

Cell structures in the cytoplasm that serve as the sites of protein synthesis.

Codon

A set of three bases in mRNA that is read by a ribosome to specify a particular amino acid.

Start codon

The codon $AUG$, which codes for methionine and serves as the ribosome's starting point on the mRNA strand.

Stop codon

A codon ($UAA$, $UAG$, or $UGA$) that indicates the end of translation.

Genetic code

The information specified by all 64 possible codons, which is unambiguous, redundant, and virtually universal among all organisms.