Ch. 3 -- Genetics: Reproducing Life And Producing Variation Flashcards
Adenine
One of four nitrogen bases that make up DNA and RNA; pairs with thymine in DNA molecules and uracil in RNA molecules
Adenosine triphosphate (ATP)
An important cellular molecule, created by the mitochondria and carrying the energy necessary for cellular functions
Amino acids
Organic molecules combined in a specific sequence by the ribosomes to form a protein
Antibodies
Molecules that form as part of the primary immune response to the presence of foreign substances; attach to the foreign antigens
Anticodons
Sequences of the three nitrogen bases carried by tRNA, they match up with the complementary mRNA codons and each designate a specific amino acid during protein synthesis
Antigens
Substances that stimulate the immune system’s antibody production
Autosomes
All chromosomes, except the sex chromosomes, that occur in pairs in all somatic cells (not the gametes)
Coding DNA
Sequences of a gene’s DNA (also known as exons) that are coded to produce a specific protein and are transcribed and translated during protein synthesis
Codominance
Refers to two different alleles that are equally dominant; both are fully expressed in a heterozygote’s phenotype
Codons
The sequences of three nitrogen bases carried by mRNA that are coded to produce specific amino acids in protein synthesis
Complementary bases
The predictable pairing of nitrogen bases in the structure of DNA and RNA, such that adenine (A) and thymine (T) always pair together (adenine and uracil (U) in RNA) and cytosine (C) and guanine (G) pair together
Cross-over
The process by which homologous chromosomes partially wrap around each other and exchange genetic information during meiosis
Cytoplasm
The fluid that fills the cell and maintains the cell’s shape
Cytosine
One of four nitrogen bases that make up DNA and RNA; pairs with guanine
Diploid
A cell that has a full complement of paired chromosomes
Essential amino acids
Those amino acids that cannot be synthesized in the body; they must be supplied by the diet
Eukaryotes
Organisms with internal compartments separated by membranes
Free-floating nucleotides
Nucleotides (the basic building block of DNA and RNA) that are present in the nucleus and are used during DNA replication and mRNA synthesis
Gametes
Sexual reproductive cells, ova and sperm, that have a haploid number of chromosomes and that can unite with a gamete of the opposite sex to form a new organism
Genome
The complete set of chromosomes for an organism or species that represents all the inheritable traits
Genomics
The branch of genetics that studies species’ genomes
Guanine
One of four nitrogen bases that make up DNA and RNA; pairs with cytosine
Haplogroups
A large set of haplotypes that may be used to define a population
Haploid
A cell that has a single set of unpaired chromosomes, half of the genetic material
Haplotypes
A group of alleles that tend to be inherited as a unit due to their closely spaced loci on a single chromosome
Heritability
The proportion of phenotypic variation that is due to inheritance rather than to environmental influence
Heteroplasmic
Refers to a mixture of more than one type or organellar DNA within a cell or a single organism’s body, usually due to the mutation of the DNA in some organelles but not in others
Heterozygous
Refers to the condition in which a pair of alleles at a single locus on homologous chromosomes are different
Homeotic (Hox) genes
Also known as homeobox genes, they are responsible for differentiating the specific segments of the body during embryological development
Homologous
Refers to each set of paired chromosomes in the genome
Homoplasmic
Refers to nuclear DNA, which is identical in the nucleus of each cell type (except red blood cells)
Homozygous
Refers to the condition in which a pair of alleles at a single locus on homologous chromosomes are the same
Karyotype
The characteristics of the chromosomes for an individual organism or a species, such as number, size, and type
Law of Independent Assortment
Mendel’s second law, which asserts that the inheritance of one trait does not affect the inheritance of other traits
Law of Segregation
Mendel’s first law, which asserts that the two alleles for any given gene (or trait) are inherited, one from each parent; during gamete production, only one of the two alleles will be present in each ovum or sperm
Linkage
Refers to the inheritance, as a unit, of individual genes closely located on a chromosome; an exception to the Law of Independent Assortment
Locus
The location of an allele, or gene, on a chromosome
Matriline
DNA whose inheritance can be traced from mother to child
Meiosis
The production of gametes through one DNA replication and two call (and nuclear) divisions, creating four haploid gametic cells
Messenger RNA (mRNA)
The molecules that are responsible for making a chemical copy of a gene needed for a specific protein (aka for the transcription phase of protein synthesis)
Microsatellitese
Specific loci in nuclear or organellar DNA that have repeated units of 1-4 base pairs in length; can be used in various genetic studies
Mitochondria
Energy-producing (ATP) organelles in eukaryotic cells; possess their own independent DNA
Mitosis
The production of identical daughter cells from an original parent cell
Monosomy
Refers to the condition in which only one of a specific pair of chromosomes is present in a cell’s nucleus
Noncoding DNA
Sequences of a gene’s DNA (also known as introns) that are not coded to produce specific proteins and are excised before protein synthesis
Nondisjunctions
Refers to the failure of the chromosomes to properly segregate during meiosis, creating some gametes with abnormal numbers of chromosomes
Nucleotide
The building blocks of DNA and RNA, comprised of a sugar, a phosphate group, and one of four nitrogen bases
Nucleus
A membrane-bound structure in eukaryotic cells that contains the genetic material
Paleogenetics
The application of genetics to the past, especially in anthropology and paleontology;
The study of genetics in past organisms
Patriline
DNA whose inheritance can be traced from father to child
Peptide bond
Chemical bond that joins amino acids into a protein chain
Pleiotropy
Refers to one gene that affects more than one phenotypic trait
Polygenic
Refers to one phenotypic trait that is affected by two or more genes
Polymerase chain reaction (PCR)
A technique that amplifies a small sample of DNA into a larger amount that can be used for various genetic tests
Polymorphism
Refers to the presence of two or more separate phenotypes for a certain gene in the population
Polypeptide
Also known as a protein, a chain of amino acids held together by multiple peptide bonds
Prokaryotes
Organisms having cells with no internal compartments
Recombination
The exchange of genetic material between homologous chromosomes, resulting from a cross-over event
Regulatory genes
Those genes that determine when structural genes and other regulatory genes are turned on and off for protein synthesis
Regulatory proteins
Proteins involved in the expression of control genes
Replication
The process of copying nuclear DNA prior to cell division, so that each new daughter cell receives a complete complement of DNA
Ribonucleic acid (RNA)
A single-stranded molecule involved in protein synthesis, consisting of a phosphate, ribose sugar, and one of four nitrogen bases
Ribosomal RNA (rRNA)
A fundamental structural component of a ribosome
Ribosomes
The organelles attached to the surface of the endoplasmic reticulum, located in the cytoplasm of a cell; the site of protein synthesis
Sex chromosomes
The pair of chromosomes that determine an organism’s biological sex
Single nucleotide polymorphisms (SNPs)
Variations in the DNA sequence due to the change of a single nitrogen base
Somatic cells (body cells)
Diploid cells that form the organs, tissues, and other parts of an organism’s body
Structural genes
Genes coded to produce particular products
Structural proteins
Proteins that form an organism’s physical attributes
Thymine
One of four nitrogen bases that make up DNA; pairs with adenine
Transcription
The first step of protein synthesis, involving the creation of mRNA based on the DNA template
Transfer RNA (tRNA)
The molecules that are responsible for transporting amino acids to the ribosomes during protein synthesis
Translation
The second step of protein synthesis, involving the transfer of amino acids by tRNA to the ribosomes, which are then added to the protein chain
Translocations
Rearrangements of chromosomes due to the insertion of genetic material from one chromosome to another
Triplets
Sequences of three nitrogen bases each in DNA, known as codons in mRNA
Trisomy
Refers to the condition in which an additional chromosome exists with the homologous pair
Uracil
One of four nitrogen bases that make up RNA; pairs with adenine
Zygote
The cell that results from a sperm’s fertilization of an ovum