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Combination of terms and vocabulary from Chapters 16 - 20


deoxyribonucleic acid; the unique genetic code for every living thing.

Watson and Crick

Scientists who proposed the double helix structure of DNA


The base that pairs with Thymine in DNA


The base that pairs Adenine in DNA


The base that pairs with Guanine with DNA


The base that pairs with Cytosine in DNA

Thomas Morgan

Documented sex-linked traits in fruit flies


The process by which a cell makes a copy of the DNA in its nucleus


A five-carbon sugar found in DNA.

Phosphate group

alternates with deoxyribose to make up the sides of DNA


used mice to discover that genetic material had a transforming factor,

Hershey and Chase

Identified DNA to be genetic material through experiments with bacteriophages


DNA replication is initiated when helicase enzyme breaks the hydrogen bonds holding the base pairs together and the DNA uncoils.


Addition of nucleotides on uncoiled DNA through polymerase.


The enzyme that joins DNA fragments together


Ribonucleic acid; a nucleic acid that plays an important role in the production of proteins

Protein synthesis

The assembly of chains of amino acids into functional protein molecules


a nitrogen-containing base found in RNA (but not in DNA)


Messenger RNA; the RNA molecule that serves as the template for protein synthesis.


Transfer RNA; the type of RNA that carries an amino acid from the cytoplasm to the ribosome for incorporation into a growing protein.


Ribosomal RNA; the type of RNA that associates with ribosomal proteins to make a functional ribosome.


A process in which DNA is used as a template to make complementary messenger RNA.


The assembly of a protein on a ribosome, using mRNA to direct the order in wich amino acids are added to the protein being made.


Start codon for protein synthesis.


A cell organelle which functions as the site of protein synthesis in the cytoplasm; consists of rRNA and protein molecules, which make up two subunits.


coding regions; parts of a gene that are expressed as amino acids


sequences of nucleotides not involved in coding for proteins


genes that cause cancer by blocking the normal controls on cell reproduction

structural genes

a DNA sequence that codes for a specific product

repressor protein

a regulatory protein that binds to an operator and blocks transcription of the genes of an operon

operator gene

controls the activity of the structured genes (switches on/off to control transcription)


change in the nucleotide sequence of DNA

Substitution Mutation

A single nucleotide is replaced by a different nucleotide

missense mutation

a type of point mutation that results in an alternate incorrect amino acid to be coded; produces a disfunctional protein

nonsense mutation

a mutation that changes an amino acid codon to one of the 3 stop codons, resulting in a shorter and usually nonfunctional protein

silent mutation

a type of point mutation in which no harmful effect is produced


The branch of biology that studies the ways in which heredity information is passed on from parents to offspring.


____ is considered the "father of genetics"....was the first to use the experimental method to study inheritance.


The physical traits that appear in an individual as a result of its genetic make up.


genetic makeup of an organism


a specific characteristic that can be inherited

test cross

the crossing of an individual of unknown genotype with a homozygous recessive individual to determine the genotype of the unknown individual

punnet square

a table used to predict possible traits in offspring

law of segregation

Mendel's law that states that the pairs of homologous chromosomes separate in meiosis so that only one chromosome from each pair is present in each gamete

principle of dominance

states that if a dominant allele is present, it will be expressed in an organism


the chance of an event occurring

Thomas Morgan

Documented sex-linked traits in fruit flies


describes a trait or an allele that is expressed only when two recessive alleles for the same characteristic are inherited


a trait that is always expressed, even in heterozygous conditions


an organism that has two different alleles for a gene


an organism that has two identical alleles for a trait


organisms that have two different alleles for a certain trait


an organism which has 2 identical alleles for a trait

law of independent assortment

states that allele pairs separate independently during the formation of gametes

monohybrid cross

a cross between individuals that involves one pair of contrasting traits

dihybrid cross

a cross that involves two pairs of contrasting traits

sex linked trait

trait that is coded for by an allele on a sex chromosome


any chromosome other than a sex chromosome


a sex-linked recessive disorder defined by the absence of one or more of the proteins required for blood clotting

color blindness

A sex-linked trait in which an individual cannot perceive certain colors.

barr body

Inactivated extra X chromosomes in nuclei, only 1 X chromosome is activated per cell

multiple alleles

Three or more different forms of a gene, each producing a different phenotype.

polygenic inheritance

Occurs when groups of gene pairs act together to produce a specific trait


Testing of the amniotic fluid for genetic birth defects

chorionic villus sampling

removal of a small piece of the chorion for genetic analysis; may be done at an earlier stage of pregnancy that amniocentesis

Huntington's disease

autosomal-dominant genetic disorder which affects cognitive and mental abilities


one of the alternative forms of a gene that governs a characteristic, such as hair color


a medical procedure in which a sample of cells from the amniotic fluid is tested for abnormalities in a fetus

Chorionic Villi Sampling

sampling of cells from the chorion to test for genetic conditions in a fetus. The cells are grown in a special medium after which a karyotype can be used to make a diagnosis.


enables direct observation of the fetus through an endoscope to allow medical professionals to safely perform various procedures directly inside the womb

Genetic Markers

any characteristic that provides information about an organism's genome

Gel Electrophoresis

can be used to generate a DNA fingerprint.

Prenatal diagnoses

____________ can be used to determine some genetic conditions and disorders

Gene therapy

_______________ is being tested as one way to reverse some of the effects of genetic disorders


Genetically modified organisms


Genetically modified foods

Chorionic Villi Sampling

Used to test for genetic defects and can be done as early as the ninth week of pregnancy

Restriction Enzymes

enzymes which recognize a specific short sequence of nucleotides (the target sequence) on a strand of DNA and cut the strand at a particular point within that sequence

Recombinant DNA

segments of DNA from two different species that are joined in a laboratory to form a single molecule of DNA

Polymerase Chain Reaction

almost entirely automated method of replicating DNA that allows researchers to target and amplify a very specific sequence within a DNA sample


a process in which an identical copy of an organism or part of an organism that has the same genetic make-up, such as the offspring of asexual reproduction, a general term for the research activity that creates a copy of some biological entity (a gene or organism or cell)

Human Genome Project

Determined the sequence of three billion base pairs that make up the human genome

Restriction Site

the specific sites at which a restriction enzyme will cleave DNA


the change in a population's inherited traits from generation to generation


A trait that helps an organism survive and reproduce.


Significant deviations from the normal biological form or structure

natural selection

process by which individuals that are better adapted to the environment are more likely to survive and reproduce than others

artificial selection

process where humans selectively breed organisms to obtain a certain phenotype

Hutton and Lyell

scientists who proposed the Earth was millions of years old due to their geological findings.

George Cuvier

scientist who proposed natural events caused previous animal species to become extinct.

Thomas Malthus

predicted the population would outgrow the food source if restrictions were not put in place


French naturalist who proposed that evolution resulted from the inheritance of acquired characteristics

Charles Darwin

English natural scientist who formulated a theory of evolution by natural selection.

fossil record

chronological collection of life's remains in sedimentary rock layers


having the same evolutionary origin but serving different functions


body structure that has no function in a present day organism but was useful to an ancestor


the study of fossils


proposed by George Cuvier,


the ship that Charles Darwin sailed in


a model of evolution in which gradual change over a long period of time leads to biological diversity


is the idea that the geologic processes that operate today also operated in the past

Hardy-Weinberg principle

theory stating that in the absence of forces that change the proportions of alleles at a give locus, the original genotype proportions will remain constant from one generation to the next, in a large population with random mating

Hardy-Weinberg Equation

p^2 + 2pq+q^2=1

Genetic drift

the change in frequencies of particular alleles in a small population, caused by chance alone

gene flow

movement of new genes into a gene pool. This movement can reduce difference between populations that were caused by isolation and genetic drift.

non-random mating

any situation in which individuals do not choose mates on a random basis, such as mating in base don proximity, relatedness, or similarity of phenotype


Permanent change in the genetic material of an organism

founder effect

cause of genetic drift due to a small group of individuals colonizing a new area; the small group probably will not contain all the genes represented in the parent population

bottleneck effect

occurs when a population is greatly reduced by events such as natural disaster or over hunting, resulting in certain alleles being overrepresented and other alleles being underrepresented or absent in the population due to chance


mating between closely related partners

assortative mating

type of non-random mating in which individuals choose partners that have similar phenotype such as size

sexual selection

selection for mating based in general on competition between males and choices made by females (ie. humans)

sexual dimorphism

the difference between males and females of the same species

chemical evolution

theory that life on Earth occurred began as the natural result of the evolution of inorganic matter

panspermia theory

suggest that life originated elsewhere in the universe and then migrated to our planet

Gaia theory

view that earth is a living super organism which is maintained and regulated by life on its surface

intelligent design theory

suggests that life mechanisms are too complex to have evolved by chance, must have been directed by an unidentified supernatural intelligence


the merging of organisms into new collectives; development of a new species through close association of organisms of different species that is of mutual benefit

Stanley Miller

designed an experiment to test the Oparin-Haldane theory by preparing an atmosphere similar to early earth with electric sparks as an energy source. Resulted in the production of several organic compounds

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