Genetics Vocabulary

Question 1

Nucleotide

Answer 1

A compound consisting of a nucleoside linked to a phosphate group. Nucleotides form the basic structural unit of nucleic acids such as DNA.

Question 2

Base pairing

Answer 2

Any of the pairs of nucleotides connecting the complementary strands of a molecule of DNA or RNA and consisting of a purine linked to a pyrimidine by hydrogen bonds. The base pairs are adenine-thymine and guanine-cytosine in DNA, and adenine-uracil and guanine-cytosine in RNA or in hybrid DNA-RNA pairing.

Question 3

DNA polymerase

Answer 3

DNA polymerase (DNAP) is a type of enzyme that is responsible for forming new copies of DNA, in the form of nucleic acid molecules. Nucleic acids are polymers, which are large molecules made up of smaller, repeating units that are chemically connected to one another.

Question 4

Gene

Answer 4

(in informal use) a unit of heredity that is transferred from a parent to offspring and is held to determine some characteristic of the offspring.

Question 5

Messenger RNA

Answer 5

The form of RNA in which genetic information transcribed from DNA as a sequence of bases is transferred to a ribosome.

Question 6

Ribosomal RNA

Answer 6

In molecular biology, ribosomal ribonucleic acid (rRNA) is the RNA component of the ribosome, and is essential for protein synthesis in all living organisms.

Question 7

Transfer RNA

Answer 7

RNA consisting of folded molecules that transport amino acids from the cytoplasm of a cell to a ribosome.

Question 8

Transcription

Answer 8

Transcription is the process by which the information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA).

Question 9

RNA polymerase

Answer 9

RNA polymerase, also known as DNA-dependent RNA polymerase, is an enzyme that produces primary transcript RNA. In cells, RNAP is necessary for constructing RNA chains using DNA genes as templates, a process called transcription.

Question 10

Promoter

Answer 10

Definition of Promoter. Promoter: In molecular biology, a site on DNA to which the enzyme RNA polymerase can bind to initiate the transcription of DNA into RNA.

Question 11

Intron

Answer 11

A noncoding segment in a length of DNA that interrupts a gene-coding sequence or non-translated sequence, the corresponding segment being removed from the RNA copy before transcription.

Question 12

Exon

Answer 12

1. The protein-coding region in the DNA.

2. The nucleic acid sequence in the DNA, or RNA transcript following genetic splicing.

Question 13

Codon

Answer 13

A sequence of three nucleotides that together form a unit of genetic code in a DNA or RNA molecule.

Question 14

Translation

Answer 14

During translation, an mRNA sequence is read using the genetic code, which is a set of rules that defines how an mRNA sequence is to be translated into the 20-letter code of amino acids, which are the building blocks of proteins.

Question 15

Anticodon

Answer 15

A sequence of three nucleotides in a region of transfer RNA that recognizes a complementary coding triplet of nucleotides in messenger RNA during translation by the ribosomes in protein biosynthesis.

Question 16

Helicase

Answer 16

Helicases are enzymes that bind and may even remodel nucleic acid or nucleic acid protein complexes.

Question 17

Okazaki Fragments

Answer 17

Okazaki fragments are short DNA formed on the lagging strand during the process of DNA replication.

Question 18

DNA ligase

Answer 18

In molecular biology, DNA ligase is a specific type of enzyme, a ligase, (EC 6.5.1.1) that facilitates the joining of DNA strands together by catalyzing the formation of a phosphodiester bond.

Question 19

Genotype

Answer 19

The genetic constitution of an individual organism.

Question 20

Phenotype

Answer 20

The set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.

Question 21

Allele

Answer 21

One of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.

Question 22

Homozygous

Answer 22

Having the two genes at corresponding loci on homologous chromosomes identical for one or more loci.

Question 23

Heterozygous

Answer 23

The genetics term heterozygous refers to a pair of genes where one is dominant and one is recessive — they’re different. Like all words with the prefix hetero, this has to do with things that are different — specifically genes.

Question 24

Dominant

Answer 24

An individual with one dominant and one recessive allele for a gene will have the dominant phenotype. They are generally considered “carriers” of the recessive allele: the recessive allele is there, but the recessive phenotype is not.

Question 25

Recessive

Answer 25

A recessive gene is a gene that is not dominant, but only manifests when a gene of both parents is the same, i.e., homozygous (where both genes are the same as in two genes for blue eyes).

Question 26

Purebred

Answer 26

An animal bred from parents of the same breed or variety.

Question 27

Hybrid

Answer 27

The offspring of two plants or animals of different species or varieties, such as a mule (a hybrid of a donkey and a horse).

Question 28

Gametes

Answer 28

A mature haploid male or female germ cell that is able to unite with another of the opposite sex in sexual reproduction to form a zygote.

Question 29

Codominance

Answer 29

Codominance is a relationship between two versions of a gene. Individuals receive one version of a gene, called an allele, from each parent. If the alleles are different, the dominant allele usually will be expressed, while the effect of the other allele, called recessive, is masked.

Question 30

Incomplete Dominance

Answer 30

Incomplete dominance refers to a genetic situation in which one allele does not completely dominate another allele, and therefore results in a new phenotype.

Question 31

Sex-Linked Genes

Answer 31

A gene located on a sex chromosome, usually the X-chromosome.

Question 32

Pedigree

Answer 32

A diagram showing the lineage or genealogy of an individual and all the direct ancestors, usually to analyze or follow the inheritance of trait.