Genetics Definitions

Question 1

DNA structure

Answer 1

DNA is made up of molecules called nucleotides. Each nucleotide contains a phosphate group, a sugar group and a nitrogen base. The four types of nitrogen bases are adenine (A), thymine (T), guanine (G) and cytosine (C). The order of these bases is what determines DNA’s instructions, or genetic code.

Question 2

chromosome

Answer 2

a thread-like structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.

Question 3

gene

Answer 3

distinct sequence of nucleotides forming part of a chromosome, the order of which determines the order of monomers in a polypeptide or nucleic acid molecule which a cell (or virus) may synthesize.

Question 4

Genome

Answer 4

the haploid set of chromosomes in a gamete or microorganism, or in each cell of a multicellular organism.
the complete set of genes or genetic material present in a cell or organism.

Question 5

Allele

Answer 5

An allele is a variant form of a given gene. Sometimes, different alleles can result in different observable phenotypic traits, such as different pigmentation

Question 6

Dominant Allele

Answer 6

The terms dominant and recessive describe the inheritance patterns of certain traits. … For a recessive allele to produce a recessive phenotype, the individual must have two copies, one from each parent. An individual with one dominant and one recessive allele for a gene will have the dominant phenotype.

Question 7

Recessive Allele

Answer 7

an allele that produces its characteristic phenotype only when its paired allele is identical. Synonyms: recessive Type of: allele, allelomorph. (genetics) either of a pair (or series) of alternative forms of a gene that can occupy the same locus on a particular chromosome and that control the same character.

Question 8

Homozygous

Answer 8

Homozygous is a word that refers to a particular gene that has identical alleles on both homologous chromosomes. It is referred to by two capital letters (XX) for a dominant trait, and two lowercase letters (xx) for a recessive trait.

Question 9

Heterozygous

Answer 9

Heterozygous. A diploid organism is heterozygous at a gene locus when its cells contain two different alleles (one wild-type allele and one mutant allele) of a gene. The cell or organism is called a heterozygote specifically for the allele in question, and therefore, heterozygosity refers to a specific genotype.

Question 10

Phenotype

Answer 10

A phenotype is the composite of an organism’s observable characteristics or traits, such as its morphology, development, biochemical or physiological properties, behavior, and products of behavior.

Question 11

Genotype

Answer 11

The genotype is the part of the genetic makeup of a cell, and therefore of any individual, which determines one of its characteristics. The term was coined by the Danish botanist, plant physiologist and geneticist Wilhelm Johannsen in 1903

Question 12

Genetic Screening

Answer 12

Genetic testing is a type of medical test that identifies changes in chromosomes, genes, or proteins. The results of a genetic test can confirm or rule out a suspected genetic condition or help determine a person’s chance of developing or passing on a genetic disorder.