Genetic Terminology Flashcards
Allele
Allele is a variant or alternate form of gene. An example: there are 2 alleles for the gene for dimples in humans. If you inherit one allele, you have dimples; if you inherit the other, you don’t have dimples.
Amino Acid
The basic building blocks of proteins. There are 20 amino acids present in the human body.
Breeding population
A group whose members mate with each other and usually not with outsiders.
Base or bond
In genetics, a chemical bond in DNA & RNA that links to another chemical bond in a specific pattern. In DNA, “A” (Adenine) always links to “T” (thymine). “C” (cytosine) always links to “G” (guanine). In RNA “A” links with “U”. “G” and “C” still link together.
Complementary Opposite
In DNA, A and T are known as complementary opposites, as are C & G.
Crossing-over
Homologous chromosomes pair up during meiosis, come close to each other & exchange segments of DNA. Result: a reshuffling of the genes from generation to generation.
Cytoplasm
The gel-like substance enclosed within a cell
Diploid cells
Cells that have two (2) sets of chromosomes
Dominant
A trait that is expressed even if only one allele for it is pre3sent. Note that dominant traits are NOT superior or stronger, despite the popular idea of dominant as powerful.
Gamete
A kind of sex cell
Gene pool
All the genes carried within a breeding population
Genome VS genotype
The genome is the genetic make up of an individual or species; genotype is an individual’s set of alleles
Haploid
A sex cell that has half the normal number of chromosomes
Heterozygous
Having two (2) different alleles.
Homozygous
Having two (2) of the same alleles.
“Master” genes
Genes that set off a cascade (καταρράκτης) of other genes
Meiosis
The production of sex cells or gametes that have half the full complement of chromosomes
Mendelian trait
Also called a monogenic trait. A trait that is coded for by only two (2) alleles so that the individual can only inherit one allele or the other (eg dimples or no dimples).
Mitochondria
Organelle (cell body) containing DNA inherited only from the mother’s line
Mitosis
The division of a cell into two (2) daughter cells that are exactly like the parent cell
Mutation
A permanent change in the DNA sequence of a gene
Nucleotide
Building a block of DNA; contains sugar, phosphate and a nitrogen base
Nuclear membrane (nuclear envelope)
The layers of molecules that enclose the nucleus and keep DNA from passing into the cytoplasm in the rest of the cell
Organelle
The small bodies within the cytoplasm that serve various functions in the cell
Phenotype
The outward, visible manifestation (εκδήλωση) of a trait; the physical appearance of a trait
Proteins
The enzymes, hormones, antibodies, antigens, nutrients & chains of amino acids that structure tissues, carry vital gases to tissues and carry our particular bodily functions
Protein synthesis
The process of making the complex chemicals (proteins) that are necessary for the functioning and repair of tissues and many other bodily activities
Punnett square
A mathematical tool, still used in genetic counseling, that takes the form of a diagram. The diagram shows the percentages of each genotype tha may appear in a generation of offspring, given the particular alleles carried by the parents.
Random Assortment (Independent assortment)
Meiotic cell division that results in each gamete carrying only one rather than a pair of chromosomes. It’s matter of change as to whether offspring inherit the mother’s of the father’s chromosome for each of the pairs.
Recessive
A trait that exists in the genotype but doesn’t appear in the phenotype unless the individual inherits two (2) of the same recessive alleles.
Recombination
The process of reshuffling genetic material that occurs during gamete formation. It refers to random assortment and crossing-over.
Ribosome
Organelle (cell body) where RNA chains amino acids into proteins
RNA
A single stranded molecule involved in carrying out DNA’s instructions.
mRNA
Messenger RNA, the strands of molecules (μόρια) that carry DNA’s code outside the nucleus. mRNA links up with tRNA at the ribosomes in a particular pattern: A to U, U to A, C to G, G to C.
tRNA
Transfer RNA, the strands of molecules that “translate” or “read” mRNA’s code at the ribosomes. tRNA uses mRNA code to chain amino acids together until they form a protein. Together amino acids at the ribosome to form proteins.
Somatic cell
Body cell
Zygote
Fertilized sex cell; fertilized gamete
