Cheat sheet 8: Molecular Genetics 2

Genome Size

Total number of nucleotides in an organism.

Gene Number

Total number of coding sequences in an organism.

Gene Density

Ratio of gene number to genome size.

Repetitive DNA

Non-coding DNA unrelated to organism function.

Unique DNA

Coding sequences specific to an organism.

Transposable Elements

DNA sequences that can change positions within the genome.

Alternative Splicing

Single gene produces multiple protein products.

Introns

Non-coding regions within genes, absent in prokaryotes.

Exons

Coding sequences that remain in mRNA after splicing.

Epigenetics

Study of heritable changes without altering DNA sequence.

DNA Methylation

Addition of methyl groups, silencing gene expression.

Histone Acetylation

Modification that increases gene expression accessibility.

Genomic Imprinting

Expression of genes depending on parental origin.

Temperature-Dependent Sex Determination

Sex determined by environmental temperature during development.

Prader-Willi Syndrome

Condition due to paternal gene deletion on chromosome 15.

Angelman Syndrome

Condition due to maternal gene deletion on chromosome 15.

Queen Bees

Genetically identical, but express different genes due to diet.

Eukaryotes

Organisms with complex cells containing a nucleus.

Prokaryotes

Simple organisms without a nucleus, fewer genes.

Non-coding RNA

RNA molecules that do not code for proteins.

Gene Complexity

Eukaryotes have more complex genomes than prokaryotes.

Junk DNA

Non-coding DNA with no known function.