2 - Genes and Genetic Diseases Flashcards
Two components of DNA structure
- Deoxyribose-phosphate backbone
- Four types of nitrogen bases (adenine, thymine, guanine and cytosine)
DNA Structure
Double Helix structure - two stands held together by hydrogen bonds
Transcription
The process in which a gene’s DNA sequence is copied (transcribed) to make an RNA molecule
Translation
The process through which information encoded in messenger RNA (mRNA) directs the addition of amino acids during protein synthesis
Genes
Segments of DNA that encode
for specific proteins
DNA
Composed of a number of
different genes
Chromosomes
Structure that organizes
DNA into various sections
Genetics
Study of genes - how they carry information, how that information is expressed, and how they are replicated
Meiosis
After chromosomal intermixing, single cell divides twice to produce four genetically unique daughter cells each containing half the number of chromosomes 4n)
Mitosis
A cell duplicates its chormosomes and segregates them, producing two identical nuclei and then splits into two identitical daughter cells, each 2n
Mutation
Effect occurs during DNA replication, has evolutionary basis resulting in positive/negative benefits, and the resulting evolution or extinction
Substitution (+ example)
Inappropriate sequence of nucleotides creating a single different amino acid than what was intended
E.g. (Sickle-cell anemia)
Insertion
Insertion of new inappropriate nucleotide, messes up the order and creates multiple new amino acids
Deletion (+ example)
Inappropriate nucleotide removed, messes up the chain order and multiple new amino acids made
E.g. Cystic Fibrosis
Base pair substitutions
One base pair replaces another base pair, results in only one amino acid change
Missense
Produce a change in a single amino acid, (still working code, just not the correct code)
Nonsense
Produce one of three stop codons (UAA, UAG, UGA)
Frameshift mutation
Insertion or deletion of one or more base pairs, greatly alter amino acid sequence, dramatic change in protiens produced
Genotype
Refers to genetic material passed between generations
Phenotype
Observable characteristics or traits of an organism
Autosomal Dominant Inheritance
Gene is located on one of the numbered, or non-sex, chromosomes. A single copy of the mutation is enough to cause disease
Autosomal Recessive Inheritance
Gene is located on one of the numbered, or non-sex, chromosomes. Two copies of mutation required to cause disease
X-linked Inheritance
Gene carried by mother (X-linked)
Female Children, become carriers, Male Children become affected.
Codon
Three sequential nitrogen bases that “code” for a specific amino acid
Number of amino acids in the body
20
