Lecture 3 - Genetics Flashcards
chromosome
- 23 chromosomes
- composed of strands of DNA in a double helix
- four bases: cytosine, guanine, adenine, thymine
- each base attached to a phosphate and sugar, and binds to a complementary base (C-G, A-T)
- has a short (p) and a long (q) arm
- 23 chromosomes from mother and 23 from father
- pinched region in the center is the centromere
genome
complete set of DNA
DNA sequence
order of the arrangement of bases on each strang
mRNA
messenger RNA - a complementary/duplicate strand of DNA that leaves the cell in order to be read by a ribosome
codon
- consists of 3 nucleotide bases
- provides instructions on which amino acid to construct
genes
complete instruction for constructing a protein
- only 2% of DNA appears to consist of genes
- 50% of gene function is unknown
- 30,000-40,000 genes per person
peptide
a string of 2-30 amino acids
protein
- longer string of amino acids, ranging up to several hundred amino acids long
- chemical properties fold the protein into a 3D shape that determines function
- perform all the work of the cell
- behave in relation to composition and surrounding proteins
Dynein complexes
- composed of 12 distinct proteins
- fundamental transportation tasks
- convert chemical energy in ATP into mechanical energy
junk DNA
- base pair repeats, do not code for a gene
- useful in forensic work
- close to genes important in embryonic development
single nucleotide polymorphisms (SNPs)
- DNA sequence variation
- lead to phenotypic differences
genetic disorders
- can be chromosomal
- can be due to gene abnormalities
- recessive genes
homeobox
stretch of DNA sequence involved in the regulation of development of animals, fungi, and plants
Hox genes
homeobox genes that determine where limbs and other body segments will grow in a developing fetus
- location of Hox genes on the chromosome parallels the location of the body that gets expressed by that segment
