click below
click below
Normal Size Small Size show me how
Biology Exam 3
Human Genetics, DNA Structure and Function, Gene Expression, Biotechnology
Term | Definition |
---|---|
incomplete dominance | no allele is completely dominant, heterozygous shows "blending" |
codominance | when different alleles are present, phenotypes of both are expressed in their pure form |
pleiotropy | one gene effects more than one phenotypic characteristics (e.g. Marfan Syndrome, Sickle Cell Anemia |
Epistasis | expression of gene that may be masked by alleles from second gene |
polygenic inheritance | phenotype by additive effects of 2 or more genes |
DNA Polymerase | enzymes that create DNA molecules by assembling nucleotides, the building blocks of DNA; important in DNA replication |
RNA Polymerase | an enzyme that is responsible for making RNA from DNA template |
mRNA | A minute particle consisting of RNA and associated proteins, found in large numbers in the cytoplasm of living cells. They bind messenger RNA and transfer RNA to synthesize polypeptides and proteins |
tRNA | small RNA molecules that carry amino acids to the ribosome for polymerization into the growing polypeptide chain when the anticodon of the tRNA pairs with a codon on the mRNA being translated |
rRNA | a molecular component of a ribosome, the cells essential protein factory. Strictly speaking, it does not make proteins. It makes polypeptides that go to make up the proteins |
introns | a segment of a DNA or RNA molecule that does not code for proteins and interrupts the sequence of genes |
exons | a segment of a DNA or RNA molecule that together containing information coding for a protein or peptide sequence |
transcription | nucleus; mRNA made by enzyme RNA Polymerase; RNA splicing; introns removed; exons left in; used as instruction for making protein |
translation | cytoplasm-on ribosomes made of protein and mRNA; synthesis of protein using mRNA as instructions; must get proper order if amino acids; start/stop codons; requires tRNA |
protein | end product of translation. It is made |
silent mutation | changing 3rd nucleotide may change amino acid due to redundancy in the triplet code |
missense mutation | changes one amino acid (usually from change in single nucleotide) |
nonsense mutation | get stop codon instead of amino acid and translation stops too soon |
frameshift | a deletion or insertion of nucleotides can change every amino acid that follows. Usually results in nonfunctional protein |
progeria | premature aging disorde; nucleotide 1824 changed from C to T, mRNA and protein is incomplete |
stem cells | undifferentiated biological cells that can differentiate into specialized cells and can divide, through mitosis, to produce more stem cells |
restriction enzymes | cut up foreign DNA, into fragments at specific locations, that gets into cell |
Polymerase Chain Reaction | makes millions of copies of DNA, then sent for sequencing, visualized by gel electrophoresis, or cloned into a plasmid for further experiments |
gene cloning | making copies of genes using bacteria |
therapeutic cloning | obtain embryonic stem cells that are a genetic match to patient; combine donor egg with cell from patient |
reproductive cloning | been done in sheep, horses, cattle, mice, cats, etc., against law for humans |
transgenic organisms | an organism that expresses DNA from another species through recombinant technology. Can be single cell or multicellular. |
gene therapy |