Structural Biochemistry/Genetics terms

From Wikibooks, open books for an open world
Jump to: navigation, search

Law of segregation- every individual possess a pair of alleles for any particular trait and that each parent passes a randomly selected copy (allele) of only one of these to its offspring.

Law of independent assortment- separate genes for separate traits are passed independently of one another form parents to offspring.

Chromosomal theory of inheritance- inheritance patterns may be generally explained by assuming that genes are located in specific sites on chromosomes.

Genome- 1 set of all chromosomes

Gene- all the DNA needed to make one protein or RNA

Dominant- allele that is fully expressed in phenotype when heterozygous

Recessive- hidden allele when heterozygous

Co-dominant- both alleles affect the phenotype in separate and distinguishable ways

Incomplete Dominance- phenotype in between two parents

Loci- position of a gene on a chromosome (locus=singular)

Allele- variations of a gene at a locus

Genotype- list of alleles (genes)

Phenotype- expression of alleles "traits"- what you observe

Heterozygous- alleles that are different

Homozygous- alleles that are the same

Telomere- ends of DNA

Epistasis- gene at one locus alters the phenotype of the gene at another locus; method to determine which gene comes first in a pathway.

3’ to 5’ phosphodiester bond- chemical linkage between adjacent nucleotides

Solenoid- circular ring of nucleosomes

Central Dogma- DNA to RNA to Proteins

Mutagens- physical or chemical agents that cause mutations

Types of mutations in substitutions- silent mutations, missense mutations, nonsense mutations

Insertions/Deletions- frameshift

More accurate replication- Nucleotide selection, DNA proofreading, Mismatch repair

Chromosome Shape- Metacentric, Acrocentric, Submetacentric, Telocentric

Robertsonian Translocation- Short arm of an acrocentric chromosome is exchanged with the long arm of another creating a large metacentric chromosome + a fragment that fails to segregate and is lost.

Character or Characteristic- An attribute or feature

Syndromes- Down (age of mother) chromosome 21, Patau chromosome 13, Edward chromosome 18, Turner XO, Triplo-X XXX or (XXXX: extra X chromosome can be inactivated, not necessarily active), Klinefelter XXY (or XXXY), Jacob XYY (gigantism)

Nondisjunction- failure of the chromosome pairs to separate properly usually during anaphase stage.

Crossing Over- exchange of genetic material between chromosomes

Synapsis- pairing of two homologous chromosome during meiosis

Parts of chromosome- telomere, centromere, kinetochore, spindle microtubules, tetrad, centrioles

Vector- DNA that self replicates and inserts/transfers DNA to host cells.

Parthenogenesis- The development of a person from an egg that was never fertilized.

Oncogenes- Genes that are associated with cell cycle and cell reproduction. A mutation in these can cause a cancerous tumor.

Multifactorial- The idea that multiple factors contribute to the end product such as genetic factors and environmental factors contributing to make one person.

Ligase- An enzymatic protein that participates in cell repair or gluing.

Probe- A single strand of DNA that is labelled radioactively or in other methods to be identified later.

Pedigree- An organized diagram of the hereditary passing of one gene. Follows the gene through generations to see how the gene is passed on.

Nonsense Mutation- A stop codon is coded for early in the sequence resulting in an unfinished protein. [1]

Reference[edit]

  1. genetic terms, November 20, 2012.

1.Reece, Jane (2011). Biology. Pearson. ISBN 978-0-321-55823-7. 

Example of Structural Biochemistry in Genes.

DNA is far from perfect. It generates mutations more frequently than we think of, but there are proteins that help correct these mutations so the cell isn't as affected by these mutations. one big complex of molecules that work together incorporate several different proteins, each with their own "job". The first protein is called BRCA1. When there is a mutation in a DNA strand, the strand breaks. When this happens, one of two things follow, a protein called 53BP1 comes in and chops the pieces of DNA in order to avoid making a bad copy. this unfortunately means that that chromosome is not working anymore and depending on how important that was for the life of the cell it could kill the cell. This can hopefully be avoided by having BRCA1 bind to that site making impossible for 53BP1 to come in and chop the piece of DNA. Once BRCA1 is in place a series of other small proteins attach to help correct the mutation. one of the protein is PalB2. The major job of this protein is to provide a binding site for two proteins that can interact together. one protein is RAD51. Every chromatid has a sister chromatid that is identical. RAD51 is essentially the scanner of the protein complex, looking for the sister chromatid and scanning it so the complex knows how to fix the mutation. finally BRCA2 is what actually fixes the mutation taking what RAD51 "scanned" and staying where the mutation with the help of the binding proteins PalB2 and BRCA1. This is how a lot of mutations are corrected to avoid problems that could pose very negative results to the cell and the organism as a whole.[1]