Genes

Genes Genes Define the following terms A section of DNA that codes for a particular characteristic (via the production of a specific protein) Gene: ……………………………………………………………………………………………………………………………………………... The specific location of a gene on a particular chromosome Locus: ……………………………………………………………………………………………………………………………………………... An alternate form of a gene Allele: ……………………………………………………………………………………………………………………………………………... Label the parts of the following chromosome p arm (shorter) 1. ………………………………………………………… 1 3 centromere 2. ………………………………………………………… q arm (longer) 3. ………………………………………………………… telomere 2 4. ………………………………………………………… 4 Complete the following table comparing the genetic composition of various organisms Genome Size Diploid Number Number of Genes T2 Phage (virus) 0.17 Mb Not applicable 280 E. coli (bacteria) 4.6 Mb Not applicable ~4,200 470 Mb 24 ~38,000 P. japonica (canopy plant) 150,000 Mb 40 Unknown D. melanogaster (fruit fly) 130 Mb 8 P. equorum (round worm) 185 Mb 4 14,000 C. familiaris (dog) 2,900 Mb 78 20,000 P. troglodytes (chimp) 3,300 Mb 48 ~22,000 3,300 Mb 46 ~21,000 O. sativa (rice) H. sapiens (human) ~13,000 Define genome The totality of genes in a cell, organism or organelle ………………………………………………………………………………………………………………………………………………….......... List three potential applications of the completed Human Genome Project Screening for known genetic conditions 1. …………………………………………………………………………………………………………………………………………………... Discovering new drug treatments and medications (e.g. phamacogenomics) 2. …………………………………………………………………………………………………………………………………………………... Establishing ancestral lineages 3. …………………………………………………………………………………………………………………………………………………... Mutations Identify three types of mutagens (including an example of each) Physical (e.g. radiation) 1. …………………………………………………………………………………………………………………………………………………... Chemical (e.g. tobacco and other carcinogens) 2. …………………………………………………………………………………………………………………………………………………... Biological (certain viruses) 3. …………………………………………………………………………………………………………………………………………………... Distinguish between somatic and germline mutations Somatic mutations affect body cells and cannot be inherited by offspring (mutation restricted to affected tissue) ………………………………………………………………………………………………………………………………………………….......... Germline mutations affect sex cells and will be passed on to offspring (will affect all cells in offspring) ………………………………………………………………………………………………………………………………………………….......... ………………………………………………………………………………………………………………………………………………….......... Explain the consequences of a base substitution mutation in the development of sickle cell anaemia • Mutations changes GAG to GUG on the mRNA transcript ……………………………………………………………………………………………………………… (this is a change of CTC to CAC on the antisense strand) ……………………………………………………………………………………………………………… • Mutation affects the 6th codon of the haemoglobin beta chain gene ……………………………………………………………………………………………………………… • The mutation change the amino acid from Glutamic acid to Valine (Glu to Val) ……………………………………………………………………………………………………………… • This causes the haemoglobin to form insoluble strands (and clump together) ……………………………………………………………………………………………………………… • The red blood cells adopt a characteristic sickle cell shape ……………………………………………………………………………………………………………… • The sickle cells break down, leading to anaemia and reduced oxygen transport ……………………………………………………………………………………………………………… • The sickle cell mutation demonstrates co-dominance ……………………………………………………………………………………………………………… • The trait shows heterozygous advantage (resistance to malaria) ………………………………………………………………………………………………………………