The equipment for translation is located in the ___________________ where tRNA is found. tRNA consists of 3 loops. One of the loops has a 3-nucleotide sequence called an _______________ that is complementary to the genetic code. This enables tRNA to bind to mRNA through hydrogen bonding. The 3 stop codons are ________, _____________, & ____________.
A ribosome has ___ binding sites. The first site holds ____________ so that its codons are accessible to tRNA. The _____ site holds a tRNA molecule that is carrying its specific amino acid. The ___ site holds a tRNA molecule that is carrying its specific amino acid attached to the growing protein chain.
GENE EXPRESSION
Every cell must be able to regulate when particular genes are used. Otherwise, there would be no order to the cell. Every function that an organism carries out is the controlled expression of genes.
An ______________ is a cluster of genes that codes for proteins with related functions. The operator controls RNA polymerase’s access to the structural genes. It acts like a switch, turning the operon on or off. When a ___________________ is bound to the operator, the operon is turned off. Transcription can resume when an ___________________ removes the repressor.
A ______________________ __________ is a region of intense transcription in eukaryotes. It is believed to form in order to make the genes in that region more accessible to RNA polymerase.
MUTATIONS
Changes in the organism’s hereditary information are known as mutations. Not all mutations are bad – some may lead to positive changes. Mutations in _____________ may be passed on to the offspring whereas somatic cell mutations are not. Some mutations may alter the chromosome, but ____________ mutations change only 1 or a few nucleotides. There are 2 types of these:
1. _________________________ - replace 1 nucleotide with another
2. _________________________ - 1 or more nucleotides are added or deleted
_______________________ are environmental agents that cause mutations. Examples include ___________, __________________, & ____________________. Carcinogens are cancer-causing agents.
______________________ is abnormal cell growth. Usually these result from cells that do not respond to factors that inhibit cell growth. A ______________ is a mass of cells. They may be benign ( held within a protective capsule) or malignant ( break off & spread throughout the body). The spread of cancer is called _______________________________. An _________________________ is a gene that, when mutated, can cause a cell to become cancerous.
Gene technology is a prominent issue in health and biological sciences today. It is able to stir debate and save lives.
The process of isolating a gene from the DNA of 1 organism and transferring the gene into the DNA of another is called ______________ ____________________. It involves building recombinant DNA, a molecule made from pieces of DNA from separate organisms. This process has 4 distinct steps:
1. ___________________ - the gene to be transferred is cut out of the host
2. ___________________ - the DNA is put into the vector (carrier – can be viruses or plasmids)
3. ___________________ - a culture of bacteria is grown with the infected vectors and allowed to grow
4. ___________________ - the bacterial cells with the preferred gene are found & isolated
Genetic engineering is possible because of a universal genetic code.
A _______________ is a member of a population of genetically identical cells produced from a single cell.