Biology Quiz 4 Flashcards
what does the term ‘base pair’ refer to
A base pair refers to two bases which form a “rung of the DNA ladder.” A DNA nucleotide is made of a molecule of sugar, a molecule of phosphoric acid, and a molecule called a base.
What is a bacteriophage?
a virus that parasitizes a bacterium by infecting it and reproducing inside it.
Name the parts of a bacteriophage from top to bottom
Head- contains the DNA Neck Collar Sheath Tail Fiber Base Plate
What is a nonsense mutation?
a mutation in which a sense codon that corresponds to one of the twenty amino acids specified by the genetic code is changed to a chain-terminating codon.
What is a silent mutation?
Silent mutations are mutations in DNA that do not significantly alter the phenotype of the organism in which they occur. Silent mutations can occur in non-coding regions (outside of genes or within introns), or they may occur within exons.
what is a nucleotide
a compound consisting of a nucleoside linked to a phosphate group. Nucleotides form the basic structural unit of nucleic acids such as DNA.
Translation the process
in initiation, a ribosome assembles with the mRNA and th initiator tRNA bearing the first amino acid. Beginning at the start codon, the codons of the mRNA are recognized one by one by tRNAs bearing succeeding amino acids. The ribosome bonds the amino acids together. With each addition, the mRNA translocates by one codon through the ribosome. When a stop codon is reached, the completed polypeptide is released.
What is alternative splicing
Alternative splicing is a regulated process during gene expression that results in a single gene coding for multiple proteins. In this process, particular exons of a gene may be included within or excluded from the final, processed messenger RNA (mRNA) produced from that gene.
Cloning by nuclear transplantation
in nuclear transpantation, a nucleus from an aduly body cell is injected into a nucleus free egg cell. Teh resulting embryo may then be used to produce a new organism.
What is an enhancer?
In genetics, an enhancer is a short (50-1500 bp) region of DNA that can be bound by proteins (activators) to activate transcription of a gene. These proteins are usually referred to as transcription factors.
What is gene regulation?
The turning on and off of genes
Define malignancy
the state or presence of a malignant tumor; cancer.
miRNA
A micro RNA (abbreviated miRNA) is a small non-coding RNA molecule (containing about 22 nucleotides) found in plants, animals and some viruses, that functions in RNA silencing and post-transcriptional regulation of gene expression.
What in an oncogene?
a gene that in certain circumstances can transform a cell into a tumor cell.
A normal gene with the potential to become an oncogene is called a
Proto-Oncogene
