Chapter 19

• What is the function of protein kinase a


  Activate ensymes and proteins by phsohylration
• What are transcription factors


  Proteins or non coding rna that regulate the transcription of genes
• How does cAMP levels within the cell affect the rate of lactose metabolism? Explain with reference to the lac operon.

  Move glucose into cell decreases cAMP levels --> less transcription of lac operon --> less lactose metabolised
• What type of genes are homeotic and or homeobox

  Regulatory
• Give one way of post-transcriptional gene regulation.

  Maturing of mRNA through removal of introns.
• What is a homeobox gene?

  A gene controlling the anatomical development of an animal, plant or fungus.
• What is the function of the enzyme lactose permease

  Allows lactose to enter the bacterial cell
• What is an exon?


  A coding region of dna
• What is a silent point mutation


  A change to the DNA base triplet sequence that has no effect on the amino acid sequence in a protein.
• What is pre-mRNA?


  a form of mRNA that contains introns and exons
• What activated protein kinase a

  Cylic amp
• At which states would the dna be during cell division- heterochromatin or euchromotin

  Heterochromatin
• What is structural gene


  A gene that codes for a functional protein
• What is a gene mutation?


  change in a single gene
• What is a homeodomain sequence?

  A sequence of 60 amino acids encoded by the homeobox sequence.
• What conditions are necessary for the lac operon to be switched off

  Glucose present, lactose absent
• What is a hox gene?

  a group of related genes that control the body plan of an embryo
• What is alternative splicing?

  regulated process during gene expression that results in a single gene coding for multiple proteins
• What does the gene lacl code for

  The repressor protein
• What is a translocation in chromosome mutations


  A section of a chromosome breaks off and joins another non-homologous chromosome
• What had happened if a transciription factor has repressed a gene

  The tf has attached to the promoter preventing rna polymerase and the expression of the gene
• Where does the repressor protein bind in the lac operon ?

  The operator region
• What is a nonsense point mutation?

  A change to the DNA base triplet sequence resulting in a termination triplet that leads to a truncated protein.
• How is apoptosis different to cell death due to trauma

  Apoptosis does not involve hydrolytic enzymes.
• Why are homeobox genes highly conserved?

  - very important genes

  - mutation likely to have significant effects/alter body plan, and be fatal/lethal, so selected against

  - mutations would affect many other genes
• Give one way of translational gene regulation that inhibits translation

  Degrade mRNA
• What enzyme catalysed the formation of camp from atp

  Adenyl cyclase
• Why can gene expression only occur with euchromatin?

  Loosely wound DNA, therefore RNA polymerase can access/bind to genes
• How can the action of rna polymerase in lac operon be upregulates


  Binding of the crp-cANP complex to rna polymerase
• What is the function of the enzyme beta galactosidade

  Hydrolyses lactose into glucose into galactose
• What is a bleb in terms of apoptosis?

  A protusion from a cell early on in apoptosis.
• What conditions are necessary for the lac operon to be switched on

  glucose absent, lactose present
• Give one way of post-translational gene regulation.

  Cyclic AMP to activate CRP or kinases / protein modification or further folding
• What is a mutagen?

  anything that causes a mutation
• What is a homeobox sequence?

  Sequence of 180 base pairs (excluding introns) found within genes that are involved in regulating patterns of anatomical development in animals, fungi and plants.
• Give one way of translational gene regulation that uo regulated translation


  Activating initiation factors ti help mature mRNA to bind to ribosomes
• What is a frame shift


  A mutation in which a nucleotide is either removed or added. Includes Insertion and Deletion.
• What is mature mRNA

  mRNA containing only exons (introns have been removed).
• What does gene lacz code for

  beta-galactosidase
• What is the triplet code?

  a series of non overlapping, three-nucleotide words