Gene technology Flashcards
What are gene mutations?
Changes in the sequence of nucleotide bases in DNA.
How do gene mutations occur?
They occur spontaneously, often during DNA replication, and can be increased by mutagenic agents (e.g., X-rays, benzene).
What is the result of mutations in DNA?
Mutations can result in a different amino acid sequence in the polypeptide due to an altered DNA base sequence.
Why don’t all mutations affect the amino acid sequence?
Due to the degeneracy of the genetic code, some mutations don’t change the amino acid coded for.
What are the types of gene mutations?
Substitution, deletion, addition, duplication, inversion, and translocation.
What is a substitution mutation?
The replacement of one or more bases by different bases, which may or may not alter the amino acid sequence.
What is a deletion mutation?
The removal of one or more bases, causing a frame shift that alters the downstream sequence.
What is addition mutation?
Adding one or more bases, which also results in a frame shift.
What is duplication mutation?
Repeating one or more bases, resulting in a frame shift.
What is inversion mutation?
A sequence of bases is reversed.
What is translocation mutation?
A sequence of bases is moved to another location within the genome.
How can mutations lead to tumour development?
By mutations in proto-oncogenes (becoming oncogenes) or tumour suppressor genes, leading to uncontrolled cell division.
What are the two types of tumours?
Benign (non-cancerous) and malignant (cancerous).
What are the key differences between benign and malignant tumours?
Benign tumours grow slower, do not metastasise, and have normal nuclei, while malignant tumours grow faster, metastasise, and have larger, darker nuclei.
What are stem cells?
Undifferentiated cells capable of dividing by mitosis and differentiating into specialised cells.
What are totipotent stem cells?
Cells that can differentiate into any type of cell and occur in early mammalian embryos.
What are pluripotent stem cells?
Cells found in embryos that can differentiate into almost any type of cell.
What are multipotent stem cells?
Cells found in mature mammals that can differentiate into a few types of cells (e.g., blood cells from bone marrow).
What are unipotent stem cells?
Cells that can only differentiate into one type of cell (e.g., cardiomyocyte stem cells into heart muscle cells).
What are induced pluripotent stem cells (iPS cells)?
Pluripotent cells produced from unipotent stem cells by introducing transcription factors to reprogramme them.
How do transcription factors regulate gene expression?
By binding to promoter regions of genes and either promoting or inhibiting RNA polymerase recruitment.
What is the role of oestrogen in gene expression?
Oestrogen binds to receptor proteins, activates transcription factors, and promotes RNA polymerase binding to initiate transcription.
How does RNA interference (RNAi) regulate translation?
siRNA binds to specific mRNA and guides enzymes to hydrolyse the mRNA, preventing translation.
What is epigenetics?
Changes in gene function without altering the DNA base sequence, influenced by environmental factors.
How does increased DNA methylation affect gene expression?
It prevents transcription factor binding, inhibiting gene expression.
How does histone acetylation affect gene expression?
Increased acetylation loosens chromatin, making genes accessible for transcription, while decreased acetylation condenses chromatin, inhibiting transcription.
What tools are used in DNA technology?
Restriction enzymes, gel electrophoresis, PCR, DNA primers, and DNA probes.
What are the applications of recombinant DNA technology?
Producing proteins like insulin, treating genetic diseases, and creating genetically modified organisms.
What is genetic fingerprinting?
A method of analysing VNTRs to determine relatedness, identify individuals, and diagnose diseases.
