M2: Molecular Genetics & Biotechnology Flashcards
What is a gene?
Genes are made up of DNA and are inherited by parents
What is the “central dogma of molecular biology”?
The flow of genetic information in the cell. > Transcription control > RNA processing and stability > Tranlational control > Protein processing > Protein activity and stability
What is transcriptional control and why is it important?
Determines when and in what cells a gene is transcribed to produce mRNA. It is is the 1st step determining how many individual proteins are produced in a cell
If every cell in the body has the same genetic code, how is it that different organs of the body are so unique?
about 1000-2000 genes are unique to a specific cell type
Briefly outline the process of transcription
The process where a DNA sequence is copied into an RNA molecule
Briefly outline the process of translation
synthesis of proteins
What are the key regulatory elements of a gene?
> Promoter - DNA sequence at which transcription factors bind and recruit RNA polymerase
AUG
UAG
What are the key elements of the transcribed region of a gene?
Transcribed region - sequences of DNA that are copied into RNA.
The transcribed RNA is processed so that it can be translated
What is a transcription factor and how do they control gene expression?
Gene is only expressed when both activator and transcription factors are present and the repressor is absent
what are Mendel’s law of inheritance?
- Law of Segregation
- Law of independent assortment
- Law of dominance
What is the difference between heterozygous and homozygous mutation, and how would each be inherited?
Heterozygous:
> Only one of the enzymes have been knocked out (from either mum or dad) and the other copy has sufficient enzyme to catalyse the reaction.
Homozygous:
> Both enzymes form mum and dad have been knocked out. So the enzyme before will do their job up until here and form a cumulation. The enzymes after will not have any substrate to work with so will have no effect.
From a genetic perspective, why are we all different?
Unique combination of alleles from out parents
PKU is a disorder of phenylalanine breakdown. How does altering a single protein in the phenylalanine breakdown pathway lead to disease?
It causes the amino acid phenylalanine to build up in the body
What are the major symptoms of PKU and how does this relate to the defect in the processing pathway?
black urine - homozygous mutations of the enzyme leading to the pathway not being completed (?)
With regards to to mutations in enzymes involved in metabolic pathways, would a mutation to an enzyme near the start of the pathway, or near the bottom be expected to lead to a more severe phenotype?
end (?)
What is the link between genotype and phenotype?
Genotype determines pehnotype
How can phenotype be altered by the environment?
providing too much or not enough of something
Briefly outline the process of translation
A genes is transcribes and mRNA is produced. mRNA goes to the cytoplasms where the ribosomes are . The ribosomes bind to the end of mRNA and scans along until it find the start (AUG) codon. Base pairing between tRNA and codon. mRNA is translated through the actions of tRNA recognising the codons. Release factor is a protein and is able to recognise the stop codon.
Use the codon table to determine the amino acids encoded by the DNA sequence CAC and GTA
CAC -> GTG (Val)
GTA -> CAT (His)
How could a genetic test for a specific disease-causing mutation . be carried using PCCR?
Heating to allow for the polymerase to be added and then cooled to allow the primers to bind. This happens on re[peat to form many copies.
Why is it important to tightly control cell number?
could lead to cancer
What is the difference between germline mutations and somatic mutations?
Germline mutations are found in gamete cells and can be passed onto the next generation.
Somatic Mutation occur in other cells and cannot be passed on
What is cancer?
collection of related diseases. Cancer cells are cells within the tissue that longer respond to many of the signals. Over time these can become increasingly resistant. In the late stages, it can break through normal tissue boundaries and spread to other regions
What 2 types of genes cause cancer when mutated?
Tumor suppressor genes
Onco-genes
