Examination questions Flashcards
What is a nonsense mutation?
type of mutation in a sequence of DNA that results in a premature stop codon in the transcribed mRNA.
What is a missense mutation?
type of point mutation in which a single nucleotide change results in a codon that codes for a different amino acid.
What is silent mutation?
change in the sequence of nucleotide bases in DNA that does not result in a change in the amino acid sequence of the protein.
What is a frameshift mutation?
type of genetic mutation caused by insertions or deletions of a number of nucleotides in a DNA sequence that is not divisible by three.
What is a no frameshift mutation?
mutation does not cause a change in the reading frame. in-frame insertions or deletions, where number of nucleotides inserted or deleted is a multiple of three
What is a substitution mutation, and what types of substitiution mutations are there?
One single base is replaced by another, types are:
Silent
Missense
Nonsense
(Frameshift, borde inte gå, enligt definition, står dock i hennes slide)
What is a insertion mutation and what types are there?
one or more extra nucleotide are inserted types are:
No frameshift
Frameshift
What is deletion mutation and what types are there?
one or more nucleotides are skipped, types are:
No frameshift
Frameshift
Describe the structure of a nucleosome in detail.
consists of a segment of DNA wound around eight histone proteins and resembles thread wrapped around a spool.
Each nucleosome is composed of a little less than two turns of DNA wrapped around a set of eight proteins called histones, known as a histone octamer.
Each histone octamer is composed of two copies each of the histone proteins H2A, H2B, H3 and H4.
The nucleosome core particle consists of DNA wrapped in left-handed superhelical turns around a histone octamer.
Core particles are connected by stretches of linker DNA.
a nucleosome is defined as the core particle plus one of these linker regions; however the word is often synonymous with the core particle.
Linker histones such as H1 and its isoforms are involved in chromatin compaction and sit at the base of the nucleosome near the DNA entry and exit binding to the linker region of the DNA.
Non-condensed nucleosomes without the linker histone resemble “beads on a string of DNA” under an electron microscope
How does nucleosomes affect gene transcription in human cells?
Thought to carry epigenetically inherited information in the form of covalent modifications of their core histones.
Nucleosome positions in the genome are not random, and it is important to know where each nucleosome is located because this determines the accessibility of the DNA to regulatory proteins.
What are the differences between monogenic and polygenic diseases?
Monogenic diseases are caused by a mutation in a single gene.
Polygenic diseases are caused by the combined action or interaction of multiple genes.
What are the main methods used to analyze monogenic diseases?
Pedigree Analysis
determining the inheritance pattern of single-gene diseases.
Gene Sequencing
sequencing the specific gene known to cause the disease
Noninvasive Prenatal Diagnosis
targeted linked-read sequencing on high molecular weight (HMW) DNA of parents and plasma DNA from pregnant mother to determine fetal haplotypes according to parental haplotypes.
Preimplantation Genetic Testing for Monogenic diseases (PGT-M)
detect specific genetic conditions in embryos created through IVF before pregnancy.
What are the main methods used to analyze polygenic diseases?
Genome-Wide Association Studies (GWAS)
Uses single nucleotide polymorphism (SNP) arrays to investigate genetic factors associated with the disease
Polygenic Risk Scores (PRS)
Weighted sum of the number of risk alleles an individual carries.
Targeted Sequencing
Sequencing specific regions of the genome known to be associated with the disease.
Explain how 20 000 protein-coding genes in humans can result in over a million protein
variants?
complex biological processes that allow a single gene to code for multiple proteins.
Alternative Splicing
exons are spliced together in different ways to produce multiple distinct mRNA molecules from a single gene.
Post-Translational Modifications
after protein is synthesized, it can be modified in various ways, such as by the addition of a phosphate group (phosphorylation), a sugar molecule (glycosylation), or a lipid molecule (lipidation).
Protein Cleavage
inactive precursors that are later cleaved to produce the active form of the protein.
RNA Editing
nucleotide sequence of an mRNA molecule is altered after transcription, resulting in a protein that is different from what would be expected based on the DNA sequence.
Describe Transfection
process of deliberately introducing naked or purified nucleic acids into eukaryotic cells.
powerful analytical tool enabling studies of gene products and functions in eukaryotic cells
used to study gene function and protein expression, produce recombinant proteins, or inhibit gene expression.
