D1.3 SL / HL Flashcards
Mutation
a change in the DNA sequence of a cell or organism. Mutations can be harmful, beneficial, or neutral.
Locus
the physical location of a gene on a chromosome
Point mutation
A genetic alteration caused by the substitution of a single nucleotide for another nucleotide. Also called point variant.
Substitution
a mutation that replaces one base or amino acid with another
Insertion
the addition of DNA, the attachment of a muscle to a bone, or the placement of something into something else
Deletion
a genetic change where a section of DNA is missing
Frameshift
a genetic mutation that occurs when a DNA sequence is inserted or deleted by a number of base pairs that isn’t a multiple of three
Base substitution mutation
a genetic mutation that occurs when a single base in DNA is swapped for another
Degenerate code
when multiple codons can code for the same amino acid
Single nucleotide polymorphism (SNP)
a variation in DNA that occurs when a single nucleotide is replaced by another
Silent mutation
a DNA change that doesn’t affect the amino acid sequence of a protein
Missense mutation
a DNA change that replaces one amino acid with another in a gene
Nonsense mutation
a genetic mutation that causes a protein to stop being made early
Hemoglobin
an iron-rich protein in red blood cells that carries oxygen from the lungs to the body’s tissues and organs
Hb gene
a gene that provides instructions for making beta-globin, a subunit of hemoglobin
alleles
different versions of a gene that occur at the same location on a chromosome
HbA
the most common type of hemoglobin in adults.It’s also known as adult hemoglobin
HbS
sickle cell hemoglobin, is a genetic variation of hemoglobin that causes sickle cell anemia.
Sickle cell disease
An inherited disease in which the red blood cells have an abnormal crescent shape, block small blood vessels, and do not last as long as normal red blood cells
HTT gene
the gene that provides instructions for making the huntingtin protein
trinucleotide repeat expansion
a genetic mutation that occurs when a series of three nucleotides in DNA is repeated too many times
Huntington’s disease
a genetic brain disorder that causes nerve cells to break down over time
CCR5 gene
codes for a protein that is a key part of the immune system’s response to inflammation, infection, and other conditions.It’s also a co-receptor for HIV, which uses it to enter cells.
CCR5 receptor proteins
a protein that helps control the entry of HIV into cells.It’s also involved in immune responses and inflammation
chemokines
proteins that signal cells to move to specific locations in the body.They are involved in the immune system, inflammation, and other biological processes
Gene mutations
a permanent change to the DNA sequence of a gene
Molecular clock
a tool used to estimate when species diverged from each other
High energy (ionizing) radiation
a type of radiation that has enough energy to remove electrons from atoms or molecules
Chemical mutagens (carcinogens)
a substance that changes DNA and increases the risk of cancer
Euchromatin
a loosely packed form of chromatin that is rich in genes and is transcriptionally active
heterochromatin
a densely packed form of chromatin that contains repetitive DNA sequences and is relatively inactive
Non-coding regions
parts of DNA that don’t code for proteins
Mutation hotspots
areas of DNA that are more likely to mutate
CpG sites
a DNA sequence where cytosine (C) is followed by guanine (G)
CpG islands
DNA sequences that are rich in cytosine and guanine nucleotides
Somatic cells (body cells)
the cells in the body that are not reproductive cells, or germ cells
Germ cells (sex cells)
reproductive cells that develop into eggs and sperm
Lactase
an enzyme that breaks down lactose into glucose and galactose in the small intestine
