Genetics’
No description yet. This curated deck is ready for daily study.
Card preview (24)
How many chromosomes in human body ?
23
What are somatic cells ?
Normal body cells
How many somatic cells do humans have ?
22 pairs so 44
How many sex chromosomes do humans have ?
2 sex chromosomes
What is a gene ?
Section of DNA that codes for a polypeptide chain
What are autosomal chromosomes?
They are any chromosomes that are not sex chromosomes
How many chromosomes do gametes have ?
22 single autosomal chromosomes and 1 sex chromosome as they have 23 chromosomes
What are exons ?
They are regions of coding DNA of a gene that code for a polypeptide chain
What are introns ?
They are regions of non coding DNA of a gene which is removed during splicing to form mature MRNA
What did the human genome project of 2003 identify ?
It identified 25,000 genes across a set of 24 chromosomes Found that genes only make up 2% of all our DNA Found that DNA is which codes for a gene is called an exon and region between these genes which are non coding are called introns
What does sequencing mean?
Reading the DNA letters in order
What are the 4 nitrogenous bases in DNA ?
Adenine which forms 2 hydrogen bond with thymine Cytosine which forms 3 hydrogen bonds with guanine
What does the order of nitrogenous bases determine ?
How proteins are made How cells function How an organism develops
What is a variant ?
This is when you have a variations which means change in the sequence of a gene. We can use sequencing as a reference point to find variants
What percentage of rare diseases are genetic?
80%
How many people do rare genetic diseases affect ?
1 in 2000 people
How do rare disease occur ?
Due to mutation in one or more genes Some are inherited Some are spontaneous
How many people in the UK have a rare disease ?
3.5 million
How many rare conditions are identified in the Uk ?
Out of the 3.5 million, only 7000 rare diseases are identified
Definition of a genetic disorder ?
A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can caused by a mutation in a single or multiple genes or by chromosomal abnormalities
Name the 3 types of genetic disorders ?
Single gene disorders Chromosomal disorders Mitochondrial disorders
What are single gene disorders caused by ?
Mutation in one gene
Where are single gene disorders ?
Depending on where the gene is located, they can be autosomal dominant, autosomal recessive or sex linked which means on the X or Y chromosomes
How are single gene disorders spread and why ?
These disorders are hereditary which means it’s passed down families. This is because the mutation is in every cells DNA so every cell is effected