3.1 Genes Flashcards
Define gene.
A heritable factor that consists of a sequence of DNA and influences a specific trait.
Define locus.
The position of a gene on a chromosome.
Define allele.
The alternate forms of a gene that code for the
different variations of a specific trait.
Define genome.
It describes the totality of genetic information in an organism, including all genes and non-coding sequences.
Describe the basics of the human genome project.
Founded in 2003 and mapped the entire base sequences of human genes.
Name the 3 main conclusions that came from the human genome project.
- Human cells have mostly 46 chromsoomes.
- The human genome consists of roughly 3 billion base pairs.
- It contains roughly 21,000 genes
Describe the correlation between genetic complexity and chromosome numbers.
There is no clear correlation between either.
Define a gene mutation.
The change in the base sequence of a DNA coding for a particular characteristic.
What are the two types of gene mutation?
Somatic - occurs in body cells and affects a tissue
Germline - occurs in a gamete and affects offspring
What can point mutations include?
Substitutions (silent, missense or nonsense)
Frameshifts (insertions or deletions)
What base substitution change is the cause of sickle cell anemia?
GAG -> GUG
What amino acid change is the cause of sickle cell anemia?
Glutamic acid -> Valine (Glu -> Val)
Name 4 consequences of sickle cell anemia.
- Alters haemoglobin structure (insoluble strands)
- Can’t transport oxygen efficiently (causes fatigue)
- Red blood cells form a sickle shape (clots)
- Sickle cells are destroyed at a higher rate (anemia)
Name the heterozygous advantage of sickle cell anemia.
It is a codominant trait and heterozygous individuals demonstrate an increased resistance to malaria.
