Week 4 - Inheritance of genes Flashcards
Centromere
The region of a duplicated chromosome where the two sister chromatids touch;
Chromatid
One of the two identical components of a duplicated chromosome, each containing a single double stranded DNA molecule
Gene
A unit of heredity; a length of DNA on a chromosome that contains the code for a protein (or RNA)
Phenotype
All observable characteristics of an individual or the observable trait as a result of the genetic make-up of one (or more) specific genetic locus (loci)
Recessive
A phenotypic trait is recessive when it occurs in homozygotes only
What reaction does DNA polymerase catalyse?
(dNMP)n + dNTP —-> (dNMP)n+1 + PPi
where dNTP: deoxyribonucleoside triphosphate
Describe gene linkage.
Two genes that are close together on the same chromosome are said to be linked and are said to co-segregate.
The process of crossing-over and recombination can result in two linked alleles being separated during meiosis.
The frequency of recombination between two loci can give information with respect to how close loci are to each other.
Allele
An alternative form of a gene
What is stage G0?
G0 is a stage where a cell does not prepare to divide or is dividing, i.e. it is a phase where a cell does not receive any signals to enter the “cell cycle”.
This could be a temporary phase (the cell starts to prepare for cell division again, once the appropriate signals are received) or for many cells a final, mature stage e.g. nerve cells and heart muscle. Cell cycle is halted in the early stages of G1 and is then often called “cell cycle arrest”. In this case, regulation of growth is clearly one of its main purposes.
Environmental factors that can influence genotype/phenotype:
- Radiations
- Mutagens
- Chemicals that affect cell growth
- Diet
- Lifestyle
Hemizygous
Only 1 allele of a gene on the X chromosome (that is, males only)
What gene codes for glycoproteins on the surface of red blood cells?
Isoglutamin
Complementation
More than one gene is involved in producing a phenotype
