Theme 2d Flashcards
What happens in the G1 and G2 phases
Synthesis of proteins, RNA, metabolites and other DNA
Duplication of chromatids and centrioles between phases
What happens in the s phase
DNA replication
What happens in the M phase
Mitosis
What happens in cytokinesis
Cell division
What is the G0 phase
Resting phase, exits cell cycle
What does progression of the cell cycle depend on
Activation of cyclin-dependant kinase
What are the 3 check points of the cell cycle
1) G1/S (DNA damage checkpoint)
2) G2/M (DNA replication checkpoint)
3) M (mitotic spindle checkpoint)
What is an oncogene
Positive regulators of cell cycle (gain of function)
Gene amplification
What is a tumour suppressor gene
Negative regulators of cell cycle (loss of function)
What are homologous chromosomes
Maternal and paternal pair of chromosomes
Have the same number and order of genes but alleles are different
Mitosis look at textbook
What happens in binary fission
-begins at origin
-cell elongated and bacterial chromosome separates
-cell splits in half
-mitosis evolved from this
After meiosis how are the chromosomes attached
By a protein structure called the synaptonemal complex
What happens after meiosis one (reductional division)
Number of homologous pairs of chromosomes is reduced from 2 in the parental cell to 1 in the daughter cell (haploid but 2 chromatids per chromosome)
Sister chromatids are not identical due to crossing over
What happens during mitosis 2
Same as mitosis 1 but centromere and sister chromatids separate during anaphase 2
Result is 4 cells with haploid number of chromosomes (1 chromatid per chromosome that are not identical) due to crossing over and random assortment
Germline vs somatic mutations
Germline: inherited (occurs in gametes)
Somatic: not inherited (occurs in any other cell)
What is a base substitution mutation
Single nucleotide change
What is an insertion mutation
One or more base pairs added in sequence during DNA replication resulting usually in a frame shift mutation
What is a deletion mutation
One or more base pairs skipped during replication (frame shift mutation)
What is the difference between transition and transversion mutations
Transitions: purine to purine or pyrimidine to pyrimidine
Transversions: purine to pyrimidine or pyrimidine to purine
What is a missense mutation
Causes a change in amino acid
What is a nonsense mutation
Sense codon changes into a stop codon
What is a silent mutation
Codon change doesn’t change amino acid
What is a frameshift mutation
Insertion or deletion of base pairs that changes the reading frame
What is a large scale deletion mutation
Loss of genes
What is a duplication/amplification mutation
Increasing dosage of genes
What is a translocation mutation
Interchange of genetic parts from non homologous chromosomes
What is an inversion mutation
Reversing orientation of a segment of the chromosome
What are base analogs
Mimic bases and incorporates into DNA (can cause mispairing during replication)
What is the wildtype allele
Normal form of the gene
Loss of function vs gain of function mutant alleles
LOF: reduce/eliminate gene function/expression
GOF: enhance gene expression
What is an allele
Different forms of a gene (sequence variation)
