Past papers Flashcards
What does recombinant mean?
a chromosome, cell or individual that has non parental combinantions of alleles.
What is epistasis?
Interaction betweentwo or more genes that affect a single phenotype.
What is the telomere?
Sequences at the ends of linear chromosomes that stabilise the chromosomes.
What is the synapsis?
The association of replicated homologous chromosomes that allows crossing over to occur during Prophase 1 of MEIOSIS
What is linkage disequilibrium?
the association of particular SNP’s with each other in a population.
What is the pseudoautosomal region?
a region of homologous DNA on the X and Y chromsomes of mammals.
What is monosomy?
Where a cell or organism has one chromosome of a homologous pair missing.
What is non disjunction?
Aberrant segregation of chromosomes or chromatids during meiosis.
What is the centromere?
A region of DNA on a chromosome that becomes attached to the meitoic spindle.
What is the haplotype?
A set of SNPs close together in a small region of a chromosome.
What is a barr body?
The inactive X chromosome in cells of female mammals.
What are sister chromatids?
Two identical copies of a chromosome derived from replication of the chromosome and held together by cohesion.
What is a morphospecies?
populations designated as seperate species based on differences in form.
What does fixation mean?
All organisms have the same allele at the same locus in a population.
What is the founder effect?
genetic drift resulting from the establishment of a new population by a small number of individuals.
What is gene flow?
the movement of alleles between populations.
What is the gene pool?
random changes in allele frequencies caused by sampling error.
What is genetic drift?
is the change in the frequency of a gene variant (allele) in a population due to random sampling
What is overdominance?
heterozygotes have higher fitness than homozygotes.
Which are derived from common ancestors and which are a result of adaption to a similar environment?
Dorsal fins of porpoise and salmon.
Bones of human arm/bat wing.
Jointed leg of ladybird/leg of robin.
Rhesus monkey’s tail/human coccyx.
Giant panda’s thumb/human’s thumb
Homologous:
Human arm/bat wing bones.
Human coccyx/monkey’s tail.
Analogous the rest.
Where is the Trophectoderm?
outside layer in gastrulation.
What are Orthologous genes?
same gene in different organisms.
What are Paralogous genes?
Duplicated genes within a single genome.
What are Homologous genes?
Genes that share a common ancestral gene.
What are Homeotic mutations?
A mutation that results in the transformation of one body structure to another.
What is the most abundant DNA polymorphism in humans?
Single nucleotide polymorphisms.
What results in down syndrome?
Trisomy of chromsome 21.
non disjunction occuring during the first meiotic division in the mother.
what are mesochymal steam cells?
multipotent stromal cells that can differentiate into a variety of cell types
Where is the SRY region located?
Just outside the pseuodoautosomal region.
What are Kuru and vCJD examples of?
prion diseases.
Advantages of studying a mouse?
Mammal and strong genetics.
Why is the inner cell mass pluripotent but not totipotent?
can give rise to all cell types, including somatic and germ cells, but not the extraembryonic membranes.
What can the molecular clock use?
DNA sequences (coding and non) and protein sequences.
When did the Cambrian explosion occur?
500 million years ago.
