1. The genetic Basis of Life Flashcards
what is evolution
is the change in one or more heritable traits found in a population of individuals over time
what are acquired characteristics?
(eg. muscle gain/loss resulting from exercise) not heritable characteristics
What is the germ plasm theory?
we are made out 2 fundamentally different material: germ plasm and somato plasm
only characteristics in the germ line are passed on
Where are genes located?
on chromosomes
What is natural selection?
emergence of characteristics (phenotype) that confer to reproductive advantage will more likely be passed onto the next generation
What were Mendel’s interpretations of his results?
- inheritance of characteristic trait is predictable
- each form of a character is controlled by a certain heritable characteristic
- obtained results are best explained by the existence of such factors in pairs
- each parent only passes to its progeny one of its two factors for the character
what is a gene
is a heritable characteristic
what is an allele
is a version of a gene
Who was the first one to observe chromosomes and thier segregation during cell division
Flemming
What is the chromosome theory of inheritance
- chromosomes show specific forms and sizes
- nr. of chromosomes is characteristic of each species
- chromosomes segregate equally between daughter cells during cell division
- in most plants and animal cells chromosomes were present in pairs
How did Thomas Hunt Morgan proof that genes were passed on through chromosomes?
He did cross breeding of genes that were located on the sex chromosome
What was Morgan able to say after causing other mutant gene alles in addition to WHITE that were similarly transmitted by the X chromosomes
more than one gene could be associated/transmitted (proved theory of inheritance)
What is a diploid cell
two copies of each chromosome in the nucleus, hence two copies of each gene
What is a pair of homologous chromosomes
(one chromosomes from dad and one from mum) have the same genes on the same locus but different alleles
Do the proteins expressed by 2 different alleles of the same gene function differently?
No the perform the same function
What occurs during somatic cell division?
- each homologous chomosome pair is replicated
- sister chromatids are separated into daughter cells during mitosis
- genetic information is not mixed
are progeny cells from somatic cell division, the same as parental cells?
Yes they are genetically the same
Are progeny cells from germ cell division differnt parental cells?
Yes. Progeny cells are recombined and are haploid
What occurs during meiosis?
- recombination of homologous chromosomes leads to mixing of the genetic material (cross over)
- after completion of meiosis, the resulting haploid gametes are genetically distinct from each other and their parental cells
What was Griffth able to conclude after he injected harmless R bacteria and harmless heat killed S bacteria, and the mouse died?
R strain bacteria must have taken up the transformation principle from the S bacteria.
This caused R bacteria to transform to S bacteria
What is the agent that causes genetic transformation? Protein, RNA or DNA?
DNA is the agent causing genetic transformation of the passive R form to virulen S form.
- no DNA, no transformation
What did Hershey and Chase do to test whether DNA or protein carried genetic instructions?
they radioactively labelled DNA’s phosphorus and protein’s sulfur
Are radioactively labelled protein coats of phages able to inject radioactivity into the cell?
No. Only DNA is passed on
