Chapter 1 Flashcards
What is the blending theory of inheritance?
Commonly held view that inheritance worked like the mixing of fluids such as paints
Red and white paints give pink
One tall parent and one short parent yield middle height child
What did Gregor Mendel do?
Australian monk who worked to understand rules that govern transmission of traits after hybridization among variety of pea plants
Cross pollinated or intermated different varieties of the pea plant
Discovered 2 particles each parents had that control traits (these were genes)
Determined one allele is dominant to other as well
Page 3
What are alleles?
One of the variants a gene can come in
Ex: purple and white alleles for flowers in Mendels experiment (purple is dominant allele)
How was Mendel’s work rediscovered?
He originally published in 1866 but it’s implications and importance went under appreciated for over 30 years
William Bateson became a relentless apostle of Mendel’s work and later coined the term genetics (study of inheritance)
What is the chromosome theory of inheritance and who proved it?
Chromosome theory demonstrates that Mendel’s genes are located on chromosomes
First proposed by Walter Sutton
Proved by Thomas H Morgan using fruit flies
What is the multifactorial hypothesis?
Who discovered it?
States that continuous traits are controlled by multiple Mendelian genes
Discovered by Ronald Fisher
What is the one-gene-one-enzyme hypothesis?
Who discovered it?
States that genes encode enzymes that perform metabolic functions within cells
Edward Tatum and George Beadle used bread mold
In the case of pea plant, there is a gene that encodes an enzyme required to make the purple pigment in the cells of a flower
Who were the first to give compelling evidence that genes are made of deoxyribonucleic acid (DNA)?
Oswald Avery
Colin MacLeod
Maclyn McCarty
Showed DNA extracted from a virulent strain of bacteria carried the necessary genetic information to transform a nonvirulent strain into a virulent one
Who discovered the molecular structure of DNA and what is it?
James Watson and Francis Crick discovered the double helix model of DNA
2 strands of DNA wound side by side like a ladder
The rings of the latter were made up of 4 bases:
Adenine (A)
Thymine (T)
Guanine (G)
Cytosine (C)
the bases face the center and each base is hydrogen bonded to the other base facing the other way
Adenine always paired with thymine by double hydrogen bond
Guanine always paired with cytosine by triple hydrogen bond
How are genes regulated?
Genes have regulatory elements that regulate gene expression (whether a gene is turned on or off)
Regulatory elements are specific DNA sequences to which a regulatory protein bonds and acts as activator or repressors
What is the central dogma of molecular biology?
Phrase introduced by Francis Crick to represent the flow of genetic information within cells from DNA to RNA to protein
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What is DNA replication?
What is transcription?
What is translation?
DNA rep- a copy of the DNA is produced by each of the 2 daughter cells having a complete copy of all the DNA in the parent cell
Transcription- RNA synthesis from DNA template (mRNA made by transcription)
Translation- translating specific sequence of bases in the mRNA into the sequence of amino acids that compose a protein
What is a codon?
Set of 3 consecutive nucleotides in the mRNA that specifies an amino acid in a protein
What are model organisms?
What are the 4 things that make a good model organism?
Species used in experimental biology with the presumption that what is learned from the analysis of that species will hold true for other species, especially close related species
- Small organisms that are easy and inexpensive to get
- Short generation time to study more generations
- Small genome is useful, easier to find genes looking through small genome
- Easy to cross or mate and that produce large numbers of offspring are best
What are DNA polymerases?
Nucleases?
Ligases?
DNA polymerases- make a copy of a single DNA strand by synthesizing a matching strand with the complete complementary sequence of As Cs Ts Gs
Nucleases- cut DNA molecules in specific locations or degrade an entire DNA molecule into single nucleotides
Ligases- can join 2 DNA molecules together end-to-end using DNA polymerase or other enzymes
What is transformation in genetics?
Geneticists have developed methods to insert foreign DNA molecules into the genomes of many species
Can transform genes of one species into the genome of another
Recipient then becomes a genetically modified organism (GMO)
How are geneticists using hybridization?
Hydrogen bonds of DNA strands can be broken by heat (denature) in aqueous solution to give 2 single stranded DNA molecules
Solution is cooled and DNA will preferentially hybridize with one another
What is DNA sequencing?
Method used to determine the exact sequence of all the As, Cs, Gs, and Ts in the genomes, chromosomes, or genes of an organism
What are single nucleotide polymorphisms (SNPs)?
Simplest form of genetic variation at a single nucleotide site
Difference in the nucleotide base present
Most common type of variation
Single nucleotide site in the genome where individual organisms in a population have different nucleotide bases
Top of page 16
What are point mutations?
Which two scientists worked together on mutations first?
Change if one letter in the DNA code to another that can occur during DNA replication
Wilhelm Weinberg and JBS Haldane
What is a de novo point mutation?
A unique variant that occurs in a child’s DNA that is not in either of its parents (top of page 18)
These ones arise in germline (special lineage of cells that divide to produce eggs in women and sperm in men)
What is the difference of contributing new mutations to their offspring between fathers and mothers?
Fathers contribute 4 times as many new mutations to their offspring as do mothers
The number of new mutations passed on from a father to his children rises with the age of the father
What us quantitative trait locus (QTL)?
Genetic locus that contributes incrementally or quantitatively to variation for a trait
QTL have alleles that usually engender only partial changes such as the difference between a pale purple and a medium purple
Rice QTL example page 21
What are ethylene response factors (ERFs)?
Genes that encode regulatory proteins that bind to regulatory elements in other genes and and thereby regulate their expression
