BIOL 111 Exam 3 Flashcards
Gregor Mendel
“Father of Genetics” ; independent assortment and law of segregation
Fredrick Meischer
First scientist to successfully isolate DNA molecule and show that the dominant molecule in the nucleus was not the protein
Pheobus Levene
Determined structure/composition of nucleotides and how they were linked together
Frederick Griffith
Utilize an in vivo experiment to provide evidence that transformation occurs; determined how living “R” bacteria transformed into pathogenic “s” bacteria
Avery, McLeod, and McCarthy
Performed an in vitro study to identify DNA as the transforming principle; Determined that DNA is substance that is transmitted from one generation to the next
Erwin Chargaff
Analyzed base composition for DNA; saw that composition of DNA nucleotides are different between differing species, but within a species % of A and T are roughly the same and the % of G and C are roughly the same
Wilkins and Franklin
Developed method of x-ray imaging that could detect and visualize molecular structure of DNA; found double-helical structure; responsible for famous “photo 51”
Hershey and Chase
Utilized bacteriophages to provide evidence that DNA is inherited from one generation to the next
Watson and Crick
Interpreted “photo 51” and developed a working double-helical model of DNA; concluded specific pairing in nucleotides and how base pairs differ the number of hydrogen pairs formed
Meselson and Stahl
Tested possible models of DNA replication; found that semi-conservative hypothesis was correct
What is complimentary strand for the sequence 5’ AAACGCTT 3’
5’ AAGCGTTT 3’
What strand would be the same as 5’ AAACGCTT 3’
3’ TTCGCAAA 5’
You discover a new organism and analyze its DNA. If you find 17% of nucleotides are adenine, which of the following is true:
33% are guanine ; Remember % A roughly equals % T in a species/organism and % G roughly equals % C.
Methylation
Used to decrease expression of genes by causing increase compaction of the DNA around its histones
Acetylation
Increases the expression of genes because it reduces the compaction of DNA by decreasing the interaction of the histone proteins
Heterochromatin
Function is to silence euchromatic gene expression to protect chromosome integrity; consists of repetitive DNA sequences; gene poor; highly condensed; transcriptionally silent; unexpressed genes; telomeres and centromeres
Euchromatin
Participates in active transcription of DNA to mRNA products; loosely packed; enriched in genes; under active transcription; easily translated; distal arms of chromosome
Correct order of cell cycle
G1, S, G2, Mitosis, Cytokinesis
Diploid plant with 16 pairs of chromosomes. How many chromatids after S phase?
64 ; diploid plant, so 16x2 chromosomes and 32x2 chromatids
Which of the following is a major difference between Binary Fission and Mitosis?
Binary Fission does not have a nucleus to break down and reform as part of its process, while mitosis uses Prophase and Telophase to break down and reform the nucleus.
The typical human body cells contains 46 chromosomes. How many does a typical human egg cell contain?
23
Mitosis has
2n to 2n cell division; divide DNA so each daughter cell receives the correct amount of DNA and number of chromosomes; single round of cell division resulting in diploid daughter cells; used my somatic cells
Meiosis has
2n to 1n cell division; divide DNA so each daughter cell receives the correct amount of DNA and number of chromosomes; double round of cell division resulting in haploid daughter cells; produces gametes
If a parent cell of a certain organism has 16 chromosomes total in each somatic cell and it undergoes meiosis, the resulting daughter cells will have ____ chromosomes
8
Homologous chromosomes may differ from each other in terms of _____________
types of alleles
Which of these lead to genetic diversity in a population?
Mutations, crossing over, independent assortment, recombination
After a certain meiotic division in a human male, 4 gametes were obtained with the following number of chromosomes: 22, 22, 24, 24. In which stage of meiosis did nondisjunction take place?
Anaphase I
What is the correct order of the steps of DNA replication?
I. New nucleotides are added to the template strand by DNA polymerase III.
II. The DNA helix is unzipped by helicase.
III. Topoisomerase creates nicks in the DNA.
IV. Primase adds a RNA primer to the template strand in a 5’ to 3’ direction.
V. RNA nucleotides are replaced with DNA nucleotides by DNA polymerase I.
VI. DNA ligase forms covalent bonds between fragments in the backbone of the newly synthesized DNA strand.
III, II, IV, I, V, VI
What is the basis for the difference in how the leading and lagging strands of DNA molecules are synthesized?
DNA polymerase can join new nucleotides only towards the 3′ end of a pre-existing strand, and the strands are antiparallel