Genes and the genome Flashcards
What are Medel’s Law of Inheritance
What were the key contributions to DNA discovery
1870 was first discovery of DNA
What is the difference between a nucleotide and nucleoside
Nucleotide: phosphate group (tide=3, phosphate sugar and base)
Nucleoside: no phosphate group
What is Chargaff’s rule in complementary base pairing
Concentration of purines=pyrimidines
What are purines and pyrimidines
Purines have imidazole ring
Explain the Watson-Crick Proposal
- DNA is composed of two chains of nucleotides
- The two chains are antiparallel, run in opposite directions
-5’ end has phosphate group attached - The sugar-phosphate backbone is the exterior of the molecules, and bases are interior
- Bases are perpindicular to sugar-phosphate backbone
- The two chains form a spiral pair of right-hand helices
- DNA chains are held together by hydrogen bonds between bases
-G-C has 3 H-bonds (1 more than A-T) thus is harder to seperate - Pyrimidines always paired with purines
- Double helix width 2nm
- Only A-T and C-G pairs fit within double helix
- Complete turn is 10 base pairs
- Molecule has a major groove and minor groove
- Complementary base sequences on each of the 2 strands
-Each parental strand can form a double helix daughter strand
Describe the central dogma
How can we identify chromosomes and what are karyotypes
What is a gene and genome
What are the levels of chromosome organization in a mitotic cell
DNA double helix: chromosome = single, continuous DNA strand
DNA wrapped around histone: nucleosome
-structural unit of chromosome
-DNA + histone
Nucleosomes coiled into a chromatin fiber
Further condensation of chromatin
-Looped domains
Duplicated chromosome
-Condensed form of chromatin (mitotic chromosome)
Continuous complex packing of DNA (large) to fit inside nucleus (small)
What are the specialized DNA sequences and their role in DNA replication and chromosome segretation
Replication:
-Replication origin is site where DNA replication begins
-Telomere has repeated nucleotide sequences at end of chromosome
-> replication end of chromosome and protective cap
Segregation:
-Centromeres role in separation of duplicated chromosomes
Differentiate chromosome vs chromatid vs chromatin
Chromosome: individual DNA strand in interphase
Chromatids: One of two identical halves of a replicated chromosome connected by centromere
Chromatin: DNA + histones
How small is DNA
Describe nucleosome structure
Describe histone structure in nucleosomes
Minor groove interacts with histones
Describe the structure of 30-nm chromatin fiber
What are the types of chromatin and their function
Describe facultative heterochromatin and inactive X chromosome in Calico cats
Explain the histone code hypothesis
Phosphorylation, acetylation and methylation can modify protein binding and thus transcription (gene expression)
What is the correlation between transcriptional activity and histone acetylation
What is epigenetics
Describe the flow of information throughout the cell
