Chapter 8: Genome Structure, Chromatin, and the Nucleosome Flashcards
How long is the human genome?
2 meters
How do prokaryotes and eukaryotes differ in regards to genomes?
Prokaryote genomes are circular and usually have one copy of chromosome. Eukaryote genomes have 2 to 100 chromosomes.
How does the genome size correlate to the species complexity?
A larger complex organism can call genomes into action in more complicated events then a smaller, less complex organism
How does the genome density correlate to the species complexity?
More complex organisms have decreased gene density due to intergenic sequences
What are genomes?
Genomes are wound around nucleosomes and condensed into in chromosomes
During mitosis, chromosomes are found with two identical strands called ____________
Sister strands
How are overlapping genes arranged in eukaryotes?
Genomes are typically antiparallel in eukaryotes
Define sex chromosomes
Carry sex-determining genes.
True or False:
Humans are 99% identical to other mammals
False
Humans are 92% identical to other mammals
Explain the chromosome 2 Fusion
The Chromosome 2 fusion is a fusion in humans, but separate in other primates
Explain the 44 Chromosome Man
Chromosome 14 and 15 are fused.
How genetically similar are humans to all neanderthals?
99.84% generally identical
How genetically similar are humans to all chimps?
98.77% generally identical
What plays an important in distinguish humans from other animals, and affects expression/regulation?
Introns and noncoding intergenic DNA
Who (males or females) undergo X inactivation?
Females
How did the Y chromosome evolve?
The Y chromosomes evolved from the X chromosome. Was once identical to X. Evolves fast.
Describe repetitive intergenic DNA
50% of the human genome DNA is repetitive
Describe PAR
It is the pseudoautosomal regions (PAR1 and PAR2) of the Y chromosome, homologous to the X chromosome. Genes in this region are inherited in an autosomal rather than a strictly sex-linked fashion
Describe SRY
It is the male-specific transcription factor for sex determination
Chromatin is made up of ______ and ______
DNA, Protein
What is the smallest virus?
Hepatitis delta virus (1700 nt)
True or False:
Eukaryotes have polyploid cells
True
The more complex an organism, the _____ its gene density
less
The larger an organisms genome size, the ________ its complexity
greater
More complex organisms have decreased gene density due to __________
Intergenic sequences
True or False:
The mitochondria genome had genes with overlapping exons
True
True or False:
There are 6 million base pairs of DNA per diploid cell
True
Define X inactivation
One X undergoes inactivation in the cells of females
True or False:
Sex ratio is 50% in all animals
True
Define intron
A segment of DNA or RNA molecule which does not code for proteins and interrupts the sequence of genes
What causes gene duplication?
- DNA polymerase slippage
- Unequal crossing over
- Trisomy
- Transposon
Transposons
Cut themselves out and move to different location
Retrotransposons
Transcribed by RNA polymerase into RNA. Then encodes reverse transcriptase and copies themselves somewhere else in the genome
________ are derived from ancient viral infections
Endogenous Retroviruses
What is the Alu element?
The Alu element is a transposon descended from signal recognition particle which targets proteins to ER
Explain the horizontal gene transfer
Genes can be shared horizontally between species