Term
| Chromosome organization in the human genome |
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Definition
| 3 X 10^9 nucleotide pairs organized as 24 chromosomes |
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Term
| The 24 human chromosomes are separated as |
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Definition
| 22 different autosomes and 2 different sex chromosomes |
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Term
| Each human chromosome contains how many nucleotide pairs of DNA? |
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Definition
| Between 46 X 10^6 to 250 X 10^6 |
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Term
| The diameter of a human chromosome nucleus is |
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Definition
| Approximately 10 to 15 micrometers |
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Term
| The length of DNA if stretched out is |
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Definition
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Term
| The smallest human chromosome is |
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Definition
| Approximately 4.6 X 10^7 bp. This is equivalent to ~1.4 cm of extended DNA. |
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Term
| How many fold is DNA condensed to in mitosis? |
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Definition
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Term
| In eukaryotes, genomic DNA is organized into |
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Definition
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Term
| What is the fundamental unit of chromatin? |
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Definition
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Term
| Histones constitute the major class for what proteins? |
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Definition
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Term
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Definition
| Small highly basic proteins (positive charge) that bind without sequence specificity to the negatively charged DNA |
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Term
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Definition
| octameric complexes with two each of the histone proteins |
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Term
| A nucleosome is comprised of |
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Definition
| a histone octamer that is wrapped with 146 bp of DNA (almost two complete wraps) |
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Term
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Definition
| The DNA between each nucleosome |
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Term
| Which histones are constituents of chromosomal proteins? |
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Definition
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Term
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Definition
| Regions of the chromatin more loosely packaged, lightly stained during interphase. |
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Term
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Definition
| most single copy DNA and mutable genes |
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Term
| Euchromatin will do what during interphase and what throughout S phase? |
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Definition
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Term
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Definition
| Regions of chromatin that are highly compact and heavily stained in interphase |
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Term
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Definition
| few mutable genes, and is enriched in middle and highly repetitive DNA |
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Term
| The heterochromatin region may what during interphase and what during late S phase? |
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Definition
| Not completely decondense and Replicate |
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Term
| What are the three essential components of linear chromosomes? |
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Definition
| Telomeres, centromeres, and origins of replication |
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Term
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Definition
| chromosome segregation in mitosis and meiosis |
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Term
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Definition
| The point where microtubules of the spindle apparatus attach to the chromosome |
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Term
| The simplest centromere organization is in |
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Definition
| budding yeast, Saccharomyces cerevisiae. 1 microtubule is attached. |
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Term
| Centromere structures in humans are |
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Definition
| highly complex. 10-15 microtubules attach to each centromere |
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Term
| Centromeres are required for |
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Definition
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Term
| How many centromeres are needed for proper chromosome segregation? |
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Definition
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Term
| What do telomeres protect? |
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Definition
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Term
| The female sex chromosome is considered to be what sex? |
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Definition
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Term
| The male sex chromosome is considered to be what sex? |
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Definition
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Term
| X and Y chromosomes evolved from |
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Definition
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Term
| How many bps does the X sex chromosome contain and how many genes does it encode? |
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Definition
| 153 Mbp and approximately 1,000 |
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Term
| How many bps of DNA does the Y chromosome have and how many genes does it encode? |
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Definition
| 60 bp and approximately 80-130 genes |
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Term
| The testis determining factor does? |
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Definition
| Activates the male pathway and blocks the female pathway |
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Term
| In sex linkage, what is different in outcome and what is distributed differently by sex in progeny? |
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Definition
| Reciprocal crosses and phenotypes |
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Term
| What did Thomas Hunt Morgan study? |
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Definition
| White-eye mutation that is X-linked in flies. |
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Term
| A gene on the X chromosome is considered to be? |
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Definition
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Term
| How do humans deal with imbalance of genes on the X and Y chromosomes? |
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Definition
| Inactivation of one X chromosome in females |
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Term
| How do flies deal with imbalance on the X and Y chromosomes? |
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Definition
| Hyperactivation of X chromosomes on males |
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Term
| How do worms deal with imbalance of genes on the X and Y chromosomes? |
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Definition
| Hypoactivation of both X chromosomes in females. |
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Term
| The process of X-chromosome inactivation can be divided into which three major steps? |
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Definition
1. X chromosomes are counted.
2. Choice is made as to which X chromosome(s) will be inactivated.
3. Selected X chromosome(s) actually inactivated. |
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Term
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Definition
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Term
| The XIC locus contains the |
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Definition
| XIST gene (X-Inactivation Specific Transcript), which does not encode a protein |
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Term
| XIST RNA binds only to the |
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Definition
| X chromosome it is transcribed from |
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Term
| The X chromosome is inactivated when it is completely covered with |
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Definition
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Term
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Definition
| reverse of the XIST locus |
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Term
| The TSIX locus is transcribed from |
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Definition
| the DNA strand that did not serve as the template for XIST RNA. The transcript is antisense (and its name is written backwards from XIST). |
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Term
| There is an overlap in transcription between |
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Definition
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Term
| Base pairing between TSIX and XIST RNAs destabilize the |
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Definition
| XIST RNA and leads to its rapid degradation |
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