Term
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Definition
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Term
| What type of histone is between nucleosomes? |
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Definition
| H1. It is the biggest and most charged type of histone. |
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Term
| When is the amount of compaction maximal? When it is more variable? |
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Definition
| Maximal during metaphase, variable during interphase. |
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Term
| Where can we find genes that are being expressed? |
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Definition
| In euchromatin, the less compacted regions that can be transcribed. |
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Term
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Definition
| More compact regions of DNA. This is the "archive" of information. |
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Term
| What is the "extreme case" of heterochromatic control? |
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Definition
| Barr bodies in human female cells. The inactivated X chromosome is packed into a very stable and compact form of heterochromatin. This process must be reversible in cells that will make oocytes. |
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Term
| What is an "epigenetic phenomena"? |
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Definition
| When the DNA is normal, but the packaging is not. This means the expression is also faulty. |
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Term
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Definition
| The DNA Content (or the amount of DNA per cell). In general, more complex organisms have a higher C-value. |
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Term
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Definition
| Vaguely, the collection of all the DNA in the nucleus of a eukaryotic cell. |
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Term
| What is a chromosome? What are the three pieces? |
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Definition
| An independently segregating DNA fragment. Chromosomes have a centromere in the middle, a telomere at each end, and at least one origin. |
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Term
| How much DNA do humans have anyway? |
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Definition
| 3x10^9 bp per haploid genome, which comes out to 6x10^9 bp per cell (6,000,000,000)! |
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Term
| Why is it so tricky to determine what exactly IS a gene? |
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Definition
| A gene is definitely the protein coding region, but it can also include promoters and enhancers that can be really far away. Also, some genes don't even encode a protein (like a tRNA)! |
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Term
| Where can we find rDNA in the genome? |
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Definition
| All lumped together, and repeated thousands of times! |
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Term
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Definition
| Partial repeats, often lacking introns. Possibly from transposition attempts. |
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Term
| What is an alpha-satellite? |
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Definition
| A sequence that is repeated 500,000 times! They might be a functional component of the centromere. They also represent about the same amount of DNA it takes to get around a nucleosome. |
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Term
| Why are microsatellites useful in diagnostic methods? |
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Definition
| Because the exact number of repeats at a specific site (hypervariable region or VNTRs) varies from person to person. |
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Term
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Definition
| Pieces of DNA (20% of the genome) that move around. They either "cut and paste" or move through an RNA intermediate (retrotransposons). |
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Term
| What are LINEs closely related to? |
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Definition
| Retroviruses! They even encode reverse transcriptase and are retroposons. |
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Term
| What is the L1 or KpnI family? |
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Definition
| A common LINE found in humans. Transposition may cause rare genetic disorders. |
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Term
| What do SINEs encode? Why are they useful? |
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Definition
| SINEs don't encode anything. But they do have different sequences across species and can be used to determine if that "mystery meat" came from a cow or a horse... |
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Term
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Definition
| The human SINE. It is seen once every 5,000-10,000 bp in humans. |
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