Structure and Organization of the Human Genome

Question 1

The human nuclear genome contains approximately ____ bp of DNA.

Answer 1

3.2 billion base pairs (bp)

Question 2

The much smaller mitochondrial genome, which was sequenced in 1981, contains only ____ bp of DNA and ___ genes.

Answer 2

16,569 bp; 37

Question 3

The size of the coding region of a human gene contained in the nucleus is approximately ____ bp.

Answer 3

1000-3500 bp

Question 4

How many human genes are identified so far?

Answer 4

30,073 identified genes

Question 5

Of the identified genes, how many are protein-coding? RNA genes?

Answer 5

21,598 protein - encoding genes; 8,475 RNA genes

Question 6

Of the entire human genome, how many percent is protein-coding?

Answer 6

1.1%

Question 7

4% of the entire human genome is identified to be important sequences consisting of?

Answer 7

gene regulatory sequences, and RNA genes

Question 8

Of the entire human genome, how many percent is non-coding DNA consisting of introns, untranslated regions, and pseudogenes?

Answer 8

20%

Question 9

20% of the human genome is non-coding DNA consisting of?

Answer 9

introns, untranslated regions, and pseudogenes

Question 10

75% of the genome is non-coding DNA composed of?

Answer 10

extragenic DNA

Question 11

Extragenic DNA are non-coding DNA consisting how many percent of the human genome?

Answer 11

75%

Question 12

55% of the genome is non-coding DNA composed of?

Answer 12

repeated sequences

Question 13

Repeated sequences are non-coding DNA consisting what percent of the genome?

Answer 13

55%

Question 14

____ permit, through the process of recombination (crossing over between two homologous DNA molecules), the rearrangement of parts of the genome, over time modifying the properties of existing genes and even creating new genes.

Answer 14

repetitive sequences

Question 15

Repetitive sequences permit, through the process of ____ (crossing over between two homologous DNA molecules), the rearrangement of parts of the genome, over time modifying the properties of existing genes and even creating new genes.

Answer 15

recombination

Question 16

The proportion of repetitive sequence within the human genome (>50%) is significantly higher than in other organisms, w/ the corresponding figure being only ____ in the fly and ____ in the worm.

Answer 16

3%; 7%

Question 17

In the human genome, the gene – rich areas tend to have a higher ____ content than the gene - poor regions and they tend to appear negative or pale on ____ chromosome staining.

Answer 17

guanine and cytosine (G + C); Giemsa

Question 18

The clustering of genes encoding structural proteins in part reflects ____ w/ subsequent divergence of function, facilitating evolution by ____ where the resulting new gene can provide a selective advantage.

Answer 18

ancestral small duplications; natural selection

Question 19

In the process of gene evolution, some genes become non - functional gene copies termed ____ (e.g. those within the β - globin cluster), some retain similar functions (e.g. the red – green colour vision genes) and some develop novel functions as a result of ____ or ____.

Answer 19

pseudogenes; small sequence changes or exon shuffling

Question 20

Genes encoding what proteins tend to cluster?

Answer 20

structural proteins

Question 21

Genes encoding for what proteins tend to be scattered?

Answer 21

genes of sequential steps in a metabolic pathway; subunits of complex proteins; mitochondrial and soluble forms of the same enzyme