Biochemistry, Human Genome

Front 1

69) In human cells you have about 30K genes (genome), ~150K mRNAs (transcriptome), ~1 million proteins (proteome), how can there be more mRNAs and proteins than genes?

Back 1

Due to alternative splicing, and post-translational modifications.

Front 2

70) 5% of DNA is?

Back 2

Highly conserved.

Front 3

71) 2% of DNA?

Back 3

Actually codes.

Front 4

72) 44% of DNA is?

Back 4

Non-conserved.

Front 5

73) 6% of DNA is?

Back 5

Heterochromatin.

Front 6

74) 45% of DNA is?

Back 6

Transposon repeats.

Front 7

75) 93% of mitochondrial DNA is?

Back 7

Highly conserved.

Front 8

76) Why are exons conserved elements?

Back 8

Gene sequences have different susceptibility to mutations, because mutations within some elements are less likely (they result in lethality). Therefore, the real important part of key genes must be highly conserved.

Front 9

77) What are the top 5 protein domains in the human genome?

Back 9

1)Zinc Finger (~29K copies); 2) Cadherin domain (~4K copies); 3) Epidermal growth factor domain (~3K copies); 4) Immunoglobulin domain (~2K copies); 5) Calcium-binding EF hand domain (~1,9K copies).

Front 10

78) Whole genes are concerved and important genes are?

Back 10

Duplicated.

Front 11

79) Gene length varies enormously, bigger genes have a greater susceptibility to?

Back 11

Mutations

Front 12

80) Bigger genes have higher proportions of?

Back 12

Non-coding sequence.

Front 13

81) The biggest portion of the genome is unknown for what it codes for, however, out of the genes we know what their functions is, the greatest functional breakdown is for those genes involved in?

Back 13

Metabolism

Front 14

82) What are transposons?

Back 14

Transposons (a.k.a. jumping genes) are sequences of DNA that can move around different positions within the genome of a single cell, in a process called Transposition. In the process, they can cause mutations and change the amount of DNA in the genome. Transposons are also called “jumping genes” or “mobile genetic elements”.

Front 15

83) Of the 5% highly conserved DNA in the human genome, only about 40% of these genes are coding sequences. Why are other DNA sequences conserved?

Back 15

Because, the genome also needs “handles” for its own organization (ex. DNA packing sequences, nucleosomes binding elements).

Front 16

84) What makes up about half of the genome?

Back 16

Repetitive non-coding elements (transposon repeats).

Front 17

85) Heterochromatin is?

Back 17

Permanently condensed, and transcriptionally inactive DNA.

Front 18

86) Is the sequence of heterochromatin DNA determined?

Back 18

No

Front 19

87) Satellite DNA is comprised of?

Back 19

Tandemly repeated sequence of 5-170 bp in length.

Front 20

88) Were is the location of Satellite DNA?

Back 20

Centromeres.

Front 21

89) Minisatellite DNA is comprised of?

Back 21

Repeats of 9-64bp in length.

Front 22

90) Were is the location of minisatellite DNA?

Back 22

Telomeres

Front 23

91) Microsatellite DNA is also called “simple sequence repeats”, what is it used for?

Back 23

Identification of “bad” genes in pedigrees because it is highly variable in length between individuals.

Front 24

92) If I have a free floating protein and free floating DNA in the same place, what would happen?

Back 24

They would bind together.

Front 25

93) What kind of bonds would they form?

Back 25

Non-covalent, freely reversible.

Front 26

94) Protein DNA-binding regulates the rates of?

Back 26

Transcription, and replication.

Front 27

95) Protein DNA binding is regulated by?

Back 27

Protein concentration, and small molecule effectors (allosterism)

Front 28

96) What part of the histone complex tethers DNA?

Back 28

H1 protein “binder function”.

Front 29

97) Name all of the histones in a histone complex?

Back 29

H1 (1) binder function, H2A (2), H2B (2), H3 (2), H4 (2).

Front 30

98) The core of the histone molecule is comprised of how many histones?

Back 30

8

Front 31

99) DNA that is ready to be transcribed is?

Back 31

Acetylated

Front 32

100) DNA that is transcriptionally inactive is?

Back 32

Deacetylated (a.k.a. Methylated).

Front 33

101) These changes to DNA regulate?

Back 33

Transcription and replication rates.

Front 34

102) In proteins what does the structure of Helix-Turn-Helix do?

Back 34

In proteins, the helix-turn-helix (HTH) is a major structural motif capable of binding DNA. It is composed of two alpha helices joined by a short strand of amino acids and is found in many proteins that regulate gene expression.

Front 35

103) What is retinoblastoma?

Back 35

A rare form of cancer (a.k.a. Cat’s eye) caused by mutation of the RB1 gene. This gene encodes a protein important in the cell cycle.

Front 36

104) In proteins what does the structure of Helix-Loop-Helix do?

Back 36

H-L-H proteins readily form dimers and can “mix-and-match” to modulate transcription rates.

Front 37

105) What syndrome is caused by a mutation in the TWIST gene, an H-L-H transcription factor?

Back 37

Saethre-Chotzen Syndrome (acrocephalosyndactyly type III).

Front 38

106) What DNA binding proteins are very important in steroid hormone signal transduction?

Back 38

Zinc Fingers.

Front 39

107) Zinc Fingers are very important in what type of hormone signal transduction?

Back 39

Steroid hormone.

Front 40

108) Name a few examples of human diseases caused by mutations in Zinc Finger transcription factors?

Back 40

Inherited breast cancer, Wilms Tumor (accounts for 8% of childhood cancers), and Rickets.