Structure and Function of Genes and Genomes

Question 1

What is a gene? What is it composed of?

Answer 1

It is the unit of inheritance and is composed of DNA.

Question 2

What is a genome?

Answer 2

It is a package of informational, historical, and noncoding DNA along with unknown regions.

Question 3

How many haploid bps are in a human genome?

Answer 3

3.3x10^9

Question 4

Where is most of the DNA found in a human cell? Where is the rest of it located?

Answer 4

Most of the DNA is found in the nucleus and the rest is coded into the mitochondria

Question 5

Who invented the microscope and when? What was observed?

Answer 5

Karl Von Nageli reported thread like structures (chromosomes) in 1842.

Question 6

What theory was proposed by whom in 1865?

Answer 6

Mendel proposed inheritance

Question 7

What did Watson and Crick publish in what year?

Answer 7

They described the double-helix structure of DNA in 1953

Question 8

Who came up with the x-ray technology that provided evidence of the double helix DNA?

Answer 8

Rosalind Franklin

Question 9

How much of the nuclear genome codes for genes?

Answer 9

25%

Question 10

How much larger than the mitochondrial genome is the nuclear genome?

Answer 10

5x10^6

Question 11

What did Francis Crick describe in what year?

Answer 11

In 1957, he described that DNA is transcribed to RNA which is translated into a functioning protein

Question 12

What is the difference between an intron and an exon?

Answer 12

Introns are non-coding DNA sequences removed during splicing, and exons are coding and protein assembling sequences

Question 13

What portion of the nucleus is exons/introns?

Answer 13

10% exons and 90% introns

Question 14

What are the three described parts of a DNA strand?

Answer 14

Regulatory sequences, Promoters, and Terminators

Question 15

How can we visually tell a prokaryotic from a eukaryotic gene?

Answer 15

Eukaryotic genes have introns

Question 16

What binds to what part of DNA during transcription?

Answer 16

The regulatory sequences bind regulatory proteins, and promotors bind RNA polymerase

Question 17

What are the 4 regions of RNA?

Answer 17

Ribosomal binding site, start codon, codons, and the stop codon

Question 18

What is a codon?

Answer 18

It is a three nucleotide sequence that specifies an amino acid

Question 19

What are the two proponents of a regulatory sequence of a protein coding DNA strand?

Answer 19

The promotor and the enhancer/silencer

Question 20

What direction does the sense/coding strand go?

Answer 20

5 to 3

Question 21

What strand binds to RNA polymerase?

Answer 21

The antisense/template strand

Question 22

What are the two parts of the promotor?

Answer 22

The core and the proximal/cis sequence

Question 23

What is the enhancer/silencer sequence of DNA located far from the core?

Answer 23

The distal/trans sequence

Question 24

How many polypeptide proteins are needed for optimal control of DNA transcription?

Answer 24

Approximately 60 per eukaryotic gene

Question 25

How is the preinitiation complex assembly assembled?

Answer 25

It is a binding of the TATA box binding protein (TBP) to the TFIID.

Question 26

What are the 4 core promotor sequence element positions?

Answer 26

Positions -35, -25, 1, and 30

Question 27

What is splicing?

Answer 27

It is pre-mRNA being processed to remove introns

Question 28

What are the splicing sequence elements?

Answer 28

The donor site is GU at the 5 end, and the acceptor site is ag at the 3 end

Question 29

What is alternative splicing?

Answer 29

It is a different pattern of gene splicing that allow for the diversity of proteins for different functions

Question 30

What portion of which DNA strand in which direction determines transcription initiation and directionality?

Answer 30

The promotor region of the 5 end of the coding strand

Question 31

Is DNA transcription directionality relative?

Answer 31

Yes

Question 32

What is the translation start codon?

Answer 32

ATG

Question 33

What are the three ways DNA sequences can be shared between genes?

Answer 33

1. Complementary genes are transcribed in opposite directions 2. Overlapping genes can be transcribed in the same direction but using different frames 3. Genes can be nested in larger genes(ex. NF1) within an intron in the opposite direction (ex. OGMP, EVI2A, and EVI2B)

Question 34

What is the centromere of a chromosone?

Answer 34

It is a narrowing point coated with kinetochore proteins

Question 35

How do we find the p and q chromosomal arms?

Question 36

Where are telomeres found and what is found in them?

Answer 36

They are found at each of the two chromosomal ends and they are rich in repetitive sequences

Question 37

What DNA sequence elements provide a binding site for kinetochores? hint, it is at the centromere

Answer 37

Alpha satellite DNA

Question 38

What is the kinetochore complex composed of?

Answer 38

The protein complex at the interface and microtubules from the spindle

Question 39

What happens to telomeres as we age?

Answer 39

They get shorter