CH 13 Genomes Reading Guide

Question 1

How does genome relate to chromosome(s)?

Answer 1

The genome is a complete set of chromosomes. In the case of human 23 chromosomes make up our genome

Question 2

Do you

have one or two copies of the human genome in each of your cells?

Answer 2

2 copies

Question 3

Is the genome made up of RNA or DNA?

Answer 3

DNA

Question 4

Why is it so important to fragment the genome into many random pieces?

Answer 4

With existing technologies there is much less error in sequencing small sections of the genome and adding the sections together

Question 5

With current technology can we sequence an entire chromosome in one piece?

Answer 5

No. Must fragment the chromosome into smaller sections

Question 6

How large can a human chromosome be?

Answer 6

Chromosome 1 (the largest) is approximately 250 million nucleotides long

Question 7

the genome is typically
sequenced 10-50 times over in order to determine its sequence. Why might it be a good
idea to do this?

Answer 7

To reduce the number of errors present in the final genome sequence and to minimize the number and size of the gaps where the genome sequence is incomplete

Question 8

Which

type of repeats do you think poses the greatest challenge to sequence assembly

Answer 8

Short, two nucleotides (example AT) in length repeats. Because AT can fold back on itself and pair with other AT’s

Question 9

Would it be meaningful for you, and for society/the field

of medicine, to know your particular genome sequence?

Answer 9

Yes and No.
Could allow you to plan for possible health complications, but if you don’t have the resources to help yourself then you may not want to know

Question 10

what parts are there to a protein coding gene?

Answer 10

Regulatory elements, non coding introns and protein coding exons

Question 11

Do all genes code for proteins? Explain.

Answer 11

Exon regions code for proteins and intron regions do not

Question 12

What ‘patterns’ / ‘motifs’ might be used to find a promoter?

Answer 12

TATA box

Question 13

What ‘patterns’ / ‘motifs’ might be used to find an ORF?

Answer 13

Long string of codons for amino acids with no stop codon.

Question 14

What does ORF stand for?

Answer 14

Open reading frame

Question 15

Does an ORF (open reading frame) necessarily have to contain either a start or a stop
codon?

Answer 15

Does not contain any stop codon

Question 16

Where in a gene (intron or exon) are ORFs

located?

Answer 16

Exons

Question 17

would genes that code for functional RNA molecules have ORFs

Answer 17

Yes.

The exon is the part of the gene that will become the mature RNA

Question 18

How can such mRNA sequences be used to confirm

the presence of ORFs, and intron exon boundaries, in annotated genes?

Answer 18

mRNA is simpler than the original DNA

mRNA has had the introns removed and is only left with a long string of exons with no stop codon (an ORF)

Question 19

Are 5’ and 3’UTRs (untranslated regions) part of ORFs or exons, or both? Explain.

Answer 19

They’re part of the first and last original exon from DNA. Not part of the “new” open reading frame

Question 20

If large differences in gene number does not explain the
greater complexity of the human body compared to that of the microscopic nematode
worm C. elegans, what might?

Answer 20

Human genes are able to do much more with the fewer numbers that we have ie. protein can have multiple functions

Question 21

gene number is not a good predictor of organismal

complexity. How about genome size?

Answer 21

No. A protozoa has close to 10^6 base pairs while humans have 10^10 base pairs

Question 22

Define polyploidy

Answer 22

Has more that two sets of chromosomes in the genome

Question 23

what class of organisms are you very likely to find
examples of polyploidy?

Answer 23

Plants

Question 24

What might explain the large difference in genome size between organisms that
otherwise have comparable numbers of genes?

Answer 24

Ploidy levels: Diploid vs polyploid

Some eukaryotes contains large sections of non-coding DNA.

Question 25

What is highly repetitive DNA?

Answer 25

noncoding DNA that consists of sequences present in more than 100,000 copies per genome

Question 26

What is moderately repetitive DNA?

Answer 26

noncoding DNA that consists of sequences present from 100 - 10,000 copies per genome

Question 27

Approximately how much of the human genome is sequence that actually specifies the
order of amino acids in a protein?

Answer 27

2.5%

Question 28

Are protein coding genes the only genes in the genome?

Answer 28

No

Question 29

In addition to exon sequences (specifying the order of amino acids), what other parts are
there to a gene?

Answer 29

Noncoding RNA, repetitive DNA, introns

Question 30

Transposable elements make up how much of a gene?

Answer 30

Approximately 45%

Question 31

What is the overall electrical charge of a DNA molecule and why?

Answer 31

Negative due to the phosphate back bone

Question 32

What is the overall

charge of histone proteins?

Answer 32

Positive. From the amino acids lysine and arginine

Question 33

Do mitochondria and chloroplast contain their own genetic material?

Answer 33

Yes