Junk DNA (2/21)

Question 1

What is different in organisms?

Answer 1

1. ) Sequence of bases along DNA strand
2. ) Amount of genetic material
3. ) # of genes and chromosomes

Question 2

Is the number of chromosomal pairs a reliable predictor for organism complexity?

Answer 2

No

Question 3

How many base pairs (haploid) are in a human genome?

Answer 3

about 6.4 million bases = 2 x 3.2 million base pairs

Question 4

Is the number of BP’s a reliable predictor for organism complexity?

Answer 4

No

Question 5

Is the number of protein-coding genes a reliable predictor for organism complexity?

Answer 5

Nope

Question 6

What percent of our DNA codes for proteins?

Answer 6

1.5% (98.5% of our genome is non-coding)

Question 7

What are Introns?

Answer 7

“Junk DNA”

• much of the RNA transcribed from junk DNA plays a central role in regulating the activity of protein-coding genes and proteins
• JUNK DNA ISNT JUNK!

Question 8

What percentage of our DNA comes from viruses?

Answer 8

8. 3% comes from “fossil” virus DNA, aka “retrotransposons”

- these viruses infected our ancestors and their genetic material has been passed along to us

Question 9

Do you think viruses meet all the criteria typically used to define a living organism?

Answer 9

No! They cannot reproduce themselves!

Question 10

Where do we think viruses originally came from?

Answer 10

They may have evolved from plasmids (pieces of DNA that can move between cells)

Question 11

Is there a correlation between the amount of non-coding “junk” DNA and organismal complexity?

Answer 11

Yes, but we are just starting to understand how our non-coding DNA contributes to our complexity

Question 12

What is “Gene Regulation”?

Answer 12

any mechanism used by a cell to increase or decrease the production of a specific gene product (proteins or RNA)

Question 13

What codes for Micro-RNA (miRNA)?

Answer 13

miRNA is a non-coding RNA present in all living organisms, found on tangled strips of DNA

Question 14

What does Micro-RNA do?

Answer 14

prevents RNA from translating into proteins

Question 15

When does “RNA Interface” occur?

Answer 15

translation from RNA proteins

• the interception of transcription products can strongly affect the phenotype without any modification of the genotype

Question 16

What are “transcription factors”?

Answer 16

proteins that regulate gene expression via transcription

Question 17

What do “transcription factors” do?

Answer 17

control the rate (activity) of transcription of genetic information from DNA to messenger RNA (mRNA)

Question 18

What is “Gene Expression”?

Answer 18

the extent to which genes are transcribed into functional RNA and then translated in to proteins

• the specific products of a genome can be specified by detailed regulation of gene expression
• THIS MEANS THERE IS 1 GENOME BUT MULTIPLE PHENOTYPIC POSSIBILITIES*