DNA (2/16)

Question 1

Why study DNA?

Answer 1

1. ) DNA is the fundamental basis of variation and change
2. ) DNA operates the same way in all living things
3. ) Many current issues involve an understanding of DNA (genetic engineering (GMOS), stem cells, cloning, etc.)

Question 2

How many times must your DNA replicate itself during your lifetime?

Answer 2

Replication happens an estimated 10^15 times to build a human from a fertilized egg

Question 3

Roles of Different Enzymes (Helicase, Primase, DNA Polymerase, Ligase)

Answer 3

Helicase: unzips the paired DNA strands forming a replication fork

Primase: binds leading strand and synthesizes an RNA primer completely to the DNA template; marks the starting point for DNA synthesis

DNA Polymerase: synthesizes DNA in the 5’ to 3’ direction

Ligas: DNA “glue”, links Okazaki fragments together

Question 4

Okazaki Fragments for Building Lagging Strand

Answer 4

• used on the lagging strand so that the polymerase can add to the nucleotides in the 5’ to 3’ end
• this process ends up with a bunch of little fragments that are not all connected (Okazaki Fragments)
• all eventually put together by DNA Ligase
• DNA Primase will also come in to switch out the RNA with new DNA

Question 5

What is the traditional definition of a “Gene”?

Answer 5

a segment of DNA molecule that codes for an amino acid chain to build a protein (or tRNA/rRNA

Question 6

Enzymes

Answer 6

proteins that catalyze reactions and facilitate other chemical reactions

Question 7

Central Dogma

Answer 7

the idea that DNA replication begins by being transcribed to mRNA and then is translated to proteins (DNA => RNA => Proteins)

Question 8

Where does transcription occur?

Answer 8

The Nucelus

Question 9

What is DNA transcription?

Answer 9

the process by which DNA code is turned to messenger RNA

• a template RNA is formed corresponding to DNA
• T is switched for U

Question 10

RNA Polymerase

Answer 10

similar to dNA polymerase; it is used to make mRNA strand by reading DNA strand

Question 11

Messenger RNA (mRNA)

Answer 11

the type of RNA that carries the message of DNA to be transcribed and turned in to a specific protein

Question 12

What are the differences between RNA and DNA?

Answer 12

• RNA has different sugar in the backbone
• U substitutes for T in RNA
• RNA is single stranded

Question 13

mRNA Codons

Answer 13

RNA units that are “triplet nucleotide base” called codons

Question 14

How many possible mRNA codons are there

Answer 14

4 possible bases (U G C A); 64 possible combinations

Question 15

How many amino acids are used by life?

Answer 15

20