BIO 243 LAB FINAL QUESTIONS AND CORRECT DETAILED
ANSWERS (VERIFIED ANSWERS) ALREADY GRADED A+
The purpose of using high salt concentration during a DNA extraction is
to: Ans✓✓✓strip away any proteins that are associated with the DNA
and make DNA more soluble in water
The purpose of using detergent during a DNA extraction is to:
Ans✓✓✓lyse open the cells and denature the proteins
The purpose of using isopropanol during a DNA extraction is to:
Ans✓✓✓make DNA precipitate out of the extraction buffer
Which properties can we exploit to efficiently purify and visualize
DNA? Ans✓✓✓-DNA-interacting proteins have positive charges that
can be neutralized by negatively-charged ions from salts
-DNA has a negatively-charged backbone that can attract specific dyes
-Cell membranes are made of lipids that can be disrupted by detergents
TRUE OR FALSE: The foil-protected plates demonstrate yeast viability
with full protection from (or the absence of) UV exposure. This makes
the foil the positive control for the experiment, as the other conditions
test different levels of blocking Ans✓✓✓True
TRUE OR FALSE: The plastic wrap covered plates demonstrate yeast
viability with no protection from UV exposure. This makes the wrap the
, positive control for the experiment, as the other conditions test different
levels of blocking. Ans✓✓✓False
Why are yeast a good model organism to study the effects of UV
radiation induced DNA damage? Ans✓✓✓-Yeast typically do not
survive UV exposure, so it is easy to measure the extent of DNA
damage
-Yeast are eukaryotes with similar DNA repair mechanisms as humans
-Yeast grow quickly on plates or in liquid culture
Why is it important that the yeast plates exposed to full UV radiation
still have plastic wrap on the blocking template? Ans✓✓✓The
sunscreen treatments were on plastic wrap, so this will control for any
UV protection from the wrap itself
A diploid cell with 10 chromosomes (5 homologous pairs) undergoes
two rounds of mitosis. How many chromosomes will be present in each
daughter cell after round two? Ans✓✓✓10
In which phase of mitosis does the nuclear envelope reform and
chromosomes decondense? Ans✓✓✓telophase
In which phase of mitosis does the nuclear envelope break down and the
chromosomes condense? Ans✓✓✓prophase
ANSWERS (VERIFIED ANSWERS) ALREADY GRADED A+
The purpose of using high salt concentration during a DNA extraction is
to: Ans✓✓✓strip away any proteins that are associated with the DNA
and make DNA more soluble in water
The purpose of using detergent during a DNA extraction is to:
Ans✓✓✓lyse open the cells and denature the proteins
The purpose of using isopropanol during a DNA extraction is to:
Ans✓✓✓make DNA precipitate out of the extraction buffer
Which properties can we exploit to efficiently purify and visualize
DNA? Ans✓✓✓-DNA-interacting proteins have positive charges that
can be neutralized by negatively-charged ions from salts
-DNA has a negatively-charged backbone that can attract specific dyes
-Cell membranes are made of lipids that can be disrupted by detergents
TRUE OR FALSE: The foil-protected plates demonstrate yeast viability
with full protection from (or the absence of) UV exposure. This makes
the foil the positive control for the experiment, as the other conditions
test different levels of blocking Ans✓✓✓True
TRUE OR FALSE: The plastic wrap covered plates demonstrate yeast
viability with no protection from UV exposure. This makes the wrap the
, positive control for the experiment, as the other conditions test different
levels of blocking. Ans✓✓✓False
Why are yeast a good model organism to study the effects of UV
radiation induced DNA damage? Ans✓✓✓-Yeast typically do not
survive UV exposure, so it is easy to measure the extent of DNA
damage
-Yeast are eukaryotes with similar DNA repair mechanisms as humans
-Yeast grow quickly on plates or in liquid culture
Why is it important that the yeast plates exposed to full UV radiation
still have plastic wrap on the blocking template? Ans✓✓✓The
sunscreen treatments were on plastic wrap, so this will control for any
UV protection from the wrap itself
A diploid cell with 10 chromosomes (5 homologous pairs) undergoes
two rounds of mitosis. How many chromosomes will be present in each
daughter cell after round two? Ans✓✓✓10
In which phase of mitosis does the nuclear envelope reform and
chromosomes decondense? Ans✓✓✓telophase
In which phase of mitosis does the nuclear envelope break down and the
chromosomes condense? Ans✓✓✓prophase
