BIOD 210 GENETICS ACTUAL TEST SCRIPT
WITH SOLVED QUESTIONS AND VERIFIED
ANSWERS
●● Life Cycle of the Cell
Answer: G1-G0-G1-S-G2-Mitosis
●● G1
Answer: Interphase growth period within the cell
●● G0
Answer: Interphase rest period
●● S
Answer: Interphase period of DNA replication, contents of
chromosomes double
●● G2
Answer: Second phase of interphase growth
●● Molecular Structure of DNA
,Answer: DNA, also called Deoxyribose nucleic acid, is an anti-parallel
double helix composed of nucleotides.
Each nucleotide contains a phosphate group, a 5 carbon sugar group, and
a nitrogen base (A,G,C,T)
Nucleotides are attached together to form two long strands that spiral to
create a structure called a double helix. If you think of the double helix
structure as a ladder, the phosphate and sugar molecules would be the
sides, held together by phosphodiester bonds, while the bases would be
the rungs. The bases on one strand pair with the bases on another strand:
A pairs with T, and G pairs with C, forming the DNA molecule.
A and T are held together by 2 hydrogen bonds while G and C are held
together by 3
●● Molecular Structure of RNA
Answer: The structure of RNA is made up of three components, one of
which is a five-carbon sugar called ribose sugar. One of the carbons of
the ribose sugar is attached to a nitrogenous base, which is A,G,C, or U.
Another of the carbons of the ribose sugar is attached to the phosphate
group. Yet another carbon is attached to a hydroxyl group.
What makes RNA different from DNA is that it uses Uracil instead of
Thymine and it has an OH group on the 2' carbon instead of the plain H
that DNA has.
,●● Deoxyribose sugar of DNA compared to Ribose sugar of RNA
Answer: http://www.mun.ca/biology/scarr/iGen3_02-07_Figure-L.jpg
●● Mitosis
Answer: The devision of a mother and daughter cell into genetically
identical cells. Prophase-Prometaphase-Metaphase-Anaphase-Telophase
●● Prophase
Answer: Chromosomes are condensed
●● Prometaphase
Answer: Nuclear envelope dissolves
●● Meselson and Stahl
Answer: Meselson and Stahl's experiment tested which model of DNA,
i.e., the conservative, semi-conservative, and dispersive models, was
correct.
They grew Ecoli in N^15. They then took the N^15 and put it into N^14
medium and allowed DNA replication to take place. They took samples,
spliced them, spun them in a centrifuge, and viewed which layers
emerged because N^15 was heavier than N^14. They saw that there
, wasn't just a band for N^15 and N^14, but a half dark, half light band.
This threw the conservative model out. After the second generation went
by there was an equal distribution of half light and half dark bands.
The Semi-Conservative model of DNA was supported by this.
●● Conservative Model
Answer: Every time a new molecule of DNA is produced it is
completely brand new (brand new molecule)
●● Semi-conservative Model
Answer: Each strand of DNA becomes integrated with a new strand into
a new double helix (half old molecule and half new)
●● Dispersive Model
Answer: Both original strands of DNA become interspersed throughout
the new model (unequal proportions of new DNA to old DNA)
●● Metaphase
Answer: Chromosomes align along the middle of the cell
●● Chargaff's Rules
Answer: A and T are always in the same abundance.
WITH SOLVED QUESTIONS AND VERIFIED
ANSWERS
●● Life Cycle of the Cell
Answer: G1-G0-G1-S-G2-Mitosis
●● G1
Answer: Interphase growth period within the cell
●● G0
Answer: Interphase rest period
●● S
Answer: Interphase period of DNA replication, contents of
chromosomes double
●● G2
Answer: Second phase of interphase growth
●● Molecular Structure of DNA
,Answer: DNA, also called Deoxyribose nucleic acid, is an anti-parallel
double helix composed of nucleotides.
Each nucleotide contains a phosphate group, a 5 carbon sugar group, and
a nitrogen base (A,G,C,T)
Nucleotides are attached together to form two long strands that spiral to
create a structure called a double helix. If you think of the double helix
structure as a ladder, the phosphate and sugar molecules would be the
sides, held together by phosphodiester bonds, while the bases would be
the rungs. The bases on one strand pair with the bases on another strand:
A pairs with T, and G pairs with C, forming the DNA molecule.
A and T are held together by 2 hydrogen bonds while G and C are held
together by 3
●● Molecular Structure of RNA
Answer: The structure of RNA is made up of three components, one of
which is a five-carbon sugar called ribose sugar. One of the carbons of
the ribose sugar is attached to a nitrogenous base, which is A,G,C, or U.
Another of the carbons of the ribose sugar is attached to the phosphate
group. Yet another carbon is attached to a hydroxyl group.
What makes RNA different from DNA is that it uses Uracil instead of
Thymine and it has an OH group on the 2' carbon instead of the plain H
that DNA has.
,●● Deoxyribose sugar of DNA compared to Ribose sugar of RNA
Answer: http://www.mun.ca/biology/scarr/iGen3_02-07_Figure-L.jpg
●● Mitosis
Answer: The devision of a mother and daughter cell into genetically
identical cells. Prophase-Prometaphase-Metaphase-Anaphase-Telophase
●● Prophase
Answer: Chromosomes are condensed
●● Prometaphase
Answer: Nuclear envelope dissolves
●● Meselson and Stahl
Answer: Meselson and Stahl's experiment tested which model of DNA,
i.e., the conservative, semi-conservative, and dispersive models, was
correct.
They grew Ecoli in N^15. They then took the N^15 and put it into N^14
medium and allowed DNA replication to take place. They took samples,
spliced them, spun them in a centrifuge, and viewed which layers
emerged because N^15 was heavier than N^14. They saw that there
, wasn't just a band for N^15 and N^14, but a half dark, half light band.
This threw the conservative model out. After the second generation went
by there was an equal distribution of half light and half dark bands.
The Semi-Conservative model of DNA was supported by this.
●● Conservative Model
Answer: Every time a new molecule of DNA is produced it is
completely brand new (brand new molecule)
●● Semi-conservative Model
Answer: Each strand of DNA becomes integrated with a new strand into
a new double helix (half old molecule and half new)
●● Dispersive Model
Answer: Both original strands of DNA become interspersed throughout
the new model (unequal proportions of new DNA to old DNA)
●● Metaphase
Answer: Chromosomes align along the middle of the cell
●● Chargaff's Rules
Answer: A and T are always in the same abundance.
