I took a quiz for my biology class and got a few questions wrong and need the answers to study for my exam however I can't find them in my book/notes. can anyone help?
1. What part of a nucleotide accounts for the genetic variation between individuals?
A. sugar
B. phosphate <-- I put B which was wrong
C. base
D. polymerase
2. Replication of DNA can't begin until
A. phosphate bonds between nucleotides are broken
B. hydrogen bonds between complementary bases are broken
C. covalent bonds between sugar molecules are broken
D. hydrogen bonds between nucleotides in one strand are boken <-- my answer, which was wrong
3. Bacterial cultures are sometimes exposed to ultraviolet (UV) light in order to generate organisms with new genetic traits. Why do microbiologists choose to use UV light for this purpose?
A. UV light makes all cell antibiotic-resistant
B. UV light has the ability to cause changes in DNA
C. UV light is the usual source of energy for bacteria, thus giving them more energy for evolution
D. None of the above <-- my answer, which was wrong
thanks so much to anyone who can help, I really appreciate it! :)
1. What part of a nucleotide accounts for the genetic variation between individuals?
A. sugar
B. phosphate <-- I put B which was wrong
C. base
D. polymerase
2. Replication of DNA can't begin until
A. phosphate bonds between nucleotides are broken
B. hydrogen bonds between complementary bases are broken
C. covalent bonds between sugar molecules are broken
D. hydrogen bonds between nucleotides in one strand are boken <-- my answer, which was wrong
3. Bacterial cultures are sometimes exposed to ultraviolet (UV) light in order to generate organisms with new genetic traits. Why do microbiologists choose to use UV light for this purpose?
A. UV light makes all cell antibiotic-resistant
B. UV light has the ability to cause changes in DNA
C. UV light is the usual source of energy for bacteria, thus giving them more energy for evolution
D. None of the above <-- my answer, which was wrong
thanks so much to anyone who can help, I really appreciate it! :)
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1) is C, because in biology a "base" is the common name for the part of a nucleic acid denoted "A", "C", "G", or "T". This is really important, get to know about what bases are if you have the time before the exam.
2) B, Replication cannot begin until the hydrogen bonds of the bases are broken, because to replicate, polymerase must have access to the hydrogen bond accepting/donating groups of the parent strand [note the sneaky working in D; option D actually infers self hydrogen bonds on a strand must be broken, whereas it is the intermolecular hydrogen bonds that must be broken!]
3) C. UV light has a higher energy than visible light, and thus has a greater potential to disrupt DNA (i.e. mutation occurs, and mutation drives evolution)
P.S. Don't feel bad about question 2, the question was written in a very nasty way. I'll bet it caught a lot of people out.
2) B, Replication cannot begin until the hydrogen bonds of the bases are broken, because to replicate, polymerase must have access to the hydrogen bond accepting/donating groups of the parent strand [note the sneaky working in D; option D actually infers self hydrogen bonds on a strand must be broken, whereas it is the intermolecular hydrogen bonds that must be broken!]
3) C. UV light has a higher energy than visible light, and thus has a greater potential to disrupt DNA (i.e. mutation occurs, and mutation drives evolution)
P.S. Don't feel bad about question 2, the question was written in a very nasty way. I'll bet it caught a lot of people out.
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1. bases account for genetic variability. The sugar backbone and phosphate are the same in all DNA. But it's the arrangement of bases that account for differences between people. Polymerase is just an enzyme.
2. hydrogen bonds between complementary bases are broken, performed by helicase
3. UV light changes DNA.
2. hydrogen bonds between complementary bases are broken, performed by helicase
3. UV light changes DNA.