Nucleic Acids (DP IB Biology)
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- FrontDNA & RNA Structure
True or False?
All living organisms use DNA as their genetic material.
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True or False?
All living organisms use DNA as their genetic material.
True.
All living organisms have DNA as their genetic material.
There are some viruses that have RNA as their genetic material, bur viruses are not considered to be living, so this is not an exception to the rule.
Name parts A-C on the DNA nucleotide diagram below.
Parts A-C are:
A = phosphate group
B = pentose sugar / deoxyribose sugar
C = nitrogenous base
What is the sugar-phosphate backbone of a nucleic acid molecule?
The sugar-phosphate backbone is formed when the phosphate group of one nucleotide forms a covalent bond to the pentose sugar of the next in a nucleic acid polymer.
What are the nitrogenous bases found in DNA?
The nitrogenous bases in DNA are:
adenine (A)
guanine (G)
cytosine (C)
thymine (T)
What are the nitrogenous bases found in RNA?
The nitrogenous bases in RNA are:
adenine (A)
guanine (G)
cytosine (C)
uracil (U)
True or False?
The sugar in RNA nucleotides is ribose.
True.
RNA nucleotides contain ribose sugar.
How is the 3D shape of a DNA molecule described?
The 3D shape of a DNA molecule is described as a double helix.
What does it mean when DNA strands are described as being antiparallel?
Antiparallel means that the two DNA strands run in opposite directions.
How is the genetic code carried in DNA molecules?
The genetic code in DNA molecules is carried as a sequence of nitrogenous bases (adenine, guanine, cytosine, and thymine.
What does it mean that the genetic code is universal?
The genetic code is universal, meaning that almost every organism uses the same code.
What does it mean to say that a genetic sequence is highly conserved?
A genetic sequence that is highly conserved is one that is the same across many groups of organisms.
True or False?
The genetic code provides evidence for common ancestry in living organisms.
True.
The universal nature of the genetic code is evidence that it has been inherited from a universal common ancestor.
How does the pentose sugar differ between DNA and RNA?
DNA contains deoxyribose as its pentose sugar, while RNA contains ribose.
What are the types of pentose sugar represented by A and B?
The pentose sugars are:
A = ribose (OH group on carbon 2)
B = deoxyribose (H group on carbon 2)
True or False?
Both DNA and RNA are double-stranded molecules.
False.
DNA is double-stranded, while RNA is single-stranded.
How does RNA differ from DNA?
RNA differs from DNA as follows:
RNA
DNA
Sugar
Ribose
Deoxyribose
Nitrogenous bases
Adenine, cytosine, guanine, uracil
Adenine, cytosine, guanine, thymine
Strands
One
Two
What is complementary base pairing in DNA?
Complementary base pairing in DNA refers to the specific pairing of bases:
adenine (A) pairs with thymine (T)
guanine (G) pairs with cytosine (C)
The bases are held together by hydrogen bonds.
What determines the complementarity of base pairs in complementary base pairing?
The complementarity of base pairing (i.e. which base pairs with which other base) is determined by hydrogen bonding.
Why is complementary base pairing important for DNA replication?
Complementary base pairing allows DNA to be copied during replication, ensuring accurate copying and therefore expression of the genetic code in new cells.
True or False?
DNA had a limited capacity for storing information.
False.
DNA has a very large capacity for storing information due to the diversity of possible DNA base sequences.
Which three processes does DNA directionality play an important role in?
Three process that DNA directionality are important in are:
DNA replication
Transcription
Translation
True or False?
During transcription, the coding strand is always read in the 5' to 3' direction by enzymes.
False.
The coding strand is always read in the 3' to 5' direction by enzymes. It is the mRNA strand that is synthesised in the 5' to 3' direction.
Which DNA bases are purines?
Adenine (A) and guanine (G) are purine bases.
Which DNA bases are pyrimidines?
Thymine (T) and cytosine (C) are pyrimidine bases.
Adenine–thymine (A–T) and cytosine–guanine (C–G) pairs have length, so the DNA helix has the three-dimensional structure, regardless of the base sequence.
Adenine–thymine (A–T) and cytosine–guanine (C–G) pairs have equal length, so the DNA helix has the same three-dimensional structure, regardless of the base sequence.
Which element is found in amino acids but not nucleotides?
Amino acids (that makeup proteins) contain sulfur but no phosphorus (unlike DNA).
Which two elements were bacteria grown in as part of the Hershey and Chase experiments?
Bacteria were grown in separate media containing either radioactive sulfur (35S) or radioactive phosphorus (32P).
What were bacteria infected with as part of the Hershey and Chase experiments?
Bacteria were infected with viruses as part of the Hershey and Chase experiments.
The findings of the Hershey and Chase experiments found bacteria that were infected by phosphorus (32P labelled viruses) were radioactive. What did these findings suggest about the structure of genetic material?
The findings of the Hershey and Chase experiments found that DNA (and not protein) was transferred to bacteria and is the hereditary (genetic) material. This is because DNA contains phosphorus (32P labelled viruses) and amino acids (in protein) do not.
Which scientific development made the Hershey and Chase experiments possible? (NOS)
The development of radioisotopes made the Hersey and Chase experiments possible.
What key findings was Chargaff responsible for regarding the structure of DNA?
Chargaff found that:
The number of purine bases were equal to the number of pyrimidine bases
The number of adenine bases were equal to the number of thymine bases, while the number of guanine bases were equal to the number of cytosine bases
Which hypothesis on the structure of DNA did Chargaff's data falsify?
Chargaff’s data falsified the tetranucleotide hypothesis that there was a repeating sequence of the four bases in DNA.