AP Biology : DNA and RNA Structure
Study concepts, example questions & explanations for AP Biology
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Example Questions
Example Question #11 : Dna And Rna Structure
The entire collection of DNA in a cell is called the __________.
chromosome
nucleus
DNA ladder
chromatin
genome
genome
The genome is defined as the total genetic library of a cell. It is estimate that in humans, the genome codes for about 25,000 different genes.
Example Question #11 : Understanding Differences Between Dna And Rna
DNA with its associated protein scaffold forms a complex called __________.
chromatin
chromatid
centromere
nucleotide
chromosome
chromatin
Chromatin is the DNA-protein complex and is organized as a long, thin fiber. Chromosomes are densely-packed chromatin, wrapped around proteins called histones. The centromere is the region of a condensed chromosome that connects sister chromatids to each other, and is the site at which the spindle fibers attach during mitosis in order to move them about the cytoplasm.
Example Question #11 : Understanding Differences Between Dna And Rna
In DNA adenine (A) bonds to thymine (T) and guanine (G) bonds to cytosine (C). What is the bonding scheme in RNA?
A-G and C-U
None of these
A-U and C-G
A-C and G-U
A-T and C-G
A-U and C-G
In RNA, thymine is substituted by uracil. So adenine will bond to uracil instead of thymine when RNA interacts with DNA and when RNA folds with itself to make a 3-dimensional structure.
Example Question #21 : Dna, Rna, And Proteins
Which of the following molecules is not present in DNA?
Thymine
All of these
Uracil
Phosphate
Deoxyribose sugar
Uracil
Uracil is a nitrogenous base that is only found in single-stranded RNA—it is not found in DNA. Thymine pairs with adenine in DNA, whereas in RNA, uracil pairs with adenine.
Example Question #22 : Dna, Rna, And Proteins
Which of the following base pairs is found only in RNA?
Thymine
Adenine
Cytosine
Guanine
Uracil
Uracil
Uracil is the base pair that is used in ribonucleic acid (RNA) in the place of thymine. The other three bases adenine, guanine and cytosine are found in both DNA and RNA.
Example Question #21 : Dna, Rna, And Proteins
All of the following bases are found in RNA except __________.
uracil
cytosine
guanine
adenine
thymine
thymine
Uracil is only found in RNA under normal conditions. It replaces thymine, which is only found in DNA. Therefore, thymine, adenine, cytosine, and guanine are the bases found in DNA, and uracil, adenine, cytosine, and guanine are the bases found in RNA.
Example Question #24 : Dna, Rna, And Proteins
Who were the two scientists who developed the model of DNA as a double helix in 1953?
Pauling and Corey
Gilbert and Maxam
Pasteur and Mitterand
Watson and Crick
Watson and Crick
Watson and Crick were the two scientists who developed the model of DNA as a double helix in 1953.
Example Question #25 : Dna, Rna, And Proteins
In the messenger RNA, with which base on DNA does uracil pair?
Guanine
Adenine
Thymine
Cytosine
Adenine
Uracil in RNA bonds to adenine on the DNA template during transcription. These two nitrogenous bases form two hydrogen bonds.
Example Question #22 : Dna, Rna, And Proteins
What would be the sequence of mRNA translated from the DNA segment 5' - ACGTCA - 3' ?
5' TACTTU 3'
5' UGACGU 3'
5' UCGAGU 3'
5' UGCAGU 3'
5' TGCAGT 3'
5' UGACGU 3'
mRNA contains uracil instead of thymine, therefore your answer should not contain the base thymine. Remember, DNA is read in the 3' to 5' direction and the corresponding strand is created in the 5' to 3' direction. It is important to pay attention to polarity of the strands. Adenine pairs with thymine, and/or uracil. Guanine pairs with cytosine.
Example Question #23 : Dna, Rna, And Proteins
Which of the following RNA molecules transports amino acids to ribosomes to be used to assemble the protein molecule?
mRNA
pre-mRNA
rRNA
snRNA
tRNA
tRNA
mRNA is messenger RNA, it carries the genetic code that determines the protein. snRNA directs splicing of pre-mRNA. tRNA transports the amino acids used for assembling proteins. rRNA is a component of ribosomes (the other component is protein). pre-mRNA- single strand of RNA processed to form mRNA.
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