In the nucleus, DNA is always found as a double-stranded molecule. Each strand is made up of a DNA backbone the phosphate groups and the pentose sugars and the bases. In a DNA molecule, the two strands are organized in such a way that the DNA backbone of one strand runs in the 5'-to-3' direction, whereas the DNA backbone of the other strand runs in the 3'-to-5' direction; therefore, the two strands are antiparallel to each other.
Recall that 5' and 3' refer to the carbons on the pentose sugar. A phosphate group is found on the 5' carbon of the sugar and a hydroxyl group is found on the 3'carbon of the sugar. This means that the 5' end of each strand is always characterized by the phosphate group, and the 3' end is always characterized by the hydroxyl group; therefore, both strands will have a phosphate group at their 5' end.
RNA and DNA are both types of nucleic acids; therefore, both molecules are made from nucleotide monomers. Recall that a nucleotide contains a phosphate group, a pentose sugar, and a nitrogenous base. DNA, or deoxyribonucleic acid, contains deoxyribose sugar whereas RNA, or ribonucleic acid, contains ribose sugar. The backbone only consists of the phosphate groups and the pentose sugars. Given the backbone of DNA, with the phosphate group attached to the deoxyribose via a phosphodiester bond, DNA is negatively charged.
For this reason, histones - the proteins around which DNA molecules are wrapped in eukaryotes - have lots of positively charged amino acids on their DNA-binding sites. This produces a strong attractive force between DNA and histones.
The backbone of DNA consists of a phosphate group and a deoxyribose. These two components are therefore connected by a phosphodiester bond.
The nucleotides are not included in the backbone. Instead, they make up the "rungs" of the double helical structure of DNA, which are hydrogen bonded to the bases of the complementary antiparallel strand. The two strands of DNA are actually connected by hydrogen bonds H-bonds between the nitrogenous bases. There are 2 hydrogen bonds between adenine and thymine, and 3 hydrogen bonds between cytosine and guanine. All other statements are true. DNA consists of several components. It has a phosphate-sugar deoxyribose backbone and is composed of two strands made from purine-pyrimidine hydrogen bonds in a double helix confirmation.
The purines associated with DNA include adenine and guanine and the pyrimidines include cytosine and thymine. Adenine bonds with thymine and cytosine bonds with guanine. All of the responses are correct except that eukaryotic DNA is found in the nucleus, cytoplasm, and ribosomes.
In eukaryotes, DNA is only found in the nucleus, mitochondria, and only sometimes free floating in the cytoplasm. DNA is not found in ribosomes. RNA on the other hand, is found in the nucleus, cytoplasm, and ribosomes. Note that since prokaryotes lack membrane-bound organelles, their DNA is free-floating in the cytoplasm. If you've found an issue with this question, please let us know. With the help of the community we can continue to improve our educational resources.
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Thus, if you are not sure content located on or linked-to by the Website infringes your copyright, you should consider first contacting an attorney. Hanley Rd, Suite St. Louis, MO We are open Saturday and Sunday! Subject optional. Email address: Your name:. Example Question : High School Biology. Possible Answers: Ribose. Correct answer: Deoxyribose. Explanation : DNA stands for "deoxyribonucleic acid. Report an Error. Which of the following might you find in the backbone of DNA?
Phosphate group II. Hexose sugar III. Possible Answers: I only. Correct answer: I only. Example Question 3 : Dna Structure. Possible Answers: Phosphodiesterase is needed to break the bonds between the phosphate group on the 5' carbon of one sugar and hydroxyl group on the 3' carbon of the adjacent sugar. Correct answer: Phosphodiesterase is needed to break the bonds between the phosphate group on the 5' carbon of one sugar and hydroxyl group on the 3' carbon of the adjacent sugar.
Explanation : A DNA molecule is made up of multiple nucleotides that are connected by phosphodiester bonds. Example Question 4 : Dna Structure. Possible Answers: The two strands are antiparallel and the 5' end on both strands contain a phosphate group.
The two strands are parallel and the 5' ends on both strands contain a phosphate group. Correct answer: The two strands are antiparallel and the 5' end on both strands contain a phosphate group.
Explanation : In the nucleus, DNA is always found as a double-stranded molecule. Example Question 5 : Dna Structure. The RNA backbone has uracil instead of thymine. The sugar in the RNA backbone has an extra hydroxyl group. Correct answer: The sugar in the RNA backbone has an extra hydroxyl group.
Explanation : RNA and DNA are both types of nucleic acids; therefore, both molecules are made from nucleotide monomers. Example Question 6 : Dna Structure. Possible Answers: Positive. Correct answer: Negative. Explanation : Given the backbone of DNA, with the phosphate group attached to the deoxyribose via a phosphodiester bond, DNA is negatively charged.
Example Question 7 : Dna Structure. Which of these can be found in the DNA backbone: I. Ribose III. Deoxyribose IV. Below, we look in more detail at the three most important types of RNA. The nitrogen bases in DNA are the basic units of genetic code, and their correct ordering and pairing is essential to biological function. The four bases that make up this code are adenine A , thymine T , guanine G and cytosine C.
Bases pair off together in a double helix structure, these pairs being A and T, and C and G. RNA molecules, by comparison, are much shorter 3. Eukaryotic cells, including all animal and plant cells, house the great majority of their DNA in the nucleus, where it exists in a tightly compressed form, called a chromosome 4.
This squeezed format means the DNA can be easily stored and transferred. In addition to nuclear DNA, some DNA is present in energy-producing mitochondria, small organelles found free-floating in the cytoplasm, the area of the cell outside the nucleus. The three types of RNA are found in different locations. If it receives the correct signal from the ribosome, it will then hunt down amino acid subunits in the cytoplasm and bring them to the ribosome to be built into proteins 5. Ribosomes are formed in an area of the nucleus called the nucleolus, before being exported to the cytoplasm, where some ribosomes float freely.
Other cytoplasmic ribosomes are bound to the endoplasmic reticulum, a membranous structure that helps process proteins and export them from the cell 5.
Meet The Author. Ruairi J Mackenzie. Chosen for you. Deoxyribonucleic Acid. Ribonucleic Acid. DNA replicates and stores genetic information. It is a blueprint for all genetic information contained within an organism. RNA converts the genetic information contained within DNA to a format used to build proteins, and then moves it to ribosomal protein factories.
DNA consists of two strands, arranged in a double helix. These strands are made up of subunits called nucleotides.
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