Test your knowledge with the 10 questions below on nucleic acids. Check the comments after the feedback to get your questions answered.
question 1
Regarding the functions performed by nucleic acids, it is INCORRECT to state that:
a) Transmit characteristics
b) Synthesize proteins
c) Store genetic information
d) Increase the pH of the medium
Correct alternative: d) Increase the pH of the medium.
Nucleic acids are DNA, deoxyribonucleic acid, and RNA, ribonucleic acid.
Nucleic acids are present in living organisms and are responsible for storing and transmitting genetic information. Furthermore, they participate in protein synthesis by converting information.
question 2
The basic unit of a nucleic acid is the nucleotide. Note its structure in the image below.
The numbers 1, 2 and 3 correspond, respectively, to the components:
a) Bridge of hydrogen, acid and base
b) Carbonate, ribose and deoxyribose
c) Phosphate, pentose and nitrogen base
d) Nitrate, sugar and phosphate base
Correct alternative: c) Phosphate, pentose and nitrogen base.
A nucleotide is formed by the association of 3 components: 1 – phosphate, 2 – pentose and 3 – nitrogenous base.
Phosphate: group derived from phosphoric acid
Pentose: sugar with five carbons
Nitrogen base: organic base from the group of puric and pyrimidine bases
question 3
Regarding the differences in the structures of DNA and RNA nucleic acids, it is correct to state that:
I. Although the nucleotides are formed by 3 basic parts, only the phosphate group does not have distinct elements in DNA and RNA.
II. DNA and RNA have the same pyrimidine bases and different puric bases.
III. Thymine and Uracil are the pyrimidine bases of RNA, while Uracil and Cytosine make up the DNA.
IV. The pentose of DNA is deoxyribose and that of RNA is Ribose.
The statements are correct:
a) II and III
b) I and IV
c) I, II and III
d) I, III and IV
Correct alternative: b) I and IV.
I. CORRECT The basic structure of nucleic acids is: phosphate, pentose and nitrogenous base. The phosphate group is the same for DNA and RNA. The differences in structures are in the sugars and nitrogenous bases that make them up.
II. WRONG. The puric bases that make up DNA and RNA are Adenine and Guanine, while the pyrimidine bases differ.
III. WRONG. The pyrimidine bases of DNA are Thymine and Cytosine. RNA, on the other hand, is formed by Uracil and Cytosine.
IV. CORRECT Pentose is a five-carbon sugar. In RNA, pentose is ribose and in DNA it is deoxyribose. The difference between the structures is that ribose has one more oxygen atom than deoxyribose.
question 4
The union between the nucleotides to form a nucleic acid occurs through a
a) double covalent bond
b) hydrogen bond
c) phosphodiester bond
d) anionic bond
Correct alternative: c) phosphodiester bond.
The phosphodiester bond joins two nucleotides. The phosphate group links two sugars through carbon 5 of one nucleotide and carbon 3 of the other.
question 5
Despite having similarities in composition, nucleic acids show differences in structure. DNA and RNA have distinct strands because
a) DNA is formed by a strand of nucleotides that rotates around a central plane and RNA is a straight strand of nucleosides.
b) RNA is formed by a single strand and in DNA the hydrogen bonds link two polynucleotides.
c) DNA is formed by two symmetrical strands and RNA has an asymmetrical strand.
d) RNA is formed by a spiral strand and DNA has two parallel strands.
Correct alternative: b) RNA is formed by a single strand and in DNA the hydrogen bonds link two polynucleotides.
RNA has one nucleotide strand and DNA has two spiral-shaped strands that form a double helix because there are hydrogen bonds between the nitrogenous base pairs A-T and C-G.
question 6
Adenine (A), Guanine (G), Thymine (T), Cytosine (C) and Uracil (U) are the nitrogenous bases that make up nucleic acids and are classified into pyrimidines and purines.
As for the structure, the two types of nitrogenous bases differ by the
a) Number of bonds that are able to form between the nucleotides
b) Number of rings with carbon and nitrogen atoms
c) Number of nucleic acids that can form
d) Number of terminations to make phosphodiester bonds
Correct alternative: b) Number of rings with carbon and nitrogen atoms.
Adenine and Guanine are nitrogenous bases of the purine type and are formed by two rings, one hexagonal and one pentagonal, both with carbon and nitrogen atoms.
Thymine, Cytosine and Uracil are pyrimidine-type nitrogenous bases. They are made up of a simple ring of carbon and nitrogen atoms.
question 7
(UFSM-RS) Number the 2nd Column according to the 1st.
| Column 1 | Column 2 |
| 1 - DNA | ( ) Double helix |
| ( ) Ribose | |
| ( ) Single or single tape | |
| 2 – RNA | ( ) Deoxyribose |
| ( ) Nitrogen bases: adenine, guanine, cytosine, thymine | |
| ( ) Nitrogen bases: adenine, guanine, cytosine, uracil. |
The correct sequence is:
a) 1 - 2 - 1 - 2 - 2 - 1
b) 2 - 1 - 1 - 2 - 2 - 2
c) 1 - 2 - 2 - 1 - 1 - 2
d) 2 - 1 - 2 - 1 - 1 - 2
e) 1 - 1 - 2 - 2 - 2 - 1
Correct alternative: c) 1 - 2 - 2 - 1 - 1 - 2.
(1) Double helix. DNA is made up of two spirally strands of polynucleotides.
(2) Ribose is the sugar present in the RNA structure.
(2) Single or single tape. The structure of RNA is a single-stranded and single-stranded nucleotide.
(1) Deoxyribose is the sugar present in the structure of DNA.
(1) Nitrogen bases: adenine (A) and guanine (G) are the purine bases of DNA, while cytosine (C) and thymine (T) are the pyrimidine bases.
(2) Nitrogen bases: adenine (A) and guanine (G) are the purine bases of RNA, while cytosine (C) and uracil (U) are the pyrimidine bases.
question 8
(UEPB) A DNA molecule, with base sequence GCATGGTCATAC, allows the formation of a messenger RNA with the following base sequence:
a) CGTACCAGTAGT
b) CGUACCAGUAUG
c) GCUAGGACUATU
d) CGTACCTACTCA
e) GCATGGTCATAC
Correct alternative: b) CGUACCAGUAUG
The bonds between the nitrogenous bases of DNA and RNA form the following pairs
DNA: A-T and C-G
RNA: A-U and C-G
Therefore, the sequence formed from the DNA will be:
G - Ç
Ç - G
THE - U
T - THE
G - Ç
G - Ç
T - THE
Ç - G
THE - U
T - THE
THE - U
Ç - G
know more about DNA and RNA.
question 9
(Enem/2009) The following figure represents a model of transmission of genetic information in biological systems. At the end of the process, which includes replication, transcription and translation, there are three different protein forms called a, b and c.
It appears from the model that
a) the only molecule that participates in the production of proteins is DNA.
b) the flow of genetic information in biological systems is unidirectional.
c) the active information sources during the transcription process are proteins.
d) it is possible to obtain different protein variants from the same transcription product.
e) the DNA molecule has a circular shape and the other molecules have a linearized single strand shape.
Correct alternative: d) it is possible to obtain different protein variants from the same transcription product.
Protein synthesis consists in the production of proteins through transcription and translation.
The DNA undergoes transcription through messenger RNA and the information is translated by ribosomal RNA so that the transporter RNA picks up the amino acids of the protein to be formed.
There is an association, called the genetic code, between nitrogenous bases and amino acids formed by codons, that is, a sequence of 3 nitrogenous bases that encodes an amino acid.
Therefore, the existing 64 codons correspond to the 20 types of amino acids that make up proteins.
Because of the different start codons, which start the process, and stop codons, which end a sequence of amino acids, different proteins can be formed.
know more about protein synthesis.
question 10
(ENEM 2013) DNA (deoxyribonucleic acid), the genetic material of living beings, is a double-stranded molecule, which can be extracted in a homemade way. from fruits, such as mashed strawberries or bananas, using detergent, table salt, commercial alcohol and a sieve or a strainer. paper. The role of detergent in this DNA extraction is
a) agglomerate the DNA in solution so that it becomes visible.
b) promote mechanical lysis of tissue to obtain DNA.
c) emulsify the mixture to promote DNA precipitation.
d) promote enzymatic activities to accelerate DNA extraction.
e) break cell membranes to release DNA into solution.
Correct alternative: e) break cell membranes to release DNA into solution.
Detergents have both polar and non-polar regions. The cell membrane has a lipoprotein composition. Membrane phospholipids have an amphilic character, as well as detergent. While the polar portion is hydrophilic and faces outwards, the nonpolar portion is hydrophobic and faces the interior of the membrane.
Therefore, the detergent's function is to break down the lipid molecules in the membrane and disrupt the structure so that the DNA is dispersed in the solution.
Gain more knowledge with the contents:
- What are nucleic acids?
- Difference between DNA and RNA
- Nucleotides
- Nitrogen bases
- DNA exercises