5 min read•Last Updated on November 18, 2024
Jed Quiaoit
Danna Esther Gelfand
Jed Quiaoit
Danna Esther Gelfand
Nucleic acids are large complex molecules that play a crucial role in the storage, transmission, and expression of hereditary information. They are made up of monomers called nucleotides, which consist of a 5-carbon sugar, a nitrogenous base, and a phosphate group.
There are two main types of nucleic acids: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). DNA is the genetic material that stores the instructions for building proteins, while RNA is involved in the synthesis of proteins from the instructions stored in DNA. 🍭 Genes are a specific unit of inheritance that contain the instructions for synthesizing particular proteins. They are made of DNA and are found on chromosomes. The sequence of nucleotides in a gene determines the sequence of amino acids in a particular protein, which in turn determines the protein's function. 🔧
Deoxyribonucleic acid (DNA) is a molecule that stores and transmits genetic information. It is responsible for directing its own replication, causing the synthesis of messenger RNA (mRNA), and using mRNA to control protein synthesis. The sugar in DNA is deoxyribose.
Nucleic acids have a linear sequence of nucleotides that are linked by covalent bonds. The sequence is defined by the presence of a hydroxyl group (-OH) on the 3' carbon of one nucleotide and a phosphate group on the 5' carbon of the next nucleotide. During DNA and RNA synthesis, nucleotides are added to the 3' end of the growing strand, forming covalent bonds between adjacent nucleotides. This process is essential for the replication and expression of genetic information. 🧠
The nitrogenous bases in nucleic acids are important because they are the key players in the genetic code. There are five nitrogenous bases in total: cytosine (C), thymine (T), uracil (U), adenine (A), and guanine (G).
Uracil is only found in RNA, while thymine is only found in DNA. The nitrogenous bases can be divided into two categories: purines and pyrimidines.
Base pairing rules of purines and pyrimidines
A prime (ʹ) identifies the carbon atoms in the ribose, such as the 2ʹ carbon or 5ʹ carbon. DNA is structured as an antiparallel double helix, with each strand running in opposite 5’ to 3’ orientation, and the 5’ end of one molecule is paired with the 3’ end of the other molecule and vice versa.
A researcher isolates a sample of DNA from a species of plant and finds that it contains the following amounts of the four nitrogenous bases: adenine (A) = 40%, thymine (T) = 40%, and cytosine (C) = 10%.
According to Chargaff's rule, what is the percentage of guanine in the sample?
To solve this problem, we can use Chargaff's rule, which states that in a double-stranded DNA molecule, the percentage of A is equal to the percentage of T, and the percentage of G is equal to the percentage of C.
Since the percentage of A in the sample is 40% and the percentage of T is 20%, we know that the percentage of G must be equal to the percentage of C, which is 10%. Therefore, the percentage of guanine in the sample is 10%!
While it's highly unlikely for an AP Biology standalone MCQ or FRQ to ask about the similarities and differences between DNA and RNA, it's important to learn the foundational knowledge to answer more complex, application-centered questions down the road!
⭐ Key similarities between the two:
Both are nucleic acids, meaning they are made up of nucleotides.
Nucleotides in both DNA and RNA consist of a sugar molecule, a phosphate group, and a nitrogenous base.
Both contain the nitrogenous bases adenine, guanine, and cytosine.
Both are involved in the transmission of genetic information.
Both play important roles in the synthesis and regulation of proteins. ⭐ Key differences between the two:
The sugar molecule that they contain. DNA containsdeoxyribose, which is a sugar molecule with one less oxygen atom compared to ribose, the sugar molecule found in RNA. Another difference is the presence of different nitrogenous bases.
Nitrogenous bases. DNA contains the bases adenine, guanine, cytosine, and thymine, while RNA contains the bases adenine, guanine, cytosine, and uracil.
Structure. DNA is usually double-stranded, meaning it has two complementary strands that are held together by hydrogen bonds. RNA, on the other hand, is usually single-stranded, although some RNA molecules may be partially or fully double-stranded.
Orientation and directionality for DNA. Uniquely In double-stranded DNA, the two strands are oriented in opposite directions, with one strand running 5' to 3' and the other running 3' to 5'. This is known as antiparallel orientation. These structural differences between DNA and RNA are important because they contribute to the unique functions of these two types of nucleic acids. DNA is responsible for storing genetic information and transmitting it to future generations, while RNA plays a variety of roles in the synthesis and regulation of proteins, as well as other cellular processes.
Check out the AP Bio Unit 1 Replays or watch the 2021 Unit 1 Cram
Nitrogenous base found in DNA and RNA that pairs with thymine (in DNA) or uracil (in RNA) through hydrogen bonds.
Term 1 of 22
Nitrogenous base found in DNA and RNA that pairs with thymine (in DNA) or uracil (in RNA) through hydrogen bonds.
Term 1 of 22
Nitrogenous base found in DNA and RNA that pairs with thymine (in DNA) or uracil (in RNA) through hydrogen bonds.
Term 1 of 22
Nucleic acids are large biomolecules essential for all known forms of life. They include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid), which carry genetic information.
DNA (Deoxyribonucleic Acid): The molecule carrying genetic instructions used in growth, development, functioning and reproduction.
RNA (Ribonucleic Acid): A nucleic acid present in all living cells. Its principal role is to act as a messenger carrying instructions from DNA for controlling the synthesis of proteins.
Genome: The complete set of genes or genetic material present in a cell or organism.
Nucleotides are the basic building blocks of DNA and RNA. They consist of a sugar, a phosphate group, and a nitrogenous base.
Deoxyribose: This is the sugar found in DNA nucleotides. It's called 'deoxyribose' because it's missing an oxygen atom compared to regular ribose.
Phosphate Group: This is part of every nucleotide. It acts like glue, connecting one nucleotide to another in the DNA or RNA strand.
Nitrogenous Base: This is the part of the nucleotide that varies between different types. There are four types in DNA (adenine, thymine, cytosine, guanine) and four in RNA (adenine, uracil, cytosine, guanine).
DNA is a molecule that carries most of the genetic instructions used in the development, functioning and reproduction of all known living organisms and many viruses.
Genes: These are specific sequences of nucleotides in DNA or RNA that are responsible for carrying information to produce proteins.
Chromosomes: These are thread-like structures located inside the nucleus of animal and plant cells. Each chromosome is made up of protein and a single molecule of DNA.
Nucleotide: This is an organic molecule that serves as the subunit, or building block, of nucleic acids like DNA and RNA.
RNA is a molecule similar to DNA that plays a crucial role in coding, decoding, regulation, and expression of genes.
Messenger RNA (mRNA): This type of RNA carries instructions from DNA for controlling the synthesis of proteins.
Transfer RNA (tRNA): tRNA is responsible for bringing amino acids to the ribosome where they are assembled into proteins.
Ribosomal RNA (rRNA): rRNA combines with proteins to form ribosomes, which serve as sites for protein synthesis.
Genes are segments of DNA that carry hereditary information and have specific functions in living organisms.
Allele: An allele is one variant form of a gene at a particular location on a chromosome.
Genotype: The genotype refers to an organism's complete set of genes or genetic composition.
Phenotype: Phenotype refers to an organism's observable characteristics or traits that result from its genotype interacting with its environment.
Chromosomes are thread-like structures located inside the nucleus of animal and plant cells. Each chromosome is made up of protein and a single molecule of deoxyribonucleic acid (DNA).
Autosome: Autosomes are chromosomes that are not involved in determining the sex of an individual.
Sex Chromosome: Sex chromosomes are those that participate in sex determination. Humans have two types - X and Y.
Centromere: The centromere is the part of a chromosome where it constricts during cell division, where the spindle fibers attach during cell division to pull sister chromatids apart.
mRNA is a type of RNA that carries genetic information from the DNA in the nucleus to the cytoplasm, where it serves as a template for protein synthesis.
Transcription: The process by which genetic information is copied from DNA to mRNA.
Codon: A sequence of three nucleotides on an mRNA molecule that corresponds with a specific amino acid or stop signal during protein synthesis.
Translation: The process by which the genetic code carried by mRNA is decoded to produce the specific sequence of amino acids in a polypeptide chain.
Cytosine is another one of the four nitrogenous bases found in both DNA and RNA molecules. In both cases, it pairs with guanine (G).
Guanine (G): The nitrogenous base that pairs with cytosine in both DNA and RNA.
Pyrimidines: A type of nitrogenous base that includes cytosine, thymine, and uracil. They are single-ringed structures.
Purines: A type of nitrogenous base that includes adenine and guanine. They are double-ringed structures.
Thymine is one of the four main nucleobases found in the nucleic acid DNA. It pairs with adenine.
Adenine (A): A component of DNA or RNA that forms a base pair with thymine (in DNA) or uracil (in RNA).
Deoxyribose Sugar: The sugar component present in each nucleotide that makes up DNA; it binds to both thymine and phosphate group to form part of the backbone structure.
DNA Replication: The process by which an entire double-stranded molecule of DNA creates two identical copies.
Uracil is a nitrogenous base found only in RNA. It replaces thymine from DNA and pairs with adenine during transcription.
Transcription: The process by which genetic information encoded in DNA is transferred to messenger RNA.
Ribonucleic Acid (RNA): A molecule similar to DNA but contains ribose sugar and uracil instead of deoxyribose sugar and thymine.
Messenger RNA (mRNA): Type of RNA molecule that carries instructions from DNA for protein synthesis.
Adenine is one of the four nitrogenous bases found in DNA and RNA molecules. In DNA, it pairs with thymine (T), while in RNA it pairs with uracil (U).
Thymine (T): The nitrogenous base that pairs with adenine in DNA.
Uracil (U): The nitrogenous base that replaces thymine in RNA and pairs with adenine.
Base Pairing Rule: The rule stating that cytosine pairs with guanine and adenine pairs with thymine or uracil depending on whether the molecule is DNA or RNA.
Guanine is one of the four nucleobases in the nucleic acids DNA and RNA. It pairs with cytosine (C) through three hydrogen bonds.
Adenine (A): This is another nucleobase found in DNA and RNA that pairs with thymine in DNA or uracil in RNA.
Nucleotide: The basic building block of nucleic acids such as DNA and RNA. A nucleotide consists of a sugar molecule attached to a phosphate group and a nitrogen-containing base (like guanine).
Base Pairing: The process by which nitrogenous bases form hydrogen bonds during the formation of molecules like DNA or RNA. For example, guanine forms three hydrogen bonds with cytosine.
Purines are one of the two types of nitrogenous bases found in nucleotides, which make up DNA and RNA. The two purines are adenine (A) and guanine (G).
Adenine (A): One of the two purine bases that pairs with thymine in DNA or uracil in RNA.
Guanine (G): The other purine base that pairs with cytosine in both DNA and RNA.
Nucleotide: The building block of DNA and RNA consisting of a sugar, a phosphate group, and a nitrogenous base (either a purine or pyrimidine).
Pyrimidines are one of the two types of nitrogenous bases found in nucleotides, which make up DNA and RNA. The three pyrimidines are cytosine (C), thymine (T), and uracil (U).
Cytosine (C): A pyrimidine base that pairs with guanine in both DNA and RNA.
Thymine (T): A pyrimidine base that pairs with adenine only in DNA.
Uracil (U): A pyrimidine base that replaces thymine in RNA; it also pairs with adenine.
Hydrogen bonding is an attractive force between polar molecules where hydrogen is bound to a highly electronegative atom such as oxygen, nitrogen or fluorine.
Polarity: A property of molecules that have regions of positive charge and regions of negative charge due to uneven distribution of electrons.
Covalent Bonding: A type of chemical bond formed when two atoms share electrons.
Van der Waals Forces: Weak forces that contribute to intermolecular bonding between atoms.
A double helix refers to the structure formed by double-stranded molecules of nucleic acids such as DNA.
Nucleotide: The basic building block of nucleic acids such as DNA and RNA.
Chromosomes: Thread-like structures located inside the nucleus of animal and plant cells that carry genes made from long strands of DNA.
Genes: Segments within a chromosome that contain instructions for making specific proteins.
The sugar-phosphate backbone forms the structural framework of nucleic acids, including DNA and RNA. It consists of alternating sugar and phosphate groups, to which nitrogenous bases are attached.
Deoxyribose: The sugar component in the backbone of DNA, which is connected to a phosphate group and a nitrogenous base.
Phosphate Group: A molecule in the DNA backbone that links two sugars together.
Nitrogenous Base: One of the three components of nucleotides, they are attached to the sugar within the backbone and are responsible for base pairing.
In biology, antiparallel orientation refers to the opposite arrangement of the sugar-phosphate backbones in a DNA double helix. One strand runs from 5' to 3' direction, and the other runs from 3' to 5'.
Complementary Base Pairing: This is when specific nitrogenous bases in DNA or RNA molecules pair up due to hydrogen bonding. Adenine pairs with thymine (in DNA) or uracil (in RNA), and cytosine pairs with guanine.
Double Helix: This term describes the structure of DNA, which looks like a twisted ladder or spiral staircase. It consists of two strands that twist around each other.
Hydrogen Bonding: A type of chemical bond that occurs when a hydrogen atom bonded to an electronegative atom forms an electrostatic connection with another electronegative atom nearby.