Question

For each of the following, fill in the blank with the correct response(s). All of the following pertain to nucleic acids. a. The substance in the nucleus of the cell that stores and transmits genetic information is DNA, which stands for _________ b. The basic repeating monomer units of DNA and RNA are called _______ c. The pentose deoxyribose is found in DNA, whereas ________is found in RNA. d. The basic linkage in DNA or RNA between the sugar molecule and phosphoric acid is a phosphate _______ linkage. e. The bases on opposite strands of DNA are said to be __________ to each other, which means the bases fit together specifically by hydrogen bonding to one another. f. In a strand of normal DNA, the base__________is always always found paired with cytosine. g. A given segment of the DNA molecule, which contains the molecular coding for a specific protein to be synthesized, is referred to as a _______ h. During protein synthesis, ______RNA molecules attach to and transport specific amino acids to the appropriate position on the pattern provided by _______RNA molecules. i. The codes specified by ________are responsible for assembling the correct primary structure of proteins.

Short answer

a. Deoxyribonucleic Acid b. Nucleotides c. Ribose d. Ester e. Complementary f. Guanine g. Gene h. Transfer (t)RNA, Messenger (m)RNA i. Codons

Step-by-step solution

Answer a

The acronym DNA stands for Deoxyribonucleic Acid.

Answer b

The basic repeating monomer units of DNA and RNA are called Nucleotides.

Answer c

The pentose ribose is found in RNA.

Answer d

The basic linkage in DNA or RNA between the sugar molecule and phosphoric acid is a phosphate Ester linkage.

Answer e

The bases on opposite strands of DNA are said to be Complementary to each other.

Answer f

In a strand of normal DNA, the base Guanine is always found paired with cytosine.

Answer g

A given segment of the DNA molecule, which contains the molecular coding for a specific protein to be synthesized, is referred to as a Gene.

Answer h

During protein synthesis, Transfer (t)RNA molecules attach to and transport specific amino acids to the appropriate position on the pattern provided by Messenger (m)RNA molecules.

Answer i

The codes specified by Codons are responsible for assembling the correct primary structure of proteins.

Key concepts

DNA

DNA, or Deoxyribonucleic Acid, is a fundamental molecule found in all living organisms. It is located primarily in the nucleus of the cell. Its main role is to store and transmit genetic information.

This genetic material is organized into structures called chromosomes, which consist of long strands of DNA wound around proteins. The primary function of DNA is to provide the instructions needed for an organism to grow, survive, and reproduce.

• DNA is composed of two strands that coil around each other, forming a double helix.
• The strands are made up of nucleotides, which include a sugar, a phosphate group, and a nitrogenous base.
• The sequence of these bases encodes genetic information.

Understanding DNA is crucial for fields like genetics, medicine, and evolutionary biology, as it contains the blueprint for all hereditary traits.

RNA

RNA, or Ribonucleic Acid, plays a different role than DNA in the cell. While DNA is the blueprint, RNA is more like the messenger and builder. It carries information from DNA to the cell machinery that makes proteins.

RNA is single-stranded and contains the sugar ribose, in contrast to DNA's deoxyribose. In RNA, the base uracil replaces thymine, one of the four nitrogenous bases found in DNA.

• There are several types of RNA, each with specific functions:
• Messenger RNA (mRNA) – carries the genetic code copied from DNA in a form that can be translated into proteins.
• Transfer RNA (tRNA) – brings the appropriate amino acids to the ribosome to be added to the growing protein chain.
• Ribosomal RNA (rRNA) – together with proteins, makes up the ribosomes, the "machines" that synthesize proteins.

RNA is essential for translating genetic information into the proteins that perform most of the functions in a cell.

Nucleotides

Nucleotides are the building blocks of nucleic acids like DNA and RNA. Each nucleotide is composed of three components: a nitrogenous base, a sugar molecule, and a phosphate group. These components are connected by covalent bonds to form the structure of nucleic acids.

In DNA, nucleotides contain the sugar deoxyribose, and in RNA, the sugar is ribose. The nitrogenous bases can be one of the following:

• Adenine (A)
• Thymine (T) – DNA only
• Uracil (U) – RNA only
• Cytosine (C)
• Guanine (G)

These bases pair specifically (A with T in DNA or A with U in RNA, and C with G) to form the "rungs" of the nucleic acid "ladder." The sequence of nucleotides determines the genetic code that is ultimately expressed as proteins.

Protein Synthesis

Protein synthesis is the process through which cells build proteins. It involves two main stages: transcription and translation.

**Transcription** takes place in the nucleus where a segment of DNA is used as a template to create mRNA. This mRNA carries the genetic instructions out of the nucleus and into the cytoplasm.

**Translation** occurs in the ribosome, where the mRNA code is read and translated into an amino acid sequence by tRNA. Each set of three bases on the mRNA, called a codon, corresponds to a specific amino acid.

• The ribosome moves along the mRNA strand, reading codons one by one and using tRNA to add the correct amino acids to the growing protein chain.
• Protein synthesis is critical as proteins perform a vast array of functions essential to life.

This process is tightly regulated and essential for the maintenance and cellular function of all living organisms.

Genetic Information

Genetic information refers to the instructions encoded within an organism's DNA. This information dictates not only the physical traits of the organism but also guides essential biological functions.

Each gene, a specific sequence on the DNA, carries information necessary to produce proteins, which are crucial for growth, repair, and overall function. Genes are inherited from one generation to the next, which ensures continuity of life's instructions.

• Mutations, or changes in the genetic information, can lead to variations in traits and sometimes cause diseases.
• Genetic information is expressed when genes are transcribed into RNA and then translated into proteins.
• The study of genetic information is constantly advancing, with applications in medicine, agriculture, and forensics.

Understanding genetic information can empower advancements in numerous fields and offer insights into the complexity of living organisms.