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 found paired with the base adenine, whereas ______ is 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. thymine, guanine g. gene h. transfer RNA (tRNA), messenger RNA (mRNA) i. mRNA

Step-by-step solution

a. DNA full name

The full name of DNA is Deoxyribonucleic Acid.

b. Monomer units of DNA and RNA

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

c. Pentose in RNA

The pentose deoxyribose is found in DNA, whereas ribose is found in RNA.

d. Linkage between sugar molecule and phosphoric acid

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

e. DNA bases bonding

The bases on opposite strands of DNA are said to be complementary to each other, which means the bases fit together specifically by hydrogen bonding to one another.

f. DNA base pairs

In a strand of normal DNA, the base thymine is always found paired with the base adenine, whereas guanine is always found paired with cytosine.

g. DNA segment for protein synthesis

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.

h. Protein synthesis RNA molecules

During protein synthesis, transfer RNA (tRNA) molecules attach to and transport specific amino acids to the appropriate position on the pattern provided by messenger RNA (mRNA) molecules.

i. Codes for protein primary structure

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

Key concepts

DNA Structure and Function

The blueprint of biological inheritance, DNA or Deoxyribonucleic Acid, is a remarkable molecule found in the nucleus of cells. Its structure is elegantly simple, consisting of two long strands that twist around each other to form a double helix. Each strand is made of four types of nucleotides, which are the monomer units, including adenine (A), thymine (T), cytosine (C), and guanine (G). These nucleotides are paired specifically—A with T and C with G—creating a system that’s complementary. This intricate pairing is possible thanks to the hydrogen bonds that form between the bases, creating stability in the structure.

The function of DNA goes beyond its structural ingenuity, entailing the storage of genetic information. It serves as a template for replicating itself during cell division, ensuring that genetic details are passed down from one generation to the next. This replication process is meticulous, with enzymes unzipping the double helix and creating two new strands alongside the original strands.

Understanding the Code

The sequence of bases in DNA constitutes a code that dictates every biological process in an organism. In regions called genes, specific sequences provide the instructions for building proteins, which are essential for cellular functions and form the basis of physical characteristics. The segment-to-protein synthesis is a complex dance of transcription and translation, instrumental in life's diversity and functionalities.

RNA and Protein Synthesis

RNA, or Ribonucleic Acid, plays a central role in the journey from DNA to proteins. Unlike DNA's double helix, RNA is usually single-stranded, and its sugar component is ribose. It comes in various forms, each with a definitive purpose in protein synthesis. The most well-known types of RNA are messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA).

mRNA: The Messenger

mRNA is synthesized during transcription, a process where the DNA sequence of a gene is copied into an RNA version—a message that can exit the nucleus. This message is a mirror-image of the DNA template strand, transcribed by the enzyme RNA polymerase, and later processed before it takes the genetic instructions into the cytoplasm.

tRNA: The Supplier

Transfer RNA (tRNA) is shaped like a cloverleaf and transports specific amino acids to the ribosomal complex during translation. Each tRNA molecule has an anticodon that matches codons on the mRNA strand, ensuring the correct amino acids sequence in the forming protein. It's this precision that facilitates accurate protein synthesis, one amino acid at a time.

rRNA: The Facility

Ribosomal RNA (rRNA) combines with proteins to form ribosomes, the cellular 'machines' that assemble proteins based on the sequence directed by mRNA. During translation, the ribosome moves along the mRNA strand, matches the tRNA anticodons to mRNA codons, and links amino acids into a polypeptide chain, which will fold into a functional protein.

The central dogma of molecular biology revolves around this RNA-mediated process, with protein synthesis being a crucial determinant of an organism's phenotypic traits.

Genetic Coding

The concept of genetic coding is rooted in the fact that sequences of three bases—or triplets—along the DNA and RNA molecule dictate the synthesizing process of proteins. These triplets are known as codons in mRNA and are crucial for determining which amino acids will be incorporated into a protein. When a cell needs a particular protein, it uses the DNA's code to create an mRNA transcript through transcription.

Genetic coding relies on the universality of the genetic code, which is nearly the same in all living organisms. This shared language allows for immense diversity within the biological spectrum. It comprises 64 codons, of which 61 specify the twenty standard amino acids, while the remaining three are stop signals, marking the end of protein synthesis.

The genetic code is redundant, meaning that multiple codons can encode the same amino acid. This redundancy helps protect against mutations by lessening the impact errors in the genetic sequence might have on the protein's function. Despite this built-in error tolerance, the code is precise, with no overlap or punctuation, ensuring accurate and efficient protein synthesis.

With advancements in biotechnology and genetics, understanding genetic codes has profound implications. It leads to innovations in medical treatments, the development of biofuels, improvements in crop varieties, and a wealth of knowledge about the fundamental processes that define life as we know it.