Chapter 22 (DNA Biology & Technology) Flashcards
What is the unabbreviated name of DNA?
DNA: Deoxyribonucleic acid.
Know the components of DNA and understand how the components are ordered in a DNA molecule:
DNA has three types of chemical component: phosphate, a sugar called deoxyribose, and four nitrogenous bases—adenine, guanine, cytosine, and thymine. Two of the bases, adenine and guanine, have a double-ring structure characteristic of a type of chemical called a purine.
The chemical components of DNA are arranged into groups called nucleotides, each composed of a phosphate group, a deoxyribose sugar molecule, and any one of the four bases. It is convenient to refer to each nucleotide by the first letter of the name of its base: A, G, C, and T.
Know the possible nitrogenous bases.
A set of five nitrogenous bases is used in the construction of nucleotides, which in turn builds up nucleic acids like DNA and RNA. These nitrogenous bases are adenine (A), uracil (U), guanine (G), thymine (T), and cytosine (C).
Understand the complementary relationship between the nitrogenous bases in a base pair
The nitrogenous bases point inward on the ladder and form pairs with bases on the other side, like rungs. Each base pair is formed from two complementary nucleotides (purine with pyrimidine) bound together by hydrogen bonds. The base pairs in DNA are adenine with thymine and cytosine with guanine.
Describe which nitrogenous bases are complementary
Each nucleotide base can hydrogen-bond with a specific partner base in a process known as complementary base pairing: Cytosine forms three hydrogen bonds with guanine, and adenine forms two hydrogen bonds with thymine. These hydrogen-bonded nitrogenous bases are often referred to as base pairs.
Know the unabbreviated name of RNA.
RNA, which stands for ribonucleic acid.
What is the function of mRNA?
Messenger RNA: transcribes the genetic code from DNA into a form that can be read and used to make proteins. mRNA carries genetic information from the nucleus to the cytoplasm of a cell.
What is the function of rRNA?
Ribosomal RNA: rRNA is located in the cytoplasm of a cell, where ribosomes are found. rRNA directs the translation of mRNA into proteins.
What is the function of tRNA?
Transfer RNA: Like rRNA, tRNA is located in the cellular cytoplasm and is involved in protein synthesis. Transfer RNA brings or transfers amino acids to the ribosome that corresponds to each three-nucleotide codon of rRNA. The amino acids then can be joined together and processed to make polypeptides and proteins.
What are the similarities of DNA and RNA?
Nucleic acids, composed of nucleotides, sugar-phosphate backbones, four different types of bases.
What are the differences of DNA and RNA?
DNA: found in the nucleus and mitochondria, stores genetic info, sugar is deoxyribose, Bases are A, T, C, G, double stranded and transcribed to produce RNA
RNA: may be found throughout the cell, assists in the processing of genetic information, sugar is ribose, Bases are A, U, C, G, single stranded and involved in gene regulation and is translated to produce proteins.
Describe the components of gene expression.
Gene expression is the process by which the genetic code - the nucleotide sequence - of a gene is used to direct protein synthesis and produce the structures of the cell.
Know the definitions for transcription and translation
The process by which DNA is copied to RNA is called transcription, and that by which RNA is used to produce proteins is called translation.
Describe the sites, within the cell, of both transcription and translation
In eukaryotes, transcription and translation take place in different cellular compartments: transcription takes place in the membrane-bounded nucleus, whereas translation takes place outside the nucleus in the cytoplasm.
Know the product molecule of both transcription and translation
The product of transcription is RNA, which can be encountered in the form of mRNA, tRNA or rRNAwhile the product of translation is a polypeptide amino acid chain, which forms a protein.
