DNA

• What are the two types of nucleic acid?

  DNA and RNA

  
• Why are DNA and RNA essential for cells?

  They are needed to build proteins
• Where are DNA and RNA found?

  In all living cells
• What is the primary function of DNA?

  To hold or store genetic information
• What does DNA contain instructions for?

  Growth and development of organisms
• What is the function of RNA?

  To transfer genetic code from DNA
• Where does RNA carry the genetic code to?

  To the ribosomes in the cytoplasm
• What process occurs at the ribosomes?

  Translation to make polypeptides
• What are nucleotides made up of?

  A sugar, a base, and a phosphate

  
• What type of sugar is found in DNA nucleotides?

  Deoxyribose sugar

  
• What nitrogenous bases are found in DNA?

  Adenine, cytosine, guanine, thymine

  
• What type of sugar is found in RNA nucleotides?

  Ribose sugar

  
• What nitrogenous bases are found in RNA?

  Adenine, cytosine, guanine, uracil

  
• Why is RNA more susceptible to hydrolysis than DNA?

  Due to the 2' hydroxyl group in RNA
• What is the sugar-phosphate backbone?

  The chain of alternating sugars and phosphates

  
• What forms a phosphodiester bond?

  A condensation reaction between nucleotides
• What are the two structural forms of nitrogenous bases?

  Purines and pyrimidines

  
• Which bases are purines?

  Adenine and guanine

  
• Which bases are pyrimidines?

  Cytosine, thymine, and uracil

  
• What is the structure of DNA?

  It is a double helix of polynucleotide strands

  
• How are the two DNA strands oriented?

  They run in opposite directions (antiparallel)
• What connects the nitrogenous bases in DNA?

  Hydrogen bonds between base pairs

  
• What is complementary base pairing?

  Adenine pairs with thymine, guanine with cytosine

  
• How many hydrogen bonds form between adenine and thymine?

  Two hydrogen bonds

  
• How many hydrogen bonds form between guanine and cytosine?

  Three hydrogen bonds

  
• What is the three-dimensional shape of DNA called?

  Double helix
• What distinguishes RNA from DNA in terms of structure?

  RNA is single-stranded, DNA is double-stranded

  
• What is an example of an RNA molecule?

  Messenger RNA (mRNA)

  
• What is the role of ribosomes?

  Site of protein synthesis
• What type of RNA is part of ribosomes?

  Ribosomal RNA (rRNA)
• What do ribosomes do during translation?

  They read RNA to make polypeptides

  
• What are the two subunits of ribosomes in eukaryotic cells?

  80S ribosomes (60S and 40S)
• What are the two subunits of ribosomes in prokaryotic cells?

  70S ribosomes (50S and 30S)
• What is the role of rRNA in ribosomes?

  Catalyzes formation of peptide bonds
• Who first observed DNA?

  Friedrich Miescher
• What did Miescher name the molecule he discovered?

  Nuclein
• Why did scientists doubt DNA could carry genetic information?

  Due to its simple chemical composition
• When did the role of DNA in genetic inheritance begin to be understood?

  In the 1940s
• What significant discovery was made in 1953 regarding DNA?

  DNA carries the genetic code
• What does the triplet code in DNA allow?

  Much variation in genetic coding