Nucleic Acids

State the monomer of a nucleic acid. Nucleotides

State the three parts of a nucleotide. A phosphate group, a five- carbon sugar (deoxyribose in DNA and ribose in RNA), a nitrogenous base

State the full names of nitrogen bases (who goes with dna and who with rna)

In DNA: Adenine (A), Thymine (T), Cytosine (C), Guanine (G)

Describe a purine. Purines are nitrogenous bases characterized by a two- ring structure. They are larger than pyrimidines and include the bases that pair with specific complementary bases in nucleic acids.

State an example of a purine. Adenine (A) or Guanine (G)

Describe a pyrimidine. Pyrimidines are nitrogenous bases with a single- ring structure. They are smaller than purines and play a crucial role in the structure of DNA and RNA.

State an example of a pyrimidine. Cytosine (C), Thymine (T), or Uracil (U)

Be able to draw / label the parts of DNA and RNA nucleotides

Describe how the backbone of DNA is created. phosphate group of one nucleotide attaches to the sugar of another nucleotide (at the 3’–hydroxyl position)

State the type of bond that holds the nucleotides together in DNA backbone. phosphodiester bonds

Describe the function of RNA. Transfers genetic information in DNA to be read at ribosomes

State the 3 forms of RNA. mRNA, tRNA, rRNA

Outline the 3 types of RNA

mRNA: complementary copy of DNA strand with protein instructions written in codons (linear molecule)

tRNA: brings proper amino acids from cytoplasm to ribosome during translation (looped molecule)

rRNA: provides location to combine amino acids to make proteins, creates subunits of ribosome

Describe the function of DNA. store genetic material for protein production

very compact and stable

discuss the Hershey Chase Experiment.

Hershey Chase experiment (1952)

Radioactively labeled Sulfur (in proteins) and Phosphorus (in DNA) in a Phage virus

Next generation of viruses showed radioactive phosphorús and showed DNA help genetic information

Discuss the work of Rosalind Franklin

Used X-ray diffraction to produce pictures of DNA

Showed DNA had a helical structure

Discuss the findings of Watson and Crick

created the correct structural model of the DNA

Showed double helix and antiparallel nature of DNA with complementary nitrogen bases.

Describe structure of DNA (referencing antiparallel, 5' 3', what makes up the side chains and how the nitrogen bases form the middle) DNA has a double helix structure with two antiparallel strands running in opposite directions (5’ to 3’ and 3’ to 5’). The sides are made of alternating sugar (deoxyribose) and phosphate groups, while the nitrogen bases form the middle rungs, pairing specifically through hydrogen bonds.

Describe the types of bonds in the DNA molecule. Phosphodiester bonds hold single strands together.

Describe the relationship between purine and pyrimidine nitrogen bases. Purines (adenine and guanine) have a double- ring structure, while pyrimidines (cytosine, thymine) have a single-ring structure. In DNA, purines pair with pyrimidinesL adenine pairs with thymine, and guanine pairs with cytosine, which is crucial for the stability of DNA double helix.

Describe the structure of DNA (4 Marks) DNA is an antiparallel double helix. One strand runs 5’ to 3’ and the other strand will run 3’ to 5’. Phosphodiester bonds hold together each strand of the sugar phosphate backbone. Hydrogen bonds hold together complementary bases, with 2 between A and T and 3 between C and G.

Describe Chargaff’s rule

Complementary bases are found in same amount in DNA

only need 1 number to determine the rest

Ex: Guanine= 20%

Cytosine= 20%

Adenine= 30%

Thymine= 30%

Composition of DNA bases varies between species

Be able to calculate percentages of nitrogen bases when only given one

Describe the importance of base pairing in the genetic code.

Allows for genetic information to be replicated

one strand is template for synthesis of new complementary strand of DNA

Allows for genetic instructions to be expressed as proteins

complementary mRNA transcript creates protein at ribosome

Be able to draw and label DNA

Compare DNA and RNA.

DNA: Sugar is deoxyribose, unique nitrogen base is thymine and it is a double helix.

RNA: Sugar is ribose, unique nitrogen base is uracil, and it is a single helix.

Describe the central dogma of biology.

DNA and RNA are needed to make proteins

DNA transcribed into complementary mRNA

codons in mRNA code for amino acids

Amino acids bonded into polypeptides at ribosomes during translation

Describe the universality of the genetic code.

All cells recognize same 4 nucleotides in DNA and RNA

All recognize same 64 codons in mRNA

All cells use same 20 amino acids to make proteins