A1.2 IB DP Biology SL - Flashcard Study Guide on Nucleotides, Nucleic Acids, and DNA Structure

State the two primary functions of nucleic acids.

1. encoding data for proteins

2. Replication

State the two types of nucleic acids used in cells.

- ribonucleic acids

- deoxyribonucleic acids

Outline the meaning and implication of DNA being the genetic material of all living organisms.

The use of the genetic code across all forms of life is evidence of universal common ancestry of life

State why RNA viruses do not falsify the claim that all living things use DNA as the genetic material. ​

Viruses are not made of cells, they are not considered to be living.

List the three components of a nucleotide.

1. deoxyribose,

2. a phosphate group,

3. a nitrogen-containing base (adenine, thymine, guanine, or cytosine).

Identify and label the carbons of a pentose sugar.

The carbons of the sugar are numbered clockwise.

Draw the basic structure of a single nucleotide (using circle, pentagon and rectangle).

Define "backbone" as related to nucleic acid structure.

The covalent bond (phosphodiester bond) between the phosphate group of one nucleotide and the deoxyribose of the next is the sugar-phosphate backbone of the nucleic acid.

Explain how nucleotides connect to form a nucleic acid polymer.

The phosphodiester bond forms through a condensation reaction. The 5' phosphate group on one nucleotide forms a new covalent bond with the 3' carbon on the pentose of the next nucleotide. Water is created as a biproduct.

State the names of the nitrogenous bases found in DNA and RNA.

adenine, thymine, guanine, and cytosine.

State a similarity and a difference between the nitrogenous bases.

- all bases have different molecular structures

- all five nitrogenous bases contain nitrogen atoms

Outline how the sequence of bases in a nucleic acid serves as a 'code.'

The conversion from a DNA base sequence to an amino acid sequence is called the genetic code.

The genetic code translates each 3 bases into 1 amino acid in a protein.

They are redundant (many codes can be the same amino acid) but not vague (one code cannot be for more than one type of amino acid)

Define gene.

A specific sequence of nitrogenous bases in DNA nucleotides that codes for making a protein.

Describe the condensation reaction that forms a polymer of RNA from RNA nucleotides.

A covalent bond between the ribose sugar of one nucleotide and the phosphate group of another nucleotide forms in a condensation reaction.

The 5' phosphate group on one RNA nucleotide forms a new covalent bond with the 3' carbon on the ribose of the next nucleotide. Water is created as a biproduct.

Identify the monomer and polymer of an RNA molecule.

Draw a short section of an RNA polymer (using circle, pentagon and rectangle)

Describe the structure of a DNA double helix.

Two antiparallel DNA molecules twisted around one another.

Outline the complementary base pairing rule, including the type and number of bonds between bases.

The two DNA molecules are held together because the bases in DNA can form complementary base pairs --> A+T, C+G

Define antiparallel in relation to DNA structure.

parallel but moving in opposite directions (like a road)

Compare and contrast the structures of DNA and RNA.​

DNA:

- Double stranded

- Adenine pairs with Thymine

Cytosine pairs with Guanine

- Deoxyribose sugar

RNA:

- Single stranded

- Adenine pairs with Uracil

Cytosine pairs with Guanine

- Ribose sugar

Compare and contrast the functions of DNA and RNA.

DNA:

Passes heredity information between generations of cells

Codes for making RNA during transcription

RNA:

Codes for making proteins during translation

Compare and contrast the location of DNA and RNA in prokaryotic and eukaryotic cells.

Eukaryotic Cells:

Both found in the nucleus.

DNA: mitochondria and chloroplasts.

RNA: cytoplasm and ribosomes (free or bound to rough ER)

Prokaryotic Cells:

Both in the cytoplasm.

DNA: clumped in a region called the nucleoid.

Outline the role of complementary base pairing in maintaining the DNA sequence during DNA replication.

During DNA replication, the two strands of a "parent" DNA molecule are broken apart. Each of these strands serves as a template for the creation of a new "daughter" strand. Because of the base pairing rule, the parent template strand will always code for the complementary sequence of nucleotides in the daughter strand (A to T, C to G). The complementary base paring will maintain the sequence of the DNA from generation to generation.

​Outline the role of complementary base pairing in transmitting the genetic code in transcription and translation.

During transcription, one of the the two strands of a DNA molecule is used as a template for the creation of an RNA strand. Because of the base pairing rule, the DNA template strand will always code for the complementary sequence of RNA nucleotides in the (A to U, C to G). The complementary base paring will maintain the sequence of the gene as mRNA is translated into protein.

Outline why there is a limitless diversity of DNA base sequences.

DNA strands can be of any length and in any order

Define universal in relation to the genetic code.

Universal means that the characteristic is shared by all life. This means that the same genetic code is used by all living organisms.

Outline why conservation of the genetic code across all forms of life is evidence of common ancestry.

it is highly unlikely that multiple organisms would have developed the same genetic code individually, but very likely that they all evolved from a common ancestor with that genetic code.