Biology Essential Concepts Genetics: Nucleic Acids
Obj 1 Describe the structure of nucleic acids
Nucleic acids are complex molecules made of chains of nucleotides .
Each nucleotide consists of a 5-carbon sugar, a nitrogen-containing
5-carbon sugar base, and a phosphate group.
Nitrogenous Base
Nitrogenous Base
Nitrogenous Base, either A, G, C, or T
Nucleotides bond each other, forming a backbone of sugars and phosphates with the bases "dangling"
Phosphate
A nucleotide
DNA
RNA
Obj 2 Distinguish DNA from RNA structurally and functionally
DNA
(deoxyribose nucleic acid)
RNA
(ribose nucleic acid)
DNA’s sugar: deoxyribose
DNA’s bases:
Adenine (A)
Guanine (G)
Cytosine (C)
Thymine (T)
RNA’s sugar: ribose
RNA’s bases:
Adenine (A)
Guanine (G)
Cytosine (C)
Uracil (U)
RNA’s shape: made of one strand of nucleotides
DNA’s shape: made of two strands of nucleotides, with the bases of the two strands holding them together like a spiral ladder (a double helix )
DNA’s function:
contains coded instructions for making the proteins that control a cell's activities.
RNA’s function: decodes the instructions and assembles proteins from the instructions provided by DNA

Obj 3 Relate DNA to genes, alleles, and chromosomes
Chromosomes are made of longs strands of DNA molecules. Chromosomes are passed from both parents to their offspring and carry inherited instructions that code for the construction of unique individuals.
Particular sections of a chromosome's DNA contain instructions for an inherited trait, for example eye color. A section of DNA that codes for a trait is called a gene .
Different versions of a gene are called alleles . For instance, for the gene that controls eye color, several alleles exist that code for different eye color.
Obj 4 Describe the structure of a chromosome a chromosome, made of DNA
PDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDP
 deoxyribose sugar and phosphate backbone
A T A G G T G A G C A A G A C A T A G G T G A G
 nitrogenous bases, hydrogen bonded to bases
T A T C C A C T C G T T C T G T A T C C A C T C
of the other strand
PDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDP one gene, a section that codes for one trait another gene
The diagram above represents a VERY short chromosome. It is made up of individual nucleotides (a phosphate group, P, a deoxyribose sugar, D, and a base, A, T, G, or C). The nucleotides bond to form long chains of DNA. The "backbone" of a DNA molecule is made of the phosphate groups and deoxyribose sugars. The "rungs" between the backbones are composed of bases. The bases of one strand are "hydrogen bonded" to the bases of its complementary strand (adenine is always paired with thymine and guanine is always paired with cytosine). Instead of being flat, a chromosome twists into a spiral, a shape called a double helix.
Obj 5 Relate DNA replication to its complementary structure
DNA Replication – Unwind, unzip, complement, bond.
The steps in DNA replication (which takes place in the S phase of interphase, remember?) are:
1.
Unwind : the double helix unwinds
2.
Unzip : enzymes break the hydrogen bonds that hold the base pairs together, separating the two strands
3.
Complement : an enzymes (DNA polymerase) matches free-floating nucleotides that complement each strand's bases (adenine to thymine and guanine to cytosine)
4.
Bond : bonds form between the sugars and phosphate groups of adjacent nucleotides
Note the two chains of the original DNA serve as templates for two new strands (one new one for each original strand). The two resulting double-helix DNA strands are identical!

Phosphate
Biology Essential Concepts Genetics: Nucleic Acids
5-carbon sugar
Obj 1 Describe the structure of nucleic acids
Nucleic acids are complex molecules made of chains of ______________ .
Each nucleotide consists of a 5-carbon ___________________, a nitrogen-containing _________ , and a _______________________. Nitrogenous Base, either A, G, C, or T
Nucleotides bond each other, forming a backbone of sugars and phosphates with the bases "dangling" Nitrogenous Base
Nitrogenous Base
A nucleotide
DNA
RNA
Obj 2 Distinguish DNA from RNA structurally and functionally
DNA
(deoxyribose nucleic acid)
RNA
(ribose nucleic acid)
DNA’s sugar: ________________
DNA’s bases:
Adenine (A)
Guanine (G)
Cytosine (C)
_____________(T)
RNA’s sugar: _______________
RNA’s bases:
Adenine (A)
Guanine (G)
Cytosine (C)
___________ (U)
RNA’s shape: made of _____ strand of nucleotides
DNA’s shape: made of ______ strands of nucleotides, with the bases of the two strands holding them together like a spiral ladder (a ____________________ )
DNA’s function:
contains coded instructions for making the proteins that control a cell's activities.
RNA’s function: decodes the instructions and assembles proteins from the instructions provided by DNA

Obj 3 Relate DNA to genes, alleles, and chromosomes
____________________ are made of longs strands of DNA molecules. Chromosomes are passed from both parents to their offspring and carry inherited instructions that code for the construction of unique individuals.
Particular sections of a chromosome's DNA contain instructions for an inherited trait, for example eye color. A section of DNA that codes for a trait is called a .
Different versions of a gene are called ______________ . For instance, for the gene that controls eye color, several alleles exist that code for different eye color.
Obj 4 Describe the structure of a chromosome a chromosome, made of DNA
PDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDP
 deoxyribose sugar and phosphate backbone
A T A G G T G A G C A A G A C A T A G G T G A G
 nitrogenous bases, hydrogen bonded to bases
T A T C C A C T C G T T C T G T A T C C A C T C
of the other strand
PDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDPDP one gene, a section that codes for one trait another gene
The diagram above represents a VERY short chromosome. It is made up of individual nucleotides (a phosphate group, P, a deoxyribose sugar, D, and a base, A, T, G, or C). The nucleotides bond to form long chains of DNA. The "backbone" of a DNA molecule is made of the phosphate groups and deoxyribose sugars. The "rungs" between the backbones are composed of bases. The bases of one strand are "hydrogen bonded" to the bases of its complementary strand (adenine is always paired with thymine and guanine is always paired with cytosine). Instead of being flat, a chromosome twists into a spiral, a shape called a double helix.
Obj 5 Relate DNA replication to its complementary structure
DNA Replication – Unwind, unzip, complement, bond.
The steps in DNA replication (which takes place in the S phase of interphase, remember?) are:
5.
________________ : the double helix unwinds
6.
________________ : enzymes break the hydrogen bonds that hold the base pairs together, separating the two strands
7.
________________ : an enzymes (DNA polymerase) matches free-floating nucleotides that complement each strand's bases (adenine to thymine and guanine to cytosine)
8.
________________ : bonds form between the sugars and phosphate groups of adjacent nucleotides
Note the two chains of the original DNA serve as templates for two new strands (one new one for each original strand). The two resulting double-helix DNA strands are identical!