Module 4/5 Flashcards
DNA and RNA
are both assembled from nucleotide subunits
-5-carbon sugar
-phosphate group
-nitrogen base
What forms the sugar phosphate backbone is DNA and RNA
Each nucleotide monomer is connected by covalent bonds forming the sugar- phosphate backbone
Each linear strand of nucleotides has a ___ and ____ backbone
5’ and 3’ backbone
DNA contains
deoxyribose sugar
H-
RNA contains
ribose sugar
OH-
Which nitrogen bases are in BOTH DNA and RNA
Cytosine, Guanine, and Adenine
Which nitrogen base is found in DNA
Thymine
Which nitrogen base is found in RNA
Uracil
the three dimensional structure of proteins determines its
functional properties and enables the protein to carry out its job in the cell
What does DNA do
Store genetic information, encoded into its sequence of subunits
Encodes proteins that give structure and do work
Transmit genetic info
Polymers of nucleotides
Nucleic acids such as DNA and RNA
Nitrogen Base
A cyclic molecule that contains NITROGEN, CARBON, HYDROGEN, AND OXYGEN.
Purines
double-ringed structure
Which nitrogen bases are Purines
Adenine and Guanine
Pyrimidines
single-ringed structure
Which N-bases are pyrimidines
Thymine and Cytosine
5-Carbon sugar in DNA
Attached to the N-base
Deoxyribose
in DNA deoxyribose 2’
has a H-atom
in DNA deoxyribose 3’
has an hydroxyl group, OH-
Phosphate group make up
Consists of a central P atom, covalently bonded to four OXYGEN atoms
Phosphate group characteristics
Functional group
-polar
-negatively charged
Which C atom is the phosphate group attached to in DNA/RNA
the 5’ carbon
Phosphate group will have a NEGATIVE charge on 2 of its oxygen atoms
Why is DNA a mild ACID
DNA’s cellular pH is around 7
The free HYDROXYL GROUP attaches to the phosphorus atoms, and is IONIZED by the LOST OF A PROTON
What are monosaccharides joined by
Glycosidic Bonds
What are amino acids joined by
Peptide bonds
What are nucleotides joined by
Phosphodiester bonds
-can withstand heat, and pH changes that would break weaker bonds
Where is the phosphodiester bond in nucleotides
Vertical lines that connect the 3’ carbon of one nucleotide to the 5’ carbon of the next
C-O-P-O-C linkage is a A SERIES of covalent bonds, collectively known as a phosphodiester bond
What traces the backbone of a DNA strand
Phosphodiester bonds
Each sugar links to the phosphate group of the neighboring nucleotide by phosphodiester bonds
What gives DNA strand their directionality
The phosphodiester linkages in the DNA strand
What is directionality
Polarity
One side differs from the other
5’ end
Free 5’ phophaate
3’ end
Free 3’ hydroxyl
Why do we need to specify which end is which?
the directionality of DNA strands
Polymerize
Can grow
When are phosphodiester bonds formed
DNA SYNTHESIS
when a nucleotide with three phosphate groups (nucleotide triphosphate) joins a growing chain
A NUCLEOTIDE TRIPHOSPHATE REACTS WITH AN EXISTING DNA MOLECULE TO extend the molecule by adding new nucleotides
what is a nucleotide triphosphate
A nucleotide with three phosphate groups
Directionality of a nucleotide triphosphate added to the 3’, OH of DNA
5’ –> 3’
5’ to 3’ direction
What happens to the three phosphate groups of the incoming nucleotide triphosphates during DNA synthesis
Only 1 of the phosphate groups is used to make the sugar-phosphate BACKBONE
The other 2 phosphate groups are RELEASED or attached to each other and abbreviated PP (subscript i)
What gives nucleotides their chemical identity
The N-bases attached to the sugars
Antiparallel
DNA strands run opposite of eachother
Base pair characteristics
Each base pair has one PURINE and one PYRIMIDINE
Maintains the structure of the double helix and preserves the backbones along the length of the molecule
Base pairs
A and T
G and C
Complementary bases
Base pairs are complementary
The paired strands in a double-helix have different base sequences
Which base pairs are stronger in RNA than in RNA
A and T only form 2 H-bonds
G and C form 3 H-bonds
Why is RNA less stable than DNA
The ribose sugar has a hydroxyl group on its 2’ carbon
These groups are highly reactive functional groups
In DNA 2’ has a H+
Which base is different in RNA
Uracil replaces Thymine
RNA base pairs
A-U
G-C
Function of RNA
RNA acts as an INTERMEDIATE between DNA and proteins during PROTEIN SYNTHESIS
Function of DNA
specifies the sequence of amino acid subunits, which composes proteins, which will determine the structure and function of the protein
DNA must act through RNA
Central Dogam
The flow of information from DNA and RNA to protein
Protien
Preform cell work, provide structure
Protein subunits
Amino Acids
Ovalbumin
predominant egg white protein
A protein polymer consisting of thousands of bonded amino acids
Amino Acid Structure
- Amino Group
- Carboxyl group
- H-atom
- R-group/ side chain
Amino group
HN
Carboxyl Group
COOH
Hydrophobic Amino Acids
R groups aggregate with each other
Tend to be buried in interior of folded protein
Hydrophilic amino acids
Found on surface of protein
Glycine
R group is an H-atom
Increases flexibility of backbone
Proline
C- chain attached to amino group
Introduces kink to protein
Crysteine
Can form DISULFIDE which can connect different parts of the same protein
Dehydration synthesis reaction
Monomers are linked by covalent bonds
H2O becomes a byproduct
Hydrolysis Reaction
BREAK THE COVALENT bonds by ADDING water across the bond
Gains H+ and OH- group in the products
Peptide Bonds Link
Amino Acids to form proteins
Formation of a peptide bond is an example of
A dehydration synthesis. Creates bonds, while losing a water molecule
Peptide Bonds
The covalent linkage between the CARBON atom of the CARBOXYL group of one amino acid joined to the NITROGEN in the AMINO group of the next.
N terminus
amino end
C terminus
Carboxyl end
Peptide
A short polymer of amino acids
Poly Peptides
A long polymer of amino acids
Protein
a polypeptide folded into a stable 3D conformation
Primary sequence
Sequence of amino acids in a protein - will determind how the protein folds
Secondary Structure
Formed by interactions between stretches of amino acids in a protein
The 2 types of secondary structures of a protein
Alpha helix and Beta sheet
Tertiary structure
The 3D shape
Denatured
ProteIns can be unfolded by CHEMICAL TREATMENTS or HIGH TEMPERATURES
Proteins lose their activity
Quaternary structure
Proteins composed of 2 or more polypeptide chains or subunits
Combinations of various tertiary structures.