NU 503 Advanced Pathophysiology
MASTERY GUIDE (2025) | DNA
Replication, Bacteria/Viruses,
Cancer, Cell Signalling + Charts &
Mnemonics!
Sugar, Nitrogenous Base, Phosphate
Hydrogen Bonds
Easily broken by Heliase
Double bonds between AT
Triple bonds between CG
Pyrimidine
Cytosine
Uracil
Thymine
Purine
Adenine
Guanine
DNA
deoxyribonucleic acid, a self-replicating material present in nearly all living organisms as the main
constituent of chromosomes. It is the carrier of genetic information.
Double stranded
Stored in nucleus and mitochondria
RNA
ribonucleic acid, a nucleic acid present in all living cells. Its principal role is to act as a messenger
carrying instructions from DNA for controlling the synthesis of proteins, although in some viruses
RNA rather than DNA carries the genetic information.
Single stranded
Uracil
Transcription
RNA is produced by the enzyme RNA polymerase, which catalyzes the serial addition of
ribonucleotides. Adenine pairs with Uracil
Translation
the process whereby genetic information coded in messenger RNA directs the formation of a specific
protein at a ribosome in the cytoplasm
, How does RNA read DNA
3' to 5'
What direction does DNA replicate?
5' to 3'
Steps of DNA Replication
1. Helicases unzips parental double helix
2. Single strand binding proteins stabilize unwound DNA.
3. Leading strand is synthesized continuously in the 5'-3' direction by DNA polymerase.
4. Lagging strand is synthesized discontinuously.
5. Primase synthesizes a short RNA primer, which is extended by DNA polymerase to form Okazaki
Fragment
6. After RNA primer is replaced by DNA (by DNA polymerase), Ligase joins the Okazaki fragment to
the growing strand.
DNA Polymerase
Enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule
Decreases errors
RNA Polymerase
Enzyme similar to DNA polymerase that binds to DNA and separates the DNA strands during
transcription
Codon
A specific sequence of three adjacent bases on a strand of DNA or RNA that provides genetic code
information for a particular amino acid
tRNA
transfer RNA; type of RNA that carries amino acids to the ribosome
mRNA
messenger RNA; type of RNA that carries instructions from DNA in the nucleus to the ribosome
Cell Signaling
Direct Contact via gap junctions
Complement Binding via receptors
Paracrine System
cells secreting a chemical to affect other nearby cells (short)
Endocrine Signaline
Hormones are secreted by specialized endocrine cells and carried through circulation to distant body
sites. Ex. epinephrine and estrogen (long distances)
Autocrine Process
MASTERY GUIDE (2025) | DNA
Replication, Bacteria/Viruses,
Cancer, Cell Signalling + Charts &
Mnemonics!
Sugar, Nitrogenous Base, Phosphate
Hydrogen Bonds
Easily broken by Heliase
Double bonds between AT
Triple bonds between CG
Pyrimidine
Cytosine
Uracil
Thymine
Purine
Adenine
Guanine
DNA
deoxyribonucleic acid, a self-replicating material present in nearly all living organisms as the main
constituent of chromosomes. It is the carrier of genetic information.
Double stranded
Stored in nucleus and mitochondria
RNA
ribonucleic acid, a nucleic acid present in all living cells. Its principal role is to act as a messenger
carrying instructions from DNA for controlling the synthesis of proteins, although in some viruses
RNA rather than DNA carries the genetic information.
Single stranded
Uracil
Transcription
RNA is produced by the enzyme RNA polymerase, which catalyzes the serial addition of
ribonucleotides. Adenine pairs with Uracil
Translation
the process whereby genetic information coded in messenger RNA directs the formation of a specific
protein at a ribosome in the cytoplasm
, How does RNA read DNA
3' to 5'
What direction does DNA replicate?
5' to 3'
Steps of DNA Replication
1. Helicases unzips parental double helix
2. Single strand binding proteins stabilize unwound DNA.
3. Leading strand is synthesized continuously in the 5'-3' direction by DNA polymerase.
4. Lagging strand is synthesized discontinuously.
5. Primase synthesizes a short RNA primer, which is extended by DNA polymerase to form Okazaki
Fragment
6. After RNA primer is replaced by DNA (by DNA polymerase), Ligase joins the Okazaki fragment to
the growing strand.
DNA Polymerase
Enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule
Decreases errors
RNA Polymerase
Enzyme similar to DNA polymerase that binds to DNA and separates the DNA strands during
transcription
Codon
A specific sequence of three adjacent bases on a strand of DNA or RNA that provides genetic code
information for a particular amino acid
tRNA
transfer RNA; type of RNA that carries amino acids to the ribosome
mRNA
messenger RNA; type of RNA that carries instructions from DNA in the nucleus to the ribosome
Cell Signaling
Direct Contact via gap junctions
Complement Binding via receptors
Paracrine System
cells secreting a chemical to affect other nearby cells (short)
Endocrine Signaline
Hormones are secreted by specialized endocrine cells and carried through circulation to distant body
sites. Ex. epinephrine and estrogen (long distances)
Autocrine Process
