Uploaded August 2023 | Updated September 2026, 2 weeks ago
Virus vs ViroidWhat is the Difference?
Professor DeBacco
Virus- Nucleic Acid Wrapped in a Protein Coat
A virus is an infectious agent consisting of a segment of a nucleic acid (either DNA or RNA) surrounded by a protein coat.
Viruses cannot self replicate.
In order to multiply viruses must infect (host) cells and use components of the host cell to make copies of itself.
Viroid- Very Simple
One of the most simple structures
50–80 times smaller than the smallest viral genomes
Currently, viroids are the smallest known infectious agents that mainly cause diseases in plants.
Free floating piece of circular genetic information
Very small in size
Can only be seen with an electron microscope
Comparison
Viruses are small and simple, but viroids are smaller and even more simple
Also…
This is the appropriate time to use the word “strain”… when referring to a virus;-)
Link to Lecture Slides: drive.google.com/file/d/1SOXzI3TSf3VvEmGMLSp0EUTlw88lkvdc/view?usp=drive_link
*Due to the description character limit the full work cited for "Virus vs Viroid What is the Difference" can be viewed at... docs.google.com/document/d/1va7Y3vADzL0X_HS82j2MRWTVNlHf_IFH/edit?usp=drive_link&ouid=104237452697237972847&rtpof=true&sd=true
Virus vs ViroidWhat is the Difference?
Professor DeBacco
Virus- Nucleic Acid Wrapped in a Protein Coat
A virus is an infectious agent consisting of a segment of a nucleic acid (either DNA or RNA) surrounded by a protein coat.
Viruses cannot self replicate.
In order to multiply viruses must infect (host) cells and use components of the host cell to make copies of itself.
Viroid- Very Simple
One of the most simple structures
50–80 times smaller than the smallest viral genomes
Currently, viroids are the smallest known infectious agents that mainly cause diseases in plants.
Free floating piece of circular genetic information
Very small in size
Can only be seen with an electron microscope
Comparison
Viruses are small and simple, but viroids are smaller and even more simple
Also…
This is the appropriate time to use the word “strain”… when referring to a virus;-)
Link to Lecture Slides: drive.google.com/file/d/1SOXzI3TSf3VvEmGMLSp0EUTlw88lkvdc/view?usp=drive_link
*Due to the description character limit the full work cited for "Virus vs Viroid What is the Difference" can be viewed at... docs.google.com/document/d/1va7Y3vADzL0X_HS82j2MRWTVNlHf_IFH/edit?usp=drive_link&ouid=104237452697237972847&rtpof=true&sd=true
![Calculating Net Energy Change of a Reaction
Calculating Net Energy Change of a Reaction
Dr. DeBacco
How Its Calculated Using Bond Enthalpies
If you know the bond enthalpies of all bonds broken and formed:
ΔH = Σ (Bond energies of bonds broken) − Σ (Bond energies of bonds formed)
In other words:
Breaking bonds = energy absorbed/input (endothermic)
Forming bonds = energy released/output (exothermic)
Higher bond energy = stronger bond
So the heat of reaction tells you the net energy flow for the whole process.
Net Energy Change
To calculate the net energy change of a chemical reaction, you are essentially figuring out how much energy is absorbed or released when bonds are broken and formed.
Formula for Net Energy Change (ΔH)
ΔH = Σ(Bond energies of bonds broken) − Σ(Bond energies of bonds formed)
Breaking bonds → requires energy (positive values)
Forming bonds → releases energy (negative values)
Step-by-Step Guide
Write the balanced chemical equation.
Make sure all reactants and products are accounted for.
List all bonds broken in the reactants.
Count how many of each type of bond is broken.
List all bonds formed in the products.
Count how many of each type of bond is formed.
Use average bond energies
These are typically found in tables (e.g., C–H ≈ 413 kJ/mol, O=O ≈ 495 kJ/mol).
Plug into the formula.
Add up the energy for all bonds broken and subtract the energy for all bonds formed.
Example: Combustion of Methane
CH₄ + 2O₂ → CO₂ + 2H₂O
Bonds broken:
4 × C–H (413 kJ/mol)
2 × O=O (495 kJ/mol)
Bonds formed:
2 × C=O (799 kJ/mol)
4 × O–H (463 kJ/mol)
ΔH = [4×413 + 2×495] − [2×799 + 4×463] ΔH = [1652 + 990] − [1598 + 1852] ΔH = 2642 − 3450 = −808 kJ/mol
This reaction is exothermic, releasing 808 kJ/mol of energy.
Link to Lecture Slides: https://drive.google.com/file/d/1RVZ77V5Vt6CWEoUCQJ9D9PV3Ds_sefFR/view?usp=drive_link
*Due to the description character limit the full work cited for Calculating Net Energy Change of a Reaction can be viewed at... https://docs.google.com/document/d/1o4ZSu6akSk xD_8q9gyRspC_EypGy-b/edit?usp=drive_link&ouid=104237452697237972847&rtpof=true&sd=true Calculating Net Energy Change of a Reaction](https://i.ytimg.com/vi/iHWwrt6rrWU/mqdefault.jpg)









