virus life cycles

SUPER SIMPLE VIRUS LIFE CYCLE CHEAT SHEET

1. HIV

Human Immunodeficiency Virus

Genome Type

• +ssRNA-RT

  • Positive single-stranded RNA

  • Retrovirus

Main Idea

RNA → DNA → hides in host DNA

Fast Steps

1. Attach to CD4

2. Enter cell

3. Reverse transcriptase makes DNA

4. Integrase inserts DNA into host

5. Cell makes virus

6. Budding

7. Protease matures virus

MEMORY LINE

Attach → Reverse → Integrate → Bud

MOST IMPORTANT TERMS

• CD4 receptor

• Reverse transcriptase

• Integrase

• Provirus

• Protease

HIV FLASHCARDS

Front:

What type of genome does HIV have?

Back:

+ssRNA-RT (retrovirus)

Front:

What does reverse transcriptase do?

Back:

Converts RNA into DNA

Front:

What enzyme inserts HIV DNA into host DNA?

Back:

Integrase

2. BACTERIOPHAGE

Bacteriophage

Genome Type

• Usually dsDNA

Main Idea

Inject DNA into bacteria

LYTIC CYCLE

Fast Steps

1. Attach

2. Inject DNA

3. Make viruses

4. Cell bursts (lysis)

MEMORY LINE

Attach → Inject → Burst

LYSOGENIC CYCLE

Fast Steps

1. Inject DNA

2. DNA hides in bacterial chromosome

3. Later activates

4. Enters lytic cycle

MEMORY LINE

Hide first, kill later

IMPORTANT TERMS

• Prophage

• Lysis

• Lysogenic

• Lytic

PHAGE FLASHCARDS

Front:

What type of genome do most bacteriophages have?

Back:

dsDNA

Front:

What is a prophage?

Back:

Phage DNA inserted into bacterial DNA

Front:

What happens in lysis?

Back:

Cell bursts releasing viruses

3. INFLUENZA

Influenza A virus

Genome Type

• -ssRNA

  • Negative single-stranded RNA

  • Segmented genome

Main Idea

Must copy negative RNA into positive RNA first

Fast Steps

1. HA attaches

2. Endocytosis

3. Uncoating

4. RNA copied

5. Assemble

6. Budding

7. NA releases virus

MEMORY LINE

HA in, NA out

IMPORTANT TERMS

• Hemagglutinin (HA)

• Neuraminidase (NA)

• M2 protein

INFLUENZA FLASHCARDS

Front:

What type of genome does influenza have?

Back:

-segmented ssRNA

Front:

What does HA do?

Back:

Helps attachment

Front:

What does NA do?

Back:

Helps virus release

4. SARS-CoV-2

SARS-CoV-2

Genome Type

• +ssRNA

Main Idea

RNA goes directly to ribosomes

Fast Steps

1. Spike binds ACE2

2. Enter cell

3. RNA released

4. Ribosomes make proteins

5. RNA copied

6. Assemble

7. Exocytosis release

MEMORY LINE

Spike → ACE2 → Copy RNA → Exit

IMPORTANT TERMS

• Spike protein

• ACE2 receptor

• RNA polymerase

SARS-CoV-2 FLASHCARDS

Front:

What type of genome does SARS-CoV-2 have?

Back:

+ssRNA

Front:

What receptor does SARS-CoV-2 bind to?

Back:

ACE2

Front:

What protein helps SARS-CoV-2 attach?

Back:

Spike protein

FASTEST WAY TO MEMORIZE ALL 4

ULTRA-FAST DIFFERENCES