Module 5

Question 1

2 Main Structures of Viruses:

Answer 1

-naked virus
-enveloped virus
-*viruses don’t have cell walls; quiz question

-naked is more stable
-enveloped better at transmission

Question 2

Virus

Answer 2

means slimy liquid/poison, first virus discovered was in 1901 (yellow virus) misquito bites

Question 3

RNA Viruses Have 3 Main Ways They Replicate in the Cell:

Answer 3

-method 1: direct translation - ss RNAor one strand of dsRNA acts as mRNA and is translated in the cytoplasm by host machinery ex. Rubella
-method 2: Virus has its own viral RNA polymerase, genetic material comes in as ssRNA and uses its own RNA polymerase to make a copy that acts like mRNA and can be translated ex. Influenza
-method 3: retrovirus like HIV - virus RNA enters cytoplasm, reverse transcriptase from the virus makes a copy of the RNA into DNA, this is then integrated into the host DNA and the virus DNA gets transcribed/translated just like normal host proteins

Question 4

DNA Virus:

Answer 4

-can be ssDNA or dsDNA that enters the cell and goes to the nucleus, here transcribed by host cell machinery or a virus enzyme to form mRNA, host cell machinery translated proteins ex. HSV-2
-DNA viruses can have single stranded DNA *quiz question

Question 5

Virus Life Cycle:

Answer 5

Infecting virus
Attachment
Pentreation (entry)
Uncoating (get rid of capsid/outer shell)
Replication
Assembly
Release - either by budding off (often enveloped virus) or cell lysis

Question 6

Outcome of Viral Infection:

Answer 6

Lytic: when virus assembly, cell breaks open and cell dies
Persistent: virus just keeps using the cell to assemble and bids off, but does not destroy cell
Latent: remains dormant/latent in neurons until reactivated - HSV1/2
Cancer: 15% of all worldwide cancers may be attributed to viruses. DNA and RNA viruses can cause cancer.
DNA viruses: epstein-Barr virus, human papillomavirus (cervical cancer), hepatitis b virus, human herpesvirus-8
RNA viruses: human T lymphotrophic virus type 1 and
hepatitis C viruses

Question 7

Prokaryote vs eukaryote chart

Question 8

2 Types of Virus

Answer 8

DNA virus and RNA virus

Question 9

Gram +/- Chart

Answer 9

gram staining for bacteria only
-+ = thicker peptidoglycan
– = thinner peptidoglycan but has lipopolysaccahrids LLPS covering cell wall

+ =purple
- = pink

Question 10

Plasma/Cell Membranes in Bacteria and Eukaryotes:

Answer 10

–same = both have pores for transport, enzymes, receptors
-differences = no mitochondria in bactera PM

Question 11

Peptidoglycan

Answer 11

polymer of sugars and amino acids that from mesh like layers outside the membrane and is called the cell wall

Question 12

Pili

Answer 12

-bacteria

Functions include transfer of DNA between bacteria, motility and act as attachment sites

Question 13

Pili and other labelling on ipad

Question 14

teichoic acid

Answer 14

-adding rigidity to cell wall, may be receptors for some bacteriophages and may function in pathogenesis

Question 15

capsule

Answer 15

polysaccharide layer on outermost edge of bacteria, functions in adherence and protection

Question 16

Plasmid

Answer 16

circular genetic elements that reproduce autonomously and exist outside the normal DNA (more than 300 types), this allies genes to be transferred for survival advantages → can pick up enzymes, antibiotic resistant genes

Question 17

Bacteriophage:

Answer 17

-virus that infects prokaryotic cells
-corynebacterium diphtheriae: this bacteria needs to be infected by the beta phage to make diphtheria toxin, no page = no diphtheria disease occurs

Question 18

What is Unique about Bacterial Metabolism:

Answer 18

-similarities: can use similar glycolytic process for sugar metabolism (krebs cycle etc)
-differences: they have more ways to get energy that we can use: anaerobic respiration by using inograning components and can use fermentation to derive energy from glucose
-no mitochondria, so ETC occur on inner bacterial membrane
-GI tract and vaginal bacteria are usually facultative anaerobes or completely anaerobic

Question 19

Things That Help Bacteria Infect Better:

Answer 19

-going through a cut - break in skin
-flagella can help them propel
-catalase and coagulase
-plasmids can help antibiotic resistance if doc prescribes antibiotics
-cell wall components to protect from immune system
-virulence genes: may have plasmids or bacteriophages that encode toxic to damage the host or enzymes that help it become resistant to antibiotics or help it get more nutrients (hemolysin/fibrinolysin)
-growth curve: log/exponential growth
-unique metabolism (can go with or without oxygen)

Question 20

Streptococcus Symptoms:

Answer 20

-sore throat = group A strep
-gastro symptoms = group D strep
-infected wound = group A or D
-group B streptococcus = uti
-high wbc in urine = group D/B

Question 21

Thrush (caused by candida - an interesting fungus):

Answer 21

-dimorphic shape (yeasts can take on 2 shapes, single celled or branched)
-opportunistic fungi → doesn’t always cause disease, candida can cause thrush or no symptoms
-can cause superficial or deep infections
-may be part of bacterial vaginosis (or gardnerella and trichomonas)
-candida can enter blood and that can be deadly

Question 22

Case Study:
-2 year old presented with poor weight gain, they ate well and had a normal appearance but had frequent diarrhoea, family was back country campers

Answer 22

-child has giardia lamblia (present in untreated water) - commonly called beaver fever

Question 23

-pregnant person refuses to clean cat litter:

Answer 23

toxoplasmosis gondii
-usually will be fine as it always shed and takes about 48 hours for cat litter to become infective
-can pass i to baby and cause brain damage/ison loss
-in adults, usually just mild symptoms of flu

Question 24

Where do fungal infections come from

Answer 24

can be from environment or overflow of normal flora

Question 25

trichomonas vaginalisis

Answer 25

-infection in adults may be asymptomatic or manifest (most commonly) as vulvovaginal itching with a malodorous vaginal discharge. Neonatal infection with Is infrequently reported, but has been noted to cause urinary tract infections and vaginitis in infants as premature as 28 weeks’ gestation. In addition, infants with cultured from nasopharyngeal secretions have been reported to present with significant respiratory distress, but its causality in this clinical setting is unclear.
= trichomonas vaginalisis - can be spread as and STD, associated with adverse birth outcomes so treat before birth

Question 26

Naked Virus

Answer 26

(non-enveloped viruses):
-composed solely of a protein coat called a capsid that surrounds their genetic material, which can be either RNA or DNA.
-lack an outer lipid membrane envelope.
-rhinovirus (common cold virus), and norovirus (stomach flu virus)

Question 27

Enveloped Virus

Answer 27

-have an additional outer lipid bilayer membrane envelope surrounding their protein capsid.
-envelope is derived from the host cell membrane when the virus buds off from the host cell during the viral replication process.
- influenza virus, HIV (Human Immunodeficiency Virus), and herpes simplex virus.