Biol 240 - UW - Final Exam

Not very many proteins in the eukaryotic cytoplasmic membrane. Where did they go?

They are still in the membrane and they are still busy, but most of the proteins went to the mitochondrial membrane in eukaryotes.

Cellulose and Chitin

Use specific b-1,4-glycosidic bonds between sugars provides strength and rigidity. In algae

Fungi - Cell Wall

You have a NAG in chitin for cell walls in fungi. The cell wall is all NAGs

Cytoskeleton Function

Involved in intracellular trafficking, motion, and cell division can be observed via fluorescent microscopy

Axoneme Structure

Nine pairs of micro tubules and two more single microtubules in the middle (9 + 2 array)

A new halophile in the dead sea was found. What will its cell wall look like?

It is an archaea so something with NAG and NAT

What is the correct match for Tubulin?

FtsZ

What is the correct match for Actin?

MreB

What is the correct match for Plasmids?

ParM

What is the correct match for Cellulose?

Algae

Pseudopods

Small "false feet". Powered by actin and ATP for mobility

Heterotrophic

A carbon eater

Fungi

Heterotrophic; cell walls of chitin; used to make bread, beer, wine. Easy, cheap tool to study eukaryotic structures/gene expression

Saccharomyces cerevisiae has been heavily studied. It is the model organism for what?

Fungi

Fungi, Protozoa, and Slime Molds all use what type of metabolism?

Heterotrophic

Algae uses what type of metabolism?

Phototrophic

Which of the following may have pseudopods and often do not have cell walls?

Protozoa and Slime Molds

Which of the following eukaryotes can be non-motile?

Fungi and Algae

Which of the following eukaryotes can have flagella?

Protozoa and Algae

Fungi - Chytridiomycota

Early branching, "watermolds", Laurel Creek banks

Fungi - Zygomycota

Rhizopus, bread mold!, lab contamination

Fungi - Glomeromycota

Mycorrhizal fungi. Extremely important for plants/trees.

Fungi - Ascomycota

Called "spore shooters", cup/sac fungi, yeast

Fungi - Basidiomycota

Called "spore droppers", "club fungi", traditional mushroom producing fungi

Protozoa

As a whole, a (very) broad category. Some heterotrophic, some photosynthetic. Variable cell walls and different motility strategies. Different reproduction strategies

Protzoa - Giardia Lamblia

Genetically "old", lacks mitochondria. Causes human disease (Giardia infection, Beaver Fever). Uses fermentation metabolism

Slime Moulds - Model Organisms

Dictyostelium discoideum - NOT still protozoan. Model for studying ecology, cell motility, and cell-cell communication

Physarum - Fuses many cells into a continuous, multinucleate giant cell

Algae

Many are multicellular. All are photosynthetic with cellulose cell walls

Chlamydomonas

The model organism for algae. Has a two-flagella form good for studying eukaryal flagella biogenesis/function. Durable and easy to grow. Use an "eye" spot in the cell (little red spot) to detect light and decide how close to sit to the waters surface

Replication of Eukaryotic Microorganisms

Life cycles are more complicated due to haploid/diploid states. Possibilities for sexual or asexual reproduction

Mitosis

Basic cell division that produces two identical cells from one original cell

Meiosis

Four haploid cells from one original diploid cell. The haploid cells are genetically diverse. One round of DNA replication followed by two rounds of cell division

Genetic Recombination

Segregation of maternal/paternal chromosomes. A "crossing over" between chromosomes occurs prior to segregation, this ensures each haploid cell is genetically distinct

Saccharomyces (Fungi) Life Cycle

Can undergo meiosis to form an ascus (skin bag, the ascus is for meiosis). Haploid mating types can fuse to reproduce sexually or be maintained by asexual mitosis. Not limited to ascus formation. Budding off of smaller cells can occur or fission of identically sized cells. When the small cells bud off they leave scars behind on the larger cells

Chlamydomonas (Algae) Life Cycle

Chlamydomonas maintains a motile haploid state. In favourable environments mitosis occurs. Haploid cells differentiate and fuse into a diploid form in bad conditions (spore formation)

Dictyostelium (Slime Mould) Life Cycle

Exists in a haploid unicellular form until conditions worsen. Multicellular "slug" is formed with a stalk and a fruiting body. Spores form in the fruiting body, restarting the life cycle as haploid cells. Haploid cells can fuse into a diploid macrocyst form. Macrocyst form undergoes meiosis to generate more haploid cells

Beer. Wine. Bread. Cell Wall?

All NAGs

Why does Dictoostelium generate macrocysts?

To generate large numbers of gametes that have new genetic combinations and minimizing the impact of detrimental genes

Penicillin acts on what?

FtsI and Transpeptidation

True or False - An axoneme is an array where nine pairs of microtubules are wrapped around a core pair of microtubules

True

Endosymbiotic Theory

Life started 4.5 to 4 billion years ago, but eukaryotes appeared around 2.1 to 1.6 billion years ago. One primitive microorganism (archaea) engulfed/ingested another (bacteria, probably a proteobacteria), forming a symbiosis. At least two endosymbiotic events must have occurred (mitochondria, chloroplasts)

Evidence for Endosymbiotic Theory

Mitochondria/chloroplasts resemble bacteria in both size and shape. Double membranes (host and bacterium) has all ester linkages. "Cell" division with FtsZ. Each has its own DNA, rRNA more similar to bacterial sequences than eukaryal ones. Circular chromosome

Evidence for Endosymbiotic Theory - Exception

Amitochondriates lack mitochondria. Cells likely evolved out of using them to obtain energy (Giardia is an example)

Endosymbiosis in Modern Cells

Two cells together are better than one alone. When amoebas were infected with x-bacteria, most of the amoebas died, but some survived

Endosymbiosis Experiment

Hypothesis - Viable bacteria remained inside the surviving amoebas

Experiment - Treat amoebas with antibiotics

Results - Following treatment with antibiotics, both bacteria and amoebas died

Conclusion - Amoebas had become dependent on bacteria for survival

Paramecium ingesting algae and using them for photosynthesis.

It hosts them and allows them to continue with photosynthesis has they are exposed to the light. They take CÓ and release sugars for paramecium. When the light is gone and sugar stops being produced, the paramecium will break down the algae and digest it

Malaria

An infection of red blood cells by protists

Diseases Caused by Microbes

The challenge in treating these conditions is that we want to kill the pathogen (which is made of eukaryotic cells) but not the host (which is made of eukaryotic cells)

Fungi and Human Disease

Fungi are less likely to cause disease, but can do so in immuno-compromised individuals. Fungi can cause oral thrush and athletes foot

Fungi and Plant Disease

Protozoa and fungi can cause significant disease in plants. Potato blight and the great Irish famine, mid-1800's. Phytophthora infestans causes potato blight. Caused thousands to immigrate. Phytophthora have cell walls made of cellulose. It sort of looks like fungi and it sort of looks like plants

Rhytisma (Tar Spot)

Infects maple trees. When it rains, the tar spots will shoot spores. This interferes with the ability of the leaves to perform photosynthesis. It is a parasite of maple trees. It doesn't have a huge lasting impact, the tree generally doesn't suffer. Having these on the trees might mean that your air quality is good. Japanese maple trees are immune to this

Cordyceps

Infect ants and eat their insides. They then grow out of the ants dead bodies so that when it rains the spores will be spread to everything below

Beneficial Roles of Eukaryal Microbes

Primary producers provide energy. Some algae produce great amounts of oxygen through photosynthesis in the oceans. Biodegraders recycle nutrients. Microbial eukaryotes break down dead animals and plants so that we aren't living in a world of carcasses. Some eukaryal microbes can degrade cellulose, recycling plant matter better than animals can

Tadigrades (Water Bears)

Not always tough. They are only tough when they are in a dehydrated resting state (the tun state). But they are nowhere near are tough as gram positive bacteria

Which methanogens are the most popular in the environment?

Hydrogenoclastic

If you are out of mushrooms you are out of?

Chytridiomycota

Dough is made out what before it gets mouldy?

Ascomycota

Which of the following arrangements might result in have flagella at either end of the cell?

Amphitricus

What is the correct match for Nanoarchaeum?

Igniococcus

What is the correct match for Phytopthora?

Potato Blight

What is the correct match for termite guts?

Protazoa

What is the correct match for Cordycepts?

Arthropods

What is the correct match for amoebas?

X-Bacteria

Why is photpthora strange?

It was weird because it is a fungi but it does have the typical cell wall (which would be chitin) but it has a cell wall made of cellulose

Dimitri Ivanovski (1892)

He figured out that there was a causative agent of diseases that was smaller than cells

Felix D'Herelle

Discovered bacteriophages (coined term "plaque"). He is a French Canadian. Bacteriophages are small disease particles that infect bacteria

Spanish American War

US Forces were in Cuba and there was a problem with disease, specifically yellow fever. Walter Reed was in the US Army

Walter Reed and Colleagues

Showed that yellow fever was a virus transmitted by mosquitoes, in 1901

Virus Structure

Intracellular obligate parasites. Typically between 10 and 100nm. Genome typically a few thousand to 200,000 nucleotides long (pretty small)

Viral DNA Structure

Single or double-stranded DNA or RNA (linear or circular). Different viruses have their nucleic acids in all sorts of different arrangements.

Virus Capsid

A protein shell around genome. This is composed of many capsomere proteins. The capsid and genome together are called the nucleocapsid. Normally sized to fit the genome on the inside, bigger genome, bigger capsid

Virus Cell Envelope

Possible envelope (cell-derived membrane around capsid) on some viruses. It is a phospholipid bilayer very similar to eukaryotes because it is high-jacked from the host

Capsid Shape

Often exhibit either helical (often the RNA viruses) or icosahedral. Can also take on irregular or complex shapes.

Virus RNA

Not incredibly stable, so when the virus genome is made up of RNA we want to protect the RNA with the helical capsid

Hypodermic Syringe

Made to insert genetic materials into the cell

Enveloped Virus

A plasma membrane surrounds the nucleocapsid

Naked Virus (unenveloped virus)

No plasma membrane around the nucleocaspid

Viral Replication

1. Adhere - Stick to a host cell (!)

2. Enter

3. Uncoat - Release genome

4. Synthesis - Express and replicate genome

5. Assembly - Create new virus particles

6. Exit - New particles leave cell, sometimes killing the host in the process

Viruses Entering the Cell

Arguably the most important part in the viral replication cycle. HIV and CD4 receptors on T cells. Mechanisms vary depending on host cell. Animal viruses don't have to contend with a cell wall

Viruses Entering Animal Cells

There has to be a receptor on the animal cell. Endocytosis (of non-enveloped viruses) and membrane fusion (of enveloped cells). Enveloped cells can also enter the cell by endocytosis

Who coined the term "plaque"?

Felix D'Heurelle

True or False - All viruses are composed of nucleic acid and protein

True

All of the following compounds can be found in the bacterium Staphylococcus...

Peptidoglycan, FtsZ, Bactoprenol (this is a lipid carrier in bacteria), and a Li[id Bilayer

MreB

If you don't have this you will be spherical. This makes you a coccoid cell. So MreB is not found in Staphylococcus

Where would you classify Nanoarchaeum?

DPANN

During cell wall synthesis in bacteria, when does the pentapeptide become a tetrapeptide?

When transpeptidation occurs

True or False - Archaea have a similar RNA polymerase to one of those in eukaryotes

True

Viruses Entering Plant Cells

Often depends on damage to plant tissues to open a spot in the cell wall (insects feeding on plants, wind damage, hail/rain damage, fire damage, human-induced damage). These do not require receptors, they just require holes in the cellulose cell walls that the viruses can fall through

Viruses Entering Bacterial Cells

Like a hypodermic syringe, where DNA injected directly into the cell. These viruses have tail fibers that attach to receptors on the outer membrane of bacteria. The receptors are just normal membrane proteins that the tail fibers adapt to (so that they can latch on)

Virus Tail Fibers

When bound, a conformational change in tail fibers brings the base of the virus in contact with the host cell surface. Rearrangement of tail proteins allows inner core tube proteins to extend down into the cell wall. Contact with the plasma membrane initiates transfer of DNA through a pore formed in the lipid bilayer of the bateria

Bacteriophage Replication

Either lytic or lysogenic

Lytic Cycle

Viruses enter, replicate, and lyse host cell

Lysogenic cycle ("temperate phage")

Phage integrate their genome into host (i.e., "lysogen") cell's genome, becoming a "prophage". Prophage genome is replicated along with the host cell's until... stress... then back to lytic phase.

Temperate Phage versus Lytic Phage

Temperate phage can be both lytic or exist as a prophage ("lysogeny"). Lytic phage are lytic.

Coevolution Hypothesis

Viruses originated about the same time as other microbes and have been coevolving with them.

Regressive Hypothesis

Viruses are previously alive organisms that have evolutionarily regressed into host-dependent particles.

Progressive Hypothesis

Viruses originated from genetic material that gained the ability to replicate and be transmitted semi-autonomously

Cultivating Bacteriophage

Much trickier to work with than bacteria (very small, and they need their specific host). Uses agar plating to create plaques

Cultivating Animal Viruses

Tissue culture of host cells used to grow targets for the viruses (or in embryonated chicken or duck eggs for <$$$). Cultures must be kept sterile and bacteria-free methods have only been in place since the 1950s. Modern virology couldn't exist without these tools, many developed from first human cell line, known as HeLa cells

Viral Purification

Usually begins with simple filtration to remove large cells and cellular debris. Viruses then purified and concentrated with centrifugation