Biology

Why is it possible to say LUCA (Last Universal Common Ancestor) may have been a community?

Why is it possible to say LUCA (Last Universal Common Ancestor) may have been a community?

Web of life. Standard natural selection was not possible because true heredity was not established

What is horizontal gene transmission(transfer)?

Is the movement of genes from one genome to another (ex. Solar slugs).Lynn Margulis came up with this.

Who is Carl Woese

Figured out there was a third domain that was archaea. ⅓ of all life on earth was hiding under our noses.

What are the three domains of life?

Bacteria, Archaea, Eukarya

What types of environments can extremophile Archaeans be found in?

Hypersaline Water. Very hot water. Deep Sea vents. Anaerobic environments (ex. Lake sediments)

What do Archaeans and Eukaryotes have in common?

No peptidoglycan in cell walls. Have initiator amino acid Methionine. No growth in response to antibiotics. Both have several kinds of RNA polymerase.

What do Archaeans and bacteria have in common? ( study the chart again!)

no nuclear envelope. No membrane close organelles .Have circular chromosomes.

Who discovered them, when and using what type of data?

Woese discovered them in 1977. He used rRNA sequences to find them.

Are all Archaeans extremophiles?

Not all archaeans are extremophiles but that is generally where they want to be in these extreme environments.

Who are the Lokiarcheota and what do they mean for how we recognize the Domains of life?

It is the archaea group that is a close ancestor to the eukaryotes. It is like the hippos talked about in lecture.

What's a halophile

Euryarchaeota that require high salt concentrations. Found in brackish water, salt lakes, and desalination plants. Is Phototrophic (atp). Has bacteriorhodopsin- pigment.

Whats a thermophile. Acidophile

Crenarchaeota. Located in hot springs and hydrothermal vents. Can live in temperatures from 60-121 C. Chemosynthetic; metabolize sulfur. Lithotrophic.

What are the 4 Archaean phyla that we discussed?

5 main archean phyla in slides. Euryarchaeota(halophiles), Crenarchaeota(Thermoacidophiles), Korachaeota, Nanoarchaeota

Why might NASA be interested in extremophiles? Here is just one of many links, if you're interested:

They can live in extreme conditions and are able to survive. Nasa wants to know how they work so they can protect themselves. They also want to know how genetically how they can live in these conditions

Describe Deinococcus radiodurans. Why is it like that?

Conan the Bacterium. They can live in really tough conditions. Firstly, it has an extremely efficient DNA repair system that can quickly repair damaged DNA caused by radiation or other forms of stress. Secondly, it has thick cell walls that can protect it from damage caused by dehydration and other environmental stressors. Thirdly, it has antioxidant enzymes that help it to neutralize harmful reactive oxygen species generated under stress.

Describe the three shapes that prokaryotes can have.

The three most common shapes are spheres (cocci), rods (bacilli), and spirals

How is the cell wall of a bacterium unique with respect to the other 2 domains?

Their cell wall, which maintains cell shape, provides physical protection, and prevents the cell from bursting in a hypotonic environment

Describe how gram-staining works? Who developed it?

Developed by Hans Christian gram. Using the Gram stain, scientists classify many bacterial species into Gram-positive and Gram Negative groups based on cell wall composition. Gram-negative bacteria have less peptidoglycan and an outer membrane that can be toxic, and they are more likely to be antibiotic resistant.

A bacteria stains purple, is it gram negative or positive?

Positive due to its thick peptidoglycan wall

Describe and be able to label the two types of bacteria cell walls.

Gram-type positive, which have no outer membrane and lots of peptidoglycans, and Gram-type negative, which have an outer membrane and little peptidoglycans.

T or F: Bacteria can be found as high as 25 miles and as deep as a half mile underground.

True

What, specifically, does penicillin attack?

It causes bacteria to be unable to produce peptidoglycan

What's a capsule and what is it good for?

A polysaccharide or protein layer called a capsule covers many prokaryotes

What's a fimbria

Fimbriae (also called attachment pili), which allow them to stick to their substrate or other individuals in a colony •Sex pili are longer than fimbriae and allow prokaryotes to exchange DNA.

what's a pilus?

A pilus is In bacterial conjugation, an appendage of a male bacterium by which it attaches to a female bacterium, preparatory to the transfer of DNA from male to female.

What is taxis? Describe 2 types

In a heterogeneous environment, many bacteria exhibit taxis, the ability to move toward or away from certain stimuli. Thigmotaxis- It involves the movement or orientation of an organism in response to a physical stimulus. Chemotaxis- refers to the movement of an organism in response to a chemical stimulus. Often found in bacteria

How the flagella mechanism works

Flagella are thread-like appendages that extend from the surface of bacteria and rotate to propel themselves forward. The movement of flagella is generated by a complex molecular motor that is embedded in the bacterial cell membrane. This motor is composed of several different proteins that work together to drive the rotation of the flagella.

What are two types of interior membranes that can be found in some bacteria

Respiratory and Thylakoid Membranes

Describe the two types of DNA in a bacterium.

Plasmids and Chromosome

Plasmid examples

Insulin, PCR

Bacterial generation times are about how long?

Bacteria reproduce quickly by binary fission and can divide every 1-3 hours

What's an endospore? How can you kill it!?

Many bacteria form metabolically inactive endospores, which can remain viable in harsh conditions for centuries. Triggering germination or high enough temp at the right time will kill it

Describe Cooper and Lenski's experiment. Are the bacterial individuals getting stronger?

The experiment is an experiment using e. Coli in which they transfer bacteria to a new tube every day in order to continue its growth. This is then frozen to be able to see the bacterias evolutionary history. During the experiment, the fitness of the population increased

Describe and compare conjugation (both plasmid and chromosomal), transformation, transduction. What do these three things accomplish?

Prokaryotic DNA from different individuals can be brought together by transformation, transduction, and conjugation. A prokaryotic cell can take up and incorporate foreign DNA from the surrounding environment in a process called transformation Transduction is the movement of genes between bacteria by bacteriophages (viruses that infect bacteria). Conjugation is the process where genetic material is transferred between bacterial cells

What are the three ways that bacteria generate so much genetic diversity? About how many mutations occur in your E. coli fauna everyday?

2000 cells have mutation in a gene BUT E. coli has 4,300 genes! Um, that is 9 million/day/person! Mutations are rare but large numbers and fast reproduction make up for it. Most mutations are bad for the bacteria but 1 in a million not such a big deal!Rapid reproduction - Mutation - Genetic recombination.

What is the F-factor?

A piece of DNA called the F factor is required for the production of sex pili The F factor can exist as a separate plasmid or as DNA within the bacterial chromosome.A cell with the F factor built into its chromosomes functions as a donor during conjugation

What is an R-plasmid?

R plasmids carry genes for antibiotic resistance •Antibiotics select for bacteria with genes that are resistant to the antibiotics

What is an Hfr cell?

A Hfr cell (high frequency of recombination cell) is a type of bacterial cell that has a high frequency of exchanging genetic material with other cells through conjugation, a process where two bacteria physically connect to share DNA. Hfr cells are unique because they have a plasmid that carries the F factor, a piece of DNA that codes for the proteins necessary for conjugation

What two things are required to kill an endospore?

The first method is destruction at high temperatures in their spore state. The second method is through triggering endospore germination back to active bacterial cells that are easily killed through traditional means of sterilization

Why might a doctor cycle a drug treatment with a short period of no drugs? (Remember competition and environments!)

When one bacteria is killed another can thrive in its absence. The doctor needs to then switch to no drugs to let the other bacteria come back and kill off the new bacteria that has taken over. Oce that bacteria becomes dominant again, the doctor then has them take medicine again to kill it off. This is to keep the different bacterium at bay without letting one get too overbearing to take over the system.

Phototroph

Phototrophs obtain energy from ligh

Chemotroph

Chemotrophs obtain energy from chemicals

Autotrophs

Autotrophs require CO2 as a carbon source •Heterotrophs require an organic nutrient to make organic compound

Aerobes

require O2 for cellular respiration

Anaerobes

are poisoned by O2 and use fermentation or anaerobic respiration

Where (what bacterial group) did your mitochondria come from?

aerobic alpha proteobacteria through endosymbiosis

Why are alpha protobacteria like Rhyzobium important to plants (and us)?

Rhizobium, which forms root nodules in legumes and fixes atmospheric N2

What is binary fission?

binary fission, asexual reproduction by a separation of the body into two new bodies. In the process of binary fission, an organism duplicates its genetic material, or deoxyribonucleic acid (DNA), and then divides into two parts (cytokinesis), with each new organism receiving one copy of DNA.

What is a leading hypothesis for chlamydias causing infertility?

the leading hypothesis for chlamydias causing infertility is that the bacteria can cause scarring and blockages in the fallopian tubes, preventing eggs from reaching the uterus or sperm from fertilizing the egg

Lyme disease and syphilis are caused by

Spirochaetes

Why are cyanobacteria considered so important?

These are photoautotrophs that generate O2. Plant chloroplasts likely evolved from cyanobacteria by the process of endosymbiosis

What was the Great Oxygen Event?

The Great Oxygenation Event occurred when cyanobacteria (photoautotrophs) living in the oceans started producing oxygen through photosynthesis. As oxygen built up in the atmosphere anaerobic bacteria were killed leading to the Earth's first mass extinction. The change in diversity and the arrival of appreciable atmospheric oxygen (as evidenced by the red bands in the rocks) can be analyzed to see what happens when a resource that was scarce becomes very abundant

When did the great oxygen event happen

2.4 billion years ago

What are the three types of symbiotic relationships? Give an example.

•In mutualism, both symbiotic organisms benefit •In commensalism, one organism benefits while neither harming nor helping the other in any significant way •In parasitism, an organism called a parasite harms but does not kill its host

A disease causing bacteria is called a

Pathogenic bacteria

Describe how lyme disease is transmitted.

It is transmitted when a tick that is infected with Borrelia mayonii (a type of Spirochete) bites an animal

What are the 4 major nutritional modes in bacteria

Photoautotroph, photoheterotroph, chemoautotrophs, and heterotrophs

Photoautotrophs

Organisms that use light as a source of energy to synthesize organic substances.

Photoherotrophs

energy source=sunlight, carbon source=organic compounds

Chemoautotrophs

Organisms that use hydrogen sulfide or other chemicals as energy source instead of light.

Heterotroph

An organism that cannot make its own food.

Describe the three bacterial modes concerning oxygen use/tolerance

Aerobes: These bacteria require oxygen to grow and survive. They undergo respiration and use oxygen as the electron acceptor. anaerobes: These bacteria require the absence of oxygen to grow and survive. They lack the enzymes necessary for utilizing oxygen in their metabolic processes, and exposure to oxygen is toxic to them. Facultative anaerobes: These bacteria can grow in the presence or absence of oxygen. They are metabolically versatile, and can use oxygen when it is available or utilize alternative electron acceptors

What is nitrogen fixation

Nitrogen fixation: any natural or industrial process that causes free nitrogen (N2), which is a relatively inert gas plentiful in air, to combine chemically with other elements to form more-reactive nitrogen compounds such as ammonia, nitrates, or nitrites. nitrogen cycle

Give an example of a nitrogen fixing bacteria and where it lives.

One example of nitrogen fixing bacteria is Rhizobium, which lives symbiotically in the root nodules of leguminous plants such as beans, peas, alfalfa, and clover

What's a biofilm

In some prokaryotic species, metabolic cooperation occurs in surface-coating colonies called biofilms

What is a eukaryote

eukaryote, any cell or organism that possesses a clearly defined nucleus. The eukaryotic cell has a nuclear membrane that surrounds the nucleus, in which the well-defined chromosomes (bodies containing the hereditary material) are located.

What are the five major eukaryote groups

protozoans, algae, fungi, plants, and animals

Why is Protista considered a GRADE and not a clade?

Protista is considered a grade because the organisms grouped under this term are not all closely related to each other

What are the three nutritional strategies of eukaryotes?

Autotrophs, heterotrophs, and mixotrophs

What are the three different sexual reproduction cycles

gametic, sporic, and zygotic life cycle

Describe primary endosymbiosis of plastids. What two groups arose this way?

Primary endosymbiosis is a process by which a eukaryotic cell engulfs and incorporates a free-living prokaryotic organism, leading to the establishment of an endosymbiotic relationship. green algae and red algae

Describe secondary endosymbiosis. What 3 groups arose this way? How do we know it was secondary?

Secondary endosymbiosis is a process by which a eukaryotic cell engulfs and incorporates another eukaryotic cell that has already undergone primary endosymbiosis. We know that secondary endosymbiosis occurred because the plastids found in these organisms have more than two membranes

Who was Lynn Margulis

Came Up with the endosymbiosis theory. That organisms have developed to work together

What are the 3 groups within the Excavata

Diplomonads, parabasalids, and euglenozoans

What basic properties do the excavates share?

cytoskeleton. Modified mitochondria. Spiral or crystalline rod inside of the flagella

If an excavate has a plastid, where did it originate

It is believed that the plastids originated as photosynthetic prokaryotic endosymbionts that were engulfed by non-photosynthetic eukaryotic hosts

What is the main distinguishing feature of a Euglenozoan

The main feature distinguishing them as a clade is a spiral or crystalline rod of unknown function inside their flagella

What two groups are make up the Euglenozoa

kinetoplastids and euglenoids

What two diseases are caused by Trypanosoma infections

Chagas and sleeping sickness

What 2 groups make up the Chromalveolates?

alveolates and stramenopiles

What distinguishes alveolates? What is that for

They have an apicoplast (a non-photosynthetic organelle) which plays a vital role in lipid metabolism. Several enzymes of fatty-acid synthesis are encoded in the nucleus but translocated into the apicoplast where fatty-acid synthesis occurs.

Dinoflagellates gain nutrition by either

Autotrophic and Mixotrophic

Dinoflagellates release toxins and blooms

Red tides

Malaria is caused by the apicomplexan

Plasmodium

About how many people contract malaria each year

350 -500 million

How many people die each year from malaria

1-3 million

T or F Humans have evolved in response to malaria

True

Where do merozoites develop in your body

Liver

Where do gameocytes develop in your body

red blood cells

Sporozoites develop within a vector

Oocyst, a cyst inside the gut of the mosquito and then in bursts releasing the infectious sporozoites into the mosquito for it to spread

Ciliates have cilia and two types of nuclei

The micronucleus and the macronucleus

How do paramecia become recombinant

They undergo conjugation and swap micronuclei

How do they reproduce?

Binary fission and conjugation

Stramenopiles are characterized by what type/s of flagella

One long hair flagellum and one hairless flagellum

Diatoms of skeletons made of hydrated

Silica

Golden algae get their color from yellow and brown

Carotenoids

Some golden algae are _______________ in addition to being autotrophic

Photosynthetic

An example of brown algae is

seaweed and kelp

Are brown algae (protists) multicellular

They are muticellular

How many feet can they grow in one day

2 feet per day