General Biology 2-Chapter 24:Early Life and the Diversification of Prokaryote

4 main stages of the production of the first simple cells

• The nonliving formation of small organic molecules, such as amino acids and nitrogenous bases

• The joining of these small molecules into macromolecules, such as proteins and nucleic acids

• The packaging of these molecules into protocells, droplets with membranes that maintained an internal chemistry different from that of their surroundings

• The origin of self-replicating molecules that eventually made inheritance possible

What are Protocells and how are there appearance a key step in the origin of life

Nonliving building blocks of living cells can maintain internal chemistry due to membrane-like structure. Capable of simple reproduction and metabolism. Instead of molecules randomly mingling in an open solution, the separation of molecular systems by the membranes of protocells allows to concentration of organic molecules, helping for complex biochemical reactions inside the cell

What was the first likely genetic material

RNA, as it can store genetic information and catalyze chemical reactions.

What the two domain of life that are prokaryotes

Bacteria and Archaea

What are the most common shapes of prokaryotes

Spherical(Cocci),Rod-shaped (Bacilli), and Spiral (Spirilla)

What are the Functions of the cell walls

• Maintain cell shape

• Protect the cell

• Prevent the cell from bursting due to changes in osmotic pressure. (hypotonic environments)

What is the composition of Prokaryotes cell walls

• Bacteria-Peptidoglycan (sugar crosslinked by short polypeptides *proteins)

• Archaea-Polysaccharides and proteins

Of what is composed the prokaryote cell surface

Capsule, Fimbriae ,Endospores

Capsule

Dense, well-defined sticky layer that surrounds cell wall (made of protein or polysaccharide)

Capsule Function

• Adhesion

• Prevent desiccation (dry)

• Block host attack

Fimbriae

Hairlike appendage used for adhesion to objects.

Endospores

Multilayered protective structure that protects genetic material in lean time and extreme environment

Taxis

About ½ of prokaryote are capable of taxis ( directed movement toward or away from stimuli —> the thing it is attracted

Flagella

Appendage specialized for locomotion. Structure differ between Prokaryotes & eukaryotes

Autotroph

From inorganic carbon source

Heterotrophs

From organic carbon source

Phototrophs

Obtain energy from light

Chemotrophs

Obtain energy from chemicals

Nitrogen Fixation

The conversion of atmospheric nitrogen (N2) to ammonia (NH3). Biological nitrogen fixation is carried out by certain prokaryotes, some of which have mutualistic relationships with plants.

Symbiotic Nitrogen Fixation

The mutualistic relationship between nitrogen-fixing bacteria & plant

• Plants gain usable nitrogen

• Bacteria get carbon source

How is the prokaryote DNA structure

• Circular strand of DNA

• Located in nucleoid (region of cytoplasm - not enclosed by membrane

Plasmids

Small, self-replicating circular DNA separate from bacterial chromosome

Horizontal gene transfer

individuals are members of different species, this movement of genes from one organism

What are the 3 mechanism of genetic recombination

• Transformation

• Transduction

• Conjugation

Transformation

Uptake of DNA from the environment.DNA is released from other cells via lysis or secretion. Protein recognizes DNA from the environment and is inside the cell

Transduction

Viral transfer of DNA from one prokaryote to another

Conjugation

Transfer of genetic information via cell-to-cell contact. In bacteria, transfer is one-way street.

F-Factor

The ability to form pili and donate DNA during conjugation results from the presence of a particular piece of DNA

F plasmid

The F factor in its plasmid form. Cells containing the F plasmid, designated F+ cells, function as DNA donors during conjugation. Cells lacking the F factor, designated F−, function as DNA recipients during conjugation.

Extreme thermophiles

Thrive in very hot environment

Methanogens

An organism who produces methane as a waste product of the it obtain energy.Archaea

Extreme Thermophiles

Organisms who live in super hot environment

Bioremediation

The use of living organisms to remove pollutants for soil ,air ,water

What are two techniques that prokaryotes can grow in and degrade toxins

1. Fertilizing to enhance prokaryotic growth

2. Prokaryotic “Seeding”

Mutualism

A type of symbiotic relationship between two species where both benefit from the interaction.

Communalism

A type of symbiotic relationship between two species where one species benefits and the other is neither helped nor harmed.

Parasitism

A type of symbiotic relationship between two species where one species benefits at the expense of the other.