Chapter 1 prokaryotes

Prokaryotes

Bacteria and archaea; organisms that lack both membrane-bound organelles and a true nucleus

Nucleoid

The region in prokaryotic cells where the chromosome is located (not surrounded by a membrane)

Plasmids

Smaller rings of DNA found in some bacterial species in addition to the main chromosome

Peptidoglycan

A network of sugar polymers cross-linked by polypeptides that makes up bacterial cell walls

Gram Stain

A technique used to classify bacteria by cell wall composition

Gram-positive bacteria

Bacteria with simpler cell walls containing a large amount of peptidoglycan

Gram-negative bacteria

Bacteria with less peptidoglycan and an outer membrane that can be toxic

Endospores

Metabolically inactive structures that remain viable in harsh conditions for centuries

Fimbriae

Protein-containing appendages that allow prokaryotes to stick to their substrate or other individuals in a colony

Pili (sex pili)

Longer appendages that allow prokaryotes to exchange DNA; longer than fimbriae

Flagella

Movement

Taxis

Movement toward or away from a stimulus in a heterogeneous environment

Chemotaxis

Movement toward or away from a chemical stimulus

Bacilli

Rod-shaped prokaryotes (usually solitary, but some form chains)

Cocci

Spherical prokaryotes (can be solitary, in pairs, or forming clusters)

Spirilla

Spiral-shaped prokaryotes

Binary fission

The method of asexual reproduction in prokaryotes

Transformation

The uptake of exogenous DNA from the surrounding environment

Transduction

Virus-mediated transfer of DNA between bacteria

Conjugation

Transfer of DNA from one bacterium to another via cell-to-cell contact

Autotroph

Organisms that produce their own food using inorganic compounds

Photoautotroph

Uses light as energy source and CO₂/HCO₃⁻ as carbon source (e.g., cyanobacteria, plants)

Chemoautotroph

Uses inorganic chemicals as energy source and CO₂/HCO₃⁻ as carbon source

Heterotroph

Organisms that consume organic compounds for energy and/or carbon

Photoheterotroph

Uses light for energy and organic compounds for carbon source

Chemoheterotroph

Uses organic compounds for both energy and carbon source

Extremophiles

Organisms that live in extreme environments

Halophiles

Thrive in environments with high salt concentrations.

Thermophiles

Capable of growing and reproducing at extreme temperatures (140-180°F)

Methanogens

Live in swamps and marshes; produce methane as a waste product; strict anaerobes poisoned by O₂

Decomposers

Organisms that break down dead organisms and waste products

Bioremediation

The use of organisms (especially bacteria) to clean up environmental pollution

Symbiotic relationships

Close relationships between different organisms where both may benefit

Oxygen Using bacteria

Releasing energy from sugar using oxygen

Photosynthetic bacterium

Produce sugar from sunlight

Mitochondrion

Energy production in the eukaryotic cells

Which organelle is thought to have evolved from oxygen using bacteria

Mitochondrion

Why do chloroplast and mitochondrion have 2 membranes

One membrane came from the host cell and one from the engulfed bacterium

Chloroplast and mitochondria reproduce in a manner similar to bacteria

True

Sequence of endosymbiotic events

1. A large blob like cell engulf bacteria

2. Bacteria survive inside the host cell

3. Photosynthetic bacteria are incorporated

4. Complex eukaryotic cells evolve with mitochondria and choloroplast

Approximately when did the events described by the endosymbiotic theory begin?

2 billion years ago

The DNA found in chloroplast is circular, similar to bacterial DNA

True

What do fungi provide to trees in exchange for spurs

Nutrient from the soil

Path of sugar movement from tree to seedling

1.Sugar is produced in the leaves

2.Sugar moves down the trunk in the roots

3. Sugar enters fungal hyphae

4.Sugar reaches the roots of a neighboring seedling

What are mycorrhizae?

Sybiotic fungi associated with tree roots

Trees can use fungal network to warn neighbors about

Drought and insects attacks

Endosymbiosis refers to

One organism living inside another

The collection of fungal hyphae found underground is known as

Mycelium

Which organelle is though to have evolved from photosynthetic bacteria

Cholorplast

Mycorrhizal networks connect

Tree roots to different trees

An individual tree may be connected to many different fungal species

True

Which of the following is evidence supporting the endosymbiotic theory

Mitochondria contain their own DNA

Trees can distinguish whether signals come from their own species

True

The tread like structure that make up the fungal network are called

Hyphae

The Mycelium often spreads across a larger area than the tree root system

True

Ubiquitous

prokaryotes are everywhere!