BIOL 251 Chapter 4: Prokaryotic Cells, Chapter 5: Eukaryotic Cells, Chapter 7 Microbial Nutrition, Ecology, and Growth

What are the three basic shapes of cells?

Spherical, cubical, cylindrical

What are the two basic cell types?

Eukaryotic and Prokaryotic

What are the three basic shapes of cells?

Spherical, cubical, cylindrical

What are the two basic cell types?

Eukaryotic and Prokaryotic

What are the key characteristics of life?

Reproduction, heredity, growth, metabolism, movement, cell support, protection, and transport

What are the defining features of eukaryotic cells?

Contain membrane-bound organelles and a double-membrane nucleus with DNA

What are the defining features of prokaryotic cells?

No nucleus or membrane-bound organelles, DNA in nucleoid

What are the main components of a bacterial cell?

Cell membrane, cell wall, cytoplasm, ribosomes, chromosome (nucleoid)

What is the function of the cell membrane?

Regulates nutrient and waste transport, site of metabolic processes

What are the four types of flagellar arrangements?

Monotrichous, lophotrichous, amphitrichous, peritrichous

What is chemotaxis?

Bacterial movement in response to chemical stimuli

What is phototaxis?

Bacterial movement in response to light stimuli

What is the function of fimbriae?

Hairlike bristles that aid in adhesion to surfaces and cells

What is the function of pili?

Facilitates DNA transfer through conjugation

What is the glycocalyx?

An external coating made of sugars and proteins

What are the two types of glycocalyx?

Slime layer (loosely attached), Capsule (highly organized, tightly attached)

What is the function of the glycocalyx?

Protects from dehydration, aids in adhesion, and prevents immune system attacks

What are the two layers of the cell envelope?

Cell wall and cell membrane

What are the key differences between Gram-positive and Gram-negative bacteria?

Gram-positive: Thick peptidoglycan layer, teichoic acids, no outer membrane Gram-negative: Thin peptidoglycan layer, outer membrane with lipopolysaccharides

What is the function of peptidoglycan?

Provides structural support and prevents osmotic lysis

What color do Gram-positive and Gram-negative bacteria stain?

Gram-positive: Purple (retain crystal violet)

Gram-negative: Red (stain with safranin)

What is the purpose of Gram staining?

Differentiates bacteria for classification and medical diagnosis

What is the nucleoid?

Where genetic material is stored

What are plasmids?

Small, circular DNA molecules that carry non-essential genes

What are ribosomes?

Structures made of rRNA and protein, responsible for protein synthesis

How do prokaryotic ribosomes differ from eukaryotic ribosomes?

Prokaryotic ribosomes are smaller

What is an endospore?

A dormant, highly resistant bacterial structure for survival

What environmental conditions trigger sporulation?

Extreme heat, radiation, desiccation, and chemical exposure

What are two genera of bacteria known for producing endospores?

Bacillus and Clostridium

What are the three basic bacterial shapes?

Coccus (spherical), Bacillus (rod-shaped), Spirillum (spiral)

What are some common bacterial arrangements?

Cocci: Singles, pairs (diplococci), chains, clusters

Bacilli: Singles, chains (streptobacilli), palisades

What are the three main bacterial shapes?

Coccus (spherical), Bacillus (rod-shaped), Spirillum (spiral)

What are some variations of bacillus and spirillum shapes?

Coccobacillus: Very short and plump

Vibrio: Gently curved rod

Spirochete: Flexible, spring-like spiral

What is pleomorphism?

Variation in cell shape and size within a species

What determines bacterial arrangement?

The pattern of division and how cells remain attached after division

What are the different cocci arrangements?

Singles, Diplococci (pairs), Tetrads (groups of four), Clusters (Staphylococci), Chains (Streptococci), Cubical packets (Sarcina)

What are the different bacilli arrangements?

Diplobacilli (pairs), Chains (Streptobacilli), Palisades (side-by-side arrangement)

What are the two major domains of prokaryotes?

Archaea and Bacteria

What are some characteristics of Domain Archaea?

Adapted to extreme environments, Unique membrane lipids, No peptidoglycan in cell walls

What are the major bacterial phyla?

Phylum Proteobacteria: Gram-negative bacteria, Phylum Firmicutes: Mostly Gram-positive.

Phylum Actinobacteria: High G+C Gram-positive bacteria

How thick is the peptidoglycan layer in Gram-positive bacteria?

20-80 nm thick

What are the two acids found in the Gram-positive cell wall?

Teichoic acid and lipoteichoic acid

What is the function of teichoic acid and lipoteichoic acid?

Help maintain and enlarge the cell wall during division, Move cations (positively charged ions) across the cell envelope, Stimulate an immune response

What is the periplasmic space in Gram-positive bacteria?

A small space between the cell membrane and cell wall

Why is the thick peptidoglycan layer important?

Provides structural support and protects against lysis

What is the endosymbiotic theory?

It states that eukaryotic cells evolved from prokaryotic cells that engulfed other prokaryotic cells, forming symbiotic relationships.

How long ago did eukaryotic cells first appear?

Around 2 billion years ago.

According to the endosymbiotic theory, which organelles originated from prokaryotic cells?

Mitochondria and chloroplasts.

What evidence supports the endosymbiotic theory?

Mitochondria and chloroplasts have their own DNA, double membranes, and replicate independently like bacteria.

What are the four main groups of eukaryotic microorganisms?

Fungi, protozoa, algae, and parasitic worms (helminths).

What is the primary mode of nutrition for fungi?

Heterotrophic saprobes – they absorb nutrients from dead organic material.

What are mycoses?

Fungal infections in humans.

Name the disorder Trichophyton Mentagrophytes causes:

Athlete’s Foot/ Ringworm

Name the disorder(s) Candida albicans causes:

Candidiasis: Oral Thrush and vaginal yeast infection

Name the disorder Aspergillus causes:

Aspergilliosis (respiratory infection) and allergy to spores

Name the disorder Blastomyces causes:

Blastomycosis (respiratory infection) from fungal spores

Where does Blastomyces originate from and symptoms?

Ohio or Mississippi river valley causing flu like symptoms

What is Valley Fever (Coccidioidomycosis) and found in?

A respiratory fungal infection, found in the Southwestern U.S..

Valley Fever (Coccidioidomycosis) is caused by? and symptoms?

Coccidioides and spores. Causes flu like symptoms and rash

What is Histoplasmosis?

A respiratory infection from soil that contains large amounts of bird or bat droppings

Histoplasmosis is caused by

Histoplasma

Name the things that are good about Algae:

produce atmospheric O2 about 70%. base of aquatic food chain/web

Name the things that are BAD about Algae:

Red tide (Neurotixn)

What causes red tides and neurotoxic food poisoning?

Dinoflagellates

Where do most algae live?

Freshwater and marine environments.

What are dinoflagellates, and why are they dangerous?

They are algae that cause red tides, releasing neurotoxins that can cause paralytic shellfish poisoning (PSP).

Where is saxitoxin from red tide found?

West Coast of North America (dinoflagellates).

How do dinoflagellates in the surf zone affect humans?

Cause respiratory irritation when blown onto the beach.

Where is brevetoxin from red tide found?

Gulf Coast of Florida.

What are the two life cycle stages of protozoa?

Trophozoite: Active, feeding, motile stage Cyst: Dormant, resistant stage

What is the process of forming a cyst called?

Encystment.

What disease is caused by Plasmodium?

Malaria.

How is malaria transmitted?

By mosquitoes (insect vector).

Why are people with one copy of the sickle-cell gene resistant to malaria?

The moon shaped red blood cells make it difficult for Plasmodium to attach

What are the symptoms of malaria?

Fever, flu-like symptoms, anemia, jaundice, kidney failure, seizures, and coma if untreated.

What is the dormant form of protozoa called?

Cysts.

What are the two major types of helminths and what do they include?

Flatworms: flukes and tapeworms. Roundworms: hookworms and Ascaris.

What are trematodes (flukes)?

Flatworms with sucking mouthparts that infect the liver, lungs, or intestines.

How are trematodes transmitted?

By eating contaminated raw fish, crustaceans, or vegetables.

What are cestodes (tapeworms)?

Flatworms that live in the intestines and absorb nutrients from the host.

What are the two types of tapeworm infections?

Intestinal infection → Caused by ingesting larvae from contaminated food.

Invasive infection → Caused by tapeworm eggs migrating and forming cysts in organs.

What are symptoms of intestinal tapeworm infection?

Nausea, weakness, diarrhea, weight loss, and abdominal pain.

What happens if tapeworm larvae migrate to organs?

Organ failure and severe complications.

What is the most common roundworm infection?

Ascariasis (Ascaris lumbricoides).

_______(favorable) → ________ (unfavorable) = _________

Favorable: Trophozoite, Unfavorable: Cyst = Encystment

_______(unfavorable) → ________(favorable) = _______

Unfavorable: Cyst, Favorable: Trophozoite = Excystment

What is the most common roundworm infection?

Ascariasis (Ascaris lumbricoides).

How is Ascaris transmitted?

Ingestion of contaminated soil.

The dormant form of protozoa are called__

Cysts

Symptoms related to worm-load: Few worms leads to

no symptoms or on/off abdominal pain

Symptoms related to worm-load: Heavy infection with worms leads to

severe abdominal pain, vomiting, restlessness

Symptoms related to worm-load: Very severe leads to

complete blockage of the intestines

What is hookworm disease?

A roundworm infection where larvae penetrate the skin (bare feet in contaminated soil).

Hookworms are also known as

Ancylostoma

Where is hookworm disease most common?

Tropical and subtropical regions with poor sanitation.

What are three ways to prevent helminth infections?

Proper sanitatio: Treat sewage and avoid human feces as fertilizer.

Avoid contaminated water: Some larval forms can enter through the skin.

Cook food thoroughly: Kills larvae and eggs.

Eukaryotic microorganisms include

fungi, algae, protozoa, and helminths.

Fungi can be___________ or _________, causing __________.

saprotrophs (decomposers) or parasites, causing mycoses (fungal infections).

Protozoa have _____ life cycle stages and include _______, the cause of _______.

two; plasmodium; malaria.

________ are classified as flatworms (__________) or roundworms (___________).

helminths (worms); flukes & tapeworms; ascaris & hookworms

Prevention includes

good hygiene, clean water, and proper food handling.