microbiology exam #2-chapter 4

flagella

same purpose as bacterial flagella (motility), larger than bacteria flagella.

cilia

many hair-like appendages that cover the cell surface, offer motility, most commonly found in protozoans.

glycocalyx

a sugary outer coating that surrounds the cell membrane of many cells and bacteria, carbohydrate-rich, offer protection, adherance, biofilm formation

cell walls

a tough, rigid outer layer that surrounds the cell membrane of plants, fungi, algae, and bacteria, giving the cell extra support, shape, and protection.

• found in fungal microbes (not protozoans or helminths)

cytoplasmic membrane

phospholipid bilayer with associated proteins, regulates transport to bacteria

nucleus

holds the cell’s genome (DNA)

nuclear envelope

consists of two phospholipid bilayers

-a double-layered membrane that surrounds and protects a cell’s nucleus, acts as a barrier, separating the genetic material (DNA) from the rest of the cell.

nuclear pores

large, gate-like protein channels that span the nucleur membrane (envelope) of a cell

• transport RNA into the cytoplasm

ribosomes

a tiny cell structure that acts a factory to make proteins, 2 subunits (small and large) each made of rRNA and protein.

rough ER

an extension of the nuclear envelope surrounding the nucleus, it is “rough” because it is decorated with ribosomes.

cistern

a single ER protusion

lumen

the inner ER space separated from the cytoplasm

smooth ER

does not have associated ribosomes, site of synthesis of other macromolecules (lipids, carbohydrates).

golgi apparatus

a membrane-bound cell organelle that modifies, sorts, and packages proteins and lipids for delivery inside or outside the cell.

• consists of stack of membrane-vound compartments (with cisternae and lumen like the ER)

• in here proteins can be modified by additions of polysaccharides or lipids.

vesicles

a small, fluid-filled sac inside a living cell that is enclosed by a lipid membrane.

• carrying cargo molecules that bud off the ER and fuse with the golgi.

membrane trafficking

membrane-bound cargo goes from ER→ vesicle → golgi → vesicle which can go to..

lysosome

a tiny, membrane-wrapped part inside a cell that acts as the cell’s garbage disposal and recycling center.

• contains digestive enzymes for food or microbial invaders

vacuole

a membrane-bound sac inside a cell that acts as a storage area for water, nutrients, and waste.

cytoskeleton

a dynamic network of protein fibers inside a cell that gives it shape, offers structural support, and helps organize internal parts and movement.

actin filaments

• smallest protein fiber

• long, thin fibers

• maintain or alter local shape of the cytoplasmic membrane.

intermediate filaments

• thicker, rope-like

• anchor organelles in place, support organelle shape

microtubules

• largest protein fiber

• rigid, hollow tubes

• support whole cell shape

• transport highways

mitochondria

specialized structures found inside most cells that act as the “powerhouses” of the cell.

• all eukaryotic cells have many

aerobic respiration

a metabolic process where microorganisms use oxygen to break down nutrients (like glucose) and produce cellular energy (ATP), releasing carbon dioxide and water as waste.

mitochondria structure

1. outer membrane

2. inner membrane with folds called cristae

3. matrix within inner membrane that contains DNA and ribosomes

endosymbiosis

a biological relationship where one organism lives safely inside another organism.

• mitochondria and chloroplasts originated as free-living bacteria.

• the bacteria were engulfed by archaea-like ancestors of eukaryotes.

• host cell and bacterial parasite became interdependent over time.

microscopic fungi

generally exist as unicellular yeast, multicellular hyphae, or both (dimorphic).

mycosis (fungal infection)

• cannot be treated with antibacterial drugs

• typically affects immunocompromised individuals (e.g., people with cancer, AIDS, or other infections)

candida (candidiasis)

a leading cause of hospital-acquired infections.

• readily forms biofilms on medical devices like catheters.

• causes oral thrush, vaginal yeast infection, and cutaneous (skin) infections

protozoa

unicellular organisms that typically live outside a host in soil or aqueous environments.

cyclospora

infects the gastrointestinal tract, causing diarrhea, cramping, and fatigue. typically contracted by ingestion of contaminated water or produce, usually the result of fecal contamination.

helminths

multicellular worms with an entire organ system (sex organs, digestive tract, nervous and muscular systems).

helminths life cycle

1. fertilized egg (embryo)-shed by adults, often the infectious stage.

2. larval stage- larval development happens in the intermediate host.

3. adult stage- adulthood and mating happen in the definitive host.

pinworm

is an endemic helminth, is an obligate parasite

endemic

constantly present and naturally occurring within a specific geographic region or population

obligate parasite

a microorganism that cannot complete its life cycle or reproduce without a host organism.

infectious stage

the specific point in a pathogen’s life cycle or the course of a disease when the microorganism can successfully enter a host and cause an infection.

intermediate host

a temporary home where a parasite grows or reproduces asexually, but does not reach sexual maturity.

definitive host

also called a primary or final host, the organism in which a parasite grows into an adult and reproduces sexually

trophozoite

the active, motile, and feeding stage in the life cycle of certain protozoan parasites.

cysts

a protective, dormant stage of a microorganism, usually a bacterium or a protist, that helps it survive harsh environmental conditions.

cristae

the internal folds of the inner membrane inside a mitochondria.

cell wall composition

a tough inner layer of chitin, a polysaccharide chain consisting of N-acetyl glucosamine (NAG) monomers, an outer layer of glycoprotein and glycans (polysaccharides), followed by the glycocaclyx

chitin

a tough, natural sugar-based substance ( a polysaccharide) that provides structure, strength, and protection to the outer bodies of many animals and fungi.

evidence from the organelles

• single, circular chromosomes

• 70S (bacterial) ribosomes

• inner membranes resemble bacteria

• replication