week 7

Nucleus

Stores most of the cell's DNA and controls gene expression.

Mitochondrion

Produces ATP through cellular respiration.

Cytoskeleton

Supports cell shape, organizes organelles, and enables movement and transport.

Endomembrane system

Network of membranes that modifies, packages, and transports proteins and lipids.

Rough endoplasmic reticulum

Synthesizes proteins for secretion, membranes, and certain organelles.

Smooth endoplasmic reticulum

Synthesizes lipids and detoxifies chemicals.

Golgi apparatus

Modifies, sorts, and packages proteins and lipids.

Lysosomes

Digest macromolecules, pathogens, and worn-out cell parts.

Ribosomes

Translate mRNA to build proteins.

Gene expression

Process of using genetic information to produce RNA or proteins.

Transcription

Uses DNA as a template to make RNA.

Translation

Ribosomes read mRNA to assemble amino acids into proteins.

Sexual reproduction

Combines genetic material through meiosis and fertilization.

Meiosis

Reduces chromosome number by half and creates genetic variation.

Fertilization

Fusion of two haploid gametes to form a diploid zygote.

Endosymbiosis

One organism lives inside another and may become an integrated part of its host.

Primary endosymbiosis

A eukaryotic ancestor engulfed a bacterium that evolved into a mitochondrion or a cyanobacterium that evolved into a plastid.

Secondary endosymbiosis

A eukaryotic cell engulfed another eukaryote that already contained a plastid.

Evidence for mitochondrial endosymbiosis

Mitochondria have circular DNA, bacterial-type ribosomes, divide by binary fission, have two membranes, and share ancestry with bacteria.

Evidence for plastid endosymbiosis

Plastids have their own DNA, bacterial-type ribosomes, and an evolutionary relationship to cyanobacteria.

Kingdom Protista

Obsolete because its members do not form one exclusive evolutionary clade.

Molecular evidence

DNA and RNA comparisons reveal evolutionary relationships and ancestry.

Morphological evidence

Physical structures and observable traits used to compare organisms.

Five traditional eukaryotic supergroups

Excavata, Chromalveolata, Rhizaria, Archaeplastida, and Unikonta

Excavata

Traditional protist grouping including diplomonads, parabasalids, and euglenozoans.

Diplomonads

Protists with two nuclei and reduced mitochondria called mitosomes.

Giardia duodenalis

Diplomonad that causes giardiasis, an intestinal infection that can cause diarrhea and cramps.

Giardiasis

Intestinal disease caused by Giardia duodenalis, often transmitted through contaminated food or water.

Parabasalids

Protists with modified mitochondria called hydrogenosomes.

Trichomonas vaginalis

Parabasalid that causes trichomoniasis, a sexually transmitted infection.

Trichomoniasis

Sexually transmitted infection of the urogenital tract caused by Trichomonas vaginalis.

Euglenozoans

Protists that include euglenids and kinetoplastids, often with flagella.

Euglena gracilis

Euglenid with a flagellum and chloroplasts that can photosynthesize.

Kinetoplastids

Protists with a kinetoplast, a DNA-containing region associated with a large mitochondrion.

Trypanosoma cruzi

Kinetoplastid parasite that causes Chagas disease.

Chagas disease

Disease caused by Trypanosoma cruzi that can damage the heart and digestive system.

Trypanosoma brucei

Kinetoplastid parasite that causes African sleeping sickness.

African sleeping sickness

Disease caused by Trypanosoma brucei and transmitted by tsetse flies

Human immune system

Defends against pathogens through innate defenses and adaptive responses involving B cells, T cells, and antibodies.

Antigenic variation

A pathogen changes its surface antigens to avoid recognition by existing antibodies.

Trypanosoma brucei immune evasion

Changes its variant surface glycoprotein coat so antibodies against earlier versions become less effective.

Karenia brevis

Marine dinoflagellate that produces brevetoxins and causes Florida red tides.

Oomycetes

Water molds that are stramenopiles

Apicomplexans

Mostly parasitic alveolates with structures that help them enter host cells.

Plasmodium

Apicomplexan parasite that causes malaria and requires a mosquito and a vertebrate host.

Malaria

Disease caused by Plasmodium species and transmitted by infected female Anopheles mosquitoes.

Pseudopodia

Cell extensions used for movement and capturing food.

Primary producer

Organism that produces organic matter from inorganic carbon using light or chemical energy.

Red tide

Harmful algal bloom that can discolor water and release toxins.

Karenia brevis toxins

dinoflagellate produces brevetoxins, which can poison fish, harm marine mammals, and cause respiratory irritation in humans exposed to sea spray during red tides.

Toxoplasmosis

Infection caused by Toxoplasma gondii that can be serious during pregnancy or in immunocompromised people.