Gen bio II Exam 2 outlines

What are protists?

Eukaryotic organisms that are not plants, animals, or fungi.

Why is the Kingdom Protista considered 'not a coherent group'?

It is no longer monophyletic and is not used as an official taxonomic name.

Name the four eukaryotic supergroups.

Excavata, SAR clade, Archaeplastida, Unikonta.

What does the name 'Archaeplastida' mean?

Ancestral plastid.

Which supergroup includes all photosynthetic protists?

Archaeplastida.

What unique characteristic do unikonts have?

Cells with only one flagella.

What does 'Excavata' refer to?

A diverse clade of eukaryotic organisms with an excavated feeding groove.

What are kinetoplastids?

A type of Excavata characterized by a kinetoplast, a mass of mitochondrial DNA.

What disease is caused by trypanosomes?

African trypanosomiasis, commonly called sleeping sickness.

How are trypanosomes transmitted?

By bites from the tsetse fly.

What are Variant Surface Glycoproteins (VSGs)?

Proteins on the surface of trypanosomes that help them evade the immune system.

What is the function of the apicoplast in apicomplexans?

It is essential for survival as it contains enzymes for producing fatty acids.

What does it mean if a protist is 'haploid dominant'?

The organism primarily exists in a haploid state, such as many fungi.

Define secondary endosymbiosis.

A process where a eukaryotic cell engulfs another eukaryotic cell that has a plastid.

What is a significant feature of dinoflagellates?

They can cause red tides and have diverse ecological roles, including being endosymbionts of coral.

How does coral bleaching occur?

Stress causes corals to expel their symbiotic dinoflagellates, leading to reduced energy and possible death.

What is the significance of the term 'Alveolate'?

A group of protists that include dinoflagellates, ciliates, and apicomplexans, characterized by their membrane-bound alveoli.

What type of organism commonly infects humans causing malaria?

Plasmodium, an apicomplexan.

What are the two life stages of Plasmodium in humans?

Sporozoites and merozoites.

In the context of fungi, what does 'heterokaryotic stage' refer to?

A stage where two genetically different haploid nuclei coexist in one hypha.

What are the two major forms of hyphae in fungi?

Coenocytic hyphae and septate hyphae.

How do fungi obtain nutrients?

By secreting enzymes to break down complex molecules.

What type of organism are yeasts classified as?

Single-celled fungi.

What is the ecological role of fungi as decomposers?

Breaking down dead organic material and recycling nutrients in ecosystems.

How do mycorrhizae benefit plants?

Enhance mineral and water absorption from the soil, forming a mutualistic relationship.

What gives rise to sexual spores in fungi?

Karyogamy followed by meiosis.

What is the role of telomeres in eukaryotic chromosomes?

Prevent loss of genetic information during DNA replication.

What does the enzyme telomerase do?

Adds telomere repeats to the ends of linear chromosomes.

What occurs during plasmogamy in fungal reproduction?

Fusing of the plasma membranes of haploid cells.

Describe the significance of the Sir2 gene.

It regulates lifespan and is one of the first 'aging genes' discovered.

What happens in asexual reproduction in fungi?

Production of specialized hyphae that form fruiting bodies and spores.

How do fungi exhibit asexual reproduction?

Through the formation of spores or buds that can grow into new individuals.

Define the function of arbuscules in mycorrhizal fungi.

They penetrate plant cell walls to facilitate nutrient exchange.

What is the relevance of studying yeast in aging research?

Yeast models allow researchers to discover genetic mechanisms that control aging.

How are telomeres related to cancer?

Cancer cells often express telomerase to maintain long telomeres for continued division.

What is the Hayflick limit?

The number of times a normal somatic cell can divide before cell division stops.

What are apoptosis and its significance?

The process of programmed cell death, crucial for maintaining cellular health.

What role do fungi play as parasites?

Some fungi form parasitic relationships with plants and animals, affecting their health.

What are endophytic fungi?

Fungi that live inside plant tissues, providing protection against pathogens.

What features distinguish multicellular fungi from animals?

Fungi have cell walls made of chitin, while animals have cell membranes; their development processes differ.

What is a fruiting body in fungi?

A reproductive structure that produces and disperses spores.

Name a common feature of all fungi.

They are heterotrophic and absorb nutrients by breaking down complex organic matter.

What can occur when a yeast gene is knocked out?

It can alter the cell’s phenotype and help identify the gene’s function.

What is a significant benefit of mycorrhizae for plants?

They help increase the surface area for nutrient absorption.

What is the main composition of fungal hyphae?

Chitin, a modified glucose polysaccharide.

What is the functional significance of septate hyphae?

It allows for the isolation of damaged tissue and more efficient flow of materials.

What defines the diploid stage of the fungal life cycle?

It involves karyogamy, where two haploid nuclei fuse.

Identify two examples of higher fungi.

Ascomycetes and Basidiomycetes.

What defines a protist?

An informal term for any eukaryotic organism that is not a plant, animal, or fungus.

What general characteristic differentiates SAR clade from other supergroups?

It is a diverse grouping based on molecular phylogenetics rather than morphology.

What key role do tetrahymena play in genetic research?

They serve as a model organism for studying telomeres and histone acetylation.

How are telomeres linked to aging in humans?

Short telomeres are associated with signs of aging and increased susceptibility to age-related diseases.

What does the term 'saprophytic' mean in relation to fungi?

Fungi that obtain nutrients by decomposing dead organic matter.

Describe a unique feature of cellular slime molds.

They can exhibit multicellular behavior under stress, forming aggregates that move together.

What is the main ecological importance of fungi?

They recycle nutrients by breaking down organic matter.

How is the structure of yeast beneficial for studies in genetics?

Yeast has a relatively simple genetic structure that facilitates manipulation and study.

Why are fungi important in human health?

They are sources of antibiotics, like penicillin, and can impact human health through mutualistic relationships.

What defines the lifecycle of chitridiomycetes?

They are mostly aquatic fungi that have flagellated spores.

What is a common misconception about aging?

That it is purely a passive process without genetic control.

How do fungi use enzymes in their feeding strategy?

By secreting enzymes that break down complex organic material into simpler compounds.

What is a potential downside to the relationship fungi can have with plants?

Fungi can become parasitic, stealing nutrients from host plants.

What defines a single-celled fungus?

Yeasts are classified as single-celled fungi.

How do fungi reproduce sexually?

Through the process of plasmogamy, karyogamy, and subsequent meiosis to produce spores.