Exam 2 BIO LEC Study Guide

List unique characteristics that distinguish the archaea from bacteria

bacteria contain peptoglycan in their walls while archea dont

3 Domanin Systems

Bacteria,Eukarya , Archaea

Distinguish between prokaryotic cells =1 and eukaryotic cells =2

1 : small, simple and lack a nucleus and membrane bound organelles ex: chloroplast, divide by binary fission , unicellular

2: larger, mor complex, has nucleus and membrane bound organelles, divide by mitosis & meiosis, multi & uni cellular

Distinguish among the 3 most common shapes of prokaryotes

Cocci - spherical, Bacilli - rods , Spirrilla - spiral

Structure & staining properties of Gram +

• thick peptoglycan layer

• No outer membrane

• Purple Bluish staining

Structure & staining properties of Gram -

• thin peptoglycan layer

• Has an outer layer

• Pinkish Red staining

Transformation

A cell takes up foreign "naked" DNA directly from its surrounding environment.

Often occurs after a nearby cell dies and lyses (bursts).

Transduction

Genetic material is moved from one bacterium to another by a bacteriophage (a virus that infects bacteria).

Conjugation

Direct transfer of DNA between two temporary joined cells.

Uses a hollow tube called a sex pilus; often involves the transfer of plasmids (e.g., the F factor).

Fredrick Griffith’s Experiment 1928

Living S→ mouse dies

Living R → mouse lives

Smooth Living S ( has been heat killed ) →mouse lives

Heat killed S + Living R → mouse dies

conclusion = A "transforming principle" from the dead S cells had permanently changed the live R cells into deadly S cells.

Avery, MacLeod, & McCarty (1944): Identifying the "Principle"

They treated heat-killed S cell extract with specific enzymes that destroyed different molecules.

• Destroyed Proteins (Protease)

  Transformation still occurred.

• Destroyed RNA (RNase)

  Transformation still occurred.

• Destroyed DNA (DNase)

  Transformation FAILED.’

conclusion = Since transformation only stopped when DNA was destroyed and identified DNA as the transforming agent

Describe the various modes of bacterial nutrition

• Autotrophs usuing light to make their own food

• Photoautotrophs usuing light to make glucose

• Chemoautotrophs use Inorganic compounds to create energy

Distinguish facultative anaerobes and obligate anaerobes compared to Obligate Aerobes

Essential; cannot grow without it.,

Aerobic respiration only.

Top of tube only (highest concentration).

Distinguish between obligate aerobes compared to Facultative Anaerobes

Not required, but they grow better with it.

Switch between aerobic respiration and fermentation.

Throughout tube, but heaviest at the top.

Distinguish between obligate aerobes, facultative anaerobes compared to

Obligate Anaerobes

Toxic; killed by atmospheric oxygen.

Endotoxins

harmful lipopolysaccharides part of the outer membrane of Gram-negative bacteria, released only when the cell dies.

Exotoxins

lipopolysaccharides (LPS) in Gram-negative cell walls released upon death, causing general symptoms like fever.

are soluble proteins secreted by living bacteria (mostly Gram-positive), which are highly potent, heat-labile,

Antibiotics and its function

are a diverse group of medications designed to target and inhibit the growth or kill bacteria. They function through various mechanisms, such as disrupting bacterial cell walls, inhibiting protein synthesis crucial for bacterial survival, or interfering with essential metabolic processes within bacteria.

Key characteristics of a Virus

are microscopic parasites that lack metabolic machinery (ribosomes, organelles), requiring host cellular machinery to replicate. Their structure consists of genetic material—either DNA or RNA—surrounded by a protein coat

How do you classify Viruses?

They are named by Type/Host/Location/Strain/Year

Virus Lytic Cycle

is a fast, active process where the virus immediately replicates, killing the host cell by lysis (bursting) to release new virions.

Virus Lysogenic Cycle

where viral DNA integrates into the host genome (prophage) and reproduces silently along with the host cell without killing it immediately

Protsists

are a diverse group of eukaryotic microorganisms, mostly unicellular, that exhibit three primary modes of nutrition

Protists Mode of Nutrition

photosynthesis (photoautotrophs), ingestion (holozoic/animal-like), and absorption (saprozoic/fungus-like). Many are mixotrophs,

Endosymbiosis

eukaryotic organelles—specifically mitochondria and chloroplasts—originated as independent prokaryotic cells (bacteria) that were engulfed by a larger host cell billions of years ago

Basic Characteristics of a Fungi

• Eukaryotic: They have a nucleus and membrane-bound organelles.

• Decomposers: Most play the role of breaking down dead organic matter in the ecosystem.

• Heterotrophs

• Body Structure: Most are multicellular and made of thread-like filaments called hyphae (the mass of hyphae is called mycelium).

• Reproduction: They use spores (can be sexual or asexual)

• Absorptive Nutrition: They secrete enzymes to digest food outside their bodies, then soak up the nutrients.

• Chitin Cell Walls: Their cell walls are made of chitin (not cellulose like plants).

Identify the basic Structure of a Fungi

Fruiting Body: The visible, reproductive part of the fungus

Mycelium (plural: mycelia): The dense, underground or internal network of hyphae that digests and absorbs nutrients from the substrate (food source).

Hyphae (singular: hypha): Thin, filament-like tubes that make up the main body of the fungus, often divided by cross-walls called septa.

Sepate Hyphae

divided into distinct cellular units by these walls and have pores allowing nutrient flow, while coenocytic hyphae facilitate rapid cytoplasmic streaming

Coenocytic Hyphae

lack these walls, forming a single, continuous, multinucleated cytoplasmic tube.

What is the function of haustoria? What types of fungi would have haustoria?

branched hyphal structures that penetrate host plant cell walls—but not the plasma membrane

feeding, metabolic manipulation of the host, and delivering effector proteins to suppress host defenses.

• Rust fungi

• Powdery mildews

• Downy mildews

• Other parasitic pathogens

The Fungal Cycle

It begins with haploid spores forming mycelia

then plasmogomy- the fusion of the Hyphae from 2 individuals (+ and -)

then karyogamy - two haploid nuclei fuse creating a diploid nucleus zygote

and meiosis restoring the haploid state and creating spores

Plasmogamy

fusion of the hyphae from 2 individuals ( + and - )

Dikaryon Formation

two haploid nuclei fuse creating a diploid nucleus zygote

Karyogamy

2 haploid nuclei fuse to create a diploid nucleus zygote

Sexual and Asexual spores for each phylum

Zygomycota: Reproduces via sexual zygospores in the zygosporrum

Ascomycota: ascospore in the ascucus in the ascocarp ( fruiting body)

Basidiomycota: basidio spore on basidum as a part of the basidiocarps ( fruiting body)

Most fungi have both sexual and asexual means of reproduction. What is the

advantage of each form?

asexual reproduction allows for rapid colonization in stable environments through efficient, high-volume cloning, while sexual reproduction introduces genetic variation, enabling adaptation to changing, stressful, or harsh environments.

Life cycle of a basidiomycete

life cycle, characterized by a long-lived stage where two distinct nuclei inhabit each cell. It begins with germinating haploid,

basidiospores that form primary mycelia, which merge through plasmogamy to create a dominant, dikaryotic secondary mycelium. This forms a basidiocarp (mushroom).

Lichen – what is it? What kind of relationship does it have and with who? What

is most common form of fungi?

is a composite organism formed from a mutualistic symbiotic relationship between a fungus (the mycobiont) and a photosynthetic partner (the photobiont), usually green algae or cyanobacteria. The fungus provides structure and protection, while the photobiont produces sugar through photosynthesis.

most common form : Ascomycota