4th Quarter Bio Exam

Characteristics of Eubacteria

Characteristics of Eubacteria

• Prokaryotes

• Unicellular 

• Cell wall with peptidoglycan

• Autotroph or Heterotroph

• Some motile: move with flagella or cilia

Some  non-motile: do not move

Gram Staining

How we can first group bacteria

Gram Positive

• Peptidoglycan is exposed to stain (thick) → stains purple

Gram Negative

• Peptidoglycan is not exposed to stain (thin)→ stains pink

Coccus

Round

Bacillus

Rods

Spirillum

Spirals

Diplo-

In pairs

Strepto-

In chains

Staphylo-

In clumbs

Reproduction of Bacteria

Through Binary fission or conjugation

Binary Fission

(Asexual) Cell divides in half producing 2 identical cells.

Conjugation

• Cells exchange genetic material by connecting to each other by a bridge (pili) to increase genetic diversity.

Importance of Bacteria

They are Decomposers, can do Nitrogen Fixation, and are important in Food Products.

How is Bacteria a Decomposer?

Break down organic compounds into simpler, smaller molecules.

How does Bacteria do Nitrogen Fixation?

Bacteria convert nitrogen gas (N₂) into ammonia (NH₃) for plants.

How is Bacteria Important in Food Products?

• Bacteria carry on fermentation.

  • Ex: yogurt, cheese, milk

Why is it important to control Bacterial growth?

Bacteria can be pathogenic (can cause diseases)

Why can bacteria cause diseases?

Caused by toxins from bacteria

Ways to Fight Bacteria

• Disinfectants

• Antibiotics

• Pasteurization

• Refrigeration

Disinfectants

Chemical solutions that kill pathogens

Antibiotics

Medicine used to kill bacteria

Pasteurization

(Sterilization by heat) Most bacteria die at high temperatures.

Refrigeration

Low temperatures prevent bacteria from reproducing. 

Viruses

non-living parasites

Where can viruses be found?

air, water, and soil

How Viruses Reproduce

need to infect a host cell and use their organelles

Why are Viruses considered to be non-living?

Because of how they reproduce

Viral Structure

• A core of genetic material

• A protein coat

What is the core of a virus made of?

DNA or RNA

Capsid

Protein coat that surrounds the genetic material of a virus

What do Capsids do?

Protect the genetic material and acts like a Trojan Horse with the help of the surface proteins to enter the cell

Retrovirus

starts with RNA

Bacteriophage

virus that infects bacteria

TRUE OR FALSE: Viruses are give scientific names

FALSE

How are viruses named?

• after the disease they cause (influenza virus) or 

• given a catalog number (H1N1 Virus)

What 2 cycles can a Virus go through to produce more viruses?

• Lysogenic Cycle

• Lytic Cycle

Initial Infection of a Virus

1. The virus attaches itself to the cell’s membrane

2. Virus inserts its genetic material into the cell and fuses with the host DNA

Lysogenic Infection

• (Sleeper Agent)

• Replication:

  • When the cell DNA replicates, the virus DNA replicates too.  

• Distribution:

  • After mitosis, the new cell receives a copy of the virus DNA

    • No new viruses are made unless “activated”.

TRUE OR FALSE: Lysogenic Infection does not produce infection/disease

TRUE

Lytic Infection

• (Active Agents)

• Replication and Assembly: 

  • The virus takes over the host cell and makes physical viruses

• Lysis and Release:

  • The newly assembled viruses burst out (lysis) of the cell membrane killing the host cell

Produces infection/disease – Not good

Viral Defense

Only defense we have against viruses are: Our Immune System and Vaccines

Immune System

a network of biological processes that protects an organism from diseases.

Vaccines

• A solution containing weakened or killed viruses 

• only work against viruses that have proteins that do not change

  • HIV, Cold, Influenza (Flu): Have capsids that mutate often - do not work

Antiviral Drugs

•  used to treat infections caused by viruses

• attack the enzymes (proteins) needed for viral replication.

  • Can be used to make vaccines

• do not cure infections, but stops the spread.

  • They reduce the rate of viral growth but will not inactivate the virus already present.

Protists

• 200,000 species come in different shapes, sizes, and colors

• All are eukaryotes – have a nucleus and membrane-bound organelles

Protozoans

• Animal-like Protists

• Unicellular – made up of one cell

• Heterotrophs – they eat other organisms or dead organic matter

• Classified by how they move

Zooflagellates

• Protozoan

• AKA The Motor Boats

• Move through their flagella

• Disease: Intestinal Disease

• Size: .6 – 5 um

Sarcodines

• Protozoan

• AKA The Blobs (Amoebas)

• Move through their pseudopods

• Disease: Some brain diseases

• Size: 2.3 – 3 um

Ciliates

• Protozoan

• AKA The hairy ones (paramecium)

• Move through their cilia

• Disease: Only one – Balantidium coli.

• Size: 10 um – 4mm

Sporozoans

• Protozoan

• AKA Non-motile (The parasite)

• Movement: N/A

• Disease: Malaria

• Size: 2-100 um

Plant-like Protists

• Photosynthetic – make their own food

• No roots, stems, or leaves

• Each has chlorophyll and other photosynthetic pigments

Euglenophytes

• Plant-like protist

• Aquatic, move like animals, can ingest food if light is not available

Diatoms

• Plant-like protist

• Contain silica (glass); photosynthetic pigment (carotenoids)

Chrysophytes

• Plant-like protists

• 2 flagella; golden brown; fresh water

Dinoflagellates

• (spinning ones)

• Plant-like protists

• 2 flagella; create toxins; bioluminescent

• ex: Red tides (algae blooms), Karenia brevis

Red Algae

• Multi-cellular Plant-like protist

• Red seaweed; marine

• Photosynthetic pigment; Chlorophyll a

• Ex: Seaweed used to make agar

Brown Algae

• Multi-cellular plant-like protist

• Brown with air bladders

• Photosynthetic pigment: Chlorophyll a & c

• Ex: Kelp

Green Algae

• Multi-cellular plant-like protist

• Green; live alone or in groups fresh water;  can be multicellular, unicellular or colonial

• Photosynthetic pigment: Chlorphyll a & b

• ex: sea lettuce, Chlamydomonas, Volvox

What is the life cycle of Green Algae?

Alteration of Generations

Fungus-like Protists

• All form delicate, netlike structures on the surface of their food source

• Obtain energy by decomposing organic material

Slime molds (Cellular)

• Fungus-like Protists

• Live in cool moist, shady places where they grow on damp, organic matter

• Can live separately at cells for feeding or in groups

• Movement: Creeping movement (2.5 cm/hour)

• Reproduction: Come together for reproduction

Slime Molds (Acellular)

• Fungus-like protist

• Live in cool moist, shady places where they grow on damp, organic matter

• Many nuclei; no cell walls or membranes

• Movement: Creeping movement (2.5 cm/hour)

• Reproduction: Form spores when surroundings dry up

Water Molds

• Fungus-like protist

• Type of Fungus: Mold and mildew

• Grows in moist places; feed on dead organisms; white fuzzy

• No movement

• Reproduction: Produce asexual motile spores

Fungi

eukaryotic heterotrophs; cell wall made of chitin (complex carbohydrate); digest food outside bodies, then absorb it

Fungi Classification

• based on structure and method of reproduction 

How many known species of fungi are there?

• 100,000+

  • Many have still not been identified

Hyphae

thin filaments that make up multicellular fungi

Mycelium

• many hyphae tangled together

  • Large surface area = max. food absorption

Fruiting body

reproductive portion of mycelium; above ground

Asexual reproduction for Fungi

fragmentation of hyphae or production of spores

Sporangia

spore producing structures

Sporangiophores

tips of specialized hyphae where sporangia are found

Most spores are…

wind pollinated or carried by animals; must land in favorable environment w/ proper food, moisture, and temp.

Sexual Reproduction for Fungi

fusion of hyphae forms diploid zygote; meiosis forms haploid spore

Zygomycota

• One of the four main groups of fungi

• Common molds

• often on bread, meat, cheese

Ascomycota

• One of the four main groups of fungi

• Sac fungi or yeast

• named ascus — spore containing reproductive structure

Basidiomycota

• One of the four main group of fungi

• Club fungi

• Basidium - specialized reproductive structure that resembles a club

Deutoromycota

• One of the four main groups of fungi

• Imperfect fungi

• difficult to classify; scientists have not been able to see its life cycle.  

  • Ex:  penicillin

Evolutionary History of Fungi

• Present since life moved onto land

• Oldest fossil = 460 myo

• May have helped plants colonize land by obtaining nutrients from the ground

Heterotrophic Fungi

Mycelia grow into tissues of other organisms, release digestive enzymes and absorb food

Saprobes in Fungi Relationships

most fungi are decomposers

Parasites in Fungi Relationships

some fungi harm other organisms

Symbionts in Fungi Relationships

some fungi live closely with other organisms

Fungi as Decomposers

Maintain equilibrium by recycling nutrients by decomposing organic material

Parasitic Fungi

• Can cause serious plant and animal diseases

  • Plant diseases:  corn smut, mildew, wheat rust

  • Human diseases: athlete’s foot/jock itch/ringworm, Candida (yeast infections)

  • Other animal diseases:  Cordyceps

Mutualistic Fungi

Lichens and Mycorrhizae

Lichens in Mutualistic Relationships

algae provide food, fungi provide nutrients

Mycorrhizae in mutualistic relationships

plants provide food, fungi increase root surface area

Lichens

fungi and green algae and/or cyanobacteria

Mycorrhizae

fungi and plant roots

Plant

• multicellular

• Eukaryotes

• Cell walls made of cellulose

• Carry out photosynthesis

• Develop multicellular embryo

• Are autotrophs some are saprobes and parasites

Plant Life Cycle

• Sporophyte (diploid)

• Gametophyte (haploid)

• Some have asexual reproduction (vegetative)

Algae

• First plants — plant kingdom ancestor

• Non vascular

• No seeds

• Live near water

• Oldest type of plant

• Seaweed, brown, green, red algae

Plant Characteristics

• Green in color (due to presence of chloroplasts)

• Square or brick-like cells (cellulose)

• Non-seed Producing and Seed Producing

• Also Nonvascula

Nonvascular

• plant with no water transport tubes & vascular plants

Bryophytes

• Seedless plants

• Non-vascular

• Mosses, Liverworts, & Hornworts

  • Tiny

  • Moist places

  • Carpet-like

  • Depend on water for reproduction

Ferns

• Seedless plants

• Vascular

• Ferns, Club Mosses, horsetails

  • Leaves, stems, roots

  • Popular houseplants

  • Spores (no seeds)

Gymnosperm

• Seed plant

• Conifers, gnetophytes, cycads, ginkgoes

• Seed plants - cone bearing

Angiosperm

• Seed plant

• Flowering and fruits

• Division Anthophyta

• Subdivided into two groups – Monocots and Dicots