Encodes for the Synthesis of Proteins Making New Viruses

VIRUS

Viral Structure:

1.  Nucleic Acid – DNA or RNA

·  encodes for the synthesis of proteins – making new viruses

2.  Capsid – protein coat surrounding nucleic acid; arrangement determines shape

·  protects the nucleic acid from digestive enzymes

·  contains special sites on its protein surface that allow the virus to attach and penetrate the host cell membrane

3.  Envelope – membrane surrounding capsid; NOT found in all viruses

Viral Replication – Capsid proteins on virus must match proteins on host cell.

Lytic cycle:

1.  virus attaches to host cell and injects viral DNA

2.  viral DNA uses host cell to create new viruses

3.  new viruses assemble –destroying host

Lysogenic cycle:

1.  virus attaches to host cell and injects viral DNA

2.  viral DNA integrates with host DNA creates provirus

3.  provirus is replicated along with host cell’s DNA

4.  virus may become active, switching to the lytic cycle, destroying host

o  Capsule – sticky protective layer that helps evade immune system and adhere to substances

o  Plasmids - accessory rings of DNA; can be used as vectors to carry foreign DNA into bacteria during genetic engineering procedures; can carry resistant genes

o  Endospore – thick internal wall that encloses the DNA; formed so bacteria can remain dormant during harsh environmental conditions.

o  Pili – allow bacteria to stick to surfaces

BACTERIAL Reproduction

1.  Binary fission – grows, replicates DNA, and divides; (asexual) – identical daughter cells

2.  Conjugation – pili form bridge, exchange DNA then split; (sexual) – diversifies population

3.  Transformation – bacteria taking up free pieces of DNA secreted by live bacteria or released by dead bacteria (sexual

BACTERIA – Good or Bad??

HELPFUL

·  decomposers – break down dead matter and recycle nutrients

·  nitrogen fixation – convert atmospheric nitrogen into soil nitrogen form

·  denitrification – convert excess soil nitrogen form into atmospheric nitrogen

·  photosynthesis – produces oxygen

·  human uses – food, digest petroleum, remove waste from H2O, synthesize drugs, bacterial enzymes used in genetic engineering

·  mutualistic relationships – both organisms benefit; ex. bacteria in human colon

HARMFUL

·  pathogens – cause disease by breaking down tissue or release toxins

BACTERIAL DISEASES
Strep throat / Syphilis
Tuberculosis / Lyme disease
Typhoid fever / Pneumonia
Tetanus / Gonorrhea

Controlling Bacteria –

1.  Sterilization – kill bacteria by heat or chemical action

·  Joseph Lister created the first antiseptic to disinfect instruments before surgery (1860).

2.  Refrigeration – bacteria grows at a slow rate in cold temperatures

Kingdom Protista

· Eukaryotes

· Mostly Uni- or Some Multicellular

· First Eukaryotic organism on Earth – appeared about 1.5 billion years ago

· Most live in watery habitats

ANIMAL-LIKE PROTIST (AKA: PROTOZOANS)

1.  Zooflagellates – use flagella

2.  Ciliates – use cilia

3.  Sarcodines – use pseudopods

4.  Sporozoans - parasitic

Protozoans -

· Unicellular

· Contractile vacuole – regulate water level

· Some live symbiotically within organisms – termite and zooflagellate

Disease / Protozoan
Malaria / Plasmodium species – carrier Anopheles mosquito
Giardiasis / Giardia species – carrier beavers; contaminated H2O
African Sleeping Sickness / Trypanosoma species – carrier Tsetse fly
Amebic Dysentery / Entamoeba species – contaminated H2O

PLANT-LIKE PROTIST (AKA: ALGAE)

Unicellular Algae -

1.  Euglena

2.  Dinoflagellates – algal blooms produce red tide

3.  Diatoms – cell walls rich in silicon

Multicellular Algae (aka: seaweed) – red, brown, green algae

FUNGI-LIKE PROTIST

· Multicellular, decomposers, produce spores, cell walls made of cellulose

· Includes slime molds & water molds

· Can be parasitic to plants - cause diseases such as blight, mildews

Kingdom Fungi

STRUCTURE –

·  Cell walls – contain chitin (carb)

·  Hyphae – thin filament

·  Mycelium – thick mass of hyphae

·  Fruiting bodies – reproductive structure

REPRODUCTION –

1.  Budding (asexual) – cells break off and grow new fungus

2.  Spores (asexual) – reproductive cell germinates into new fungus

3.  Sexual reproduction – Two mating types (+ & -) fuse nuclei then divide to produce haploid spores germinate into new fungus – produce genetically diverse spores

ECOLOGICAL ROLES –

1.  Saprophytes (decomposer) - absorb nutrients from dead organic matter.

2.  Parasites - absorb nutrients from body fluids of host organism causing plant and human diseases. (wheat rust, corn smuts, ringworm, yeast infection, thrush, etc)

3.  Used to produce medicines - penicillin, cortisone, antibiotics, vitamins

4.  Fermentation process to produce food – cheese, bread, etc.

5.  Mutualistic symbionts - both reciprocate with some beneficial function.

·  Mycorrhiza – special roots and fungi association (fungi increase absorption of water/minerals and fungi release enzymes to free nutrients in the soil & plant provides product from photosynthesis)

·  Lichen – fungus and green algae association (algae carries out photosynthesis, providing the fungus with a source of energy & fungus provides water, minerals and protect the algae)

KINGDOM PLANTAE

Characteristics of Plants –
Ø  cell walls – composed of cellulose
Ø  eukaryotes
Ø  autotroph
Ø  multicellular / Survival NEEDS:
Ø  sunlight
Ø  gas exchange
Ø  water & minerals
Ø  movement of water and nutrients

Adaptations – Evolutionary trend was to move from water to land, plants had to adapt……

Adaptations for attainment of resources

Land plants evolved methods to gain vital minerals from the soil. Green algae absorb nutrients they need directly from the water they live in. Land plants have to live without being suspended in water.

o  Roots developed as a structure that allowed plants to obtain minerals and water from the soil.

o  Some plants developed vascular tissue (xylem & phloem) that act as a transport system to bring water and other substances such as minerals up the plant body, allowing for increased plant size.

o  All plants contain lignin which binds to cellulose fibers to harden and strengthen the cell walls of plants to support growth.

o  Stems developed to store and transport water & nutrients.

o  Leaves are modified to maximize photosynthesis.

Adaptations to reduce water loss

Strategies to catch and retain water were vital for the survival of land plants. Once removed from moist, swampy areas, plants risk desiccation, or drying out.

o  To prevent desiccation, many plants developed a cuticle (a thick, waxy, watertight barrier) that covers the plant and prevents loss of moisture to the air.

o  The stomata are openings in the cuticle that allow for gas exchange and transpiration of water as the plant photosynthesis.

Adaptations for reproduction

The reproductive processes of the earliest plants to evolve from green algae still required an aquatic environment. Consequently, these primitive land plants could live only in highly moist, swampy areas. Plants evolved the ability to reproduce without water and began to populate drier environments.

o  The seed allowed safe dispersal of plant embryos by supplying it with nutrition and protection against hostile conditions. Seeds can remain dormant during unfavorable conditions.

o  Pollen grains containing the male gamete could be dispersed without water.

o  Flowers developed to attract pollinators and allow for greater dispersal of the pollen.

o  Fruits developed to protect the embryo and allow for greater dispersal of the plant.

Classification –

Nonvascular Plants: Bryophytes

·  nonvascular – instead uses rhizoids for movement of minerals & water via diffusion

·  produces spores (reproductive cells) – sperm require water for fertilization

·  habitats and size of plant is limited due to lack of vascular tissue

Vascular Plants: Tracheophytes

1.  Seedless vascular – reproduce with spores

2.  Gymnosperms – produces seeds in cones

3.  Angiosperms – produces flowers and seeds in fruit

TROPISMS ~plants adjust growth in response to environmental stimuli

o  Gravitropism or Geotropism– a growth response to gravitational forces

o  Phototropism— when stems/leaves adjust the direction of growth in response to light

o  Thigmotropism— plants shift a direction of growth as they contact objects

KINGDOM ANIMALIA

·  All animals are multicellular, eukaryotes and most have tissues, organs, and organ systems. They have no cell walls.

·  Animals are aerobic heterotrophs that ingest other organisms or withdraw nutrients from them.

·  Animals reproduce sexually; many also reproduce asexually. Their embryos usually develop through a series of stages.

·  Most animals are motile; they actively move about during all or part of the life cycle.

Animal Behaviors

Behavior – anything an organism does in response to a stimulus in its environment. Behaviors develop through interactions between genes and environmental inputs.

TYPES of behaviors:

1.  Innate Behavior – inherited behaviors (You are pre-wired to recognize stimuli before being born!)

·  Reflexes

·  Instincts

Ø territoriality

Ø aggression

Ø submission

Ø courtship

Ø behavioral cycles

2.  Learned Behavior – these behaviors are acquired or learned over time. Organisms can alter their behaviors as a result of experience.

·  Habituation – organism decreases or stops its response to a repetitive stimulus that neither rewards nor harms the animal

·  Imprinting – when an organism forms an attachment to an object or other organism after birth and copies it. For example, sparrows have an innate ability to recognize their own species’ song. To sing the complete version, the young birds must first hear it sung by the adults.

Adaptations for DEFENSE

·  Mechanical defense occurs when an animal uses its physical structures such as claws, tusks, stingers and shells. Other examples of mechanical defense include camouflage, cryptic coloration, disruptive coloration, counter shading, etc…

·  Chemical defense occurs when the animal produces stinging sensations, paralysis, poisoning, or just a bad taste.