biology 20,23,28,29

What is the structure of a virus composed of?

An outer capsid made of protein subunits and a nucleic acid core made of either DNA or RNA.

What occurs during the lytic cycle of bacteriophages?

The release of new viruses lyses (ruptures) the host cell.

What characterizes the lysogenic cycle of bacteriophages?

Viral DNA inserts into the host cell chromosome, does not actively replicate, and may later trigger re-entry into the lytic cycle.

What is the life cycle of a retrovirus?

Viral RNA enters the cell, is used to make DNA, which inserts into the host chromosome; new viral RNA and capsids are produced by the host cell and released by budding.

Describe conjugation in gene transfer among bacteria.

Two bacteria are temporarily linked, allowing a donor cell to pass DNA to a recipient cell in the form of a plasmid.

What is transformation in bacterial gene transfer?

It occurs when a cell picks up free pieces of DNA from live or dead prokaryotes.

What is transduction in bacteria?

Bacteriophages carry portions of DNA from one bacterial cell to another.

What is the primary difference between autotrophs and heterotrophs?

Autotrophs make their own food, while heterotrophs rely on other organisms for food.

List and describe the three main shapes of bacteria.

Spirilli: spiral-shaped; Bacilli: rod-shaped; Cocci: round or spherical.

What is alternation of generations in plants?

Two multicellular individuals alternate, where a diploid sporophyte produces haploid spores that develop into haploid gametophytes, which then produce gametes to form a diploid zygote.

What are sepals in a complete flower?

They protect the bud before it opens and are collectively called the calyx.

What are petals in a complete flower?

Colored leaflets that constitute the corolla.

What is the function of stamens in a flower?

They are the male parts consisting of filaments and anthers where pollen is produced.

What are carpel parts in a flower?

The female parts including the stigma, stalk, and ovary.

What defines a complete flower?

A complete flower has all four parts: sepals, petals, stamens, and carpels.

List the characteristics of all plants.

Multicellular, eukaryotes, usually specialized tissues, photosynthesizers adapted to land, with an alternation-of-generations life cycle, and sessile.

What is the definition of fruit in the context of plants?

A covering for a seed derived from an ovary.

What is an archegonium?

The female gametangia that produces eggs.

What is an antheridium?

The male gametangia that produces sperm.

What plants are bryophytes

Mosses

What plants are seedless vascular plants

Ferns

What plants are gmnosperms

Cone bearing plants

What plants are angiosperms

Flowering plants

List the characteristics of all plants

Multicellular, eukaryotes, usually specialized tissues, photosynthesizers that became adapted to living on land, alternation-of-generation life cycle, sessile

Define Fruit

A covering got a seed derived from an ovary

What is asymmetry in animals?

No particular pattern to body shape.

What type of symmetry is characterized by body organized circularly?

Radial symmetry.

What type of symmetry do humans exhibit?

Bilateral symmetry.

What does the blastopore become in protostomes?

The mouth.

What are two key characteristics of deuterostomes?

Blastopore becomes anus; dorsal nerve cord.

What animals belong to the phylum Porifera?

Sponges.

What are the unique characteristics of cnidarians?

Radial symmetry, tissues, stinging tentacles.

What are the three main parts of mollusca?

Mantle, visceral mass, and foot.

What type of animals are found in the phylum Annelida?

Segmented worms, such as earthworms and leeches.

What is a unique characteristic of platyhelminthes?

Flat body and no body cavity.

What is a characteristic feature of nematodes?

Non-segmented body and some are parasites.

What defines the phylum Arthropoda?

Exoskeleton, jointed appendages, segmented body.

What symmetry do adult echinoderms exhibit?

Radial symmetry.

Which vertebrates are considered ectothermic?

Amphibians, reptiles, and fish.

What is the definition of endothermic?

An internal way to control body temperature.

Which vertebrates are endothermic?

Birds and mammals.

What is a monotreme?

A mammal that lays eggs, such as the duck-billed platypus.

What is a unique feature of marsupials?

They have pouches for immature young.

What are the main characteristics of all chordates?

Deuterostomes, postnatal tail, notochord, dorsal tubular nerve cord, pharyngeal pouches.

Radial Symmetry

Body organized circularly; similar to a wheel

Bilateral Symmetry

Definite Right and left halves

What are the differences between protstomes and deuterostomes

Protostomes: Blastopore becomes mouth; ventral nerve cord; spinal cleavage.

Deuterostomes: Blastopore becomes anus; dorsal nerve cord; radial cleavage

Porifera Phyllum

No symmetry, no tissue, filter food particles through water

What animals are in the Cnidaria phylum

Jellyfish, corals, sea anemones

Cnidaria phylum

Tissue, stinging tentacles, polyp has mouth pointed upward, Medusa has mouth pointed downward

What animals are in the mollusca phylum

Snails, clams, oysters, squid, octopus

What animals are in the annelida phylum

Segmented worms; earthworms, leeches

Annelida Phylum

Body segments repeated along length of body

What animals are in the platyhelminthes phylum

flatworms; planaria, tapeworms

Platyhelminthes Phylum

Flat body; no body cavity

What animals are in the nematoda phylum

Roundworms

Nematoda Phylum

Non-segmented body; some are parasites

What animals are in the Arthropoda phylum

Crustaceans; crabs, shrimp, lobster, crayfish

Arthropoda Phylum

Exoskeleton; jointed appendages, segmented body

What animals are in the echinodermata phylum

Starfish

Echinodermata Phylum

Deuterostomes, water vascular system, radial symmetry in adult, bilateral symmetry in larva