BIO Lesson 5,6, and 7

Why are Bacteria and Archaea placed in different domains than plants and animals?

Because Bacteria and Archaea are prokaryotes (lack a nucleus), while plants, animals, fungi, and protists are eukaryotes (have a nucleus).

Which domain contains all eukaryotic organisms?

Eukarya.

Which kingdoms belong to the domain Eukarya?

Animalia, Plantae, Fungi, and Protista.

What characteristic is used to separate the three domains of life?

Whether organisms are prokaryotic or eukaryotic.

Why is peptidoglycan important in bacteria?

It forms the bacterial cell wall and allows bacteria to be classified as Gram-positive or Gram-negative.

How do Gram-positive and Gram-negative bacteria differ?

Gram-positive bacteria have thick peptidoglycan walls that retain crystal violet stain, while Gram-negative bacteria have thin walls and an outer membrane and do not retain the stain.

Why are Gram-negative bacteria often harder to treat with antibiotics?

Their outer membrane makes them more resistant to certain antibiotics.

How do bacteria reproduce?

By binary fission, where one cell replicates its chromosome and divides into two daughter cells.

Besides mutation, how can bacteria increase genetic variation?

Through horizontal gene transfer (transformation, transduction, and conjugation).

Why can bacteria evolve quickly?

Because they reproduce rapidly and gain new genes through mutation and horizontal gene transfer.

Why aren't viruses considered living cells?

Because they are acellular and cannot reproduce independently.

What three main components can a virus contain?

Genetic material (DNA or RNA), a protein capsid, and sometimes a lipid envelope.

Why must viruses infect host cells?

They rely on the host's cellular machinery to make new viruses.

What happens during the lytic cycle?

The virus makes many new viruses and causes the host cell to lyse (burst).

What happens during the lysogenic cycle?

Viral DNA integrates into the host chromosome as a prophage and can remain dormant before entering the lytic cycle.

Which viral life cycle destroys the host cell immediately?

The lytic cycle.

Which viral life cycle can remain dormant for many generations?

The lysogenic cycle.

How do fungi obtain nutrients?

They secrete digestive enzymes into their surroundings and absorb the digested nutrients.

Why are fungi classified as heterotrophs?

Because they cannot make their own food and obtain nutrients from other sources.

What are hyphae and mycelium?

Hyphae are thread-like filaments; together they form a network called the mycelium.

What substance makes up fungal cell walls?

Chitin.

How can fungi reproduce?

Both sexually and asexually, often by producing spores.

Which kingdom is fungi more closely related to?

Animals.

Why is Protista considered a diverse kingdom?

Because it includes organisms that can be photosynthetic, heterotrophic, motile, unicellular, or colonial.

What types of organisms are included in Protista?

Algae, amoebae, and organisms that are both photosynthetic and motile.

Are most protists unicellular or multicellular?

Most are unicellular, although some form multicellular colonies.

Why are protists important evolutionarily?

They are considered ancestors of the multicellular kingdoms.

Why are protists important ecologically?

They are major components of aquatic food webs.

What two characteristics define plants?

They are multicellular photosynthetic eukaryotes with cellulose cell walls.

What is the main function of cellulose in plants?

It provides strength and support to plant cell walls.

What is alternation of generations?

A life cycle that alternates between a diploid sporophyte and a haploid gametophyte.

Which generation is dominant in flowering plants?

The sporophyte generation.

What happens to the gametophyte in flowering plants?

It is reduced to only a few cells within the flower.

Why are plants considered adapted to land?

They are primarily terrestrial, although many spend part of their life cycle in aquatic environments.

What characteristics distinguish animals from plants?

Animals lack cell walls, are heterotrophs, and are capable of movement during part of their life cycle.

How do animals obtain nutrients?

By ingesting food and digesting it internally.

What are the two main types of animal symmetry?

Radial symmetry and bilateral symmetry.

What is a coelom?

A fluid-filled body cavity found in many animals.

Why is embryonic development useful in classifying animals?

Different patterns of embryonic development help distinguish animal groups.

What major features are used to compare animal body plans?

Symmetry, presence or absence of a coelom, and embryonic development.