Diversity of living things Unit Test

Question 1

What is the endosymbiotic theory?

Answer 1

The theory that eukaryotic cells evolved from prokaryotic cells by engulfing other prokaryotes that became organelles.

Question 2

Which organelles support the endosymbiotic theory?

Answer 2

Mitochondria and chloroplasts.

Question 3

What evidence supports the endosymbiotic theory?

Answer 3

Mitochondria and chloroplasts have double membranes, their own DNA, ribosomes similar to bacteria, and replicate independently by binary fission.

Question 4

What are the main structural components of a virus?

Answer 4

Capsid (protein coat), genetic material (DNA or RNA), and sometimes a lipid envelope.

Question 5

What are the two main types of viral replication cycles?

Answer 5

Lytic cycle (virus replicates rapidly, killing host cell) and lysogenic cycle (virus DNA integrates into host genome and replicates with it).

Question 6

Why are viruses considered non-living?

Answer 6

They cannot reproduce on their own and do not carry out metabolism.

Question 7

How do viruses enter host cells?

Answer 7

They bind to specific receptors on the host cell surface.

Question 8

What are some diseases caused by viruses?

Answer 8

AIDS, COVID-19

Question 9

How do vaccines work?

Answer 9

They stimulate the immune system to produce memory cells without causing disease.

Question 10

What are the main shapes of bacteria?

Answer 10

Coccus (spherical), bacillus (rod-shaped), spirillum (spiral).

Question 11

What are the key differences between bacteria and archaea?

Answer 11

Archaea lack peptidoglycan in their cell walls and live in extreme environments.

Question 12

How do bacteria reproduce?

Answer 12

Binary fission

Question 13

What are extremophiles?

Answer 13

Archaea that thrive in extreme conditions, such as thermophiles (heat), halophiles (salt), and methanogens (methane).

Question 14

What are endospores?

Answer 14

Dormant, resistant bacterial cells that survive harsh conditions.

Question 15

What are protists?

Answer 15

A diverse group of eukaryotes that don’t fit into the plant, animal, or fungi kingdoms

Question 16

What are the three main groups of protists?

Answer 16

Animal-like (protozoa), plant-like (algae), fungus-like (slime molds and water molds)

Question 17

How do animal-like protists move?

Answer 17

Using cilia (Paramecium), flagella (Euglena), or pseudopodia (Amoeba).

Question 18

What is an example of a disease-causing protist?

Answer 18

malaria

Question 19

What are plant-like protists and their importance?

Answer 19

Algae (e.g., diatoms, red algae) perform photosynthesis and produce oxygen.

Question 20

What are the main structures of fungi?

Answer 20

Hyphae (thread-like filaments), mycelium (network of hyphae), and spores.

Question 21

What is the main cell wall component of fungi?

Answer 21

Chitin

Question 22

How do fungi reproduce?

Answer 22

Asexually or sexually

Question 23

What are the main types of fungi?

Answer 23

bread mold, mushrooms, yeasts

Question 24

What is mycorrhizae?

Answer 24

A mutualistic relationship between fungi and plant roots that helps plants absorb nutrients.

Question 25

Bacteria

Answer 25

Structure: Prokaryotic (no nucleus), unicellular, cell wall with peptidoglycan. Energy Acquisition: Autotrophic (photosynthetic like cyanobacteria or chemosynthetic) Heterotrophic (decomposers, pathogens, symbiotic bacteria) Reproduction: Asexual (binary fission) Genetic variation through conjugation, transformation, transduction Classification: Based on shape (coccus, bacillus, spirillum) Gram staining (Gram-positive has thick peptidoglycan; Gram-negative has thin peptidoglycan + outer membrane) Metabolism (aerobic vs. anaerobic)

Question 26

Archaea

Answer 26

Structure: Prokaryotic, unicellular, cell wall without peptidoglycan, different membrane lipids than bacteria. Energy Acquisition: Autotrophic (chemosynthesis) Heterotrophic (some absorb organic molecules) Reproduction: Asexual (binary fission, budding, fragmentation) Classification: Based on habitat: Methanogens (produce methane, live in anaerobic environments) Halophiles (thrive in salt) Thermophiles (live in extreme heat)

Question 27

Protista

Answer 27

Structure: Eukaryotic, mostly unicellular, some multicellular (algae). Energy Acquisition: Autotrophic (algae, Euglena) Heterotrophic (protozoa, slime molds, amoeba) Reproduction: Asexual (binary fission, budding) Sexual (conjugation in some, alternation of generations in algae) Classification: Animal-like (protozoa, heterotrophic, motile) Plant-like (algae, photosynthetic) Fungus-like (slime molds, absorb nutrients)

Question 28

Fungi

Answer 28

Structure: Eukaryotic, mostly multicellular (except yeast), cell wall made of chitin. Energy Acquisition: Heterotrophic (absorptive nutrition, decomposers, parasitic, mutualistic like mycorrhizae) Reproduction: Asexual (spores, budding in yeast) Sexual (spore formation from two mating types) Classification: Zygomycota (bread mold) Basidiomycota (mushrooms) Ascomycota (yeasts, truffles)

Question 29

Plantae

Answer 29

Structure: Eukaryotic, multicellular, cell wall made of cellulose, contains chloroplasts. Energy Acquisition: Autotrophic (photosynthesis, using chlorophyll a & b) Reproduction: Asexual (vegetative reproduction, spores in ferns, binary fission in algae) Sexual (pollen, seeds, flowers, alternation of generations in ferns/mosses) Classification: Nonvascular plants (bryophytes - mosses, liverworts) Vascular plants (ferns, gymnosperms, angiosperms)

Question 30

Animalia

Answer 30

Animalia Structure: Eukaryotic, multicellular, no cell walls, complex organ systems. Energy Acquisition: Heterotrophic (ingestion and internal digestion of food) Reproduction: Mostly sexual reproduction, some asexual (budding, fragmentation in sponges) Classification: Based on body symmetry, presence of a backbone, embryonic development: Invertebrates (sponges, mollusks, arthropods, etc.) Vertebrates (fish, amphibians, reptiles, birds, mammals)

Question 31

Xylem VS Phylum

Answer 31

Xylem is dead, only goes up, and is for water and minerals. Phloem is for sugars, goes up and down, and is alive

Question 32

Lytic Cycle

Answer 32

1. Attachment - Virus binds to specific receptors on host cell membrane. 2. Entry - Viral DNA or RNA is injected into the host cell. 3. Replication - Host cell machinery replicates viral genetic material and proteins. 4. Assembly - New viruses are assembled inside the host cell. 5. Lysis & Release Host cell bursts (lysis), releasing new viruses to infect other cells. 🔹 Fast process (happens in hours or days) 🔹 Destroys host cell

Question 33

Lysogenic Cycle

Answer 33

1. Attachment - Virus binds to host cell and injects genetic material. 2. Integration - Viral DNA integrates into host genome (now called a prophage). 3. Dormancy - Viral DNA stays dormant, replicating with host cell’s DNA for many generations. 4. Activation - Stress or environmental triggers activate the viral DNA. 5. Lytic Cycle Begins - Virus enters lytic cycle, destroying the host cell and releasing new viruses. 🔹 Long, hidden phase (can last years) 🔹 Does NOT destroy host cell immediately