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Which primary stain is applied to the fixed smear for 1–2 minutes during the Gram staining procedure?

• Safranin

• Crystal violet

• Gram’s iodine

• Decolorizing solution

Match each bacterial example to its shape.

• Coccus

• Escherichia coli

• Spirillum

• Spirillum volutans

• Bacillus

• Streptococcus thermophilus

Which statement best explains the survival value of an endospore?

• It increases the rate of binary fission under ideal conditions.

• It stores nutrients for long-term metabolism.

• It protects genetic material during unfavorable conditions, allowing later germination.

• It enables bacteria to photosynthesize when light is scarce.

Based on the observation notes, the common “clothespin” shape is associated with which morphology of Yersinia pestis cells?

• Coccobacillus

• Spiral

• Spherical

• Filamentous

Why is the genus Oscillatoria named as such?

• It oscillates in population size seasonally

• Its filaments exhibit characteristic oscillatory movements that may be visible in living cultures

• Its pigment oscillates between blue and green

• Its gene expression oscillates with the circadian rhythm

According to the instructions, what observable feature should be noted about the Anabaena strand?

• Its color patterning

• Its thin nature

• Presence of spores

• Its motility

Green algae are ancestral to the first land plants and possess which two chlorophyll types?

• c and d

• a and b

• b and c

• d and e

Which statement correctly contrasts brown algae and red algae as described?

• Both are unicellular and live only in freshwater.

• Red algae are typically found in colder waters than brown algae.

• Brown algae include kelps such as Laminaria and Fucus; red algae often occur in warmer seawater and may be complexly branched.

• Red algae have air vesicles for buoyancy; brown algae lack them.

• Brown algae cell walls are impregnated with calcium carbonate.

Some brown algae appear less green despite having chlorophyll because:

• They contain additional pigments that mask the green color of chlorophyll.

• They lack chlorophyll entirely.

• They live in environments with no light.

• Their chlorophyll is inactive.

Diatoms possess a yellow-brown pigment in addition to _______ that contributes to their color.

• chlorophyll

• hemoglobin

• melanin

• carotene