Here is the completely updated `question.php`. I added the missing `$breadcrumbs` array and defined `$category_name` and `$topic_name` right before the header is included. This ensures that `header.php` generates the correct Breadcrumb Schema, page title, and meta description for single question pages. Replace your entire `question.php` with this: ```php Bacterial Growth & Metabolism Questions
TestMaster MCQs

Bacterial Growth & Metabolism Questions

Home Science Bacterial Growth & Metabolism
Q. Binary fission is the process by which bacteria:
Form spores
Become dormant
Transfer DNA
Reproduce asexually

Explanation:

Binary fission is asexual reproduction producing two identical daughter cells.

Q. The bacterial growth curve has how many phases?
Five
Four
Two
Three

Explanation:

The bacterial growth curve has four phases: lag, log (exponential), stationary, and death.

Q. During which phase do bacteria grow fastest?
Lag phase
Log (exponential) phase
Death phase
Stationary phase

Explanation:

Log (exponential) phase is when bacteria grow and divide at maximum rate.

Q. In the lag phase, bacteria:
Form spores
Divide rapidly
Die
Adapt without dividing

Explanation:

During lag phase, bacteria adapt to new conditions but do not divide.

Q. In the stationary phase:
Growth rate equals death rate
Bacteria divide fastest
All bacteria die
Bacteria form spores only

Explanation:

Stationary phase occurs when growth rate equals death rate, so total cell number stays constant.

Q. Generation time is:
Time to form spores
Time to transfer DNA
Time to become dormant
Time for population to double

Explanation:

Generation time is the time required for a bacterial population to double.

Q. Bacteria that grow best at human body temperature are:
Mesophiles
Thermophiles
Hyperthermophiles
Psychrophiles

Explanation:

Mesophiles grow best at moderate temperatures (20–45°C), like human body temperature.

Q. Psychrophiles grow best at:
Cold temperatures (<15°C)
Neutral pH
High temperatures (>60°C)
Body temperature

Explanation:

Psychrophiles thrive at cold temperatures (below 15°C).

Q. Thermophiles grow best at:
High temperatures (45–80°C)
Cold temperatures
Low pH
Body temperature

Explanation:

Thermophiles thrive at high temperatures (45–80°C).

Q. Bacteria that require oxygen for growth are called:
Obligate aerobes
Facultative anaerobes
Microaerophiles
Obligate anaerobes

Explanation:

Obligate aerobes require oxygen; obligate anaerobes are killed by oxygen.

Q. Bacteria killed by oxygen are:
Facultative anaerobes
Aerotolerant anaerobes
Obligate aerobes
Obligate anaerobes

Explanation:

Obligate anaerobes cannot survive in the presence of oxygen.

Q. Facultative anaerobes:
Require oxygen
Grow with or without oxygen
Are killed by oxygen
Require CO2

Explanation:

Facultative anaerobes can grow with or without oxygen.

Q. Bacterial metabolism that uses oxygen as final electron acceptor is:
Fermentation
Anaerobic respiration
Aerobic respiration
Photosynthesis

Explanation:

Aerobic respiration uses oxygen as the final electron acceptor.

Q. Fermentation in bacteria produces:
Only glucose
ATP without oxygen
Only oxygen
Only water

Explanation:

Fermentation produces ATP without oxygen, generating products like lactic acid, ethanol, or acetic acid.

Q. Which bacteria are used in yogurt production?
Clostridium and Bacillus
Lactobacillus and Streptococcus
Mycobacterium and Corynebacterium
E. coli and Salmonella

Explanation:

Lactobacillus and Streptococcus species ferment milk into yogurt.

Q. Nitrogen-fixing bacteria convert:
N2 to ammonia
Ammonia to N2
N2 to nitrate
Nitrate to N2

Explanation:

Nitrogen-fixing bacteria (e.g., Rhizobium) convert atmospheric N2 into ammonia.

Q. Rhizobium bacteria form symbiotic relationships with:
Legume roots
Animal intestines
Human skin
Fish gills

Explanation:

Rhizobium forms nodules on legume roots for nitrogen fixation.

Q. Which is a selective medium for Gram-negative bacteria?
Blood agar
Chocolate agar
Nutrient agar
MacConkey agar

Explanation:

MacConkey agar inhibits Gram-positive bacteria and allows Gram-negative growth.

Q. Blood agar is classified as:
Selective only
Enriched and differential
Minimal medium
Defined medium

Explanation:

Blood agar is an enriched, differential medium showing hemolysis patterns.

Q. Autoclaving uses which combination for sterilization?
UV light
Dry heat
Filtration
High-pressure steam

Explanation:

Autoclaving uses high-pressure steam (121°C, 15 psi) for 15–20 minutes.

Q. Pasteurization uses:
Controlled heating to kill pathogens
UV light
High-pressure steam
Radiation

Explanation:

Pasteurization heats liquids (e.g., milk) to kill pathogens without sterilizing.

Q. A bacterial colony arises from:
A single cell
A virus
A spore
Multiple cells

Explanation:

Each colony arises from a single bacterial cell (or CFU — colony-forming unit).

Q. CFU stands for:
Culture Fast Unit
Cellular Function Unit
Colony-Forming Unit
Cell Fusion Unit

Explanation:

CFU stands for Colony-Forming Unit, a measure of viable bacterial numbers.

Q. Viable plate count measures:
Living bacteria
Bacterial proteins
Total bacteria including dead
Bacterial DNA

Explanation:

Viable plate count measures living (viable) bacteria that can form colonies.

Q. Antibiotic resistance can spread between bacteria via:
Binary fission only
Spore formation
Horizontal gene transfer
Capsule formation

Explanation:

Resistance spreads via horizontal gene transfer: conjugation, transformation, and transduction.

Popular Topics

```