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
Reproduce asexually
Transfer DNA
Become dormant

Explanation:

Binary fission is asexual reproduction producing two identical daughter cells.

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

Explanation:

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

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

Explanation:

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

Q. In the lag phase, bacteria:
Die
Divide rapidly
Form spores
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
Bacteria form spores only
All bacteria die

Explanation:

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

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

Explanation:

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

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

Explanation:

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

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

Explanation:

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

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

Explanation:

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

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

Explanation:

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

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

Explanation:

Obligate anaerobes cannot survive in the presence of oxygen.

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

Explanation:

Facultative anaerobes can grow with or without oxygen.

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

Explanation:

Aerobic respiration uses oxygen as the final electron acceptor.

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

Explanation:

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

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

Explanation:

Lactobacillus and Streptococcus species ferment milk into yogurt.

Q. Nitrogen-fixing bacteria convert:
Ammonia to N2
N2 to ammonia
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:
Human skin
Fish gills
Animal intestines
Legume roots

Explanation:

Rhizobium forms nodules on legume roots for nitrogen fixation.

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

Explanation:

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

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

Explanation:

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

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

Explanation:

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

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

Explanation:

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

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

Explanation:

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

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

Explanation:

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

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

Explanation:

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

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

Explanation:

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

Popular Topics

```