TTU MBIO 3401 Lab Exam 1 Review
Questions & Answers (Grade A+)
What can you not observe when heat fixing a smear prep? -
correct answer ✅-You will not be able to observe motility.
Pro of using a wet mount -
correct answer ✅You can observe motility, (think of our pond
scum experiment)
What does a negative stain mean? -
correct answer ✅a method of demonstrating the form of bacteria
present by surrounding them with a stain that they do not take up
as that they appear as sharply outlined unstained bright bodies on
a colored ground.
,TTU MBIO 3401 Lab Exam 1 Review
Questions & Answers (Grade A+)
why do we use steam for certain stains? How long is the steam step
for? -
correct answer ✅For Microbes (such as endospores) the think coat
is hard to penetrate. Steam is used to help di penetrate these
microbes, and after washing only the endospores will retain the
primary stain.
Steps of endospore stain -
correct answer ✅1. heat fix smear
, TTU MBIO 3401 Lab Exam 1 Review
Questions & Answers (Grade A+)
2. primary stain (malachite green) Steamed so that the dye
penetrates the endospores.
3. Drain and wash with water.
4. counter stain (safranin)
5. Drain and wash with water.
Vegetative cells: Red
Spores: Green
Steps of capsule stain -
correct answer ✅1. add a drop of Congo Red stain at one end of a
clean slide
Questions & Answers (Grade A+)
What can you not observe when heat fixing a smear prep? -
correct answer ✅-You will not be able to observe motility.
Pro of using a wet mount -
correct answer ✅You can observe motility, (think of our pond
scum experiment)
What does a negative stain mean? -
correct answer ✅a method of demonstrating the form of bacteria
present by surrounding them with a stain that they do not take up
as that they appear as sharply outlined unstained bright bodies on
a colored ground.
,TTU MBIO 3401 Lab Exam 1 Review
Questions & Answers (Grade A+)
why do we use steam for certain stains? How long is the steam step
for? -
correct answer ✅For Microbes (such as endospores) the think coat
is hard to penetrate. Steam is used to help di penetrate these
microbes, and after washing only the endospores will retain the
primary stain.
Steps of endospore stain -
correct answer ✅1. heat fix smear
, TTU MBIO 3401 Lab Exam 1 Review
Questions & Answers (Grade A+)
2. primary stain (malachite green) Steamed so that the dye
penetrates the endospores.
3. Drain and wash with water.
4. counter stain (safranin)
5. Drain and wash with water.
Vegetative cells: Red
Spores: Green
Steps of capsule stain -
correct answer ✅1. add a drop of Congo Red stain at one end of a
clean slide
