Part 1 Exam 1

You have discovered a new strain of pathogenic bacteria but still need to figure out how quickly it can grow and spread inside a host. In your experiment you start with 4 cells of the bacterium. (a) Assuming that 10 generations of the bacterium were produced at the end of 2 hours, what is the generation time (g) of your newly discovered bacteria? Hint 1: All 'times' in these calculations must be converted to minutes. Hint 2: You will need to use your answer in part 1 to figure out part 2!

12

You are measuring a petri dish of bacteria, and you estimate that when you start measuring there are 25 bacterial cells in the petri dish. You observe growth in the petri dish over 10 generations. Given this information, what is the total number of bacterial cells in the petri dish at the end of 10 generations?

25,600

If the doubling time for a bacterial species is 30 minutes and there are two cells at the start time, what is the population size after 2 hours? Hint: doubling time is the time taken for one cell to form 2 daughter cells.

32

You have discovered a new strain of pathogenic bacteria but still need to figure out how quickly it can grow and spread inside a host. In your experiment you start with 4 cells of the bacterium. (a) Assuming that 10 generations of the bacterium were produced at the end of 2 hours, what is the generation time (g) of your newly discovered bacteria? (b) What do you expect the size of your bacterial population to be after 3 hours? Hint 1: All 'times' in these calculations must be converted to minutes. Hint 2: You will need to use your answer in part 1 to figure out part 2!

4096

Match the bacterial cell structure to it's appropriate function: Pilus

Adhering to substrate (sometimes conjugation)

Which of these individuals is credited for the invention of the earliest known microscope?

Anthony van Leeuwenhoek

Coupled transporters that transport molecules in opposite directions of the membrane against their concentration gradient are known as

Antiport

Which of these additional features does the highly pathogenic gram-positive MRSA bacterium possess on top of its cell wall, making it difficult to penetrate?

Capsule with Slime Layer

What mechanism allows flagella to move towards or away from a specific chemical gradient?

Chemotaxis

Bacteria have -

Circular chromosomes in the cytoplasm

What is the primary stain used to distinguish between gram +ve and gram -ve bacteria?

Crystal Violet

Based on your understanding of membrane transport and concentration gradients, which of the following transport processes does not require use of energy?

Diffusion of substance from an area of high concentration outside the cell to an area of low concentration inside the cell

What does gram positive bacteria from in order to survive harsh environments?

Endospores

Match the organism to its correct cellular type: Protozoa

Eukaryote

True or False? Plasmids are a part of the chromosome

False

Bacteria that have an S-layer, and do not have an LPS layer are

Gram positive

What powers ABC transporters on the bacterial cell membrane?

Hydrolysis of ATP

How does penicillin interact with the bacterial cell wall?

It inhibits the transpeptidase enzyme

Which one of these are the amino acids of the Peptidoglycan layer?

L-Alanine

What are the 4 phases of bacterial growth in the correct order of progression?

Lag phase, Log phase, Stationary phase, Death phase

Which of these is not present in bacterial cells?

Mitochondria

Match the bacterial cell structure to it's appropriate function: Cell Membrane

Movement of substances into and out of the cell

Match the organism to its correct cellular type: Virus

Neither

What type of microbes cannot grow in the presence of oxygen?

Obligate anaerobes

Does gram negative or positive bacteria from endospores?

Positive

Match the organism to its correct cellular type: Archaea

Prokaryote

Match the organism to its correct cellular type: Bacteria

Prokaryote

Match the bacterial cell structure to it's appropriate function: Cell Wall

Protect the cytoplasm

Which of these statements does not describe a function of the bacterial cell membrane

Provides structure and rigidity to the cell

What is the property of light by which light microscopy works?

Refraction

What is the theory of Endosymbiosis?

The ancestor of a eukaryotic cell engulfed a prokaryote, which turned into mitochondria and chloroplasts

You are viewing a bacterial cell with an electron microscope and you see that it has formed a septum in the middle. What does this tell you about that cell?

The cell is dividing because the septum is an extension of the envelope that will divide a cell into two identical daughter cells

In Louis Pasteur's famous experiment disproving the theory of spontaneous generation, what did he successfully hypothesize would occur in the intact/unbroken S-shaped flask?

There would be no microbial growth in the intact flask

Which of these processes is responsible for building the peptide cross-bridges during Peptidoglycan Synthesis?

Transpeptidation

What is the third step in Koch's Postulates?

When the microbe is introduced into a healthy, susceptible host, the same disease occurs

A selective medium is a medium that

allows some bacteria to grow but not others

Which phase of bacterial growth best represents what is occurring when a pathogenic bacteria is initially introduced into a susceptible host?

lag phase

Match the Bacteria to its correct Shape- Bacillus

rod-shaped

Match the Bacteria to its correct Shape- coccus

round

Match the Bacteria to its correct Shape- Spirochete

spirally twisted

Archaea and Bacteria are most similar in terms of their ______________.

unicellular structure