Question 1

Francesco Redi's experiment in the 17th century challenged the theory of spontaneous generation. Which of the following best describes the principle demonstrated by his experiment?

Accepted Answer

Living organisms arise only from pre-existing living organisms.

Question 2

Louis Pasteur's swan-neck flask experiment was crucial in disproving spontaneous generation. What was the key feature of his experiment that prevented microbial growth in the broth?

Accepted Answer

The flask's curved neck prevented airborne microorganisms from reaching the broth.

Question 3

Which of the following statements best describes the principle of aseptic technique in microbiology?

Accepted Answer

It is a set of practices to prevent contamination of cultures and sterile materials.

Question 4

Which scientist is credited with inventing the first practical microscope, enabling the observation of microorganisms?

Accepted Answer

Antonie van Leeuwenhoek

Question 5

Which of the following is NOT a benefit provided by microorganisms?

Accepted Answer

Causing all known diseases in humans

Question 6

Which of the following correctly lists the three domains of biological classification?

Accepted Answer

Bacteria, Archaea, Eukarya

Question 7

During Gram staining, what is the primary reason that Gram-positive bacteria retain the crystal violet stain?

Accepted Answer

They have a thick peptidoglycan layer that traps the stain.

Question 8

Acid-fast staining is particularly useful for identifying which type of microorganism?

Accepted Answer

Bacteria with mycolic acid in their cell walls, such as Mycobacterium species

Question 9

Archaea are most commonly found in which type of environment?

Accepted Answer

Extreme environments such as hot springs and salt lakes

Question 10

Which of the following structures is unique to bacterial cells and is responsible for maintaining cell shape and protecting against osmotic pressure?

Accepted Answer

Peptidoglycan cell wall

Question 11

Which of the following best describes the role of microflora in the human body?

Accepted Answer

They are beneficial, aiding in digestion and protecting against pathogens.

Question 12

Which of the following statements about viruses is correct?

Accepted Answer

Viruses are acellular, typically 20-300 nm in size, and require a host cell to replicate.

Question 13

Which of the following best describes a prion?

Accepted Answer

A misfolded protein that can cause neurodegenerative diseases

Question 14

Which type of chemical bond involves the sharing of electron pairs between atoms?

Accepted Answer

Covalent bond

Question 15

Which of the following best explains why water molecules are polar?

Accepted Answer

The oxygen atom has a higher electronegativity, creating a partial negative charge, while the hydrogen atoms have a partial positive charge.

Question 16

Which level of protein structure is characterized by the sequence of amino acids in a polypeptide chain?

Accepted Answer

Primary structure

Question 17

Protein denaturation can be caused by which of the following conditions?

Accepted Answer

Extreme pH or high temperature, which disrupts the protein's structure

Question 18

Enzymes lower the activation energy of a reaction. Which of the following equations best represents the effect of an enzyme on activation energy ($$E_a$$)?

Accepted Answer

$$E_{a,\,enzyme} \u003c E_{a,\,uncatalyzed}$$

Question 19

Which of the following best describes the formation of a peptide bond between two amino acids?

Accepted Answer

A dehydration synthesis reaction forms a covalent bond between the carboxyl group of one amino acid and the amino group of another.

Question 20

Which of the following statements about the fluid mosaic model of biological membranes is correct?

Accepted Answer

Membranes are dynamic, with proteins and lipids able to move laterally within the bilayer.

Question 21

A patient is given an intravenous solution that is hypertonic relative to their blood plasma. According to the principles of osmosis, what will happen to the patient's red blood cells?

Accepted Answer

Water will move out of the cells, causing them to shrink.

BIO 1550 Midterm 1 Study Guide: Foundations of Microbiology

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