Biology Chapter on Osmosis and Organisms

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What term describes organisms that thrive in high salt concentrations?

Osmophile

Isotonic

Halophile (correct)

Hypotonic

What occurs when a cell is placed in a hypertonic solution?

Cell remains unchanged

Cell swells due to excess water

Cell gains solute from the environment

Cell loses water and shrinks (correct)

Which of the following describes a solution that has the same osmotic pressure as another solution?

Plasmolysis

Hypertonic solution

Hypotonic solution

Isotonic solution (correct)

What is the process called when a cell loses water and becomes flaccid?

Plasmolysis Signup and view all the answers

Which term refers to organisms that thrive in environments with high concentrations of solutes other than salt?

Osmophile Signup and view all the answers

What occurs to a cell when it is placed in a hypotonic solution?

The cell gains water and may burst. Signup and view all the answers

What is the effect on a cell placed in a hypertonic solution?

The cell loses water and shrinks. Signup and view all the answers

What characterizes an isotonic solution in relation to a cell?

Water moves in and out of the cell at equal rates. Signup and view all the answers

How does a plant cell respond to being placed in a hypertonic solution?

It undergoes plasmolysis and may wilt. Signup and view all the answers

In what situation does a cell remain unchanged when placed in a solution?

When in an isotonic solution. Signup and view all the answers

What is an antiseptic?

A substance that kills or inhibits the growth of microorganisms on living tissue Signup and view all the answers

What is the purpose of the filter paper disk method in evaluating antiseptics?

To determine the effectiveness of the antiseptic against bacteria Signup and view all the answers

What is the filter paper disk method used for evaluating antiseptics?

Soaking filter paper disks in antiseptic and placing them on agar plates to observe zone of inhibition. Signup and view all the answers

What is the primary function of antiseptics?

To reduce or eliminate microbial load on living tissues Signup and view all the answers

Why must antiseptics be used at lower concentrations than disinfectants?

Higher concentrations can cause tissue damage Signup and view all the answers

How do disinfectants manage higher concentrations than antiseptics?

They are applied only to non-living surfaces Signup and view all the answers

Which of the following factors does NOT affect the efficacy of antiseptics and disinfectants?

Color of the solution Signup and view all the answers

What type of chemicals are commonly used as antiseptics?

Ethyl alcohol and halogens Signup and view all the answers

Which of the following is a characteristic of disinfectants?

They are aimed at eliminating contamination on non-living surfaces Signup and view all the answers

What directly impacts the stability and effectiveness of antiseptics and disinfectants?

Their chemical properties and structure Signup and view all the answers

Which of the following is NOT a mechanism through which antiseptics and disinfectants act?

Producing a toxic gas Signup and view all the answers

What are antibiotics primarily used for?

To treat bacterial infections Signup and view all the answers

Which method is commonly used for antibiotic sensitivity testing?

Kirby-Bauer disk diffusion method Signup and view all the answers

What is a crucial factor affecting the efficacy of antibiotics?

Concentration of the antibiotic Signup and view all the answers

How do antibiotics exert their action on bacterial cells?

By disrupting cell wall synthesis Signup and view all the answers

Which of the following statements about antibiotic sensitivity testing is false?

Sensitivity testing is only necessary for viral infections. Signup and view all the answers

What is the primary difference between antibiotics and antimicrobics?

Antibiotics are derived from natural sources, whereas antimicrobics can be synthetic or semi-synthetic. Signup and view all the answers

Which of the following describes a broad spectrum antibiotic?

An antibiotic that can kill both gram-positive and gram-negative bacteria. Signup and view all the answers

What characterizes a narrow spectrum antibiotic?

It specifically targets only a few types of bacteria. Signup and view all the answers

Which of the following statements is true regarding the effective concentration of antibiotics?

Effective concentration can vary depending on the type of pathogen treated. Signup and view all the answers

What is a characteristic property of broad spectrum antibiotics?

They can disrupt normal flora in the body. Signup and view all the answers

What is the primary role of enzymes in metabolism?

To catalyze biochemical reactions Signup and view all the answers

Which of the following best describes exoenzymes?

Enzymes secreted outside the cell to break down substrates Signup and view all the answers

What distinguishes oxidation from fermentation?

Fermentation produces energy without oxygen, while oxidation requires it Signup and view all the answers

What is the defining characteristic of endoenzymes?

They catalyze reactions inside the cell Signup and view all the answers

Which statement accurately defines fermentation?

A way to generate energy in the absence of oxygen Signup and view all the answers

Which of the following best defines metabolism?

The sum of all chemical reactions that occur within a living organism. Signup and view all the answers

What role does phenol red play in sugar fermentation tests?

It acts as a color indicator for pH changes. Signup and view all the answers

Which media are used in the mixed acid fermentation test and butanediol fermentation test?

MR-VP broth and phenol red broth. Signup and view all the answers

What does a positive result indicate in the catalase test?

The release of gas bubbles. Signup and view all the answers

Which of the following bacterial genera is known to be oxidase positive?

Pseudomonas. Signup and view all the answers

What is the significance of identifying a bacterium as catalase positive?

It confirms the bacterium can detoxify harmful hydrogen peroxide. Signup and view all the answers