Concept explainers
Figure 13.6 Which of the following statements is true?
a. Gram-positive bacteria have a single cell wall formed from peptidoglycan.
b. Gram-positive bacteria have an outer membrane.
c. The cell wall of Gram-negative bacteria is thick, and the cell wall of Gram-positive bacteria is thin.
d. Gram-negative bacteria have a cell wall made of peptidoglycan, while Gram-positive bacteria have a cell wall made of phospholipids.

Introduction:
The gram stain test is used to differentiate between the gram-positive bacteria and gram-negative bacteria. The gram-positive bacteria retain the crystal violet stain of the gram stain test. While, the gram-negative bacteria, do not retain the crystal violet stain when discoloring agent is applied to it.
Answer to Problem 1ACQ
Correct answer:
Among the answers given, the correct answer is option (a) the cell wall of gram-positive bacteria us formed only of peptidoglycan.
Explanation of Solution
Explanation/justification for the correct answer:
Option (a) is the cell wall of gram-positive bacteria is formed only of peptidoglycan. The cell wall of gram-positive bacteria is thick as it contains many layers of peptidoglycan. Whereas, the cell wall of gram-negative bacteria is thin layered and is composed of peptidoglycan and other structures. Hence, this option is correct.
Explanation for incorrect answer:
Option (b) is gram-positive bacteria contains an outer membrane. The cell wall of gram-negative bacteria is surrounded by an outer membrane, while there is no outer membrane in gram-positive bacteria. Hence, this option is incorrect.
Option (c) is the cell wall of gram-negative bacteria is thick and that of gram-positive bacteria is thin. Many layers of peptidoglycan make the cell wall of gram-positive bacteria thick, while a single layer of peptidoglycan in gram-negative bacteria makes the cell wall thin. Hence, this option is incorrect.
Option (d) is the cell wall of gram-negative bacteria is made of peptidoglycan and that of gram-positive bacteria is made of phospholipids. The cell wall of gram-positive bacteria does not contain phospholipids. It is made up only of peptidoglycan. On the other hand, the cell wall of gram-negative bacteria contains other structures along with peptidoglycan. Hence, this option is incorrect.
The correct statement is that gram positive bacteria contains only of peptidoglycan. Hence, option (a) is correct.
Want to see more full solutions like this?
Chapter 13 Solutions
CONCEPTS OF BIOLOGY
Additional Science Textbook Solutions
Applications and Investigations in Earth Science (9th Edition)
Human Anatomy & Physiology (2nd Edition)
Campbell Biology (11th Edition)
Microbiology: An Introduction
Anatomy & Physiology (6th Edition)
Biology: Life on Earth (11th Edition)
- Ch.23 How is Salmonella able to cross from the intestines into the blood? A. it is so small that it can squeeze between intestinal cells B. it secretes a toxin that induces its uptake into intestinal epithelial cells C. it secretes enzymes that create perforations in the intestine D. it can get into the blood only if the bacteria are deposited directly there, that is, through a puncture — Which virus is associated with liver cancer? A. hepatitis A B. hepatitis B C. hepatitis C D. both hepatitis B and C — explain your answer thoroughlyarrow_forwardCh.21 What causes patients infected with the yellow fever virus to turn yellow (jaundice)? A. low blood pressure and anemia B. excess leukocytes C. alteration of skin pigments D. liver damage in final stage of disease — What is the advantage for malarial parasites to grow and replicate in red blood cells? A. able to spread quickly B. able to avoid immune detection C. low oxygen environment for growth D. cooler area of the body for growth — Which microbe does not live part of its lifecycle outside humans? A. Toxoplasma gondii B. Cytomegalovirus C. Francisella tularensis D. Plasmodium falciparum — explain your answer thoroughlyarrow_forwardCh.22 Streptococcus pneumoniae has a capsule to protect it from killing by alveolar macrophages, which kill bacteria by… A. cytokines B. antibodies C. complement D. phagocytosis — What fact about the influenza virus allows the dramatic antigenic shift that generates novel strains? A. very large size B. enveloped C. segmented genome D. over 100 genes — explain your answer thoroughlyarrow_forward
- What is this?arrow_forwardMolecular Biology A-C components of the question are corresponding to attached image labeled 1. D component of the question is corresponding to attached image labeled 2. For a eukaryotic mRNA, the sequences is as follows where AUGrepresents the start codon, the yellow is the Kozak sequence and (XXX) just represents any codonfor an amino acid (no stop codons here). G-cap and polyA tail are not shown A. How long is the peptide produced?B. What is the function (a sentence) of the UAA highlighted in blue?C. If the sequence highlighted in blue were changed from UAA to UAG, how would that affecttranslation? D. (1) The sequence highlighted in yellow above is moved to a new position indicated below. Howwould that affect translation? (2) How long would be the protein produced from this new mRNA? Thank youarrow_forwardMolecular Biology Question Explain why the cell doesn’t need 61 tRNAs (one for each codon). Please help. Thank youarrow_forward
- Molecular Biology You discover a disease causing mutation (indicated by the arrow) that alters splicing of its mRNA. This mutation (a base substitution in the splicing sequence) eliminates a 3’ splice site resulting in the inclusion of the second intron (I2) in the final mRNA. We are going to pretend that this intron is short having only 15 nucleotides (most introns are much longer so this is just to make things simple) with the following sequence shown below in bold. The ( ) indicate the reading frames in the exons; the included intron 2 sequences are in bold. A. Would you expected this change to be harmful? ExplainB. If you were to do gene therapy to fix this problem, briefly explain what type of gene therapy youwould use to correct this. Please help. Thank youarrow_forwardMolecular Biology Question Please help. Thank you Explain what is meant by the term “defective virus.” Explain how a defective virus is able to replicate.arrow_forwardMolecular Biology Explain why changing the codon GGG to GGA should not be harmful. Please help . Thank youarrow_forward
- Stage Percent Time in Hours Interphase .60 14.4 Prophase .20 4.8 Metaphase .10 2.4 Anaphase .06 1.44 Telophase .03 .72 Cytukinesis .01 .24 Can you summarize the results in the chart and explain which phases are faster and why the slower ones are slow?arrow_forwardCan you circle a cell in the different stages of mitosis? 1.prophase 2.metaphase 3.anaphase 4.telophase 5.cytokinesisarrow_forwardWhich microbe does not live part of its lifecycle outside humans? A. Toxoplasma gondii B. Cytomegalovirus C. Francisella tularensis D. Plasmodium falciparum explain your answer thoroughly.arrow_forward
- Comprehensive Medical Assisting: Administrative a...NursingISBN:9781305964792Author:Wilburta Q. Lindh, Carol D. Tamparo, Barbara M. Dahl, Julie Morris, Cindy CorreaPublisher:Cengage LearningConcepts of BiologyBiologyISBN:9781938168116Author:Samantha Fowler, Rebecca Roush, James WisePublisher:OpenStax College
- Biology Today and Tomorrow without Physiology (Mi...BiologyISBN:9781305117396Author:Cecie Starr, Christine Evers, Lisa StarrPublisher:Cengage LearningBiology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage LearningBiology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStax





