Gram negative bacterial cell wall

In Gram-positive bacteria, peptidoglycan makes up as much as 90% of the thick cell wall enclosing the plasma membrane. See Page 2 for a diagram of the Gram-negative cell wall and a video on Gram Staining On adding a counterstain such as safranin or fuchsine after washing, Gram-negative bacteria are stained red or pink while Gram-positive bacteria retain their crystal violet dye. This is due to the difference in the structure of their bacterial cell wall. Gram-positive bacteria do not have an outer cell membrane found in Gram-negative bacteria

Bacterial Cell Wall Structure: Gram-positive & negative

Infectious bacteria are growing increasingly resistant to drugs, which is becoming a serious threat to public health worldwide. Bacteria can be classified based on various characteristics, such as by their shape or by the type of cell wall that they have: gram-positive or gram-negative. Many gram. Gram Negative Cell Walls. The cell walls of gram negative bacteria are more complex than that of gram positive bacteria, with more ingredients overall. They do contain peptidoglycan as well, although only a couple of layers, representing 5-10% of the total cell wall Gram-negative bacteria refers to a broad category of bacteria that are unable to retain the crystal violet dye owing to their distinct cell wall structure. Know more about such bacteria with respect to their cell wall structure, examples, infections and treatment options

The cell wall structure of Gram negative bacteria is more complex than that of Gram positive bacteria. Located between the plasma membrane and the thin peptidoglycan layer is a gel-like matrix called periplasmic space. Unlike in Gram positive bacteria, Gram negative bacteria have an outer membrane layer that is external to the peptidoglycan. It constitutes about 50% of dry weight of cell wall. It is the major surface antigen of gram positive bacteria. 3. Outer membrane . Figure: Outer membrane in cell wall of gram negative bacteria. It is an additional layer present in gram negative bacteria. It is composed of lipid bilayer, protein and lipopolysaccharide (LPS) layer; Function of. The gram-positive bacteria's cell wall have muramic acid, which around 16-20% of the total dry weight of cell and even the cell wall show resistance to alkali, also contains the teichoic acid, whereas the gram negative bacteria's cell wall is sensitive to alkali, muramic acid is only 2-5% of the total dry weight and teichoic acid is absent.

Both gram-positive and gram-negative bacteria commonly have a surface layer called an S-layer. In gram-positive bacteria, the S-layer is attached to the peptidoglycan layer. Gram-negative bacteria's S-layer is attached directly to the outer membrane. Specific to gram-positive bacteria is the presence of teichoic acids in the cell wall. Some of. The cell walls of Gram-negative bacteria are more chemically complex, thinner and less compact. Peptidoglycan makes up only 5 - 20% of the cell wall, and is not the outermost layer. The peptidoglycan of Gram-negative bacteria is located between the plasma membrane and an outer, LPS membrane Peptidoglycan (murein) is the principal component of the bacterial cell wall and it is responsible for the shape and extreme tough nature of the cell wall. Based on the characteristics of the cell wall, the bacterial cells are classified into Gram Positive and Gram Negative, primarily based on the classical staining reaction called Gram Staining The cell wall of gram-negative bacteria is thin (approximately only 10 nanometers in thickness), and is typically comprised of only two to five layers of peptidoglycan, depending on the growth stage. In gram-positive bacteria, the cell wall is much thicker (20 to 40 nanometers thick)

Gram-positive vs Gram-negative Bacteria - Difference and

  1. This video discusses the cell wall structures of both Gram + and - bacteria with practice questions
  2. It is in fact an integral compartment of the gram-negative cell wall . Together the plasma membrane and the cell wall (outer membrane, peptidoglycan layer, and periplasm) constitute the gram-negative envelope (5, 9). Our entire perception of gram-positive and gram-negative walls ultimately relies on the response of bacteria to Gram staining
  3. Skills to Develop. State what color Gram-negative bacteria stain after the Gram stain procedure. Describe the composition of a Gram-negative cell wall and indicate the possible beneficial functions to the bacterium of peptidoglycan, the outer membrane, lipopolysaccharides, porins, and surface proteins
  4. Cell Wall and Cell Envelope Structure of Gram Negative Bacteria. The cell wall of gram negative bacteria is 5-10 nm thick, containing a monolayer of peptidoglycan. The peptidoglycan backbone is partially cross-linked in gram negative bacteria. Teichoic acid is not found in the cell wall of gram negative bacteria
  5. The walls of gram-positive bacteria have simpler chemical structures compared to gram-negative bacteria. Gram-positive cell wall. Gram-positive cell wall is thick measuring about 15-80 nm and more homogenous compared to gram-negative cell wall. This cell wall consists of large amount of peptidoglycan arranged in several layers
  6. In the Gram-negative Bacteria the cell wall is relatively thin (10 nanometers) and is composed of a single layer of peptidoglycan surrounded by an outer membrane. P eptidoglycan structure and arrangement in E. coli is representative of all Enterobacteriaceae , as well as many other Gram-negative bacteria
  7. Gram Staining technique is the most important and widely used microbiological differential staining technique. It categorizes bacteria according to their Gram character (Gram positive or Gram negative)

Wall-Less Forms: Two groups of bacteria devoid of cell wall peptidoglycans are the Mycoplasma species, which possess a surface membrane structure, and the L-forms that arise from either Gram-positive or Gram-negative bacterial cells that have lost their ability to produce the peptidoglycan structures A patient is infected with Gram-negative bacteria and is experiencing only mild symptoms. When the patient is given an antibiotic causing lysis of the bacterial cells, he suddenly experiences an increase in inflammation and fever, as well as the formation of blood clots 10 Differences between Cell wall of Gram positive and Gram negative Bacteria Gram staining is a special technique which is used to stain bacteria. This technique was developed by Christian Gram in 1884

Cell envelope of Gram-negative Bacteria The Gram negative cell envelope contains an additional outer membrane composed by phospholipids and lipopolysaccharides which face the external environment. The highly charged nature of lipopolysaccharides confer an overall negative charge to the Gram negative cell wall Most bacteria can be placed into one of three groups based on their color after specific staining procedures are performed: Gram-positive, Gram-negative, or acid-fast. These staining reactions are due to fundamental differences in the bacterial cell wall. Gram-positive bacteria stain purple after Gram staining while Gram-negative bacteria stain. The key difference between gram positive and gram negative cell wall is that the gram positive cell wall has a thick peptidoglycan layer with teichoic acids while gram negative cell wall has a thin peptidoglycan layer surrounded by an outer membrane To better understand the slippery distinctions between Gram-positive and Gram-negative bacteria; let's take a brief look at the definitions with their examples. Gram Positive Bacteria. In most of the gram-positive bacteria, the cell wall consists of many layers of peptidoglycan which forms a thick and rigid structure Gram positive bacteria have a thicker cell wall while Gram negative bacteria have a thinner cell wall. The peptidoglycan content in cell wall of Gram positive bacteria varies from 60-90 % while in Gram negative bacteria the same varies from 10-40%

Revealing how Gram-Negative Bacteria Build Cell Walls

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts Crystal violet dye forms a complex with iodine, which becomes trapped in the peptidoglycan cell wall structure of bacterial cells with thick cell walls (gram-positive bacteria). Safranin is the counterstain, and appears in bacteria with thin cell walls that do not hold the crystal violet-iodine staining (gram-negative bacteria) LPS Membrane: In gram-negative bacteria, peptidoglycan is not the outermost layer of the cell wall.Gram- cells have an additional, external membrane, similar to the plasma membrane, but less permeable and composed of lipopolysaccharides (LPS); a harmful substance classified as an endotoxin Even though gram-positive bacteria has a thick cell wall than the gram-negative bacteria, then why only gram-negative bacteria are more resistant to antibiotics...

Gram-positive bacteria have a greater volume of peptidoglycan (a polymer of amino acids and sugars that create the cell wall of all bacteria in their cell membranes), which is what makes the thick outer covering. This thick outer covering, or membrane, is capable of absorbing a lot of foreign material. Image: Structure of gram-negative cell wall Using the Gram staining process, Gram positive bacteria results in a purple hue, while Gram negative results in pink. All bacteria contain a layer of peptidoglycan in their cell wall, but the difference between Gram positive and Gram negative bacteria is that Gram negative has a thin layer of peptidoglycan located between two lipid layers

Bacteria: Cell Walls Microbiology - Open Oregon Stat

Gram-negative Bacteria - BiologyWis

Gram-positive cell wall. The Gram-positive cell wall is thick (15-80 nm) and more homogenous than that of the thin (2 nm) Gram-negative cell wall. The Gram-positive cell wall contains large amount of peptidoglycan present in several layers that constitutes about 40-80% of dry weight of the cell wall Gram negative bacteria cell wall is composed of a thin peptidoglycan layer and an outer membrane made of lipopolysaccharide (LPS). Plant cell walls, however, are made of cellulose Gram-negative bacteria have a cell wall that is thin and does not accept the stain, making it appear red or pink. Gram staining is used for differentiation gram-positive from gram-negative bacteria based on the characteristic of their cell wall The key difference between gram positive and gram negative bacteria is that gram positive bacteria have a thick peptidoglycan layer, hence appear in purple colour while gram negative bacteria have a thin peptidoglycan layer, hence appear in pink colour at the end of the gram staining technique

An extended-spectrum antibiotic is one that, as a result of chemical modification, affects additional types of bacteria, usually those that are gram-negative. (The terms gram-positive and gram-negative are used to distinguish between bacteria that have cell walls consisting of a thick meshwork o The major difference between the two groups of bacteria is the thickness of the cell wall and the presence of an outer membrane in Gram negative bacteria only. The bacterial cell wall ranges from. Gram-positive bacteria have a very thick cell wall made of a protein called peptidoglycan. These bacteria retain the crystal violet dye (one of the 2 main chemicals used for gram staining). Whereas, gram-negative bacteria have a very thin peptidoglycan layer that is sandwiched between an inner cell membrane and a bacterial outer membrane Gram Positive Bacteria: Gram Negative Bacteria: The bacteria remain coloured with Gram staining even after washing with alcohol or acetone. The bacteria do not retain the stain when washed with alcohol or acetone. Outer membrane is absent. Outer membrane is present. Cell wall is 20-30 nm thick. Cell wall is 8-12 nm thick. The wall is smoot Difference Between Gram Positive and Gram Negative Cell Wall Hans Christian Gram a Danish scientist developed a technique known as Gram staining in 1884; it is used to stain bacteria. The solution used to stain the bacteria, Gram stain, is a weak alkaline solution of gentian violet or crystal violet

Video: Gram Positive vs. Gram Negative Bacteria - thoughtco.co

Bacterial Cell wall: Structure, Composition and Types

The cell wall of Gram negative bacteria is more complex than those of Gram positive bacteria. Gram negative bacteria contain an extra layer of cells called outer membrane or LPS layer which surrounds the thin peptidoglycan layer. LPS layer is absent in Gram positive bacteria. Some of the main differences between Gram positive bacteria and Gram. Lipopolysaccharide (LPS) layer also called the outer membrane is the outer most layer present in the cell wall of gram negative bacteria. It is a characteristics feature of Gram negative bacteria. As in peptidoglycan biosynthesis, LPS molecules are assembled at the plasma or inner membrane. Cell wall of Gram negative bacteri Utilized 3DC.io on my iPad 12.9 to design the Gram-Negative Bacterial Cell Wall. It is just a representation. Adding too much detail will not meet my didactic experience objective. I would suggest using augmented reality to close the loop of student learning Although their cell walls are similar in chemical composition, the cell wall of a gram-negative bacteria is a thin layer sandwiched between an outer lipid-containing cell envelope and the inner.

Difference Between Gram Positive and Gram Negative Bacteri

Bacterial cell walls are made of peptidoglycan (also called murein). on the basis of their bacterial cell wall the bacteria are of two types. The first one is gram positive bacteria and second one is gram negative bacteria The bacterial cell wall has to be strong to prevent cell lysis but also porous to allow transport across the cell membrane. In this lesson, we will examine the structure of the bacterial cell wall. In 1884, Gram published his findings that bacterial cells would take up and retain specific stains. Gram-positive bacteria retained the color of Gentian violet; gram-negative bacteria bleached. Another pathologist, Carl Weigert, later discovered that gram-negative bacteria retained stain from safranin. Gram negative cells also take up crystal violet, and the iodine forms a crystal violet-iodine complex in the cells as it did in the gram positive cells. However, the cell walls of gram negative organisms do not retain this complex when decolorized. Peptidoglycans are present in the cell walls of gram negative organisms, but they only comprise. Gram-positive bacteria appear violet because they have thick cell walls that trap the crystal violet-iodine complex. The thin cell walls of gram-negative bacteria cannot hold the violet-iodine complex, but they can hold safranin. This makes gram-negative bacteria appear red under Gram staining

Gram-negative bacterial cell wall is different from gram-negative bacterial cell wall by having an outer membrane that covers the peptidoglycan layer. The peptidoglycan layers are attached to the outer membrane by lipoproteins. The outer membrane of gram-negative bacteria is composed of lipoproteins, lipopolysaccharides (LPS), and phospholipids Gram-Negative Bacteria in Indoor Environments. The designation of a bacterium as Gram-negative is based on the reaction of the organism in the Gram stain test. This test quickly classifies bacteria into two major groups, Gram-positive and Gram-negative, based on the structure of their cell walls

Differences Between Gram Positive and Gram Negative Bacteria. Gram Positive Bacteria vs Gram Negative Bacteria. Gram + and Gram -ve Bacteria differnces These cells, called Gram positive cells, will stay purple because this thick cell wall helps retain the crystal violet-iodine complex. However, cells with a thinner peptidoglycan cell wall, the. Gram-Cell-wall - Gram-negative bacteria - Wikipedia, the free encyclopedia Here is a simple explanation of what it means to be a gram-positive bacteria. Multiple Choice Questions on Gram Staining How Gram Stain works? Gram Staining Principle: Step by step procedure with explanation See mor virulence factors. In this thesis, innate and adaptive immune responses to commensal bacteria and a selected pathogen, S. pneumoniae (the pneumococcus) are studied. Cell wall structures of Gram-positive and Gram-negative bacteria The most common way to classify bacteria is according to their Gram-staining properties Want PressbooksEDU? Want to know more about PressbooksEDU plans and features? Learn more. Have questions about which PressbooksEDU tier is right for you? We're glad to talk you through the options

Membrane structure of gram-negative and gram-positive bacteria. Gram-positive bacteria have a thicker layer of peptidoglycan that makes up the cell wall and thus stain purple in a Gram stain test Gram-positive and Gram-negative bacteria exist everywhere, but pose unique threats to hospitalized patients with weak immune systems.Gram-positive bacteria cause tremendous problems and are the focus of many eradication efforts, but meanwhile, Gram-negative bacteria have been developing dangerous resistance and are therefore classified by the CDC as a more serious threat Both gram-positive and gram-negative bacteria have a cell wall made up of peptidoglycan and a phospholipid bilayer with membrane-spanning proteins. However, gram-negative bacteria have a unique outer membrane, a thinner layer of peptidoglycan, and a periplasmic space between the cell wall and the membrane

The Gram-Negative Cell Wall. As mentioned in the previous section on peptidoglycan, Gram-negative bacteria are those that decolorize during the Gram stain procedure, pick up the counterstain safranin, and appear pink (see Fig. 1) Gram-negative bacteria are a class of bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation, making positive identification possible. The thin peptidoglycan layer of their cell wall is sandwiched between an inner cell membrane and a bacterial outer membrane. In Gram staining, the. All bacteria have a cell membrane where oxidative phosphorylation occurs (since there are no mitochondria). Outside the cell membrane is the cell wall which is rigid and protects the cell from osmotic lysis. In Gram positive bacteria, the cell wall peptidoglycan layer is a much thicker layer than in Gram negative bacteria. Gram negative. Gram Negative Cell Wall: Gram-negative bacteria have a thinner layer of peptidoglycan (10% of the cell wall) and lose the crystal violet-iodine complex during decolorization with the alcohol rinse, but retain the counter stain Safranin, thus appearing reddish or pink The Cell Wall Beneath the capsule cell wall is present.It is a rigid structure that gives shape to the cell.The cell wall is necessary for bacterial growth and development.Without cell wall a cell can't grow and its division is not occurs. Gram-positive and Gram-negative Bacteri

Gram-positive bacteria - Wikipedi

Bacteria are divided into two major groups: Gram positive and Gram negative. Both groups have a cell wall composed of peptidoglycan: in Gram-positive bacteria, the wall is thick, whereas in Gram-negative bacteria, the wall is thin. In Gram-negative bacteria, the cell wall is surrounded by an outer membrane that contains lipopolysaccharides and. Cell shape and cell-wall organization in Gram-negative bacteria Kerwyn Casey Huanga,1, Ranjan Mukhopadhyayb, Bingni Wena, Zemer Gitaia, and Ned S. Wingreena,2 aDepartment of Molecular Biology, Princeton University, Washington Road, Princeton, NJ 08544-1014; and bDepartment of Physics, Clark University

Bacterial Cell Wall Structure: Gram-positive & negative - P

The cell wall in plants is composed mainly of cellulose and contains three layers in many plants. The three layers are the middle lamella, primary cell wall, and secondary cell wall. Bacterial cell walls are composed of peptidoglycan. Gram-positive bacteria have a thick peptidoglycan layer and gram-negative bacteria have a thin peptidoglycan layer The cell wall antigens (O antigens) of Gram-negative bacteria are components of LPS. LPS elicits a variety of inflammatory responses in an animal and it activates complement by the alternative (properdin) pathway, so it may be a part of the pathology of Gram-negative bacterial infections This colours all gram-negative bacteria with a red or pink colour. This happens because an outer membrane stops the penetration of the stain. The test itself is useful in classifying two distinct types of bacteria based on the structural differences of their bacterial cell walls Gram-negative Bacteria: Gram-positive Bacteria: Wall Structure: They have a thin lipopolysaccharide exterior cell wall. The peptidoglycan layer or the mesh-like structure that is seen outside the plasma membrane in these bacteria is quite thick. It is made up of close to twenty times the amount of peptidoglycan, which is present in gram. The plant cell walls are different in their thickness, but usually they are less than 100 µm thick. Most bacteria also have cell walls. In bacteria, there are two types of cell walls. The gram positive bacteria and the gram negative bacteria. The gram positive cell walls are much thicker than the gram negative ones. The gram positive cell wall.

Cell Wall - Gram Positive vs Negative Bacteria easybiologyclas

In this article we will discuss about the chemical compositions of cell wall in various bacteria's. The cell wall of bacteria is made up of network of peptidoglycan (murein, mums means wall). It is present almost on all bacterial cell wall except Halo-bacterium and Halo-coccus As shown in Figure 2-38, the gram-negative cell has an additional layer and the outside of the cell appears convoluted when compared to the gram-positive cell.The gram-positive wall is much thicker than is the gram-negative wall and its external appearance is smoother. gram-positive and gram-negative cells do share one thing in common that is unique to bacteria - peptidoglycan FIGURE 2-4 Cell walls of gram-positive and gram-negative bacteria. Note that the peptidoglycan in gram-positive bacteria is much thicker than in gram-negative bacteria. Note also that only gram-negative bacteria have an outer membrane containing endotoxin (lipopolysaccharide [LPS]) and have a periplasmic space where β-lactamases are found Click here to get an answer to your question ️ The Gram-positive bacteria have a ____ cell wall than the Gram-negative bacteria A. Thinner B. Thicke Component of peptidoglycan of Gram negative cell wall. 1. Peptidoglycan. It is present in between outer wall layer and cell membrane. The structure is similar as gram positive cell wall. There are some minor differences in the Gram positive and Gram negative peptidoglycan structure. The differences are as follows:

Gram-Negative Cell Walls • Peptidoglycan is ~5-10% of cell wall weight • Periplasmic space differs from that in Gram-positive cells - may constitute 20-40% of cell volume - many enzymes present in periplasm • hydrolytic enzymes, transport proteins and other protein Gram negative bacteria have a thinner layer of peptidoglycan (10% of cell wall), and an additional outer membrane which contains lipids. The outer membrane of gram negative bacteria will stain purple also but it falls off during the gram stain test. Its 2nd wall is what gets stained pink. We stain it pink so we have a color contrast to look at Why does the gram positive bacteria stain purple and the gram negative stain pink? Gram-positive bacteria have one cell wall with a thick layer of peptidoglycan (basically a large sugar and amino acid molecule) which retains the purple dye. Gram-negative bacteria have two cell walls with a thin peptigoglycan layer Gram-negative bacteria are spread worldwide, in virtually all environments that support life. The gram-negative bacteria include the model organism Escherichia coli, as well as many pathogenic bacteria, such as Pseudomonas aeruginosa, Neisseria gonorrhoeae, Chlamydia trachomatis, and Yersinia pestis In thick cell walls, other cell wall polymers (such as the teichoic acids, polysaccharides, and peptidoglycolipids) are covalently attached to the peptidoglycan. In contrast, the peptidoglycan layer in Gram-negative bacteria is thin (about 5 to 10 nm thick); in E coli, the peptidoglycan is probably only a monolayer thick

Cell Walls of Prokaryotes Boundless Microbiolog

bacteria-specific proteins and has no effect on human proteins. When a bacterium divides, penicillin prevents it from reforming a new cell wall, and the two daughter cells pop. However, penicillin does not combat all types of bacterial infections; it is most effective against gram-positive bacteria Cell Wall: Composed of peptidoglycan (polysaccharides + protein), the cell wall maintains the overall shape of a bacterial cell. The three primary shapes in bacteria are coccus (spherical), bacillus (rod-shaped) and spirillum (spiral). Mycoplasma are bacteria that have no cell wall and therefore have no definite shape The cell wall of Gram-negative bacteria is generally complex and multilayered. Many, exemplified by Escherichia coli and Spirillum serpens in this study, show a constrictive division in which die cell appears to be pinched in the middle and septa are not seen

Gram Positive vs. Gram Negative Bacterial Cell Wall - YouTub

The cell wall is the outer covering of bacterial cell in absence of capsule. This cell wall is rigid in nature which imparts a proper shape to bacteria. Cell wall encloses all internal parts of the cell. On the basis of typical structure, composition and Gram staining they are classified; A) Gram-positive bacteria. B) Gram-negative bacteria Antibiotic breakthrough: How to overcome gram-negative bacterial defenses all new drugs are unable to penetrate the gram-negative bacterial cell wall, Hergenrother said. How to overcome. Gram positive bacteria have multilayered cell walls while gram negative bacteria have single layered walls. Gram positive bacteria stain a purple color in a crystal violet dye while gram negative bacteria will not react to this type of dye but only to a counterstain thus giving away a pinkish colored stain

Structures of Gram-Negative Cell Walls and Their Derived

Bacterial cell division by binary fission requires the growth of the peptidoglycan cell wall as the bacterium elongates (Amir and Nelson, 2012). In rod-shaped bacteria, the cell wall grows at multiple locations along the cell. In the majority of cocci bacteria, the cell wall grows outward from the FtsZ ring in opposite directions Outside the periplasm in most microbes is the cell wall. The cell wall is important in giving the cell its shape and preventing the cell membrane from rupturing due to the high osmotic pressure it is under. Two general types of cell wall structure are found in bacteria, Gram positive and Gram negative

What can detach from a gram negative bacterium's cell wall and act as an endotoxin? Which exclusive component of gram negative bacterial cell wall acts as an endotoxin? Gram negative bacteria cell walls Dead bacteria, cells and organic debris will stain pink. In older cultures of Gram positive bacteria there are likely to be dead cells which stain pink. Since Gram negative bacteria do not give false positive reaction it is usually safe to assume that bacteria giving a doubtful reaction are Gram positive. Cell Wall Structur THE cell walls of a number of Gram-negative bacteria have been shown to contain a mucopeptide component similar in, composition to that which forms a major fraction of the cell walls of Gram.

Antimicrobial agents targeting bacterial cell walls and cell membranes K. Bush Biology Department, 1001 East Third Street, Indiana University Bloomington, IN 47405, United States of America Summary Antimicrobial agents that target the bacterial cell wall or cell membrane have been used effectively for the past 70 years. Among the agents that. State 2 chemicals that affect Gram negative cell walls positive and Gram negative Cell wall is thicker in a gram positive bacteria. Gram positive bacteria has only the inner plasma membrane and no outer membrane. Gram positive bacteria stain blue while gram negative stain red

The cell wall is smooth in the Gram-positive bacteria, but much different in the Gram-negative bacteria. In Gram-negative it is wavy, comes in contact with plasma membrane, though only in a few locations The cell wall of gram positive bacteria is smooth, whereas the cell wall of gram-negative bacteria is wavy. When the negative gram bacteria is stained with safranin or fuchsin in the experiment, it gives red or pink color Gram-positive vs. Gram-negative Bacteria. What is Difference between Gram-positive and Gram-negative Bacteria? Danish scientist Hans Christian Gram designed a method that allowed him to differentiate two types of bacteria based on their cell walls (gram-positive bacteria and gram-negative bacteria) In contrast, Gram-negative bacteria do not retain the violet dye and are colored red or pink. Compared with Gram-positive bacteria, Gram-negative bacteria are more resistant against antibodies because of their impenetrable cell wall A bacteria cell wall is an important structure for the life of bacteria.. It is present just above the cell membrane and acts as the outer most cover of the cell.. Because of this cell wall, bacteria can survive even the harshest environmental conditions like drought, heat, chemical exposure, pressure, etc