Structure of Bacterial Cells

What are the two main categories in which all living cells are classified?

Prokaryotes and eukaryotes

Which of the following is a characteristic of prokaryotic cells?

Lack true nucleus

Which organisms are typically categorized as prokaryotes?

Bacteria and Archaea

Which type of cell can be both single-celled and multicellular?

Eukaryotic cells Signup and view all the answers

What distinguishes eukaryotic cells from prokaryotic cells?

Having true nuclei Signup and view all the answers

Which type of cell encodes genetic information in DNA?

all of the above Signup and view all the answers

Which category of cells includes plants, animals, fungi, and protists?

Eukaryotic cells Signup and view all the answers

What defines the boundaries of a living cell?

A cell membrane (plasma membrane) Signup and view all the answers

Which domain do prokaryotic cells belong to?

Bacteria and Archaea Signup and view all the answers

Which type of cell is typically single-celled?

Prokaryotic cells Signup and view all the answers

Which of the following is an example of a eukaryotic single-celled organism?

Amoeba Signup and view all the answers

What is a common feature of both prokaryotic and eukaryotic cells regarding genetic information?

They encode genetic information in DNA. Signup and view all the answers

Which of the following are not considered eukaryotic cells?

Bacteria and Archaea Signup and view all the answers

What is the shape of DNA in Prokaryotes?

Circular Signup and view all the answers

Where is the DNA located in Prokaryotes?

In the nucleoid Signup and view all the answers

What do Prokaryotes lack in terms of organelles?

Membrane-enclosed organelles Signup and view all the answers

How do Prokaryotes reproduce?

Binary fission Signup and view all the answers

What is the shape of DNA in Eukaryotes?

Linear Signup and view all the answers

Where is the DNA located in Eukaryotes?

In the nucleus surrounded by a nuclear envelope Signup and view all the answers

What are the two processes involved in cell division for Eukaryotes?

Mitosis and meiosis Signup and view all the answers

What is the method of reproduction in Eukaryotes?

Mitosis and/or meiosis Signup and view all the answers

What is the method of reproduction in Prokaryotes?

Binary fission Signup and view all the answers

What is the typical size range of bacterial cells?

0.5-2.0 μm Signup and view all the answers

Which type of bacteria can measure up to 60 μm in length?

Cyanobacteria Signup and view all the answers

What term is used to describe bacteria that can have varying shapes in a single culture?

Pleomorphism Signup and view all the answers

What shape is associated with the term "coccus"?

Spherical Signup and view all the answers

How is the arrangement "tetrads" characterized?

4 cells in a cube Signup and view all the answers

What is the result of division in three planes for cocci bacteria?

Sarcinae Signup and view all the answers

How do bacilli bacteria divide?

a and b Signup and view all the answers

What is the term for random division in grapelike clusters?

Staphylo Signup and view all the answers

Which type of bacteria can only divide in one plane?

Bacilli Signup and view all the answers

What is the term used to describe bacteria shaped like a Rod-shaped?

Bacilli Signup and view all the answers

What term is used to describe rigid wavy-shaped spiral bacteria?

Spirillum Signup and view all the answers

What is the function of the bacterial cell wall?

Preventing osmotic lysis Signup and view all the answers

Which structure lies outside the cell membrane?

Cell wall Signup and view all the answers

What is the composition of peptidoglycan?

Polysaccharide chains cross-linked by polypeptides Signup and view all the answers

What is the additional molecule found in the cell wall of G+ve bacteria?

Teichoic acid Signup and view all the answers

Which type of bacteria have a thick layer of peptidoglycan?

G+ve bacteria Signup and view all the answers

What forms the outermost layer of the cell wall of G-ve bacteria?

Outer membrane Signup and view all the answers

Why are G-ve bacteria less sensitive to many antibiotics?

Because of the presence of lipopolysaccharides Signup and view all the answers

What attaches the outer membrane to peptidoglycan in G-ve bacteria?

Lipoproteins Signup and view all the answers

What is the function of 'porins' in the outer membrane?

Forming water-filled channels for transport Signup and view all the answers

Which type of bacteria has an outer membrane composed of lipopolysaccharides?

G-ve bacteria Signup and view all the answers

Which structure is considered one of the reasons why G-ve bacteria are less sensitive to many antibiotics?

Outer membrane Signup and view all the answers

What are Lipopolysaccharides (LPS) also known as?

a and b Signup and view all the answers

What is the function of Lipopolysaccharides (LPS) in bacterial cells?

They identify G-ve bacteria Signup and view all the answers

What is the integral part of the outer membrane of bacterial cells?

Lipopolysaccharides (LPS) Signup and view all the answers

What is the role of Lipid A in G-ve bacteria?

It is responsible for toxic properties Signup and view all the answers

What is the function of the Periplasmic space?

It contains digestive enzymes Signup and view all the answers

Which type of bacteria is more likely to have a well-observed Periplasmic space?

G-ve bacteria Signup and view all the answers

What is the main function of transport proteins in the Periplasmic space?

Transferring metabolites into the bacterial cytoplasm Signup and view all the answers

How do antibiotics like penicillins and cephalosporins control bacteria?

They inhibit the formation of peptidoglycan cross-links Signup and view all the answers

Which enzyme in tears and other body fluids digests peptidoglycan?

Lysozyme Signup and view all the answers

What distinguishes Mycoplasma from other bacteria in terms of cell wall?

They have no cell wall Signup and view all the answers

How do Mycoplasma protect themselves from osmotic swelling and bursting?

sterols Signup and view all the answers

What are wall-deficient bacteria strains that lose the ability to form a cell wall called?

L-forms Signup and view all the answers

How can bacteria lose the ability to form a cell wall and become L-forms?

Naturally or due to chemical treatment Signup and view all the answers

What role do L-forms play in diseases?

They play a role in chronic or recurrent disease Signup and view all the answers

What is the function of the cell membrane in bacterial cells?

all of the above Signup and view all the answers

What is the primary composition of the cell membrane?

Phospholipids and proteins Signup and view all the answers

What is the structure of the cell membrane bilayer?

Hydrophilic and hydrophobic chains of phospholipids Signup and view all the answers

Which component is responsible for adding rigidity to the cell membrane in Mycoplasma?

Sterols Signup and view all the answers

How is the fluid mosaic model described?

phospholipid in fluid state, proteins form mosaic pattern. Signup and view all the answers

How does some antimicrobial kill bacteria by affecting the cell membrane?

It causes leaks in the cell membrane Signup and view all the answers

What is the role of proteins in the cell membrane?

They act as carriers and form pores for material entry Signup and view all the answers

In addition to phospholipids and proteins, what does Mycoplasma have in its cell membrane for added rigidity?

Sterols Signup and view all the answers

What are some of the functions performed by the cell membrane in bacteria that are similar to those carried out by mitochondria in eukaryotic cells?

ATP production and respiration Signup and view all the answers

Which antimicrobial agents kill bacteria by causing leaks in the cell membrane?

Polymyxin and daptomycin Signup and view all the answers

What is the composition of cytoplasm in bacterial cells?

4/5 water, 1/5 dissolved substances Signup and view all the answers

Where do most anabolic and catabolic reactions occur in bacterial cells?

Cytoplasm Signup and view all the answers

What is the function of ribosomes in bacterial cells?

Protein synthesis Signup and view all the answers

How is the size of ribosomes and their subunits determined?

Sedimentation rate Signup and view all the answers

What is the composition of a whole bacterial ribosome?

30S + 50S subunits Signup and view all the answers

What is the nuclear region in bacterial cells?

Region containing genetic material Signup and view all the answers

What are plasmids in bacterial cells?

smaller circular molecules of DNA Signup and view all the answers

What is sporulation in bacterial cells?

Preparation for adverse conditions Signup and view all the answers

What are the main components of a bacterial spore?

dipicolinic acid + ca+2 +water Signup and view all the answers

What is the role of dipicolinic acid in bacterial spores?

contribute to heat resistance Signup and view all the answers

How long can bacterial endospores survive in adverse environmental conditions?

More than 10,000 years Signup and view all the answers

What triggers the germination of bacterial endospores?

very little water & are highly resistant to heat, drying, acids, bases, disinfectants & even radiation Signup and view all the answers

What is the composition of a flagellum?

Protein Signup and view all the answers

What is the function of a flagellum in bacterial cells?

Locomotion Signup and view all the answers

How is the flagellum attached in the cell membrane?

It extends out of the cell Signup and view all the answers

What is a bacteria with a single polar flagellum called?

Monotrichous Signup and view all the answers

In which type of bacteria are flagella located at both ends?

Amphitrichous Signup and view all the answers

What is chemotaxis?

a and b Signup and view all the answers

What is the term for movement away from a repellent?

Negative chemotaxis Signup and view all the answers

How do bacteria detect changes in concentration for chemotaxis?

Certain structures on cell surface Signup and view all the answers

What is the special type of flagella in spirochetes called?

a and b Signup and view all the answers

What is the composition of pili?

Pilin Signup and view all the answers

What is the function of conjugation pili?

DNA transfer between bacterial cells Signup and view all the answers

How does attachment pili contribute to pathogenicity?

Enhancing colonization on cell surfaces Signup and view all the answers

What is glycocalyx composed of?

Polysaccharides Signup and view all the answers

What is the purpose of a capsule in certain bacteria?

Protection from host defenses Signup and view all the answers

What is the main function of a slime layer?

Protecting against drying Signup and view all the answers

What are microbial biofilms?

Surface-associated communities with an extracellular matrix Signup and view all the answers

What is dental plaque an example of?

Biofilm Signup and view all the answers

How do biofilms affect bacterial resistance to antimicrobials?

Enhanced tolerance/resistance Signup and view all the answers

What percentage of chronic human infections are estimated to be implicated with biofilms?

Around 80% Signup and view all the answers