L1

What is the nucleoid region in bacteria

An irregularly shaped region containing the chromosome

How many nucleoids are usually present in a bacterial cell

Usually one per cell

What type of DNA is found in the nucleoid

Double stranded DNA

What is the typical shape of the bacterial chromosome

Circular

Why does the chromosome not appear circular under a microscope

It is too large and appears knotted

What size range can bacterial nucleoids have

About 0.5 to 10 megabase pairs

What essential functions are encoded by the nucleoid

Nutrition and cell division

What are plasmids

Small DNA molecules separate from the chromosome

Are plasmids always circular

No some can be linear

What does plasmid copy number refer to

The number of plasmids in a cell

What is a consequence of high plasmid copy number

Metabolic burden and slower growth

What is a consequence of low plasmid copy number

Not all daughter cells receive plasmids

Do plasmids replicate independently

Yes they replicate independently of the chromosome

Are plasmids essential for bacterial survival

No they are not required for growth or reproduction

What advantages can plasmids provide

Traits like antibiotic resistance or toxin production

What are inclusions in bacteria

Storage granules of organic or inorganic material

Name one type of carbon storage inclusion

Glycogen

What is PHB used for in bacteria

Lipid carbon storage

When are inclusions most visible

During stationary phase

What is the structure of the cytoplasmic membrane

Phospholipid bilayer

What are integral membrane proteins

Proteins that span the membrane

What are peripheral membrane proteins

Proteins attached to one side of the membrane

What is the main component of gram positive cell walls

Peptidoglycan

What additional structures are in gram negative cell walls

Outer membrane and periplasm

Do eukaryotes contain peptidoglycan

No

What stain is used in the gram stain test

Crystal violet

What color do gram positive bacteria appear after staining

Purple

What are the two sugars in peptidoglycan

N acetylglucosamine and N acetylmuramic acid

What links the sugar chains in peptidoglycan

Peptide bridges

What enzyme targets peptidoglycan

Lysozyme

What acids are found in gram positive walls

Teichoic acid and lipoteichoic acid

What is the function of teichoic acid

Helps membrane movement and immune recognition

What is unique about gram negative cell walls

They have two membranes

What are porins

Channels that allow small molecules to pass through membranes

What is lipid A

Toxic component of lipopolysaccharide

What is the O antigen

Variable carbohydrate region of lipopolysaccharide

What is the function of a bacterial capsule

Protection and attachment

What are capsules made of

Polysaccharides

What is an S layer

A protein layer on the cell surface

What is one function of S layers

Anti phagocytic protection

What are flagella used for

Movement and attachment

What is a monotrichous arrangement

One flagellum

What are fimbriae

Short protein appendages for attachment

What are pili used for

Conjugation and attachment

What is the conjugation pilus used for

Transfer of plasmids

What is a biofilm

A surface associated bacterial community

Why do bacteria form biofilms

To attach and resist removal

What are the two ribosomal subunits in bacteria

50s and 30s

What is the total bacterial ribosome size

70s

Which rRNA is used for bacterial identification

16s rRNA

Why is 16s rRNA useful for identification

It varies between species

How is evolutionary distance calculated

By comparing sequence differences

What rRNA is found in eukaryotes

18s rRNA

Why classify bacteria

To organize diversity and aid identification