Prokaryote Cell Biology

Glycocalyx

Gel like, sticky substance surround the outside of the cell made up from proteins and complex sugars. Protects cell from dying out , helps in causing disease, sticks to surfaces, and resists the host immune response

Capsule and Slime Layer

What are the two types of glycocalyx?

Capsule

A thickened, hard glycocalyx that is able to firmly attach itself to the surface of host cells and tissues. Acts as a camo that hides bacteria from hosts immune system. Can be slippery or frictionless that makes it hard for leukocytes to grab hold of

Slime Layer

Watery glycocalyx that is loosely attached to the cell and very sticky that allows itself to attach to surfaces and other cells. Can also use this to trap nutrients and store them

Flagella

Long filament like structures that extend beyond cell surface to provide the bacteria cell the ability to move, not all bacteria have this though.

Made of Filament, Hook, and Basal Body

Filament

A hollow tube that extends into the environment and is made of flagellin protein

Flagellin

Deposited in a helix at the lengthening tip, the filament is the longest part of the flagella

Hook

Curved shaft that connects the filament to the basal body

Basal Body

Passes through the cell wall anchoring the filament and the hook to the cell membrane. Composed of a rod and proteins rings that embed into the cell wall and membrane respectively

Monotrichus

One flagella on only one side

Amphitrichous

Having a single flagellum on each of the opposite ends

Lophotrichous

Multiple flagella at one end or one point

Peritrichous

Having flagella all over or covering the entire surface

Positive Taxi

Movement towards a favorable stimulus

Negative Taxi

Movement away from unfavorable stimulus

Run

Movement in a single direction cause by a counterclockwise rotation of the flagella. Can increase speed if stimulus is present

Tumble

Turning or change in direction caused by a clockwise rotation of the flagella. Can increase speed if stimulus is present

Fimbriae

Sticky, rod like projections that are shorter than flagella and used by bacteria to adhere to one another and to substances in the environment. Can be hundreds on a single bacteria cell

Biofilm

A slimy/sticky substance fimbriae and attach to or form

Pili

A special type of fimbriae, that allows cells to transfer DNA to those around them, sometimes called a sex pilus or conjugation pilus. Longer than fimbriae but shorter than flagella

Typically only two pili per cell

Conjugation

Name of the process for bacteria transferring DNA through to sex pilus to other cells around them

Cell Walls

Give strength and maintains the cells shape and protects the cell from water pressure. Allows some bacteria to attach to others in groups

This can be targeted with antibiotics since animals cell lack this

Peptidoglycan

Primarily what bacteria cell walls are composed of, a sugar polysaccharide composed of alternating sugars N-acetylglucosamine (NAG)and N-acetylmuramic (NAM)acid sugars

Covalent Bonds

How is NAG and NAM linked together to form long chains?

Tetrapeptide Cross Bridge

Chains of alternating NAM/NAG are linked together by this. The bridges themselves are held together by short connecting chains of amino acids

NAM

What does the tetrapeptide cross bridge always attach to?

Gram Positive Cell Walls

Contains a thick layer of peptidoglycan that has teichoic acid which adds stability by keeping the peptidoglycan tightly packed

Lipoteichoic acids bind to and anchor the peptidoglycan to the cell membrane

Retains crystal violet dye and turns purple

Gram Negative Cell Walls

Contains thin layer of peptidoglycan and has a second bilayer membrane on top of it. This outer layer contains phospholipids, proteins and lipopolysaccharides (LPS). Does NO retain crystal violet dye and will appear pink

Lipopolysaccharides

Part of the Gram Negative cell wall. Contains lipid A that is attached to complex sugar, will be released into the environment when the cell dies and can cause vasodilation, inflammation, shock, and seizure.

O antigen can be detected by antibodies to target and destroy gram negative bacteria

Periplasmic Space

Part of the Gram Negative Cell wall.

Space between the outer membrane and cell membrane that contains water, nutrients, and substances secreted by the cell such as digestive enzymes and proteins involved in transport.

Phospholipid Bilayer

Two layers of phospholipids

Hydrophobic tail faces inside and hydrophilic head faces the outside

Cell Membrane

Made up of a phospholipid bilayer and contains integral proteins, peripheral proteins, and cholesterol. Some proteins can have sugars attached and are called glycoproteins

Channel Proteins

Allow water soluble or charged chemicals to move across membrane

Carrier Proteins

A chemical binds to a part of the protein, it then changes shape allowing the chemical to pass through

Transmembrane Proteins

Integral proteins that span the entire cell membrane and involved in transport of chemicals

Peripheral Proteins

Proteins on the surface of one side of the membrane, attach themselves to protein filaments that are part of the cytoskeleton and support the plasma membrane.

Some may be involved in chemical reactions and function as enzymes

Selectively Permeable

Allows only some chemicals to pass through to enter or leave the cell

Passive Transport

Move chemicals into or out of the cell without using energy

Active Transport

Using energy to move chemicals into or out of the cell

Photosynthetic

Some bacteria can convert light energy into chemical energy that the cell can use

Cytoplasm

Gel like material inside the cell, water with chemicals like minerals, sugars, and proteins dissolved in it

Cystosol

The liquid portion of the cytoplasm that is mostly water

Nucleoid

The region in the cytoplasm that contains DNA (no nucleus), usually organized into one circular chromosome

Inclusions

Reserve deposits of biochemicals such as lipids, starches, minerals, etc.

Ribosomes

Made up of both RNA and protein and is the site of protein synthesis that translates mRNA into said protein

Cytoskeleton

A network of protein filaments that plays a role in forming the cells basic shape

Vegetative Cells

Active, living form of bacteria that grow and reproduce

Endospore

A dormant, metabolically inactive form of bacteria that allows it to protect itself against unfavorable or harsh environmental conditions. Will transform into this if nutrients are limited. Become resistant to alcohol, bleach, boiling, heat, radiation, and toxic chemicals. Allows bacteria to survive in this form for years and will germinate back to vegetative form if conditions improve

Invagination

A second cytoplasmic membrane forms and separated the copied DNA in a vegetative cell

Cortex

Made of peptidoglycan, calcium, and dipicolinic acid. Forms in a vegetative cell and is covered by a spore coat that completes formation of the endospore