Chapter 3 Cells

What is not a characteristic of all living things?

Movement

What are the two types of Prokaryotes?

Bacteria and Archea

What are Prokaryotic Characteristics?

• No Membrane Bound Organelles

• No Nucleus

• Can read DNA and Make protein simultaneously

• Lack Phospholipid membrane-Bound internal structures

• small (1 micrometer)

What are the types of Eukaryotes?

Algae, Protozoa, fungi, Animals, Plant cells

Eukaryotic Characteristic

• Have a Nucleus

• Membrane Bound Organelles

• Larger 10-100 micrometers

• Complex

What are Glycocalyx/Glycocalyces. What type does it belong to?

• Sticky Gelatinous substance on the outside of prokaryote cells

• Composed of polysaccharides and polypeptides

• Stops drying to death, sticking of bacteria, protection against immune system

What is a capsule for prokaryotes?

• Type of Glycocalyx

• Organized repeating subunits and holds tightly to cell surface

• Sugar Coat properties

• Disguises against the immune system, preventing the bacterium from being eaten

What is a Slime Layer for prokaryotes?

• Less organization compared to capsule, loosely attached

• Water soluble

• Sticky layer that allows for surface attachment

What are Flagella specifically for Prokaryotes?

• Responsible for movement

• Long structures that extend beyond the cell surface

• Not all prokaryotes possess flagella

What type of Flagella arrangement is this?

Monotrichous - Single Flagella

What type of Flagella arrangement is this?

Amphitrichous - Flagella on both ends

What type of Flagella arrangement is this?

Lophotrichous - Multiple Flagella coming out of one end

What type of Flagella arrangement is this?

Peritrichous - Flagella all over the surface of the cell

How do Flagella move in Prokaryotes?

• When it needs to go forward it Runs via Counterclockwise Rotation

• When it tumbles it goes Clockwise

What type of Bacteria is this, and why is it special?

• Spirochetes: spiral shaped bacteria

• The flagella is called endoflagella and it is inside the periplasmic space

• Axial filaments wrap around the cell, when they move they move in a corkscrew motion

• Beneficial as it can move through viscous fluid and remain undetectable to the immune system

What is this?

• Fimbriae: Bristle like extensions composed of protein

• Their function is to adhere to surfaces and each other, shorter than flagella

• Hundreds of Fimbriae per cell

• Important function in biofilms

What is this? Yellow Arrow

• Pili: Protein structure that cells construct to connect themselves with another cell

• A cell can now send a copy of DNA to the other cell

• Longer than Fimbriae, shorter than flagella

• 1-2 Pili per cell

• Mediate conjugation

What is this, and what type of prokaryote does it belong to?

• Hami: It is a fimbria like structure used to attach archaea to surface

• Archaea have glycocalyces to help them form biofilms

• Archaea contain Flagella

What are biofilms?

• Organized layer of accumulated bacteria and other microbes living together on a surface via their fimbriae

• Biofilms are hard to get rid of, cause many industrial problems

• However beneficial in water treatment systems

Why do Bacteria Prefer to live in Biofilms?

• Allows for more communication between bacteria

• Allows for more resistance against different environments

• Different genes

What are the cell walls of Bacteria called, and what are they composed of?

• Peptidoglycan: Composed of NAG and NAM subunits that are linked by amino acid crossbrdigees

• Peptidoglycan provides structure and shape, protects against osmotic pressure

• Can assist to help attatch to other cells and be resistant to antimicrbobial drugs.

What is Peptidoglycan composition?

• NAG and NAM which are modified glucose

• NAG and NAM are attached via tetrapeptide crossbridges,

• Peptidoglycan is the same cell wall structure in both Gram negative and positive bacteria

What are the defining characteristic of Gram Positive Cell walls

• Thick Peptidoglycan Layer

• Presence of Teichoic Acids/Lipoteichoic Acids within the cell wall, helps stabilization

• Peptidoglycan is outside of the cell membrane

• Retains crystal Violet dye, Appears Purple, due to thick peptidoglycan layer

What is Lipoteichoic Acid and why is it different than Teichoic Acids? And where do you find them?

• Teichoic Acids embed themselves within the peptidoglycan

• Lipoteichoic Acid is formed when Teichoic Acid covalently links to lipids, and it anchors from to the cell membrane to the peptidoglycan

• Found in Gram postive cells

When Gram Positive cell walls are stained, what color does it appear and why?

• Appears Purple/Violet due to thick peptidoglycan layer holding on to dye

What is a acid fast group?

• Variation of Gram Positive bacteria that contain up to 60% mycolic acid in their cell wall

• Creates a waxy texture, Hydrophobic

• Survives Desiccation (Drying Out)

What are the defining characteristics of Gram Negative Cell Walls

• Thin Peptidoglycan Layer that is sandwiched between two cell layers

• The outermost layer is a Bilayer membrane that contains proteins, phospholipids, and Lipopolysaccharides (LPS)

• LPS is an Endotoxin and activates our immune system

• When stained, it appears pink it can’t retain the purple dye

When stained what color do Gram negative cell walls appear as?

• Pink due to cell walls not being able to retain purple dye

Can Bacteria exist without cell walls?

• Yes, but only a few

• Mistaken for viruses due to the bacteria size

• Mycoplasma do not have cell walls, have features of prokaryotes

What are the defining characteristic of Archea Cell walls

• No peptidoglycan

• Cell wall composed of proteins, polysaccharides

• Gram positive=Purple

• Gram Negative=Pink

What are the defining characteristics of a Prokaryote cytoplasmic membrane?

• Consists of hydrophobic heads and hydrophilic tails, allows for a phospholipid bilayer to separate water inside and outside

• Fluid Mosaic: allows for proteins to move around sideways on the layer

• Contains integral, peripheral, and glycoproteins

What do Integral Proteins do?

• Span across the entire membrane both hydrophobic and hydrophilic

• Forms channels to get ions through

• Forms Carriers/Pumps to active move substances

What do Peripheral Proteins do?

• Inside of the lipid bilayer, loosely attached

• Communicate signals coming from integral proteins, detects shape change to start activity in cell

What do Glycoprotein do?

• Protein with sugar attached

• Sticks out on the surface to ID itself, communicatoin

• works as a receptor

What is the functions of the cytoplasmic membrane in relationship to energy?

• Capable of producing a electrical gradient by pushing hydrogen ions outside

• Captures light in photosynthesis

• Selectively permeable

• Proteins can do passive and active transport

What is diffusion?

When a molecule is small enough, or it’s composition allows it can pass through the membrane. Tend to be hydrophobic, no charge

What is Facilitated diffusion

Requires a channel that allows certain molecules to cross, or a channel can also let several types of molecules cross

What is Osmosis?

Diffusion of water through special integral proteins called aquaporins

What is an isotonic solution?

• Inside and Outside the cell has the same concentration of solutes

• No Overall Change

What is a hypertonic solution?

• The outside of the cell has a higher concentration of solutes compared to inside the cell, causing water to go outside the cell and crenating the cell

• The inside of the cell would be considered hypotonic

What is a hypotonic solution?

• The outside of the cell has a lower concentration of solutes compared to inside the cell

• Water will go inside the cell causing it to swell and break

What is active transport?

A form of moving substance against a concentration gradiant

Would require ATP

Special proteins in the membrane do this

What is Uniport?

• One type of molecule crosses the membrane using a protein against the gradient

• Uses up ATP

• Going from Low to High

What is Antiport?

Molecules moving in opposite directions in the membrane

Uses ATP

What is Coupled Transport?

• Uniport+Symport

• Uniport moves one substance across the membrane against the gradient. Requires ATP

• The molecule moved across combines with another molecule and come back into the membrane via symport. NO ATP

What is cytosol? Prokaryote

Liquid portion of cytoplasm

What are inclusions? Prokaryote

• Storage for excess nutrients and material for survival

• Are not considered Organelles

What are endosphores? Prokaryote

• Unique structures that bacteria make

• Contains important material until their environment returns back to normal

• Not all bacteria can do this, Gram Positive are capable

What are ribosomes? Prokaryote

• Site of protein synthesis

What are cytoskeletons? Prokaryote

• Proteinaceous fibrils: Composed of long protein filaments

• Maintains structure

• Much simpler than eukaryote cytoskeleton

Do Eukaryotic Cells have glyoccalyces?

• Some do, however it is not as organized as if it was on a prokaryote

• Serves the same purpose of attaching cells to cells

• Strengthening cells, protection against dehydration

What Eukaryotes have a cell wall but no Glycocalyx?

Fungi, Algae, Plants, and some Protoza

What Eukaryotes have a Gloycocalyx?

Animal Cells

What are plant cell walls composed of?

Cellulose

What are Fungal Cell walls composed of?

Cellulose, Chitin, and or glucomannan

What are Algae Cell walls composed of ?

Cellulose, Proteins, Agar, Carrageenan, Silicates, Algin, Calcium carbonate, or a combination

Very Diverse

What are Eukaryote cytoplasmic membrane properties?

• Composed of phospholipids, cholesterol, and steroid lipids

• Also follows fluid mosaic model like prokaryotic cytoplasmic membrane

• Membrane rafts allow for substances produced by the cell to be stored in a special area

• Allows for passive diffusion, facilitated diffusion, active transport, and osmosis

• Special cells can perfume endo/exo cytosis

What does adding cholesterol and steroid lipids to the cytoplasmic membrane of eukaryotes do?

It allows for more stabilization and fluidity

What is Phagocytosis?

A form of endocytosis, where a cell eats a solid

What is a pinocytosis

A form of endocytosis, where a cell eats a liquid

Do Eukaryotes have Flagella?

Some do

How does the Flagella of Eukaryote cells move?

Instead of spinning clockwise or counter clockwise, Eukaryotic Flagella they udulate (wave) back and forth rhythmically

What are Eukaryotic Flagella characteristics?

• The entire flagella is covered by a cytoplasmic membrane

• It is composed of tubilin proteins that are arranged as microtubules

• The Shaft is arranged in a 9+2 doublet Arrangement

• The Basal body/Anchor is arranged in a 9+0 Triplet Arrangement

• Instead of being hooked to the cell, it is anchored without a hook

• Moves by Udulate

What is Eukaryotic Flagella made of?

Tubilin arranged to form microtubules

Can you find Cillia on a Prokaryote?

No, it is strictly a eukaryotic cell structure.

What are Cillia composed of?

Tubulin arranged in microtubultes. Cillia also follows the 9+0 Triplet at the basal/anchor

9+2 Doublet at the shaft

What are cillia characteristics

• Shorter and more abundant compared to flagella

• Coordinated beating movement can move the cell and move things across the cell

• Cillia are covered by cytoplasmic membrane

What are Ribosomes for Eukarytotes?

• Protein synthesis

• Larger than Prokaryotic ribosomes (70S:50S+30S)

• Eukaryotes (80S: 60S+40S)

What are Cytoskeleton for Eukaryotes?

• More extensive compared to Eukaryote cytoskeleton

• Composed of Tubulin that get arranged to microtubule and Actin that gets arranged to microfilaments

• The functions are that it anchors organelles, endocytosis, movement of amebas

Can Eukaryotes have non-membrane bound orangelles?

Yes

What are Centrioles in Eukaryotic Cells?

• 9+0 Triplet arrangement Made into Microtubules

• Role is Mitosis, Division, Cytokinesis

• Form Cilia and Flagella

• Not all cells have centrioles

What is the Nucleus?

• Largest Organelle

• Contains most of DNA

• Nucleoplasm: Liquid Part Contains chromatin

• Nucleolus makes rRNA and assembles ribosomes

• Nuclear Envelope surrounds it

What is Chromatin in the nucleus?

DNA+histones

What is the nuclear envelope of the Nucleus?

Double membrane that consists of two phospholipid bilayer that contains nuclear pores

What is the Endoplasmic Reticulum?

• Transport system in the cells it is continuous with the nuclear envelope

• The Smooth ER synthesis lipids

• The Rough ER synthesizes proteins and transports them. Has ribosomes on it

What is the Glogi?

• Receives vesicles of Proteins/Lipids from the ER

• Processes and export molecules. Gets sent out in secretory vesicles

• Can be sent to different organelles or go to cytoplasmic membrane of the cell

What are Vesicles?

Stores and Transfer chemicals within cells

What are Lysosomes?

Catabolic enzymes in vesicles

What are Peroxisomes

Vesicles that contain enzymes that break down poisonous waste

What are mitochondria

• Many Folds inside create Crista which serves to increase surface area. ETC here

• Inner matrix contains 70S ribosomes and circular molecule of DNA

What is Chloroplasts?

• Harvest light

• Two phospholipid bilayer membrane and DNA

• 70s ribosomes

What is the Endosymbiotic theory?

A big anaerobic prokaryote swallowed a smaller aerobic prokaryote, instead of eating it the aerobic prokaryote lived inside the larger anaerobic prokaryote. Over time the larger cell depended on the smaller cells aerobic ATP producing ability. This cell become mitochondria. Same story for chloroplast

What is the evidence for The Endosymbiotic theory?

Mitochondria and Chloroplasts have their own DNA and own ribosomes, reproduce by binary fission. Have double membrane.