BIO 343 - Exam 1

microorganisms

• species too small to be seen by the naked eye and are the most populous group of organisms on earth

• involved in: recycling essential elements back into the environment, being a nutrient source for other organisms, photosynthesis involvement, and antibiotic involvement

Prokaryotes:

• lack a true membrane-bound nucleus

• has 1 chromosome that’s circular

• no histone proteins

• no organelles

• has a peptidoglycan cell wall

• replicate by binary fission

• 70S ribosomes (smaller)

• gyrase enzyme

Eukaryotes:

• have a membrane-bound nucleus

• have paired chromosomes that are linear

• has histone proteins

• has organelles

• some have a polysaccharide cell wall

• replicate through mitosis

• 80S ribosomes (bigger)

• no gyrase

What are the major differences between Eukaryotes and Prokaryotes?

True

Prokaryotes do not have any membraned structures inside them

True or False:

Prokaryotes lack organelles

False

Viruses are not cells

Viruses need host cells to survive

But they are the smallest microbes

True or False:

Viruses are the smallest cells

viruses

the smallest of all microbes

viruses are composed of:

1) a nucleic acid (its genetic material)

2) protein

What are viruses composed of?

prions

defective, misfolded proteins

prions

named after “proteinaceous infection” because it can cause other properly-folded copies of a protein to misfold

1) Bacteria

2) Archaea

3) Eukarya

What are the classifications of microorganisms?

Bacteria and archaea

__________ and __________ are the domains classified as prokaryotes

Archaea

prokaryotes usually found in extreme environments

False

most bacteria are NOT pathogenic

it’s true that archaea are not pathogenic

True or False:

Most bacteria are pathogenic but archaea are not pathogenic

Bacteria cell walls have peptidoglycan (most types)

Archaea do not have peptidoglycan

What is the difference between the cell walls of Bacteria and Archaea?

True

True or False:

Fungi are part of the Eukaryotic domain

Anthony von Leeuwenhoek

the first person to observe and describe microorganisms and inventor of the first microscope

spontaneous generation

What scientific theory did scientists think led to the creation of life prior to the 1600’s?

spontaneous generation

the theory that living organisms can develop from non-living or decomposing matter

biogenesis

the theory that living organisms are created from other life forms (that life begets life)

Francesco Redi

__________ was the scientist that studied maggots and fly eggs on decaying meat to prove the flaws in spontaneous generation

John Needham

__________ was the scientist that put mutton broth in a flask, boiled it, sealed it, and then saw that the broth became cloudy (microorganisms formed), thus he believed that spontaneous genereation occurred

the broth was sealed after boiling, allowing contamination from the open air to get into the flask (that’s why the microorganisms grew after sealing)

What was the flaw with John Needham’s broth experiment?

Lazzaro Spallanzani

__________ was the scientist that put broth in a flask, sealed it, then boiled it, and showed that the broth did not cloud, thus disproving the theory of spontaneous generation

Louis Pasteur

__________ was the scientist that used broth in swan-neck flasks to trap microorganisms, refuting spontaneous generation

John Tyndall

__________ was the scientist that demonstrated that dust carries microorganisms and provided evidence for the existence of heat-resistant forms of bacteria

studying plants

scientists discovered that a disease in silkworms was created by a fungus microbe

How did scientists first figure out microbes are involved in human diseases?

Lister

__________ was the scientist that first used aseptic techniques during surgery to prevent infections

Koch’s postulates

1) the microorganism must be present in every case of the disease and absent in healthy people

2) suspected microorganisms must be isolated and grown in a pure culture (so that the microorganism can be characterized)

3) the same disease must result when the isolated microorganism is inoculated into a healthy host

4) the same microorganism must be isolated again from that diseased host

The set of criteria used to establish a link between a certain microorganism and a certain disease. What are the 4 criteria?

microbes

first living organisms

• microbes are ubiquitous

• ubiquitous means they live everywhere life is possible

__________ are ubiquitous. What does that mean?

• Bacteria are categorized by their gram stain reaction

• there are gram positive bacteria and there are gram negative bacteria

How are Bacteria categorized?

1) bacilli - rod-shaped

2) cocci - spherical

3) spirilla - rigid helix

4) spirochetes - flexible helix

List the 4 main bacteria shapes:

spirilla

What is the bacteria shape?

spirochetes

What is the bacteria shape?

diplococci

What is the bacteria shape?

staphylococci

What is the bacteria shape?

streptococci

What is the bacteria shape?

vibrio

What is the bacteria shape?

sarcinae

What is the bacteria shape?

tetrad

What is the bacteria shape?

streptobacili

What is the bacteria shape?

coccobacilli

What is the bacteria shape?

True

True or False:

Most bacteria are monomorphic, meaning they maintain the same shape throughout their life cycle

nucleoid

the area of the cell where most DNA is concentrated

protoplasts

bacterial cells that have had their cell walls removed

the detergent will cause cell lysis (since the protoplast lacks a protective cell wall) and only the nucleoid will remain intact

What happens when detergent is added to protoplasts?

• closed DNA

• circular

• double-stranded

• some DNA attaches to the cell membrane

• millions of nucleotides in length

Describe prokaryotic chromosomes:

False

Prokaryotic DNA is double-stranded

True or False:

Unlike Eukaryotic DNA (which is double-stranded), Prokaryotic DNA is single-stranded

HLP (histone-like proteins)

proteins involved in the folding and compacting of DNA in the nucleoid

plasmids

a small, closed, circular ring of DNA that is present in some bacterial cells’ supercoiled nucleoid, and provide those cells with a selective advantage

False

they just don’t have the advantage the plasmid provides

True or False:

Cells without plasmids are harmed

True

• plasmids may not get accurately segregated during division, causing one cell to end up with 2 plasmids and the other to end up with 0

• the cell that has no plasmid is said to be “cured of plasmid”

True or False:

Bacterial cells can have 2 plasmids at the same time

True

plasmids replicate independently from the bacterial chromosome

True or False:

Plasmids have their own replication origin

R-Plasmids

plasmids that encodes for drug resistance and a pillus

F-Plasmids (Fertility Plasmids)

plasmids that encode for the building of a pillus (a protein bridge that connects two conjugating/mating cells) and allowing for easier movement of DNA (genetic exchange/mating) of one bacterium to the other bacterium

ribosomes

the site of protein synthesis in the cell

1) protein

2) rRNA

What are ribosomes made of?

False

Prokaryotes have 70S ribosomes

Eukaryotes have 80S ribosomes

the “S” stands for Svedberg which is the unit by which ribosomes are measured (determined by its buoyancy)

True or False:

Prokaryotes and Eukaryotes have the same-sized ribosomes

cytoskeleton

homologous proteins of the elements of the __________ in Eukaryotes have recently been found in from Prokaryotes

cytoskeleton

the functions of this organelle include: cell shape, cell division, protein localization

inclusion bodies

granules of organic or inorganic material that are stockpiled by the cell for future use

False

inclusion bodies are not present in all bacteria

but inclusion bodies do lack a membrane

True or False:

The inclusion bodies that are present in all bacteria have no membrane

True

True or False:

All living organisms have membranes

cell membrane

separates the cell from its environment

gram positive rod

This bacterial cell is a __________ (shape and cell wall description)

inclusion body

What is structure A?

capsule

What is structure B?

cell wall

What is structure C?

plasma membrane

What is structure D?

fimbriae

What is structure E?

capsule

What is structure F?

cytoplasm

What is structure G?

Ribosomes

What is structure H?

cell wall

What is structure I?

plasma membrane

What is structure J?

nucleoid

What is structure K?

plasmid

What is structure L?

flagella

What is structure M?

the cell membrane being a selectively permeable barrier allows for some molecules to pass into and out of the cell using the aid of transport systems

it allows for a more efficient transport of molecules

Why is it important that the cell membrane is selectively permeable?

False

The cell membrane contains receptors and allows molecules to pass through

True or False:

The cell wall contains receptors that detect chemicals to know what should and shouldn’t be allowed to pass through

• the cell membrane is a phospholipid bilayer, which contains:

  • a phosphate head - polar and hydrophilic

  • a phospholipid tail - non-polar and hydrophobic

• there are proteins and pores embedded in the layers

What is the cell membrane made out of? Describe it

1) Peripheral proteins - embedded on the outside of the membrane

2) Integral proteins - embedded in the membrane

3) Transmembrane proteins - type of integral protein that spans the whole membrane (reaches outside to inside)

What are the types of proteins present in the cell membrane?

cell membrane

The __________ is described as a “fluid mosaic model”

peptidoglycan

Bacterial cell walls are made of __________

cell wall

the main function of this structure is to prevent osmotic lysis

osmotic lysis

occurs when cells are placed in hypotonic solution, and the movement of water into the cell causes swelling and bursting due to the build up of pressure

penicillin inhibits the synthesis of peptidoglycan in bacterial cell walls, causing these cells to lyse

How does penicillin help antibiotic resistance?

lysozyme

the enzyme that breaks down the cell wall

peptidoglycan

polymer of disaccharides NAG (N-acetylglucosamine) and NAM (N-acetylmuramic acid) that are linked by polypeptides

Gram positive

• has a thicker envelope

• less complex

• has lipoteichoic acid and teichoic acids embedded in the peptidoglycan

• has a small periplasmic space located between the plasma membrane and the cell that’s smaller

Gram negative

• has a thinner envelope but is surrounded by an outer membrane

• more complex

• has lipopolysaccharide in the outer membrane, lipids, and Braun’s lipoproteins, and porin (protein channels)

• has a large periplasmic space

What is the difference between gram-positive and gram-negative bacteria?

False

Some archael membranes are composed of a monolayer structure

True or False:

All prokaryotes have a phospholipid bilayer membrane

glycocalyx

the network of polysaccharides extending from the surface of the cell, and its function is to protect the cell from phagocytosis and harsh environments, and to attach to surfaces

bacteria cell walls have peptidoglycan

archae cell walls vary but usually contain heteropolysaccharides

What is the main difference between bacteria cell walls and archae cell walls?

capsules and slime layers are types of glycocalyx

__________ and __________ are both types of glycocalyx

capsules

glycocalyx composed of polysaccharides and are well-organized

slime layers

glycocalyx composed of polysaccharides and are loosely-organized and easily removed

protein

fimbriae are made of __________

fimbriae

short, hair-like proteinaceous appendages on some bacterial cells

• attachment to surfaces

• twitching/gliding motility in some bacteria

What are the main functions of fimbriae?

sex pili

long, thick proteinaceous appendages on some bacterial cells

to create a bridge for DNA between two bacterial cells that are mating (conjugating)

What is the main function of sex pili?