Intro to Microbiology Midterm 1

What is Microbiology

The study of microbes and how the interact with humans,food, and how they can be used

what is a microbe

A microbe is a living thing so small you can’t see it with your naked eye.

What is a prokaryotic cell/eukaryotic cell

Prokaryotic cells are simple, unicellular organisms without a nucleus or membrane-bound organelles, while eukaryotic cells are complex, can be unicellular or multicellular, and contain a nucleus and organelles.

What are some examples of Eukaryotic macroorganisms

Eukarya: animals and plants

What are some examples of prokaryotic macroorganisms

none known

What are some examples of Eukaryotic microorganisms?

Eukarya: Algae, fungi, protozoa

What are some examples of Eukaryotic microorganisms?

Protozoa are tiny single-celled organisms, found mostly in water and soil, that move around and eat food a bit like very small animals. They also have a nucleus

What are some examples of prokaryotic microorganisms?

archaea and bacteria

what did Robert Hooke do for Microbiology?

he was able to create the first description of microbes: fruiting structures of “molds” which were fungi

what did Antonie van leeuwenhoek do for microbiology

he improved the microscope lens and was the first to be able to describe bacteria

list 5 reasons why we should study microbiology

first life on earth, mutlicellular organisms (us) evolved from microorganisms, microorganisms will be on earth forever, we still dont know that much about microorganisms on earth, over half of biomass on earth is microorganisms, studying genetics of microbes can help us use microbes to benefit humans

what are the 6 core features of life?

metabolism, growth, reproduction, evolution, adaptation, homeostasis

what is homeostasis?

Homeostasis is how a living thing keeps its inside conditions, like body temperature and water levels, steady even when the outside environment changes. For example, you sweat when you’re hot and shiver when you’re cold to stay at the right temperature.

How do microbes get energy? 2 different thingies

autotrophs build their own food, and heterotrophs eat food that’s already been made.

what is ATP?

ATP is the molecule cells use as their energy currency, releasing a burst of energy when one of its phosphate groups is broken off. Autotrophs make it using energy from sunlight or chemicals, while heterotrophs make it by breaking down food through cellular respiration.

What is the Subunit, function, and dry weight of cell (%) of the macromolecule polypeptide

Amino acids, they catalyze most of the biochemical reactions in the cell, 50-55% of the weight

What is the macromolecule, function, and dry weight of cell (%) of the subunit deoxyribonucleotides (DNA)

nucleic acid, DNA provides the instructinos for assembly and reproduction of the cell, 2-5% of the weight

What is the macromolecule, function, and dry weight of cell (%) of the subunit Ribonucleotides (RNA)

nucleic acids, many functions, mainly production of polypeptides, 15-20% of the weight

What is the Subunit, function, and dry weight of cell (%) of the macromolecule Lipids

Diverse Structures, they make up the cellular membranes, 10% of the weight

What is the Subunit, function, and dry weight of cell (%) of the macromolecule polysaccharides

Sugars, they are also structural, like cellulose, and energy storage, like glycogen and starch, 6-7% of weight

What are the domains of the phylogenetic tree, and what are they based on?

divided into three domains, bacteria, archaea and eukarya, and they are based on RNA Sequences

For the Domain bacteria, does it have nuclear membrane, membrane bound organelles, plasma membrane, cell wall, RNA polymerases, Histones

nuclear membrane - No
membrane bound organelles - rare
plasma membrane - similar to eukarya
cell wall - yes, almost all, made up of peptidoglycan
RNA polymerases - single polymerase
Histones - histone like proteins

For the Domain archaea, does it have nuclear membrane, membrane bound organelles, plasma membrane, cell wall, RNA polymerases, Histones

nuclear membrane - No
membrane bound organelles - rare
plasma membrane - different from the others (bacteria, eukarya)
cell wall - yes, almost all, made up of various materials
RNA polymerases - single polymerase, eukaryal like RNA pol II
Histones - yes

For the Domain eukarya, does it have nuclear membrane, membrane bound organelles, plasma membrane, cell wall, RNA polymerases, Histones

nuclear membrane - yes
membrane bound organelles - multiple types, found in all species
plasma membrane - similar to bacteria
cell wall - rare, made up of various materials
RNA polymerases - has RNA pol I, II and III
Histones - yes

what is Pol I and its function?

RNA pol I transcribes most ribosomal RNA (rRNA) genes, producing the RNA that forms the core of ribosomes. It works in the nucleolus, a dense region of the nucleus dedicated to making ribosomes.

what is Pol II and its function?

RNA pol II transcribes protein-coding genes into messenger RNA (mRNA), along with some small regulatory RNAs. It’s the most heavily regulated of the three, since it controls which proteins a cell makes.

what is Pol III and its function?

RNA pol III transcribes transfer RNA (tRNA) and these are all short, abundant RNAs that support protein synthesis.

how long ago was the formation of earth, and the chemical evolution and synthesis

4.5 Billion Years ago

how long ago was the origin of life

4 billion years ago

how long ago was the first O2 producing bacteria

3 billion years ago

when was the O2 atmosphere established

2 billion years ago

when was the origin of complex eukarya

1.5 billion years ago

when was the origin of simple animals, origin of multicellular organisms, and the origin of land plants

around/less than 1billion years ago

when was the origin of flowering plants and origin of mammals

aroudn 0.5 billion years ago

list 3 reasons as to why early earth conditions were harsh

little oxygen in the atmosphere, high temperatures, high CO2, Earth’s surface was chemical soup

What are the 3 requirements of early life

A way to store genetic information, a way to speed up/catalyze reactions within the cell, A boundary that keeps the cells contents inside itself, In modern cells this is a membrane made of lipids

What are ribozymes? and what are 3 things that they do/did

Ribozymes are RNA that behaves like enzymes, they sped up/catalyzed reactions, they stored genetic information, and they were self replicating

Who conceived the RNA world

Carl Woese

in the RNA World, what were 5 things that happend (timeline)

RNA became self replicating, the boundary membrane of the cell was created, early cellular life used RNA for catalysts and coding of the cell, RNA was used to create protein in the cell, and these proteins become the new catalysts

Double Stranded DNA

its more stable than RNA, and provides a backup copy of the genetic information (of DNA)

What happened with the molecules 4-4.5 billions years ago (2 things)

lots of starting and failing

approximately how long have microbes dominated the planet?

3.5 billion years

What are 3 RNA’s that DNA can be transcribed into

messenger RNA, mRNA, transfer RNA, tRNA, ribosomal RNA, rRNA

what does messenger RNA do? (mRNA)

mRNA (messenger RNA) carries the instructions for building a protein

what does ribosomal RNA do? (mRNA)

rRNA (ribosomal RNA) is a building part of the ribosome itself. It doesn’t carry instructions. Instead, it forms the core of the machine that reads the mRNA and joins amino acids together.

what does transfer RNA do? (tRNA)

tRNA is a small RNA molecule that carries one specific amino acid on one end, and the other end has a three-letter sequence (the anticodon) that matches a codon on the mRNA.

what is the endosymbiotic theory of the origin eukaryotes

early prokaryotic microbes ate other microbes, starting a symbiotic relationship between the two of them, forming the first basic eukaryotes

What is spontaneous generation theory, and what did Louis Pasteur say about it?

the theory that microbes could spontaneously form from nonliving matter, and louis pasteur disproved it in the 1800’s

What are some things that Louis Pasteur did

invented pasteurization, sanitization, disproved spontaneous generation and developmed methods to control microbe growth, explained how alchol fermentation works, developed vaccines for anthrax, cholera, and rabies

What are some things that Robert Koch did?

he discovered the cause of anthrax and tuberculosis, and created basic rules for determining which microbes caused which diseases (koch’s postulates)

What are koch’s postulates? explain and 4 things

they are used to show a microbe causes a specific disease:
- the microbe is in every person with the disease
- the microbe itself is obtained
- the microbe + a healthy host causes the disease
- the microbe can be recovered from the host who caught the disease

give an example when koch’s postulates were used

in 1980, researches found a microbe that caused stomach ulcers/gastric ulcers, originally thought to be from excess acid

list 3 ways that infection can be prevented

safe food and water, sanitation improvements, personal hygiene, vaccinations, antibiotics, antiseptics

List 5 different shapes/mophology of bacterial cells

spherical, rod-shaped, comma-shaped, spiral, pleiomorphic (not fixed shape, can vary)

some bacteria can also assume multicellular organizations, name 3

hyphae (branching filaments of cells)
mycelia (tufts of hyphae)
trichomes (smooth unbranched chains of cells)

What are the cell size ranges of prokaryotes, bacteria and eukayotic cells

prokaryotes: 0.2um to just bigger than 700um
bacteria: 0.5um-4um wide and 1-15um long
eukaryotic cells: 10um to just bigger than 200um

what is the size ranges of what you can see with an electron microscope, light microscope and your human eye

electron microscope- above 0.005um
light microscope - above 0.2um
human eye - above 100um

Why is it good for a cell to be small? 3 things

greater rate of nutrient and waste exchange, higher metabolism, faster growth and evolution rate

What is the composition and function of a DNA Nucleoid in the cytoplasm of bacteria

DNA, RNA, protein, genetic info storage and gene expression

What is the composition and function of chromosome-packaging proteins in the cytoplasm of bacteria

protein, protection and compaction of DNA

What is the composition and function of the enzymes that synthesize DNA and RNA in the cytoplasm of bacteria

protein, replicates genomes through transcription

What is the composition and function of regulatory factors in the cytoplasm of bacteria

RNA and protein, control of replication, transcription and translation

What is the composition and function of ribosomes in the cytoplasm of bacteria

RNA and protein, Translation, or protein synthesis

What is the composition and function of plasmids in the cytoplasm of bacteria

DNA, they code non-chromosomal genes for a lot of different functions

What are non-chromosomal genes

genes that are located outside the main chromosome, and they are usually extras, such as antibiotic resistance or the ability to break down unusual nutrients.

What is the composition and function of enzymes that break down substrates in the cytoplasm of bacteria

protein, energy production

What is the composition and function of inclusion bodies in the cytoplasm of bacteria

various polymers, they store carbon, phosphate, nitrogen and sulfur

What is the composition and function of Gas vesicles in the cytoplasm of bacteria

protein, and they are there for bouyancy

What is the composition and function of magnetosomes in the cytoplasm of bacteria

made up of protein, lipids and iron, and they orient the cell during movement

What is the composition and function of cytoskeletal structures in the cytoplasm of bacteria

protein, they help with cell wall synthesis, cell division, and seperating chromosomes during replication

How does DNA compress within the nucleoid of bacteria

no membrane surrounds the nucleoid, no histone proteins unlike archaea and eukaryotes, small postively charged proteins bind to chromosome to maintain a condensed structure, topoisomerases modify dna to supercoil to be smaller

What do sulfur globules do in bacteria

they store sulfure for energy

what do polyhydroxybutyrate granules do in bacteria

they store carbon

what do carboxysomes do in bacteria

this is where carbon fixation reactions happen

What does the bacterial cytoskeleton proteins do?

its a series of internal proteins and they help in keeping everything in the right place, some of them create cell walls during cell division, and may also move internal items

what are the roles of the plasma membrane

captures energy, holds sensory systems, and is a permeability barrier

what is a plasma membrane made out of? 3 things

usually composed of a phospholipid bilayer with embedded proteins, hydrophobic core (hates water), hydrophillic surface, connected by ester links

how do items cross the plasma membrane? O2, CO2 and H2O

O2 and CO2 are small and can diffuse across easily, H2O is pushed along by protein channels

What is facilitated diffusion?

when a molecule crosses the cell membrane through a protein channel, going from high to low concentration. No ATP energy needed, just flows from high to low conc

What is Co-transport

Co-transport is a form of active transport, and is when two substances go through a protein channel, and crosses the cell membrane, and the two substances either go together (one pulls the other, symport), or one substance goes in, while another goes out (antiport)

What is symport?

symport is a kind of co-transport, where 2 substances go together through the protein channel, and crosses the cell membrane

what is antiport?

antiport is a kind of co-transport, and is when one substance’s downhill movement powers the other’s uphill movement the other way, basically the substances go in opposite directions

What are ABC Transporters?

ABC transporters is an example of active transport, and they are membrane proteins that use ATP directly to pump substances across a cell membrane

Does protein secretion for bacteria use ATP energy?

yea

What are the roles of plasma membrane? 3 things

Capturing energy, holding sensory systems, and is a permeablity barrier (controls what goes in out), but doesnt control the cell’s shape or strength

What is the bacteria cell wall?

They give the cell their shape, and protects the cell from osmotic lysis/mechanical forces, and is made up of a matrix of crosslinked strands of peptidoglycan subunits

what is osmotic lysis?

Osmotic lysis is when a cell bursts because too much water flows in, which bacteria normally prevent with their strong cell wall.

What are peptidoglycan subunits made of

N-acetylmuramic acid (NAM), peptide chains, and N-acetylglucosamine (NAG)

What do B-lactam antibiotics do?

they prevent peptidoglycan crosslinking by creating a ring, and some bacteria can destroy this

What are 3 features of gram-postitive cells?

they have a thick outer layer of peptidoglycan, they have a narrow periplasmic space, and have negatively charged teichoic acids within the peptidoglycan

what are 3 features of gram-negative cells?

they have a very thin layer of peptidoglycan, their periplasmic space varies, and the outer membrane is made out of lipopolysaccharides (LPS)

What did Hans Christian Gram do?

he created the stain method to seperate cells into 2 classes

using the hans christian gram stain method, what will the end result be?

gram negative cells will be stained pink, and pram positive cells will be purple, alcohol will be absorbed by the large pores in gram positive cells, and the alcohol removes outer membrane lipids in gram negative cells

How do nutrients get through the cell wall of gram negative and positive cells?

gram positive - the peptidoglycan layer has large pores which let nutrients sink through
gram negative - they have TonB Proteins in the outer membrane that help it through

What are flagella?

flagella are made up of protein subunits and are like little hairs that extend from the cell that provide motility for the cell

What are 4 kinds of flagella?

monotrichous - has one hair
amphitrichous - 2 hairs, one on each side,
lophotrichous - a tuft of hair on one side,
peritrichous - a bunch of hair all over

What are the three pieces of a flagella?

the filament of multiple flagellin proteins, the hook protein, which connects the filament to the basal body, and the basal body, a disk like structure that turns the filament like a propeller

What is the term for the energy force used to spin flagella

proton motive force (PMF)

How do cells move using flagella?

it either is tumbling to turn around, or running in a straight line. it can either:
randomly walk around
positive chemotaxis - run towards something, like a chemical
negative chemotaxis - run away from something, like a chemical

how do cells without flagella move?

it can either have gliding motility, or twitching motility, twitching motility uses pili that extend, attach to something and it pulls itself along