Biology 101: Intro to Biology Ch 15. Microbiology: Cellular Structure & Processes in Bacteria & Protists

Bacteria

a single-celled unicellular microorganism that doesn’t have a nucleus or any other membrane-bound organelles

Prokaryotes

• means ‘before the nut’

• they don’t have a nucleus and lack membrane-bound organelles

Capsule

protective, often slimy, coating, often of sugars, that helps to protect the bacterium

Virulent

more likely to cause disease

Cell Wall Peptidoglycan

• a protein and sugar compound

• gives the cell some rigidity and protection

Cell Membrane

• acts by coordinating the passage of molecules into and out of the cell

• protective layer that helps to separate the cell from its external environment

Cytoplasm

serves as a medium through which molecules are transported, as well as a system to maintain conditions (like temperature and pH) that are best for the cell

Ribosomes

• main site for the bacterium’s protein synthesis

• organelles responsible for synthesizing all proteins

Nucleosome

a basic unit of chromatin

Nucleiod

the region where the bacterium’s DNA is located

Flagellum

the means by which the cell moves around

Taxonomy

classification

Domains

a taxonomic level that is higher than a kingdom, and based on an organism’s DNA

Shape

• bacilli are round shaped

• cocci are round

Gram stain

• bacteria are subjected to a chemical stain

• depends on the amount of peptidoglycan in the cell wall

Antibiotic Sensitivity

preventing the peptidoglycan from forming properly

Oxygen Requirement Aerobes

require oxygen to carry out their day-to-day metabolic processes

Anaerobes

• the ones that live in the human digestive tract

• an organism that doesn't require oxygen for growth

Nutrition Autotrophs

they can make their own food

Heterotrophs

• require an outside source of nutrition

• organisms that source their nutrition from organic matter with carbon

Which of the following terms describes a bacterial cell that does not require oxygen for its metabolic processes?

1. Aerobe

2. Heterotroph

3. Anaerobe

4. Autotroph

Anaerobe

You discover a new species of bacteria. In your notes, you write down that it requires oxygen to carry out its metabolic processes, that it has a very thin wall of peptidoglycan in its cell wall, and is unable to make its own food. Which of the following terms correctly describes this form of life?

1. Aerobic, Gram negative, heterotrophic

2. Anaerobic, Gram positive, autotrophic

3. Anaerobic, Gram Negative, autotrophic

4. Aerobic, Gram positive, heterotrophic

Aerobic, Gram negative, heterotrophic

Which of the following is NOT one of the current classifications of domains of life?

1. Monera

2. Bacteria

3. Archaea

4. Eukarya

Monera

Which of the following terms correctly describes the shape of the bacteria cells in the picture below?

1. Spirilli

2. Gram positive

3. Bacilli

4. Cocci

Bacilli

Which of the following statements about peptidoglycan is FALSE?

1. Peptidoglycan is affected by the use of antibiotics.

2. A thicker layer of peptidoglycan means the cell is Gram positive.

3. A thicker layer of peptidoglycan means the cell would be pink after Gram staining.

4. Peptidoglycan is a protein/sugar complex.

A thicker layer of peptidoglycan means the cell would be pink after Gram staining.

Phylogenetic Tree

traces the evolutionary history organisms, and indicates common ancestors

Microbes

tiny, single-cell organisms which cannot be seen by the naked human eye

Flagella

thread-like structures that allow organisms to move by propelling them through their environment

Peptidoglycans

• a molecule composed of both protein and sugar rings

• a complex molecule composed of alternating units of N-acetylglucomine (NAG) and N-acetylmuramic acid (NAM) cross linked by short peptides

Extremophiles

organisms that are adopted to extreme environments

Some bacteria:

1. are eukaryotes

2. can form spores

3. are large enough on their own to be seen unaided, with the naked eye

4. are archaea

can form spores

Archaea have been found to live in:

1. all answer choices are correct

2. freezing waters

3. hot springs

4. pools with high salt content

all answer choices are correct

E.coli, Salmonella, and Lactobacillus are

1. extremophiles

2. archaea

3. bacteria

4. eukaryotes

bacteria

Halococcus is ...

1. an archaea.

2. a eukaryote.

3. a bacterium.

4. non-existant.

an archaea.

Archaea and bacteria:

1. do not share common shapes

2. are genetically different

3. have the same genes for flagella

4. differ in size

are genetically different

The Tree of Life:

1. has three major branches: archaea, bacteria and eukarya

2. has two major branches: archaea and eukarya

3. has two major branches: archaea and bacteria

4. has two major branches: eukarya and bacteria

has three major branches: archaea, bacteria and eukarya

Cocci

spherical, resembling tiny balls

Bacilli

small rods, longer than they’re wide

Spiral

twisted in helices and resemble little cork screws

Single

lives as one cell

Diplo

live in pairs

Tetrad

four cells forming a flat square

Sarcina

cube-like group of eight cocci

Strepto-

form long chains

Staphylo-

form an irregular, grape-like cluster

Vibrio-

curved, resembling a comma

Spirillum

thick cell walls and flagella

Spirochete

thin, flexible cell walls that lack flagella

Under a microscope, which organism would appear as a chain of rod-shaped cells?

1. Diplobacillus

2. Streptobacillus

3. Sarcina

4. Vibrio

Streptobacillus

Which of the following BEST describes the bacteria in this image?

1. Staphylococcus

2. Sarcina

3. Diplobacillus

4. Streptococcus

Staphylococcus

Under a microscope, which organism would appear as a grape-like cluster of round cells?

1. Vibrio

2. Sarcina

3. Staphylococcus

4. Streptococcus

Staphylococcus

The three forms of spiral bacteria are _____.

1. spirochete, bacillus and cocci

2. staphylococcus, streptococcus and tetrad

3. vibrio, spirillum and spirochete

4. vibrio, spirillum and sarcina

vibrio, spirillum and spirochete

Bacillus is a genus of bacteria that also refers to what cell shape?

1. Vibrio

2. Spherical

3. Sarcina

4. Rod

Rod

Aerobe

an organism that needs oxygen to grow

Obligate Anaerobe

organisms that use an anaerobic metabolism to grow and are killed in the presence of oxygen

Aerotolerant Anaerobes

organisms with an anaerobic metabolism that can live in oxygen or oxygen-free environments

Facultative Anaerobes

prefer to grow using aerobic metabolic processes but can switch to an anaerobic metabolism in the absence of oxygen

Archaea

a domain of single-celled microorganisms

Methanogens, acetogens, and staphylococcus are all examples of:

1. Anaerobes

2. Fungi

3. Aerobes

4. Viruses

5. Obligate aerobes

Anaerobes

Organisms that prefer to grow using aerobic metabolic processes but can switch to an anaerobic metabolism in the absence of oxygen are known as:

1. Aerotolerant anaerobes

2. Obligate aerobes

3. None of the answers are correct

4. Facultative anaerobes

5. Obligate anaerobes

Facultative anaerobes

An organism that needs oxygen to grow is known as:

1. An anaerobe

2. An obligate anaerobe

3. An aerobe

4. None of the answers are correct

5. An aerotolerant anaerobe

An aerobe

Organisms with an anaerobic metabolism that can live in oxygen or oxygen-free environments are known as:

1. Obligate anaerobes

2. Obligate aerobes

3. Facultative anaerobes

4. None of the answers are correct

5. Aerotolerant anaerobes

Aerotolerant anaerobes

Organisms that use an anaerobic metabolism to grow and are killed in the presence of oxygen are known as:

1. Facultative anaerobes

2. Obligate anaerobes

3. None of the answers are correct

4. Aerotolerant anaerobes

5. Obligate aerobes

Obligate anaerobes

Osmosis

the movement of water through a semipermeable membrane from areas of low solute concentration to areas of high solute concentration

Cell Envelope

composed of cell membrane and a cell wall

Cell Wall

rigid, carbohydrate-containing structure that surrounds the bacterial cell

Gram-Positive

multiple peptidoglycan layers forming very thick, rigid cell walls

Gram-Negative

only one or two layers of peptidoglycan that is covered by an outer membrane

Periplasm

jelly-like layer between the outer membrane and the cell membrane

Starting from inside the cell, what is the correct order of cell envelope components in Gram-negative bacteria?

1. Outer membrane, peptidoglycan, cell membrane

2. Phospholipid bilayer, porins, LPS,

3. Cell membrane, peptidoglycan layers

4. Cell membrane, periplasmic space, peptidoglycan, outer membrane

5. Cell membrane, periplasmic space, peptidoglycan

Cell membrane, periplasmic space, peptidoglycan, outer membrane

What is the relationship between osmosis and the bacterial cell wall?

1. The cell is hypotonic and the wall prevents lysis from osmotic pressure.

2. The cell is hypertonic and the wall prevents lysis from osmotic pressure.

3. The cell is hypotonic and the wall prevents water molecules from leaving.

4. The wall allows the cell to expand when water enters and increases the osmotic pressure.

The cell is hypertonic and the wall prevents lysis from osmotic pressure.

Which statement about the cell wall is FALSE?

1. Cell walls allow some molecules to pass through.

2. Peptidoglycan is the primary component of cell walls.

3. Different bacterial species can have different cell wall structures.

4. All bacteria have a cell wall.

5. The cell wall maintains the cell shape.

All bacteria have a cell wall.

What are the two major functions of the peptidoglycan structural layer?

1. To prevent cell lysis and prevent water from leaving the cell

2. To separate the cell membranes and generate energy for the cell

3. To transport ions through the wall and produce endotoxins

4. To transport nutrients into the cell and synthesize porins

5. To prevent cell lysis and allow molecules to pass through the wall

To prevent cell lysis and allow molecules to pass through the wall

Which statement is TRUE of Gram-positive bacteria?

1. They use teichoic acid to move ions across the cell wall.

2. They are freely permeable to disinfectants.

3. They have a double membrane.

4. They have a thin peptidoglycan layer.

5. They can release porins to poison the host.

They use teichoic acid to move ions across the cell wall.

Protist

any eukaryotic organism that isn’t an animal, plant, or fungus

Organelles

tiny organs that each serve a different function within the cell

Mitochondria

organelles responsible for turning food into energy

Chloroplasts

organelles that are able to capture sunlight and turn it into sugars

Eyespot

organelle that helps them detect light, so they can head towards or away from light as they desire

Bioluminescence

glowing in the dark

Red tide

reddish/brownish water you might see at coastlines

Algae

plant-like protists

Protists that are able to make their own food are called:

1. dinolflagellates

2. diatoms

3. photosynthetic

4. kelp

photosynthetic

Protists might use any of the following structures to move, except

1. feet

2. flagella

3. false feet

4. cilia

feet

Which protist is responsible for making ocean water glow?

1. giant kelp

2. diatom

3. paramecium

4. dinoflagellate

dinoflagellates

An eyespot would help a protist find

1. light

2. bacteria

3. other protists

4. food

light

Which word best describes Protists?

1. plain

2. typical

3. common

4. diverse

diverse

Gametes

germ cells

Binary Fission

• represents the primary method of asexual reproduction in protists

• one protist pinches in and divides into two

How do slime molds mature?

1. They require different hosts for their larval and adult stages

2. They go through multiple larval stages before reaching maturity

3. They go into a chrysalis and emerge later as full adults

4. They reach maturity immediately as a result of asexual reproduction

They go through multiple larval stages before reaching maturity

Which of the following is NOT true of protists?

1. Parasitic protists might need multiple types of hosts in their life cycle

2. They are prokaryotic

3. They reproduce both sexually and asexually

4. They can be single- or multi-celled organisms

They are prokaryotic

Why would a protist go through a dormant larval stage?

1. There are no protists that go through a dormant stage

2. All protists go through one as a part of their life cycle

3. They would go through one only if they were a slime mold

4. They might go through one if resources were scarce

They might go through one if resources were scarce

What biological category do protists fall under?

1. Plant

2. Animal

3. None of the answers are correct

4. Fungus

None of the answers are correct

Which of the following is true of asexual reproduction in protists?

1. Gametes combine to form a new organism

2. The daughter cells are genetically identical to the parent

3. It begins with the parent absorbing another protist into itself

4. It requires two separate protists to start the process

The daughter cells are genetically identical to the parent

Heterotrophic Protists

• feed on organic nutrition sources

• examples include water molds and slime molds

Sexual Reproduction

genetic material from two parents contributes to the formation of offspring

Asexual Reproduction

reproduction where one parent doubles its DNA and splits into two cells

Budding

occurs when a daughter nucleus is generated and splits from the ancestral nucleus along with a portion of the cell's cytoplasm

Sexual Conjugation

a sexual process whereby two organisms temporarily connect and exchange genetic material

Filter Feeding

the organism's own structures generate a flow of water towards it, whereby a filter catches small nutrient pieces