MCRO 251: Unit 1

Which of the following acts as a selective barrier between the interior and exterior of a cell?

** - cytoplasmic membrane - cell wall - capsule

The cells of which microorganisms contain membrane-bound organelles?

**Eukarya Bacteria Archaea

Eukaryotic organisms can be:

**Multi-celled Acellular **Single-celled

Technically speaking, viruses are not microorganisms because they are not:

**composed of cells big enough for life

Characteristics of archaea that are similar to bacteria include the:

**energy sources used **shapes **method of multiplication **prokaryotic cell structure ribosomal RNA sequences

Symptoms associated with small amounts of lipopolysaccharide (LPS) in the body tissues (such as muscle tissue) are due to:

**the body's defense system trying to remove the perceived invader direct toxicity of the LPS molecule in human cells

Functions of proteins embedded in the cytoplasmic membrane include:

- **providing the cell with a mechanism to monitor and adjust to its surroundings - **allowing nutrients to enter and waste products to exit the cell - providing the cell with ability to move towards light - **catalyzing chemical reactions that are essential to the cell

Bacterial cell components are medically relevant because they:

- Are potential targets for antibacterial medications used to treat infectious diseases - Can be used to help identify bacterium causing an infectious disease

Which of the following are medically relevant endospore-producing genera?

- Bacillus - Clostridium

Which of the following are functions of membrane transport systems?

- Breakdown nutrients for energy creation - **Allow nutrients to enter cell - **Expel wastes from cell

Parts of the lipopolysaccharide molecule:

- Lipid A - O antigen

If you interfered with the ability of a bacterium to produce a capsule or slime layer, the cell might no longer be able to:

- adhere to teeth - form biofilms - adhere to rocks

Endospores

- are very resistant to damaging conditions, including high heat, toxic chemicals, and UV light - can germinate to produce vegetative cells, which can then multiple - are common in soil, and therefore can be found nearly anywhere

Bacillus and Clostridium vegetative cells are likely to begin sporulation in response to _______.

- depletion of nitrogen - depletion of carbon

Which eukaryotic cell types have a cell wall?

- fungal - plant

Which eukaryotic cell types have a cell wall?

- plant - fungal

Bacterial cells have _______ (number) chromosomes

1

One endospore gives rise to _______ vegetative cell.

1

What two macromolecules make up the major component of cell membranes?

Lipids Proteins

Which of the following bacterial components is/are referred to as endotoxin?

Lipopolysaccharide

Which of the following bacterial components is/are referred to as endotoxin?

Lipoposaccharide

Spirochete

Long spiral-shaped cell with a flexible cell wall and a unique mechanism of motility

Who helped disprove spontaneous generation?

Louis Pasteur

Which term is used exclusively to describe water's movement across a selectively permeable membrane?

Osmosis

_____________ is the most thoroughly studied of a group on antibiotics that prevents the cross-linking of adjacent glycan chains in peptidoglycan.

Penicillin

What is responsible for synthesizing proteins?

Ribosomes

Isotonic

Solution that is equal in concentration

Which of the following statements is false?

Some bacteria obtain energy from foods similar to what humans eat Bacteria typically multiply by binary fission Some bacteria obtain energy from sunlight Some bacteria obtain energy from sources not used by animals or plants **Most bacteria cause serious diseases Shapes include rod-shaped, spherical, and spiral

Which cell structure provides strength and rigidity to a cell?

cell wall

Which structure acts as a cell's gatekeeper, determining what can enter and exit the cell?

cytoplasmic membrane

The prokaryotic cell envelope consists of which of the following?

cytoplasmic membrane capsule (if present) cell wall

The _______ is a flexible molecule framework throughout the cytoplasm that anchors organelles and permits shape changes in some organisms.

cytoskeleton

Which of the following describes the effect of lysozyme on a bacterial cell?

damages peptidoglycan that has already been synthesized

Which of the following are groupings of cells resulting from the division process?

diplococci grape-like clusters cubical packets chains

A significant difference in which of the following characteristics provides the basis for separating archaea and bacteria into two different domains?

energy sources used **ribosomal DNA sequences cell wall composition habitats

For the name Streptococcus pyogenes, the first part (Streptococcus) indicates the ___________ and gives information about the shape of the organism.

genus

The _________ stain technique allows microbiologists to differentiate bacteria based on their cell wall composition/structure.

gram

Based on the genus name Staphylococcus, a reasonable assumption is that the cells form which common grouping?

grape-like clusters

What triggers endospore germination?

heat

Prions are

infectious proteins

The outer membrane of a gran-negative cell is a lipid bilayer that contains

lipopolysaccharide

Compared to the diversity of plants and animals, microbes as a group are:

more diverse

The structure of peptidoglycan can be compared to a

multi-layer chain-linked fence (it is flexible)

Plasmids carry _______ genes.

nonessential

The chromosome of bacterial cells is found in the ___________.

nucleoid

The key structural difference between eukaryotic and prokaryotic cells is the presence or absence of a ________.

nucleus

Neisseria gonorrhoeae is a diplococcus. This indicates that the bacteria occur as:

pairs of cells

The strength of the bacterial cell wall is due to the layer of:

peptidoglycan

Bacteria that often vary in their shape are known as _________ bacteria.

pleomorphic

The periplasm filled with ________, involved in many cellular activities.

proteins

Eukaryotes such as algae and protozoa are also referred to as

protists

Lipid A

recognized by the immune system as a sign of invading Gram-negative bacteria

The cell membrane is a ________ permeable barrier of the cell

semi

Vibrio

short, curved rod

Compared to sporulation, the process of germination is _________.

shorter/faster

molecules that pass freely through a lipid bilayer can move across the cytoplasmic membrane by ____ diffusion

simple

Some bacteria are covered with a diffuse and irregular substance called a __________ ___________.

slime layer

A coccus is bacterium that has a ________ shape, whereas a rod (or bacillus) is a bacterium that has a ________ shape.

spherical; cylindrical

If a cell has more than enough of a carbon source, but not enough nitrogen, then that cell might produce _____________.

storage granules

Hypertonic

the more concentrated solution

O antigen

used to distinguish among different species or strains of bacteria

Unlike the term microorganism, the term microbe also includes:

viruses

Prokaryotic ribosomes are _____; eukaryotic ribosomes are _____.

70S;80S

If you discover a single-celled organism that is 50 micrometers wide and has a nucleus, it most likely belongs to which domain?

Bacteria **Eukarya Archaea

Motile bacteria move toward a chemical attractant or away from a chemical repellent by a process called ________.

Chemotaxis

Spirillium

Curved rod long enough to form spirals

T/F: The gram-negative cell wall has thicker peptidoglycan than the gran-positive wall

False

Long protein structures responsible for most types of prokaryotic motility are called _____________.

Flagella

Which type of cell wall has the thickest layer of peptidoglycan?

Gram positive

Hypotonic

The less concentrated solution

Some scientists were skeptical of Pasteur's results because they

They could not reproduce his results

T/F: Eukaryotic microbes are generally larger than prokaryotic microbes

True

T/F: Materials can be transferred form the lumen of one organelle to another.

True

Which of the following is/are true regarding viruses?

Viruses are nonliving (cannot reproduce independently) Viruses are smaller than most bacteria Viruses are acellular

Which microorganisms typically lack a nucleus?

Yeast Algae **Archaea **Bacteria Protozoa

Peptidoglycan is composed of:

an alternating series of three major amino acid subunits **glycan chains connected by peptide chains

The main function of fimbriae is to _______ to cells and other surfaces.

attach

Penicillin interferes with the synthesis of peptidoglycan and lysozyme degrades peptidoglycan. Based on this information, you can conclude that penicillin and lysozyme may result in bursting (lysing) of which type of cells?

bacteria