double practice 456 microbiology

What does the Endosymbiotic Theory tell us?

1. Explains how eukaryotes developed into multicellular structures

2. How eukaryotes developed membrane-bound organelles such as the mitochondria and chloroplasts

How did the mitochondria of eukaryotes organisms evolve?

They came from a symbiotic relationship in which non-photosynthetic prokaryotes were engulfed by a larger cell

How did the chloroplasts of organisms evolve?

They came from a symbiotic relationship in which photosynthetic prokaryotes were engulfed by a larger cell

What are characteristics of prokaryotes?

1. no nucleus

2. no membrane-bound organelles

3. simple structure

4. all unicellular

5. single circular chromosomes

What are characteristics of eukaryotes?

1. nucleus with DNA

2. complex cells

3. membrane-bound organelles

4. multiple linear chromosomes

5. can be unicellular or multicellular

Plasma membrane

Rough ER

Nucleus

Smooth ER

Mitochondria

Ribosome

Cytoskeleton

Flagella

Golgi apparatus

Describe the function of the plasma membrane

Phospholipid bilayer that is a selective barrier and interfaces with extracellular environment

Describe the function of the Cell wall

provides rigidity and protects the cell from mechanical and osmatic stress; gives shape

Describe the function of the glycocalyx

- important in cell adhesion

- protection

- cell communication

Describe the function of the flagella

motility

Describe the function of the cilia

motility and protection (like airways in humans)

Describe the function of the ribosomes

production of proteins

Describe the function of the cytoskeleton

- provides cell shape

- plays an important role in cell movement

- facilitates cargo transport

- protects the cell against external mechanical stress forces

Describe the function of the nucleus

houses the cells DNA and serves as the cells command center

Describe the function of the nucleolus

ribosome production

Describe the function of the nuclear membrane

regulates what goes in and out of the nucleus

Describe the function of the nuclear pores

breaks in the nuclear membrane

Describe the function of the endoplasmic reticulum

- protein production

- modification and folding

- lipid production

- detoxification

Describe the function of the golgi apparatus

-modifies cellular proteins

- build lipids

- sort and distribute the final products

- central to secretion

Describe the function of the mitochondria

generate most of the cells ATP

Describe the function of the peroxisomes

- breaks down fats and amino acids

- protects the cell from hydrogen peroxide

Describe the function of the vacuoles

stores and transports substances

Define endocytosis

process that brings substances ( solid or liquid) into the cell

Describe three types of endocytosis

1. Pinocytosis: (cell drinking) brings liquids into the cell

2. Phagocytosis: (cell eating) brings solids into the cell

3. Receptor-mediated endocytosis: brings specifically targeted substances into the cell

Define exocytosis

Process that exports substances out of the cell

What are 2 ways that eukaryotic cells can divide?

1. Mitosis- asexual division; makes 2 daughter cells that are genetically identical to each other and the original parent cell

2. Meiosis- sexual division; makes 4 haploid daughter cells that are genetically unique

Is binary fission more like mitosis or meiosis?

Mitosis

List the 4 kingdoms of eukaryotes

1. Animalia

2. Plantae

3. Protists

4. Fungi

Define the term saprobe

Organisms that absorb nutrients from dead plants and animals in the environment

What does it mean for fungi to be dimorphic

It can cycle between life forms; one having hyphae (filaments) and yeast-like forms

What are hyphae?

Collections of tubular, filament-like structures used for growth

How are fungi classified

by the type of reproductive spores they produce

What are the 3 groups of protists

1. Protozoans (animal-like)

2. Algae (plant-like)

3. Slime molds and water molds (fungus-like)

What are the 4 groups of protozoans

1. Ciliated

2. Flagellated

3. Amoeboid

4. Spore-forming (apicomplexans)

What is a pseudopod?

"false feet", extensions of their cytoplasm; used for motility and feeding

Define Genetics:

the study of genes, their function, and how variations arise in genomes

Who is the "Father of Genetics"

Gregor Mendel

What is the difference between genotype and phenotype?

Geneotype is the genetic makeup of an organism (their genes) and phenotype is the physiological traits or an organism (their appearance and characteristics)

DNA stands for what?

deoxyribonucleic acid

RNA stands for what?

ribonucleic acid

Nucleic acids, such as DNA, are built from smaller structures called what?

Nucleotides

What are the 4 bases found in DNA?

Adenine, Thymine, Cytosine, Guanine

Is DNA single or double stranded?

double

The sides of the structure are made up of phosphates and sugars held together by what kind of bonds?

Phospodiester

The middle of the structure is made of complementary bases held together by what kind of bonds?

Hydrogen

What are the 4 bases found in RNA?

Adenine, Uracil, Guanine, Cytosine

What are the 3 types of RNA?

Messenger RNA (mRNA)

Ribosomal RNA (rRNA)

Transfer RNA (tRNA)

DNA and RNA are connected through the "Central Dogma of Molecular Biology" This states that:

-DNA directs production of RNA

-RNA directs assembly of proteins

Replicated DNA contains an original parent DNA strand a newly formed DNA strand. Therefore, this is a ________ process.

semiconservative

DNA must be transcribed into what?

mRNA

What are the 3 steps of transcription?

1. Initiation (promoter)

2. Elongation

3. Termination (termination site)

mRNA is translated into what?

protein

What are the 3 steps of translation?

1. Initiation

2. Elongation

3. Termination

Define mutation:

changes in genetic material of a cell or virus

What are some different kinds of mutations?

-Silent

-Reversion

-Nonsense

-Missense

-Frameshift

True of false: All mutations cause harm to the cell?

False

What is a mutagen?

chemicals or physical or biological agents that can increase the rate of mutation in an organism

_____ gene transfer occurs when genetic information passes between cells by a process other than cell division

Horizontal

What are examples of Horizontal gene transfer?

-Conjugation

-Transformation

-Transduction

-Transposons

______ is a type of gene transfer where bacteria take up DNA from their environment

Transformation

Virology

The study of viruses.

Viruses that infect humans

Approximately 220 viruses.

What is a virus?

A small acellular pathogen.

Is a virus living?

No.

Virion

A single infectious particle.

Structural parts of a virus

Viruses contain a capsid and genetic material (nucleic acid), and some may contain spikes and envelopes.

Shapes of animal viruses

Helical, icosahedral, and complex.

Naked virus vs Enveloped virus

Naked viruses lack a coating; enveloped viruses have a lipid structure surrounding the capsid.

Function of viral peplomers (spikes)

They allow viruses to attach to host cells.

Classifying viruses

Viruses can be grouped by type of nucleic acid, capsid symmetry, envelope presence, and genome architecture.

Highest classification level for viruses

Order.

Steps of bacteriophage replication

Attachment, Penetration, Replication, Assembly, and Release.

Attachment (adsorption) in bacteriophage replication

Phage binds to bacterial cell.

Penetration (entry) stage

Phage injects genetic material into the cell.

Replication (synthesis) stage

Phage commandeers host cell factors to transcribe and translate viral genes.

Assembly (maturation) stage

Genome packed into capsid and phage structures assembled.

Release stage in bacteriophage replication

Bacterial cell lyses and new phages are released.

Viral replication pathways

Lytic and Lysogenic.

Lytic pathway

Immediate construction of new virions leading to the destruction of host cells.

Lysogenic pathway

Virus incorporates into host genetic material, forming a prophage.

Additional step in animal virus replication

Uncoating step.

Purpose of uncoating in animal viruses

To get the virus genome into the host cell.

Chronic persistent infections

Viruses continuously release virions, leading to a slow progression of disease.

Example of chronic persistent infection

HIV.

Latent persistent infections

Infections with flare-ups or outbreaks and periods of dormancy.

Example of latent persistent infection

Herpes simplex virus.

Treatment for viral infections

Limited antiviral drugs available.

Target of antiviral drugs

Any step along the replication pathway.

Prion

Infectious misfolded proteins.

Example of prion disease

Transmissible spongiform encephalopathies such as mad cow disease.

Bacteriophages

Viruses that infect bacteria.

Animal viruses

Viruses that infect animals and humans.