UPDATED BIO 1101 EXAM 4 OSU

What is the number of bacteria in one human's mouth compared to the total number of people who have ever lived?

Greater than the total number of people who have ever lived.

Where do more than half of our antibiotics come from?

Soil bacteria of the genus Streptomyces.

What are the five characteristics of bacteria?

Prokaryotic cells, reproduce by binary fission, have peptidoglycan, single circular strand of DNA, and no nucleus.

What is peptidoglycan?

A vital component of the bacterial cell wall that gives strength to the cell wall.

How do bacteria reproduce?

By binary fission.

What is the shape of bacteria classified as 'Coccus'?

Round (berries).

What is the shape of bacteria classified as 'Bacillus'?

Rod-shaped (staff).

What is the shape of bacteria classified as 'Spiral'?

Various spiral shapes (coiled spring shape).

What percentage of human illnesses are caused by bacteria?

Approximately 50%.

How quickly can a bacterium reproduce under ideal conditions?

Every 20 minutes.

What are the two types of bacterial toxins?

Endotoxins and exotoxins.

What is an example of a potent exotoxin?

Exotoxin from clostridium botulinum.

What is botulism?

A type of food poisoning caused by eating food containing exotoxins.

What is an endospore?

A specialized bacterial cell structure that can withstand extreme conditions.

What do viruses consist of?

Either DNA or RNA as a genetic core and a tough protein coat/capsule.

What is the first step in the viral infection process?

Viral Attachment: the virus attaches to host cell

What happens during viral penetration?

Viral genetic material enters the host cell.

What enzyme does HIV use to convert RNA into DNA?

Reverse transcriptase.

What is the significance of viral DNA incorporation?

Infection can become permanent after this step.

What are the two basic release pathways for viruses?

Budding and lysis.

Why is herpes considered a permanent viral infection in humans?

It integrates into the host's DNA.

What is MRSA?

A bacterial infection largely controlled with one antibiotic but can become resistant.

What colors do gram-positive and gram-negative bacteria stain?

Gram-positive stains purple; gram-negative stains red.

What is the role of plasmids in bacteria?

They provide additional DNA, which can confer extra characteristics.

What is the typical lifespan of an endospore?

Can last centuries.

What is the primary function of antibiotics targeting peptidoglycan?

To stop bacterial growth.

How does botox work?

It is a neurotoxin that kills part of a nerve cell, allowing the body to repair it.

What is the result of a single bacterium reproducing every 20 minutes for 10 hours?

It can produce 1 billion bacteria.

What virus invades nerve cells permanently?

Herpes

What is the typical cycle of the West Nile Virus?

Mosquitoes and birds

What happens when mosquitoes can't find birds?

They may bite humans, causing infection.

What percentage of humans infected with West Nile Virus become ill?

10%.

What is the mortality rate for humans infected with West Nile Virus?

1%.

What is the mortality rate for horses infected with West Nile Virus?

40-60%.

What pathogen causes influenza?

An RNA virus called influenza.

How many types of influenza virus are known?

Four specific types: A, B, C, and D.

What tissue is primarily affected by influenza in humans?

Lungs.

How many deaths does influenza cause on average per year in the U.S.?

About 20,000.

What is the natural reservoir for influenza?

Birds.

What was the death toll of the 1918 Spanish Flu pandemic?

50 million deaths.

What was the death toll of the 1957 Asian Flu pandemic?

1-4 million deaths.

What is antigenic drift in influenza?

It occurs when the virus is mutated during assembly.

What is antigenic shift in influenza?

It occurs when an organism is infected with multiple strains, creating a new strain.

Why do we get flu shots every year?

Due to antigenic drift and shift.

What are the two surface antigens of the influenza virus?

N (enzyme) and H (fixed protein type).

How can washing hands inactivate the influenza virus?

Soap and water break apart the lipid envelope of the virus.

What is the most common virus causing the common cold?

Rhinovirus.

How far can particles from a sneeze travel?

2-3 meters.

What is a prion?

A pathogenic protein that can influence other proteins to change configurations.

Who suggested that pathogenic proteins can influence other proteins?

John Stanley Griffith.

Who won the Nobel Prize in 1997 for research on prions?

Stanley B. Prusiner.

What do spongiform encephalopathies cause in nerve tissue?

They cause it to become spongy.

What is a consequence of prion proteins changing the shape of nerve tissue?

Loss of motor functions.

What causes mad cow disease?

Prions

How do prions affect the nervous tissue?

They puncture holes, causing loss of motor functions.

What is scrapie?

A prion disease in sheep that causes them to scrape themselves.

What happens when sheep start scraping due to scrapie?

They scrape until they kill themselves or are culled by farmers.

What is CJD?

A permanent and deadly prion disease in humans.

What is chronic wasting disease?

A prion disease in deer/elk that makes them feel chronically full.

How does chronic wasting disease affect deer/elk?

They stop eating and wither away.

How are prion diseases spread?

Through body fluids or consumption of infested tissue.

Are normal disinfectant methods effective against prions?

No, they are useless.

What temperature is needed to deactivate prions in meat?

No temperature safely deactivates the prion.

What does the term evolution refer to in biology?

The confusion of abiogenesis, evolution, and speciation.

What is abiogenesis?

The beginning of life, the point when there was no life.

What are the three distinct subjects often confused in biological evolution?

Abiogenesis, evolution, and speciation.

What is the significance of the Earth's age in relation to abiogenesis?

It relates to the time frame when life began.

How old is the Earth?

4.6 billion years

What is the age of the oldest rocks containing life forms?

3.5 billion years

What does organic 'biological' evolution deal with?

Living organisms

How long ago did the idea of evolution date back to?

At least 3,500 years ago (500-600 BCE)

Who developed the idea of inheritance of acquired characters?

Jean-Baptiste de Lamarck

What did Malthus document about populations?

Populations rapidly increased in numbers

What is spontaneous generation?

The idea that complex living organisms arise spontaneously from non-living materials

Who disproved spontaneous generation in the 1600s?

Louis Pasteur

What is the hypothesis proposed by Louis Pasteur?

Cells arise from cells; cells do not arise by spontaneous generation

What is the title of Darwin's book published in 1859?

The Origin of Species

What is natural selection?

The mechanism that drives evolution

What does 'survival of the fittest' mean?

Individuals best adapted to their environment survive and leave offspring

What is the relationship between evolutionary fitness and offspring?

Evolutionary fitness is defined as leaving offspring

What happens to individuals that are 'selected against'?

They are less likely to survive and reproduce

What is artificial selection?

Restricting mating to individuals with desired characteristics

What is directional selection?

A shift in allele frequencies in a single constant direction

What can cause resistance in organisms?

Direct selection for traits that afford tolerance to exposure

How long does the average fruit fly live?

30 days

How many generations did it take to make fruit flies starvation resistant for 160 hours?

60 generations

How many days is 160 hours?

6.6 days

Are species immutable?

No, species can change over time

Can fruit flies become starvation resistant?

Yes

What is an example of an exotic species studied in evolution?

Golden Rain Tree Fruit

What is the native fruit studied alongside the exotic species?

Balloon vine fruit

How long was the time frame for studying the introduction of exotic species?

35 years

What did Isaac Lea study?

Mollusks

What was Isaac Lea's belief about species?

He believed species were immutable, which was later proved wrong.

What is the significance of the Galapagos Islands in Darwin's research?

Darwin visited the Galapagos Islands to collect data for his theories on evolution.

Who independently developed a theory of evolution similar to Darwin's?

Alfred Wallace

Endotoxins

Substance that is part of the bacterial cell (cell well)

Exotoxins

Substance secreted by the bacteria cells (clostridium tetani)

What is the second step in the viral infection process?

Viral Penetration: viral genetic material enters host cell

What is the third step in the viral infection process?

DNA formation: viral genetic material is made into DNA