Bio 101/ Natural Selection-Bugs that Resist Drugs {ch. 14}

In strains of bacteria that are not resistant to beta-lactams, which of the following parts of the bacterial cells are disrupted by the antibiotic?

the cell walls

Which of the following changes in a bacterial cell might reduce the effectiveness of beta-lactam antibiotics?

the presence of enzymes that are able to break down the antibiotic

The _______ _______ allows the virus to bind to cell-surface proteins of a host cell and move in to the cell {The specific binding of the virus to cell receptor restricts the virus to infecting only certain cells }

viral capsid

the Capsid may possess a _______ __________ ---> a lipid bilayer membrane formed by the host cell

viral envelope

Which of the following factors may prevent most people from developing more than minor skin blemishes when they suffer a staph infection?

- Their immune systems are preventing the infection from spreading. - Helpful bacteria on their skin keep staph in check. - Their skin is a physical barrier that keeps out the bacteria.

Why aren't human populations evolving to produce immune systems that are able to fight off MRSA and other "superbugs"?

- because we may not have the mutations that would improve our immune systems - because the rate of human evolution is much slower than bacterial evolution

Which of the following processes have been shown to contribute to the evolution of antibiotic resistance in S. aureus?

- gene swapping with other bacterial strains - genetic mutations during S. aureus reproduction

What are the three countries where polio is still endemic?

1. Pakistan (originated here) 2. Afghanistan 3. Nigeria

What are the 3 ways that Natural selection can alter variation in a population?

1. Stabilizing selection. 2. Directional selection. 3. Disruptive selection

Why is the evolution of antibiotic resistance in bacteria happening so quickly?

A-D! a. because of overuse of antibiotics in humans b. because bacteria can reproduce so quickly c. because any use of antibiotics will select for resistant bacteria d. because of overuse of antibiotics in livestock

The process by which populations become better suited to their environment as a result of natural selection

Adaptation

Chemicals that either kill bacteria or slow their growth by interfering with the function of essential bacteria cell structures. {really should be called anti-bacterials}

Antibiotics

Antibiotic-resistant strains of bacteria tend to first be found in hospitals. Which of the following factors explains why this is the case?

Antibiotics are more likely to be present in hospitals, thus selecting for resistant strains.

The _____ ______ mosquito is from S.E. Asia and can transmit West Nile Virus, several forms of encephalitis, and Dengue Fever. {they breed in very small bodies of water, such as the base of bromeliads... They can breed in very small collections of water in your backyard!}

Asian TIger

__________ populations exist nearly everywhere, including on and in our bodies; most are harmless or even beneficial, but some can cause disease. They reproduce asexually and acquire genetic variation by mutation and gene transfer.

Bacteria

a type of asexual reproduction in which one parental cell divides into two.

Binary Fission

what refers to to an individual's or group's ability to survive and reproduce under particular environmental conditions?

Biological Fitness

Viruses are infectious particles enclosed in a protein coat ________.

Capsid

Viruses are __________ __________. The host range may be very limited, or may be broad.

Cellular Parasites

A type of natural selection in which organisms with phenotypes at one end of a spectrum are favored by the environment {acts against individuals at one of the phenotypic extremes}

Directional Selection

How can ecological disturbance, such as habitat loss, contribute to the outbreak of a new viral disease in humans?

Disturbances bring humans and reservoir hosts together in new ways

A type of natural selection in which organisms with phenotypes at both extremes of the phenotypic range are favored by the environment. {favors individuals at both extremes of the phenotypic range (common in formation of new 'species.')}

Diversifying Selection or Disruptive Selection

once you contract it, which has the greatest risk of death?

Ebola

Change in allele frequencies in a population over time

Evolution

The relative ability of an organism to survive and reproduce in a particular environment.

Fitness

What is the natural reservoir host for Hendra virus?

Fruit bats

Viral proteins are made in the _______ cell using genetic information from the _______ genome!

HOST VIRAL

_______ _______ _____________ copies DNA.

Host DNA Polymerase

_______ _____ ______________ makes RNA - has a much higher error rate than DNA Polymerase!

Host RNA Polymerase

Viruses that can move between different species are almost __________ to eradicate because the virus is basically hiding in various species when it is not infecting humans.

Impossible

which is a greater public health risk in the United States?

Influenza

What is a zoonotic disease?

It is a disease that moves from an animal to humans

How was the Asian Tiger Mosquito introduced to the United States?

It was first identified in Houston, TX, in the 1980's

A bacterial cell that is resistant to a particular antibiotic may spend a large amount of energy producing the modified proteins that are needed for resistance. In such a case, what would be the effect on this cell's fitness if no antibiotic was present?

Its fitness would be lower than other strains that lack resistance because it is spending energy that the resistant strains can use for other purposes, such as reproduction.

In the ____________ cycle, the bacteriophage genome of the host bacterium and is replicated every time the bacterium divides, but without the production of intact viruses.

Lysogenic

In the _______ cycle, bacteriophage grow and bacterium lyses to release the newly formed viruses

Lytic

Differential survival and reproduction of individuals in response to environmental pressure that leads to change in allele frequencies in a population over time

Natural Selection

________ _____________ acts on populations; not individuals. Individuals can not evolve!

Natural Selection

A group of organisms of the same species living together in the same geographic area.

Population

within ANY ______________, there is genetic variation among individuals.

Population

The viral genome contains a gene that encodes for ________ _____________ ---> a unique enzyme that can use RNA as a template for the synthesis of DNA.

Reverse Transcriptase

Anyone who has had Chickenpox, __________ ______ the virus!

STILL HAS

___________ is the result of dormant Varicella-Zoster virus (it causes Chickenpox), becoming reactivated. The virus travels along nerve pathways and erupts at the skin.

Shingles

Naturally occurring _________ was largely eradicated by the 1980's due to a worldwide vaccination program. {This was the FIRST disease eliminated due to human efforts}

Smallpox

in 1918 the "_________ _____" Pandemic caused 20-50 million deaths

Spanish flu

A type of natural selection in which organisms near the middle of the phenotype range of variation are favored by the environment {favors intermediate phenotypes}

Stabilizing Selection

What is a valid summary of Natural Selection?

The individuals with most favorable characteristics have the most offspring.

What is meant by 'Survival of the Fittest?'

The offspring that just happen to have the inheritable characteristics that allow them to survive are favored.

If you examine a natural population of bacteria, it is common to find some antibiotic-sensitive and some antibiotic-resistant strains, even if the population has never been exposed to any antibiotic. Which of the following explanations could account for this situation?

The resistant strain developed as a mutation and had no negative effect on fitness.

Viruses may be transmitted between hosts by a _________. Biting insects commonly serve as vectors -- this is basically a delivery system for the virus.

Vector

development of _________ _________ is due to accumulation of mutations and reorganization of genetic material

genetic diversity

An organism's fitness depends on its __________.

ability to survive and reproduce

An individual who carries staph but isn't sick is referred to as _______.

colonized

what are the patterns of natural selection?

diversifying selection stabilizing selection directional selection

In a _____________ _________ __________ , those individuals who have the greatest reproductive success shape the characteristics of future generations!

genetically diverse population

Viruses can NOT replicate on their own -- they must take residence within the cells of a ________.

host

What is a host?

individuals of the same species or between different species

How is West Nile Virus transmitted?

mosquitoes

What is the evolutionary process that causes antibiotic-resistant bacteria to increase and antibiotic-sensitive bacteria to decrease in an environment where antibiotics are present called?

natural selection

Currently, there is an outbreak of _______ in Syria. The civil war has disrupted vaccination programs and international efforts are underway to vaccinate the population.

polio

populations of ____________ reproducing organisms acquire genetic variation by mutation and by meiosis and fusion of gametes.

sexually

A bacterial cell with which of the following modifications might be resistant to antibiotics such as methicillin?

the ability to produce an enzyme that breaks down the antibiotic