BIO212 Exam 2 (Mcgraw-Hill & Quizzes)

Order the following steps for replication cycle of an animal virus 1. release from host cell 2. adsorption (attachment) to host cell surface 3. synthesis of viral nucleic acid and proteins 4. synthesis of viral nucleic acid and proteins 5. assembly of viral particle 8. Penetration and uncoating

2, 6, 3, 5, 1

Most of the medically important multicellular parasites are helminths. TRUE or FALSE

TRUE

Non-enveloped and enveloped viruses both may enter the host via endocytosis. TRUE OR FALSE

TRUE

Pattern recognition is involved in innate immunity TRUE or FALSE

TRUE

Smoking impairs the ciliated cells of the middle portion of the respiratory tract. Many analgesic drugs (painkillers) impair peristalsis (the churning motion of the digestive tract). The result of either of these activities leads to an increased risk of infection in their respective areas. Why?

The actions of the cells in these areas help to propel pathogens out of the area, serving as a part of the physical barrier system. When they are impaired/slowed, bacteria and other pathogens have an easier time adhering to the tissues in the area and causing an infection.

Genotype

The genetic makeup of the organism—in other words, the DNA sequence.

Phenotype

The organism's observable characteristics. For example, presence of a flagellum.

Repressible

These are produced routinely, but their synthesis can be turned off when they are no longer required. These are generally used in anabolic (biosynthetic) pathways.

How do cytokines function?

They are secreted by one cell type, then bind to a receptor on target cell causing a signal within that cell that turns on (or off) certain genes to achieve a response.

If a DNA triplet is AGT, the mRNA codon would be ______ and the tRNA anticodon would be______.

UCA; AGU

Coccidioidomycosis is

a fungal disease caused by Coccidioides sp.

What is required for prion replication?

abnormal prion protein

Phase variation is a phenomenon used by some bacteria (such as E. coli) to evade host immune mechanisms. In this process, the cells

alternately turn genes on/off to adjust bacterial behavior

What is the definitive host in the life cycle of a parasite?

an organism in which sexual reproduction or the adult form of a parasite occurs

Proteins that react specifically with the chemical structures in the antigen that induced them are called

antibodies

Macrophages and dendritic cells are

antigen-presenting cells

Genetic exchange is segmented viruses that allows a zoonotic virus to infect humans is an example of

antigenic shift

Influenza viruses bud from the host cell. Based on this information, the viruses most likely

are enveloped

The Ames test is useful as rapid screening test to identify those compounds that

are mutagens

Normal microbiota

are the organisms that typically reside on and in your body AND protect against infection by pathogens.

Protozoans are an important part of the food chain, ingesting large numbers of

bacteria and algae

viruses that infect bacteria are referred to as

bacteriophages

Chemical mutagens that mimic the naturally occurring bases are called

base analogs

In humans, the stem cells from which all blood cells arise are found in the

bone marrow

What term refers specifically to the process shown in the figure?

budding

Which statement about complement proteins is FALSE? a. They may be activated through three different pathways. b. They disrupt the cytoplasmic membrane of invading bacteria and foreign cells. c. They are part of the specific immune defense system. d. They are a group of blood proteins produced by the liver. e. They are part of the innate immune response.

c. They are part of the specific immune defense system.

Antigenic variation is a phenomenon used by some bacteria (such as Neisseria gonorrhoeae) to evade host immune mechanisms. In this process, the cells

can change the characteristics of certain surface proteins on the bacteria, forcing immune response to constantly adapt.

Expression of viral oncogenes in infected animal cells

can mimic proto-oncogenes, causing an imbalance in cell cycle control towards unchecked proliferation, leading to tumor formation

What are the characteristics of fungi?

cell wall contains chitin AND they use nutrients from dead or decaying organic matter

Cytotoxic T cells primarily are responsible for

cell-mediated immunity

The attraction of leukocytes to the area of inflammation is referred to as

chemotaxis

All fungi have ______ in their cell wall

chitin

In virology, a plaque is a(n)

clearing in a lawn of bacteria

Not all bacteria can take up DNA from the environment. Those that can are referred to as

competent

Gene transfer that requires cell-to-cell contact is

conjugation

Horizontal gene transfer can occur via

conjugation

The "voices" of a cells, which carry messages are

cytokines

Bacterial cells that have been genetically modified to carry an antibiotic resistance gene can be separated from susceptible (non-resistant) microbes by using a ______ selection method using agar plates with antibiotic.

direct

Describe tapeworms

dont have a digestive system AND they may be transmitted by eating undercooked meat

When a non-enveloped animal virus adsorbs to the host cell with its protein spikes, the virions are taken into the cell by the process of

endocytosis

What 2 functions do phagocytes serve in immune response

engulfment/destruction of foreign cells AND alerting the other cells of the immune system to an invader

The mechanism of exit for an animal virus is primarily determined by whether or not the virus has a(n) _____.

envelope

The (+) strand of DNA acts as a template during transcription TRUE or FALSE

false

Pyrogens are

fever-inducing substances

Fungi are important for

food production, food spoilage, production of antibiotics, and disease of plants

The enveloped viruses typically obtain their envelope

from the host cytoplasmic membrane as they exit the host

In conjugation, transformation, or transduction, the recipient bacteria is most likely to accept donor DNA

from the same species of bacteria

How are genomic and pathogenic islands related?

genomic islands are large DN segments in a cell's genome that originated in other species, pathogenicity islands are genomic islands that code for factors that allow an organism to cause disease

Enveloped viruses

have a lipid bilayer membrane containing various proteins

Which is the CORRECT sequence of immune events when a pathogen enters a host? i. Activation of immune components such as phagocytes and interferon. ii. Breaching of first line defenses. iii. Elimination of invader. iv. Invader detection by PPRs on sentinel cell

ii, iv, i, iii

The first host response to a nonspecific tissue injury is described as

inflammation

White blood cells/ leukocytes are important to

innate immunity

mRNA

type of RNA molecules that contains the genetic info that decodes during translation

tRNA

type of RNA that carries the amino acid to the growing peptide chain during translation

Reverse transcriptase synthesizes

viral DNA from viral RNA

Rabies virus, which can be transmitted from animals to humans, is classified as a(n) ______ virus.

zoonotic

CD4 cells are also known as

T helper cells

What are the differences between DNA and DNA

- DNA is double- stranded, RNA is single-stranded - DNA nucleotides contain deoxyribose whereas RNA nucleotides contain ribose - multiple types of RNA with different functions, only one type of DNA

Place steps for animal virus replication in the correct sequence 1. Virus attaches to receptors on the host cell cytoplasmic membrane. 2.New viral particles assemble and mature 3. Multiple copies of the viral genome are synthesized. 4. Virus enters the host cell by fusion or endocytosis. 5. Structural and catalytic viral genes are expressed. 6. Viruses are released from the host cell by budding or during apoptosis of the host cell. 7. Viral genome is uncoated.

1, 4, 7, 5, 2, 6

DNA replication

1. semiconservative 2. starts at an origin of replication 3. bidirectional 4. requires RNA primers

Does DNA polymerase able to proofread the DNA sequence? TRUE or FALSE

TRUE

What is true about helminths? 1. Trematodes have a regular digestive system with a mouth that takes in food and an anus through waste is eliminated. 2. Cestodes do not have a digestive system; they absorb predigested nutrients from the host through their skin. 3. Nematodes have a mouth but no anus; food and wastes enter and exit the same opening on the head of the worm. 4. Blood flukes are hermaphroditic, having male and female sex organs in the same worm. 5. Trematodes attach to the intestinal wall of the host by means of the scolex, which has hooks and suckers.

2. Cestodes do not have a digestive system; they absorb predigested nutrients from the host through their skin.

Which statement about skin and mucous membranes is NOT correct? 1. They are the first line of innate immunity. 2. They are the first line of adaptive immunity. 3. They act as physical barriers to infection. 4. They contain antimicrobial secretions. 5. They separate us from our environment.

2. They are the first line of adaptive immunity.

What is FALSE about the RNA transcript? 1. It's formed using the DNA - strand as a template 2. It has the same 5'-3' orientation as the DNA + strand 3. It's made in short fragments that are then stitched together 4. Template starts at the promoter region

3. It's made in short fragments that are then stitched together

Which of the following statements regarding tapeworms is FALSE? 1. They absorb nutrients from the host's gut through their skin 2. a single worm contains broth male and female reproductive organs 3. They complete their life cycle in a single host 4. They can sometimes cause neurological signs and symptoms in the host 5. They do not have a digestive system

3. They complete their life cycle in a single host

You are studying a cell 20% of its DNA composed of T nucleotides. What percentage of the nucleotides are C?

30

What is a naive lymphocyte?

A lymphocyte that has an antigen receptor but has not yet encountered the antigen recognized by the receptor.

Frameshift Mutation

A mutation resulting from an insertion or deletion of bases that causes a change in the reading frame of the mRNA

Synonymous mutation

A mutation that changes a codon into a different codon, but both codons specify the same amino acid; this causes no change in the resulting polypeptide

Nonsense Mutation

A mutation that changes a codon that specifies an amino acid to a stop codon, resulting in premature termination of polypeptide synthesis.

Missense Mutation

A mutation that results in changing a codon such that a different amino acid is specified

How do prions accumulate in brain tissue?

Abnormal prions proteins change normal prion proteins into the abnormal form

Which is not a component of innate immunity?

Antibodies

Which of the following are lymphocytes?

B cells, T cells, AND NK cells

What doesn't refer to the shape of the virus?

Bacillus

Chronic granulocytic leukemia is a disease in which too many WBC are produced in which tissue/organ is this likely to occur in?

Bone marrow

Central tolerance

Central tolerance takes place as lymphocytes mature; it eliminates immature T and B cells found to recognize certain "self" molecules.

Describe Chronic viral infection

Characterized by continuous production of low levels of viral particles, potentially even absence of active symptoms of disease. The organism is usually still highly infectious during this time

The nucleocapsid is composed of

DNA or RNA, and protein

Why would it be more difficult to treat diseases in humans cause by members of the Eukarya than diseases by the Bacteria?

Eukaryotic microbes use many of the same enzymes and systems as humans, so we lose the ability to target certain molecules that might be present ONLY in the cell type we want to eliminate

T cells are responsible for directly manufacturing antibodies TRUE or FALSE

FALSE

A missense mutation has a greater impact on a cell than does a frameshift mutation. TRUE or FALSE

False

Fever allows the body to fight microbial invaders by which of the following mechanisms?

Fever prevents microbes with lower optimum temperatures from growing, giving the immune system time to eliminate those cells.

How does Ascaris lumbricoides, an intestinal parasite, cause choking and pulmonary symptoms in some people?

Ingested Ascaris larvae penetrated intestinal capillaries, from where they are carried to the lungs causing coughing and shortness of breath

Describe latent viral infection

Long periods of time with essentially zero viral replication, punctuated by outbreaks of active replication and disease manifestation. Infected individuals are largely non-infectious between outbreak periods.

DNA in cells can encode for thousands of different proteins. Why do cells require mechanisms to regulate expression of the genes that code for these proteins?

Not all proteins are needed at all times, or in equal amounts. Regulating their expression saves energy and time

inducible

Not routinely produced at significant levels, but their synthesis can be turned on when needed. These are often used in the transport and breakdown of specific energy sources.

What is the role of MHC molecules?

Presenting antigens to T lymphocytes

Viroid

Single-stranded RNA molecules forming a closed ring

Constitutive

Synthesized constantly, these enzymes usually play a critical and indispensable role in central metabolic pathways

A virus usually infects only certain types of cells due to

interactions between viral and cellular surface molecules.

Planar molecules used as chemical mutagens are called

intercalating agents

Signal transduction

is the relay of info about conditions outside a cell to inside the cell

Influenza vaccines must be changed yearly because the viral antigens change from year to year. Based on this information, which of the following is most likely true about the influenza virus?

it has an RNA genome

The cells responsible for adaptive immunity are the

lymphocytes

what has the codon?

mRNA

The term "segmented" refers to viruses that

may contain several pieces of RNA

Dimorphic Fungi

may grow as mycelia or yeast AND are often associated with disease in humans

The role of viral surface proteins or spikes

means of attachment to host cell surface

Outside of living cells, viruses are

metabolically inert

Repair mechanisms that occur during DNA synthesis are

mismatch repair & proofreading by DNA polymerase

Consider the figure of replica plating. If the purple liquid was distilled water, the researcher would expect the number of colonies on plate A to be _____ as the number on plate B.

more or less the same

The terms yeast, mold, and mushrooms refer to fungal

morphology

The source of variation among microorganisms that were once identical is

mutation

A tangle of fungal hyphae is generally known as

mycelium

The first kind of leukocyte lured to the site of inflammation is the

neutrophil

How to classify viruses

nucleic acid, shape, size and host range

An infection in which the virus is continually present in the body is referred to as

persistent

Viroids cause disease in

plants

A limiting factor for viral infection of animal cells is

presence of specific receptor molecules on the host cell

Interferons secreted by a viral-infected cell

prevent viral replication in nearby cells

Peripheral Tolerance

prevents B cells and T cells that escaped central tolerance from reacting to self molecules

What are the correct terms for the regions before and after in transcription?

promoter and terminator

Transcription begins at the _______ and ends at the _______, while translation beings at the ________ and ends at the _______.

promoter; terminator; start; stop

A virion is composed of

protein, either DNA or RNA, and possibly lipid

The ability to exist as either a trophozoite or a cyst is characteristic of many

protozoa

The four cardinal signs of inflammation are

redness, heat, swelling, pain

Transcription is often controlled by DNA-binding proteins. A(n) ______ is a regulatory protein that blocks transcription, while a(n) ______ is a regulatory protein that facilitates transcription.

repressor; activator

Retroviruses such as HIV have a unique enzyme that allows them to synthesize DNA from an RNA template. The name of the enzyme is ______.

reverse transcriptase

The genome of retroviruses is made of

ssRNA

In translation, the codon at which the process begins is called the ______ codon, while the codon at which the process ends is called the ______ codon

start; stop

What has the anticodon?

tRNA

Direct selection involves inoculating cells onto growth media on/in which

the mutant but not the parent cell type will grow

T cells mature in the

thymus

The mechanism by which genes are transferred into bacteria via viruses is called

transduction

Which of the following requires that cells be competent?

transformation

Gene regulation may entail

turning on genes only when needed & turning off genes when not needed & turning on or off entire groups of genes

rRNA

type of RNA molecule present in ribosomes