BIOS 209 - Exam 2

1. Which statement is true?

a.       A virion contains DNA and RNA.

b.       Viruses are acellular.

c.       Viruses replicate outside of the cell.

d.       Most viruses are easily visualized with a light microscope.

 

1. Which statement is true?

a.       A virion contains DNA and RNA.

b.       Viruses are acellular.

c.       Viruses replicate outside of the cell.

d.       Most viruses are easily visualized with a light microscope.

 

a.       Viruses are acellular.

The viral ________ play(s) a role in attaching a virion to the host cell.

a.       core

b.       capsid

c.       envelope

d.       both b and c

d. both b and c

3. Viruses_______.

a.       all have a round shape

b.       cannot have a long shape

c.       do not maintain any shape

d.       vary in shape

d. vary in shape

Which statement is not true of viral replication?

a.       The full lysogenic cycle ends by killing the host cell.

b.       Most lytic viruses follow the same basic steps in the viral replication cycle.

c.       Viral replication does not affect host cell function.

d.       Newly released virions can infect adjacent cells.

c. Viral replication does not affect host cell function

Which statement is true of viral replication?

a.       In the process of apoptosis, the cell survives.

b.       During attachment, the virus attaches at specific sites on the cell surface.

c.       The viral capsid helps the host cell produce more copies of the viral genome.

d.       mRNA works outside of the host cell to produce enzymes and proteins.

B. During attachment, the virus attaches at specific sites on the cell surface.

Which statement is true of reverse transcriptase?

a.       It is a nucleic acid.

b.       It infects cells.

c.       It transcribes RNA to make DNA.

d.       It is a lipid.

c. It transcribes RNA to make DNA

Oncogenic virus cores can be_______.

a.       RNA

b.       DNA

c.       neither RNA nor DNA

d.       either RNA or DNA

d. either RNA or DNA

People with the CCR5Δ32 mutation of a T-cell surface protein can be exposed to some strains of HIV-1 without becoming sick. What step of the virus life cycle is likely to be inhibited with this mutation?

a.       Release

b.       Reverse transcription

c.       Uncoating

d.       Attachment

d. Attachment

Which is true of DNA viruses?

a.       They use the host cell’s machinery to produce new copies of their genome.

b.       They all have envelopes.

c.       They are the only kind of viruses that can cause cancer.

d.       They are not important plant pathogens.

a. They host the cell’s machinery to produce new copies of their genome.

A bacteriophage can infect ________.

a.       the lungs

b.       viruses

c.       prions

d.       bacteria

d. bacteria

Which of the following is NOT used to treat or prevent viral disease?

a.       Vaccines

b.       Antiviral drugs

c.       Antibiotics

d.       Prophylaxis

c. Antibiotics

Vaccines_______.

a.       are similar to viroids

b.       are only needed once

c.       kill viruses

d.       elicit an immune response

d.       elicit an immune response

Which of the following is not associated with prions?

a.       Replicating shapes

b.       Mad cow disease

c.       DNA

d.       Infectious proteins

c. DNA

Which statement is true of viroids?

a.       They are single-stranded RNA particles.

b.       They reproduce only outside of the cell.

c.       They produce proteins.

d.       They affect both plants and animals.

a. They are single-stranded RNA particles.

T/F - Bacteria and Archaea have been found everywhere scientists have looked

True

T/F - The process of endospore formation can be described as binary fission

False

T/F - Bacteria have in-folded membranes that perform similar functions to those of the organelles

True

C, H, O, N are important elements found in the macromolecules of life

True

T/F - Symbiosis describes an unchanging interaction between living organisms

False

T/F - Prokarya are unable to generate genetic variation because they do not complete meiosis

False

Archaeplastida

Primary endosymbiosis

Storage molecule: Starches, triglycerides

Structural biomolecule: cellulose

Example clade or organisms: rhodophyta, viridiplantae

Economic contribution: nori, fuel, fiber, food

TSAR

Secondary endosymbiosis

Storage molecule: laminarin, oils

Structural biomolecule: none or chitin

Example clade or organisms: amoeba, slime molds

Economic contributions: food, medicines, diseases

Excavata

Rarely secondary endosymbiosis, heterotrophs

No storage molecule

No structural biomolecule

Example clade or organisms: trypanosoma, giardia

Economic contribution: significant human parasites

Primary Endosymbiosis

a eukaryotic cell engulfing a cyanobacteria, the enclosed cell becomes a chloroplast

Secondary Endosymbiosis

a photosynthetic eukaryotic organism is swallowed by a eukaryotic organism resulting in the later organism now becoming photosynthetic as well by adopting the chloroplast as its own

Horizontal Gene Transfer

uptake of DNA from the environment, or transmitted through a virus mediator, or via sex pili

Endosymbiotic Gene Transfer

transfer of organeller DNA to host genome such that the mitochondria/chloroplast can no longer be free living on ther own

Mitosis

asexual reproduction for growth, development and repair: DNA remains the same (with exception of typos/mutations that are created during DNA replication).

Meiosis

sex cell formation: DNA content is halved (ex: from 46 chromosomes to 23), DNA is extensively shuffled btween homologous pairs during crossing over in Prophase I.

If asexual replication is possible and common, why do organisms go through the extra effort of meiosis?

Meiosis = genetic recombination —> new traits, better fitness (hopefully), prompts natural selection and thus evolution

Asexual reproduction: same traits regardless of degree of fitness

What event is thought to have contributed to the evolution of eukaryotes?

a. global warming

b. glaciation

c. volcanic activity

d. oxygenation of the atmosphere

d. oxygenation of the atmosphere

What characteristic is shared by prokaryotes and eukaryotes?

a. cytoskeleton

b. nuclear envelope

c. DNA-based genome

d. mitochondria

c. DNA-based genome

Mitochondria most likely evolved by ____________.

a. a photosynthetic cyanobacterium

b. cytoskeletal elements

c. endosymbiosis of proteobacteria

d. membrane proliferation

c. endosymbiosis of proteobacteria

Which of these protists is believed to have evolved following a secondary endosymbiosis?

a. green algae

b. cyanobacteria

c. red algae

d. TSAR

d. TSAR

Which of the following observations about a bacterium distinguishes it from the last eukaryotic common ancestor?

a. a double-stranded DNA genome

b. Lack of a membrane-bound structure surrounding the genome

c. Fatty acids in the lipid bilayer of the plasma membrane

d. enclosed by a cell wall

b. Lack of a membrane-bound structure surrounding the genome

Alternation of generations describes which of the following?

a. The haploid form can be multicellular; the diploid form is unicellular

b. The haploid form is unicellular; the diploid form can be multicellular

c. Both the haploid and diploid forms can be multicellular

d. Neither the haploid nor the diploid forms can be multicellular

c. Both the haploid and diploid forms can be multicellular

An example of carbon fixation is _________.

a. photosynthesis

b. decomposition

c. phagocytosis

d. parasitism

a. photosynthesis

Which parasitic protist evades the host immune system by altering its surface proteins with each generation?

a. Paramecium caudatum

b. Trypanosoma brucei

c. Plasmodium falciparum

d. Phytophthora infestans

b. Trypanosoma brucei

Which of the following is not a way that protists contribute to the food web?

a. They fix carbon into organic molecules

b. They occupy the apex producer niche

c. They enter symbiotic relationships with animals

d. They recycle nutrients back into the carbon and nitrogen cycles

b. They occupy the apex producer niche

T/F - The lifecycles of nonvascular plants require water for sperm movement

True

T/F - The grade nonvascular plants have no economic or ecological value

False

What environmental challenges and opportunities did plants face when coming into land?

Challenges: gravity (biomolecules - lignin and complex cellulose), sunlight (waxy surfaces), drying (again, waxy surfaces and controllable stoma/pores in leaves and stems)

Opportunities: nutrients (better nutrients in soil), gas exchange (water uptake and transport), sunlight (evolution of leaves)

What are the three organs of plants?

Roots, stems, leaves

• evolved in seedless vascular plants

• Function: movement of water and nutrients through the plant body

Describe two adaptations that are present in mosses, but not hornworts or liverworts, and which challenges of moving onto land and the evolution toward land plants do these represent?

Microphylls - first enation (outgrowth from plant) with a vascular bundle within, allowing for increase in surface area for light harvest and the ability to move the produced sugars further and quicker

Vascular bundles - plants can grow larger than without if transduction does not have to rely on plasmodenta alone

Meristem in plants

An area capable of continued growth, equivalent to stem cells in humans

Which statement is true?

a.       A virion contains DNA and RNA.

b.       Viruses are acellular.

c.       Viruses replicate outside of the cell.

d.       Most viruses are easily visualized with a light microscope.

b. Viruses are acellular

The viral ________ play(s) a role in attaching a virion to the host cell.

a.       core

b.       capsid

c.       envelope

d.       both b and c

d. both b and c

Viruses_______.

a.       all have a round shape

b.       cannot have a long shape

c.       do not maintain any shape

d.       vary in shape

d. vary in shape

Which statement is not true of viral replication?

a.       The full lysogenic cycle ends by killing the host cell.

b.       Most lytic viruses follow the same basic steps in the viral replication cycle.

c.       Viral replication does not affect host cell function.

d.       Newly released virions can infect adjacent cells.

c. Viral replication does not affect host cell function

Which statement is true of reverse transcriptase?

a.       It is a nucleic acid.

b.       It infects cells.

c.       It transcribes RNA to make DNA.

d.       It is a lipid.

c. It transcribes RNA to make DNA

Oncogenic virus cores can be_______.

a.       RNA

b.       DNA

c.       neither RNA nor DNA

d.       either RNA or DNA

either RNA or DNA

Which statement is true of viroids?

a.       They are single-stranded RNA particles.

b.       They reproduce only outside of the cell.

c.       They produce proteins.

d.       They affect both plants and animals.

a. They are single-stranded RNA particles

Transformation

Acquisition of DNA from the environment; also utilized for scientific activities that introduce DNA into organisms from outside sources

Transduction

viral-mediated, bacterial DNA transfer. During lytic stage, virions can pick and DNA, even host cell

Conjugation

Transfer of DNA through a sex-pili. Often involves replication with subsequent transfer of small accessory, circular DNA call plasmids

Von Leeuwenhoek

first microscope utilized to observe microbio, father of microbio

Jenner

immunity can be gained from exposure

Koch

scientific processes used for identification of disease-causing agents

Pasteur

safe food through heating processes

Semmelweis

hand-washing to lower transmission of microbial disease

The first forms of life on Earth were thought to be _________.

a. single-celled plants

b. prokaryotes

c. insects

d. large animals such as dinosaurs

b. prokaryotes

Microbial mats, present in stromatolites, _______.

a. are the earliest forms of life on Earth

b. obtained their energy and food from hydrothermal vent

c. are multi-layered sheets of prokaryotes including mostly bacteria but also archaea

d. all of the above

d. all of the above

The first organisms that oxygenated the atmosphere were

a. cyanobacteria

b. phototrophic organisms

c. anaerobic organisms

d. all of the above

d. all of the abonve

Halophiles are organisms that can tolerate ________.

a. a salt concentration of at least 0.2

b. high sugar concentration

c. the addition of halogens

d. all of the above

a. a salt concentration of at least 0.2

Many of the first prokaryotes to be cultured in a scientific lab were human or animal pathogens. Why would these species be more readily cultured than non-pathogenic prokaryotes?

a. Pathogenic prokaryotes are hardier than non-pathogenic prokaryotes.

b. Non-pathogenic prokaryotes require more supplements in their growth media.

c. Most of the necessary culture conditions could be inferred for pathogenic prokaryotes

d. Pathogenic bacteria can grow as free bacteria, but non-pathogenic bacteria only grow as parts of large colonies.

c. Most of the necessary culture conditions could be inferred for pathogenic prokaryotes

The presence of a membrane-enclosed nucleus is a characteristic of ________.

a. prokaryotic cells

b. eukaryotic cells

c. all cells

d. viruses

b. eukaryotic cells

Which of the following consist of prokaryotic cells?

a. bacteria and fungi

b. archaea and fungi

c. protists and animals

d. bacteria and archaea

d. bacteria and archaea

The cell wall in bacteria is _______.

a. interior to the cell membrane

b. exterior to the cell membrane

c. a part of the cell membrane

d. interior or exterior, depending on the particular cell

d. interior or exterior, depending on the particular cell

Peptidoglycan is a characteristic of the walls of _______.

a. eukaryotic cells

b. bacterial prokaryotic cells

c. archaean prokaryotic cells

d. bacterial and archaean prokaryotic cells

b. bacterial prokaryotic cells

Which of the following elements is not a micronutrient?

a. boron

b. calcium

c. chromium

d. manganese

b. calcium

Cyanobacteria harness energy form the sun through photosynthesis, and oxidize water to provide electrons for energy generation to fix atmospheric carbon. Thus, we classify cyanobacteria as __________.

a. photolithotrophs

b. photoautotrophs

c. chemolithoautotrophs

d. chemo-organotrophs

b. photoautotrophs

In addition to providing yogurt with its unique flavor and texture, lactic acid-producing bacteria also provide which additional benefit during food production?

a. Providing xenobiotics

b. Lowering the pH to prevent growth of pathogenic bacteria

c. Pasteurizing milk products

d. Breaking down lactose for lactose-intolerant individuals

b. Lowering pH to prevent growth of pathogenic bacteria

What role do microbes play in the Carbon cycle?

Some fix carbon (attach atmospheric C) to other carbon chains, many release carbon from life and most release carbon during metabolism

What role do microbes play in the Nitrogen cycle?

Some fix N from the atmosphere either as free-living or in symbiosis with plants. Others help convert N forms (nitrate to nitrite to ammonia).  Some release N back to the environment as N₂

Apical meristem function

elongate body

Axillary meristem function

diversifying body shape, side-branching

Intercalary meristem function

stretch existing body segments

Lateral/Cambial meristem function

deepen body tissues, adds girth

Catabolism (aerobic respiration)

C₆H₁₂O₆ + 6 O₂ → 6 CO₂ + 6 H₂O + Energy (ATP)

Anabolism (photosynthesis)

6 CO₂ + 6 H₂O + Energy (light) → C₆H₁₂O₆ + 6 O₂

Alternation of generations means that plants produce _________.

both haploid and diploid multicellular organisms

Which of the following traits of land plants allows them to grow in height?

a. alternation of generations

b. waxy cuticle

c. tracheids and lignin

d. sporopollenin

c. tracheids and lignin