basic functional unit of the body capable of replication.
Cytoplasm
- interior of the cell containing soluble non-membranous components of the cell.
DNA
- double-stranded molecule that acts as the genome (genetic information) of many organsims
Enzymes
- proteins that drive biochemical reactions by binding precursors and converting them intoproducts.
Eukarotic
- (eu=true, karyon=kernel) Cells that have nuclei and membrane-bound organelles
Genome
- the entire set of genes for an organism. Can be DNA or RNA.
Lysosomes
- membrane-enclosed bag of digestive enzymes that degrade all major classes of molecules.
Nucleus
- cellular organelle in which genetic information is stored as DNA.
Nuclear membrane
Nuclear membranematerial of eukaryotic cells.
Organ
- an organized group of tissues specialized to perform specific functions, i.e. liver, thymus.
Plasma membrane
- layer of lipid (fat) and protein that covers and encloses the cellular contents.
Prokaryotic
- (pro=before, karyon=kernel) Cells that lack a nucluar envelope and membrane-bound organelles such as bacteria.
RNA
- single-stranded molecule that acts as an intermediate step between genetic information andproteins. Can also act as the genetic information for certain viruses.
Tissue
- an organized group of similar cells specialized to perform specific functions, i.e. muscle, skin.
Vacuoles
- membrane-bound vessicles formed by phagocytosis of food or other things found on theoutside of the cell.
Vessicles
- membrane-enclosed sacs. Basically, they are "pinched-off" portions of the plasma membranemoving from one place in the cell to another.
Adsorption
- binding of the virus to the cell via a specific cell surface receptor. First step in the virus infection cycle.
Capsid
- core protein coat that provides shape and symmetry. Composed of repeated individual, identical proteins called capsomeres.
Eclipse period
- period during which viral genes are expressed, new virus genetic information and viral proteins are produced. Third step in the virus infection cycle.
Enveloped virus
-viruses that are composed of nucleic acid and protein coat surrounded by an envelope consisting of a lipid bilayer and envelope proteins (usually derived from the host cell)
gp120
- HIV envelope glycoprotein that binds to CD4 on helper T cells and macrophages
HIV
- Human Immunodeficiency Virus.
HIV Life Cycle
consists of seven events: 1) Adsorption, 2) Penetration and uncoating, (Eclipse 3-6)3) Synthesis of viral DNA, 4) Integration into cellular DNA, 5) Synthesis of viral RNA, 6) Synthesis ofviral proteins, 7) Assembly and budding of virus.
HIV protease
- enzyme coded for by the pol gene and essential for production of virus. It is requiredfor the cleavage of HIV polyproteins (a large protein made from the entire genome and then cleaved toproduce several different, smaller proteins).
Latency
- a state of viral infection in which viral genetic material remains hidden in the cell but novirus is produced.
LTR - l
- long terminal repeats: regions of repeated nucleotide sequences at each end of linear viral DNAproduced by reverse transcription. LTRs are important for several steps in the life-cycle of retroviruses.
Penetration and Uncoating
- entry of virus into the cell and removal of the protective protein coat.Second step in virus infection cycle.
Retrovirus
- viruses that store genetic information in the form of RNA.
Reverse transcriptase (RT)
an enzyme unique to all retroviruses that reads (transcribes) RNA andmakes a DNA copy. (Also has two other activities, ribonuclease H and DNA polymerase.)
Virus
viruses are the simplest micro-organisms that exist and are obligate intracellular parasites thatrequire cellular machinery and energy to replicate. Smallest infectious agent.
Virus assembly
new infectious viral particles are assembled and released from the cell causing alarge increase in infectious virus in the host. Fourth and final step in virus infection cycle.
Gag
gene found in all retroviruses encoding coat proteins that make up the inner virus (core)particle.
Pol
gene found in all retroviruses encoding reverse transcriptase (RT). In HIV it codes forother essential enzymes, HIV protease and integrase.
Env
gene found in all retroviruses encoding the viral envelope proteins, gp120 and gp 41.
Tat and rev s.
regulatory HIV genes essential for production of virus. Tat promotes efficientelongation of viral RNA during transcription. Rev activates export of unspliced viral RNA outof the nucleus.
Nef, vpr, vif, vpu -
HIV genes of unknown function not essential for production of virus. Nefhas several functions including down-regulation of CD4. Vpu enhances degradation of newlysynthesized CD4. Vpr is involved in nuclear import. Vif is involved in viral particl assembly.
Antibody
Special Y-shaped proteins composed of constant and variable regions. Thevariable region has a special configuration that matches that of the antigen and bindsto it, the constant region helps to eliminate it.
Antigen
Antibody-generating substance, a substance that stimulates the immuneresponse.
B cells
Lymphocytes that are produced in the bone marrow. When B-cells arestimulated by antigens, they are converted into plasma cells that secrete antibodies.
B cell antigen receptor
membrane-bound immunoglobulin on the surface of B cellsthat specifically recognizes intact antigen and triggers a B cell immune response.
Bone marrow -
blood-cell producing tissue inside the bones that makes the red(erythrocytes) and white (leukocytes) blood cells.
Cell-mediated response
The activation of T-cells, B-cells and other cells involvedin the immune response.
Cytokines -
- (interleukins, IL) growth factors and hormones that stimulate the divisionand maturation of leukocytes.
Helper T-cells
Lymphocytes that, when exposed to an antigen, stimulate otherimmune-system responses. Cells with the T4 (CD4) antigen on their surface.
Humoral response
The production of antibodies by plasma (B) cells; the defenseby fluids ("humors") - the antibody response.
Immunity
natural or acquired (specific) resistance to infection or disease
Immunoglobulin (Ig)
-another name for an antibody molecule. 5 classes, IgG& IgM(humoral response), IgA (found in tears, saliva and milk), IgD (plays a role in B celltriggering) and IgE (histamine/inflammatory response).
Interferon
A substance produced by the body that inhibits viral DNA-RNAtranscripts.
Interleukin-2
- a naturally occurring protein that functions as an immune-systemactivator.
Killer T-cells
Lymphocytes that directly kill viruses, bacteria or body cells infectedwith them. Cells with the T8 (CD8) antigen on their surface. Also called cytotoxic Tcells (CTCs).
Lymph nodes
-secondary lymphoid organs found throughout the body that containmature lymphocytes capable of responding to foreign antigens.
Lymphocyte
-A grouping of white blood cells, which includes T-cells and B-cells.
Macrophages
- Large phagocytic ("cell eating") white blood cells that engulf anddestroy invaders or present them to other immune-system cells (antigen-presentingcells, APCs). Located in the tissues (see monocyte).
Major histocompatibility complex (MHC) proteins -
Specific cell surface proteinsthat characterize the tissue or cell as self or non-self. These proteins also help toregulate the immune response of the T-cells. In humans, they are coded for by agroup of genes on the sixth chromosome
Class I MHC
found on all nucleated cells, "self molecules"
Class II MHC
found onmacrophages, B and T cells.
Memory cells
a population of B-cells that after exposure to an antigen the first timeacquire a "molecular memory", so that on a second exposure to the same antigenthey respond more quickly.
Monocyte
A phagocytic white blood cell that is circulating in the blood (seemacrophage).
Nonspecific response
a nonspecific response is immediate and general in nature;physical barriers such as the skin, chemicals such as lysozyme and the inflammatoryresponse are involved in nonspecific responses.
Phagocyte
Any cell that can engulf other cells or substances.
Plasma cell
antibody-producing B cell.
Specific immune response
An immune response to a specific antigen. Thisresponse can have a cell-mediated component and a humoral component (theproduction of antibodies).
Supressor T cells
- Diminishes/controls specific immune response. Carries the T8(CD8) antigen on their surface.
T cell receptor (TCR)
T cell antigen receptor that specifically recognizes processedantigens bound to MHC class I and II molecules.
Thymus
- primary lymphoid organ located above the heart from which T cells arederived.
Which of the following choices represent exceptions to the Central Dogma of
Biology?
i. DNA into RNA
ii. RNA into DNA
iii. RNA into Protein
iv. DNA into Protein
v. Protein into RNA
B
Which of the following molecules could be another term for fat?
A. Nucleic Acids
B. Amino Acids
C. Carbohydrates
D. Lipids
E. Proteins
D. Lipids
What is the difference between endocytosis and exocytosis?
A. Endocytosis is importing into the cell; exocytosis is exporting out of the
cell.
B. Endocytosis is exporting out of the cell; exocytosis is importing into the cell.
C. They’re really the same thing.
D. None of the above.
A.
Which describes the cellular process of transcription?
i. DNA into RNA
ii. RNA into DNA
iii. RNA into Protein
iv. DNA into Protein
v. Protein into RNA
A. i only
B. ii only
C. iii only
D. none of the choices
A.
In the 5 kingdom system, eukaryotes are not found in the Kingdom
Monera.
True
False
True
Which describes translation?
i. DNA into RNA
ii. RNA into DNA
iii. RNA into Protein
iv. DNA into Protein
v. Protein into RNA
A. i only
B. ii only
C. iii only
D. none of the above choices
C.
Which of the following organelles is mainly responsible for breaking down
macromolecules?
A. Mitochondria
B. Endoplasmic Reticulum
C. Lysosome
D. Nucleus
C.
What is considered to be the basic unit of all things defined as organisms?
A. Nucleic Acids
B. Proteins
C. Lipids
D. Carbohydrates
E. None of the above.
E.
Amino acids are not the building blocks of proteins.
True
False
False
Which of the following statements is not true?
A. Eukaryotic cells have a nucleus; prokaryotic cells do not have a nucleus.
B. Prokaryotic cells have a nucleus; eukaryotic cells do not have a
nucleus.
C. Cells’ plasma membranes may have proteins embedded within them.
B.
RNA is found in both bacteria and eukaryotes.
True
False
True
What is pinocytosis?
A. "Cell lysis"
B. “Cell reproduction”
C. “Cell drinking”
D. “Cell replication”
C.
All viruses use RNA as their genetic material; none uses DNA.
True
False
False
A reason viruses are not considered living organisms arises from the
fact that they cannot reproduce in the absence of a host cell.
True
False
True
The capsid of a virus ________.
A. is a lipid bilayer
B. is a protein coat
C. serves to enclose the viral genome.
D. A and C
E. B and C
E
Which of the following factors cannot potentially lead to activation of a virus?
A. Change in nutritional intake
B. Exposure and infection by a new pathogen
C. Stress
D. Illicit drug use
E. None of the above. (they all can)
E.
Where does the envelope of an enveloped virus come from?
A. The virus is able to synthesize its own envelope.
B. The host cell’s plasma membrane.
C. The virion keeps the exact same envelope coating it had before infection.
D. None of the above.
B.
The lytic viral infection cycle does not involve integration of viral nucleic acids into the host’s genome.
True
False
True
Which lifecycle(s) result in an immediate cessation of normal host cell function?
A. Lytic
B. Lysogenic
C. Both Lytic and Lysogenic
A.
Which lifecycle(s) involve the entry of viral genetic material into a host cell?
A. Lytic
B. Lysogenic
C. Both Lytic and Lysogenic
D. Neither
C.
Which is generally associated with a latency period?
A. Lytic
B. Lysogenic
C. Both Lytic and Lysogenic
D. Neither
B.
Which lifecycle(s) result in immediate production of viral proteins?
A. Lytic
B. Lysogenic
C. Both Lytic and Lysogenic
D. Neither
A.
Which of the following statements properly describe the role of the “matrix” in HIV?
A. It serves to maintain the structure of the virion.
B. It helps a DNA copy of HIV’s genome to enter the nucleus.
C. It is the inner most protein coat found in HIV virions. (describes the capsid)
D. A and B
E. All of the above.
D or E
If HIV does not have gp120 sticking out of its surface, then it cannot infect cells.
True
False
True
tion 3 of 7
1.0 Points
Which of the following HIV proteins is the most antigenic?
A. reverse transcriptase
B. gp120
C. protease
D. nuclease
E. gp41
B.
In the virion, the genome of HIV is made of
A. two identical strands of DNA.
B. two identical strands of RNA.
C. two different strands of DNA.
D. two different strands of RNA.
E. both RNA and DNA.
B.
Which of the following statements regarding reverse transcriptase are true?
A. It transcribes RNA into DNA.
B. It is necessary for formation of the provirus.
C. It is an enzyme normally produced by humans.
D. A and B
E. All of the above.
D.
The initial polyprotein formed from the HIV “pol” gene is fully functional.
