Exam 2 Chapters 6-10 Flashcards
(123 cards)
1
Q
What is a virus?
A
A virus is obligate intracellular parasites.
Meaning: (They can’t do anything until they first infects a host cell)
THEY ARE NOT CELLS.
2
Q
What are the functions of the viral capsid
A
- It protects nucleic acid from physical destruction, chemicals and nuclease.
- Contains binding sites for host cell attachments.
- It is responsible for virion shape.
3
Q
What are the two structural shape of a virus?
A
Icosahedral structure
Helical structure
4
Q
The capsid is made up of:
A
Individual protein units called capsomeres
5
Q
What is the viral envelope?
A
And outer lipid membrane surrounding virion.
Meaning: A piece of the cell membrane of the host cell it infected.
6
Q
Why not all viruses have a lipid envelope?
A
Only the virus that leaves their host cells by the process of budding.
It is that covering around the virus.
7
Q
What are viral spikes?
A
Viral spikes are glycoprotein on the outer surface of a virus.
8
Q
What happens if the virus has a spike protein on the surface?
A
If the virus has a spike protein on its surface, it plays the major role to the attachment of the virus. Binding.
9
Q
What are the functions of Viral Spikes?
A
- Attachments to host cell receptors; initiate entrance
- Host makes antibodies specific for spikes.
- Virus evades immune response
10
Q
Icosahedral Structure Virus Shape
A
- Resembles a hollow sphere
- Many side structures
- Made by putting many capsomeres together
11
Q
Helical Viral Structure
A
- Are all RNA virus
- The viral nucleic acid and the capsomeres are helically coiled together to form a hollow rod.
12
Q
What are the FOUR major divisions of viruses
A
- Non-Enveloped Iscosahedral
- Enveloped Icosahedral
- None Enveloped Helical
- Enveloped Helical
13
Q
What is the viral size?
A
1nm= 1 millionth of a mm
1um= 1 thousands of a mm
- Too small to be seen with light microscopes
14
Q
Viruses are grouped into families based on?
A
- Virion shape
- Virion Size
- Presence or absence of a viral envelope
- Type of nucleic acid (DNA or RNA)
- Form of nucleic acid
- Existence of single or multiple pieces of nucleic acid in the Virion.
15
Q
Most if not all cells are able to be infected by virus… BUT:
A
A very specific virus interaction causes a specific interaction for the host cells it will infect.
16
Q
What are the FIVE STEPS in the interaction of a virus with its host cells?
A
- Attachment
- Penetration
- Uncoating and Biosynthesis
- Self-assembly
- Release
17
Q
Describe the first step of the interaction of the virus with its host cell.
A
Attachment: virus attaches to SPECIFIC receptors on host cell surface.
* Spikes play important role *
It is the most important step to inhibiting viral infection.
18
Q
Describe the second step in the viral interaction with host cells.
A
Penetration: Virus enters host cell.
19
Q
The penetration of a host cell has two processes. Name the process and Describe how it works.
A
Endocytosis (viropexis): Virus DOES NOT have a lipid envelope. Binds around, wraps and takes it in.
Membrane fusion: HAS a lipid envelope. Viral envelope fuses with host cell.
20
Q
Describe the third step in the virus interaction
A
Used as a factory to mass produce all of the parts of the virus. The virus proteins and nucleic acid.
21
Q
Describe the fourth step of the virus interaction
A
Self-Assembly within host cell
If it a DNA virus, assembly take place in the NUCLEUS host of the cell
If is a RNA virus, assembly takes place in the CYTOPLASM host of the cell
22
Q
Describe the fifth step in the virus interaction with host cell
A
Release: Newly assembled visions LEAVE host cell.
23
Q
The fifth stage of the Viral Replication involves two processes. Name and describe them
A
- Lysis: If the virus is non-enveloped, it leaves by destroying the host cell with this process
- Budding: If the virus is an enveloped virus it acquires a piece from the cell membrane
24
Q
What is the effects of viral infection?
A
A single virus can produce hundreds to thousands of viral particles in one host cell.
Drastically changes or kills to host cell.
25
What is Viral Latency?
The virus enters the host cell, and stays in a dormant state. OR remains separate from host cell DNA in a repressed state.
26
Why do people want to study viruses?
Purpose:
- To isolate and identify viruses in clinical specimens
- To prepare viruses for vaccines
- To research
System used:
- Animal model
- Bird embryo
- Cell culture
27
The Study of Animal Viruses: Cells Culture. The types of cells:
Primary: Cell culture. (Few generations) Cells from animal organs
Diploid: Cell strains. Cells derived from embryonic tissue
Permanent: Cell lines. Cells are transformed, as in they continue to grow.
28
Bacteriophages
Bacteriophages are viruses that infect bacteria cells.
29
Bacteriophages has three structures. What are those structures
- Icosahedral
- Helical
- Complex
30
Explain the Bacteriophage of the complex structure
-The structure consists of a hollow head(capsid). Consists of DNA viruses.
-The tail that consists of a hollow core with a protein contractile sheet around it
-The tail fibers.
31
T-Even Bacterial Structure has two types. What are the types
1. Lytic Cycle
2. Lysogenic Cycle
32
Describe or explain the Lytic Cycle
The bacteria phage attaches to very specific receptors on the cell wall of that bacteria.
-Full (5 step) replication cycle. A.P.T.R.A.R
33
What is the burst time?
The burst time refers to the time the attachment of the phage, until the host bacterial cell is destroyed
Average time is normally 20-40minutes.
34
What is the burst size?
The number of newly made phage that was contained in that bacteria cell.
Average amount is 100-200 per host bacterial cell
35
Describe or Explain the Lysogenic cycle
You do not go through the full generation cycle.
The viral DNA inserts itself in the chromosome and stays there.
The inserted piece of viral DNA is called the PROPHAGE.
36
What is the difference between a Lytic cycle and Lysogenic cycle.
The Lytic cycle the bacteria enters the phase and goes through the full generation cycle and is always leaves the cell by lysis (destruction of the host cell.)
WHILE
The lysogenic cycle you do not have production of new viral particle, instead that piece of viral DNA inserts into the chromosome of the host cell (The inserted piece is called a PROPHAGE)
37
What is the difference between the Plasmid versus the Prophage.
A plasmid is a closed circular piece of DNA that’s not part of the bacterial cell chromosome. NON viral in origin meaning it DID NOT come from a viral DNA.
IN CONTRAST
A PROPHAGE is an inserted piece of viral DNA meaning it came from a DN. It came from a viral DNA.
38
Viruses and Human Cancers.
Oncogenic Viruses:
Are viruses that are capable of producing tumors or abnormal growth.
39
Viruses and Cancers.
Describe Early event:
Viruses have an increase ability to insert themselves into the chromosome of that host cell.
40
Viruses and Cancers.
Describe what is Transformed cells:
The cells are no longer complete normal after being infected with the virus.
More rapid rates of growth.
Changes in cell surface molecules
Lose ‘contact inhibition’(keeps growing and dividing) and divide for an infinite period
41
All normal healthy cells has two sets of genes that controls the proliferation of the cell.
What are the two genes?
1. Protooncogene
2. Tumor Suppressor Genes (TSG)
42
What is a Protooncogene?
Genes which encode proteins that stimulate proliferation (meaning it encodes proteins to turn on causing those cells to grow and divide)
43
What are Tumor Suppressor Genes?
Genes which encodes proteins to suppress proliferation, (meaning that stops the cells from growing and dividing.)
44
The constant growing and dividing of abnormal cells are called:
Cancer
45
DNA Virus linked to human cancers are:
1.Epstein-Barr Virus
(Burkitts lymphoma; Nasopharyngeal Carcinoma)
2.Hepatitis B
(Liver cancer)
3.Human Papilloma virus (HPV)
(Cervical cancer)
4.Human Herpes Virus-8
(Kaposi sarcoma)
46
RNA Virus linked with cancer:
1. Retroviruses
(Leukemia and lymphoma. HIV)
2. Hepatitis C
(Liver cancer)
47
What is Nutrition?
The process by which chemical substances (nutrients) are acquired from the environment.
For metabolism growth
48
What is essential nutrients?
Any substance that an organism needs for growth and metabolism
49
What are the requirements for Microbial Growth
- Chemical Requirements
- Transport Mechanisms
- Environmental Factors That Influence Growth
- Study of Microbial Growth
50
What are the chemical requirements needed for bacteria to manufacture macromolecules in its metabolism
- Carbon
- Hydrogen
-Oxygen
51
Carbon
-Heterotroph
Obtains carbon from organic source
-Autotroph
Uses CO2 to make organic compounds
52
Hydrogen
Formation of Hydrogen bonds
53
Oxygen
Metabolism (aerobic respiration)
54
Nitrogen
Needed to make amino acids, nucleic acids and ATP
55
Phosphorus
Needed to make nucleic acids and phospholipids
56
Sulfur
Needed to make key vitamins and amino acids.
Formation of disulfide bonds in proteins (bonds that form between two sulfurs)
57
Enzymes
- Are biological catalyst, they speed up biological reactions
58
Minerals
- Needed in small amounts by some oranisms
Major roles for bacterial cell is to act as a cofactor. It binds to the enzyme to form the fully intact functional enzyme.
59
Growth factors
- Are essential organic nutrients that an organism cannot synthesize and must be provided in its environment.
Example: amino acids, nitrogenous, vitamins
60
Passive Transport
Do NOT require energy
Involves movement from area of higher concentration to an area of lower concentration. A process called diffusion
61
What are the two types of passive transport diffusion:
1- Simple diffusion
2- Facilitated diffusion
62
Define and explain Simple diffusion
Movement of particles from higher concentration to lower concentration
Simple diffusion are simple compounds across the membrane naturally such as oxygen, small molecules and lipid loving.
63
Define and explain facilitated diffusion
Higher to lower concentration
Needs the help of a membrane protein.
No energy, changes that facilitate transport of substances.
Once transported, carrier resumes original shape
64
Define active transport
Active transport requires energy to move substances across the membrane.
65
There are three types of Active transport.
What are they?
1- Carrier medicated
2- Group Translocation
3- Endocytosis
66
Define and explain Carrier mediated transport
Specific protein carrier binds to a substance and uses the energy stored in ATP to pump the substance across the membrane
*PUMP*
67
Define and explain Group translocation
Carrier protein binds to substance and transports it across the membrane, but in the process the substances is CHEMICALLY ALTERED
68
Define and explain Endocytosis
Substances being transported into the cells because the cell membrane wraps around the substance and ENGULFS in it.
*ENGULF*
69
Two types of Endocytosis
- Phagocytosis: larger particles taken into the bacterial cell
- Pinocytosis is water being transported to the bacterial vesicles
70
Define Exocytosis
The process of fusing with the cell membrane and the contents are dumped out of the cells
71
Environmental factors that influence Microbial Growth
Temperature:
Psychrophile - 0 degree Celsius to 15 degree Celsius
Psychrotroph - 15 degree Celsius to 30 degree Celsius
Thermophile - Warm loving; greater than 45 degrees Celsius
Mesophile - 20 degrees Celsius to 40 degrees Celsius
Extreme thermophile - greater than 80 degrees Celsius
72
Gas Requirements
Carbon dioxide
Oxygen
Not all bacteria needs oxygen for growth, it depends on the species
73
pho Requirements
The amount of acidity or alkalinity of a solution.
A scale from 0-14
7neutral
7–> 1 is more acidic
7–>14 is more alkaline
Bactria cells must be in a narrow range around neutral (6-8 range)
74
Define Osmotic pressure
The flow of water across the membrane to balance solute concentration
75
There are three conditions of Osmosis. What are they?
1- Isotonic condition
2- Hypotonic condition
3- Hypertonic condition
76
Define and explain Isotonic solution:
Equal concentration inside the bacterial cell and outside and the bacterial cell, no net flow of water, bacterial cells are happy
77
Define Hypotonic conditions
Under
Solute concentration is lower outside of the cell than inside.
Water flows INTO cell
78
Define Hypertonic conditions
Over
Solute concentration is greater outside than inside cell.
Water flows OUT of cell
79
What conditions are preferred by most organisms
Isotonic conditions
(Same outside and inside the cell, no net flow of water across the membrane)
80
The study of Microbial Growth
Bacterial Growth in regards to Bacteria
Is the increase in the number of bacterial cell. NOT SIZE! A process called Binary Fission
81
Define Logarithmic Function
Logarithmic increase means with each round of binary fission you double the amount of cell you in your culture.
82
Define Generational time
The time it takes for one round of binary fission to occur. For one bacteria cell to go through binary fission and divide into two.
About 30-60 mins
83
Define bacterial Growth Curve
Plot which shows growth of bacteria culture over time.
Follow the culture overtime to see the relative number of cells in that culture
84
There are four phases of bacteria growth.
What are they?
Lag Phase
Log Phase
Stationary Phase
Death Phase
85
Explain Lag Phase
The cells are just adapting
86
Explain Log Phase
Increase in number of cells, bacteria cells are most susceptible to the effects of antibiotics and radiation
87
Stationary Phase
The number of cells growing and dividing is equally the number of cells dying off because nutrients are depleting
88
Death Phase
The number of cells dying off is greater than the number of cells reproducing
89
Measurement of Bacterial Growth
Turbidity:
- Turbidity measures the amount of light going through a sample
- Uses a spectrophotometer
- Measures loving and dead bacteria
90
Measurement of Bacterial Growth
Direct Microscopic Count:
A special microscope slide
Liquid per millimeter
Solid per gram
91
Measurement of Bacterial Growth
Plate count:
Bacteria sample is serially diluted with sterile water
-# of bacteria/ml = colonies x final dilution factor/ml of the dish
ONLY COUNTS LIVING BACTERIA
92
Of the three methods of bacteria counting, which method counts only living cells
Plate count
93
Define Microbial Metabolism
All chemical and physical workings in a cell
94
Microbial Metabolism has two major categories.
What are those two categories?
1- Catabolism
2- Anabolism
95
Describe and explain the Catabolism category
The break down of larger molecules into smaller molecules to release energy
96
Describe and explain Anabolism
Smaller molecules are joined together to form larger molecules and in this process energy ATP is needed
97
ATP
Is the universal energy storage in the cell.
Can be produced, saved, spent, replenished
98
ATP has three parts, what are they
-Nitrogen (Adenine)
-Ribose
-Phosphate
99
Anabolism (biosynthesis)
Smaller molecules joined together to form larger ones
*The building up of molecules
100
Catabolism
Larger molecules are broken down into smaller molecules, usually with the release of energy.
*Breaking down of molecules
101
What are Enzymes (-ase)
Are large globular three dimensional proteins. THEY ARE PROTEINS
Their function is they are biological catalyst.
Components that speed up biological reactions because they lower the activation energy (energy required in order for a reaction to take place) in that cell
*LOCK AND KEY*(only one specific for the substrates)
102
What is considered an enzyme-substrate complex?
A very specific binding reaction. The enzyme binds to the specific active site of the enzyme forming.
103
What is biosynthesis?
Is responsible for putting the building blocks together.
Example: Putting amino acids together, you’d get proteins. Putting fatty acids together, you’d make simple lipids etc.
104
What is Membrane transport?
Passive(no energy) transport, based on diffusion.
Active transport(energy needed)
Endocytosis.
105
What are cofactors?
Cofactors are metals, that help to bind to the enzyme to make them fully functional.
106
What are coenzymes?
To remove a chemical from one substrate molecule and add it to another.
107
What are Exoenzyme?
*Means out of*
Enzymes produced inside of the bacteria cell and released outside of the bacteria cell.
108
What is the function of the exoenzymes?
To breakdown large foods that require water by a process called ‘Hydrolysis Reaction’
109
What are Endoenzyme?
Enzymes that are produced and stays in the bacteria cell.
110
What is the function of endoenzyme?
Important for the synthesis of major macromolecules are made.
Ex: Amino acids are jointed to make proteins. As each bond is formed, one water molecule is lost by a process called ‘dehydration syntheses reaction’
111
What do we need for enzyme activities?
1. pH - most bacteria enzymes function at a neutral pH (7.0). Too hot denatures it.
2. Temperature - Increasing in temperature for full function. 30-40 degrees Celsius
3. Substrate Concentration - Increase in substrate concentration for full function.
112
Photosynthesis
Specialized anabolic process in which the organism can make its own food.
‘Self feeders’
113
There are two phases in Photosynthesis. What are they?
Light-Dependent reactions
Light- Independent Reactions
114
What are the organisms that carry out the process of Photosynthesis?
Blue-Greeb Algae
Purple and Green Sulfur Bacteria
Purple and Green Non-Sulfur Bacteria
Heliobacteria
Algae
115
What is sterilization?
Destruction of ALL forms of microbes, including endoscopes
116
What is disinfection?
Destruction of pathogenic microorganisms, but NOT NECESSARILY ALL microbial life.
117
What is antiseptic?
Chemical substance applied to skin or mucous membranes of body to inhibit or destroy microorganisms
118
What is disinfectant?
Chemicals substances used on non-living or inanimate objects to inhibit or destroy microorganisms
119
What is decontamination?
Mechanical removal of most microbes from animate or inanimate surface
120
Suffix:
Static - Inhibits
Cidal- Kills
121
What is Microbial death?
Permanent loss or reproductive function even under optimal growth conditions
122
What are the factors that influence the effectiveness of physical or chemical method of control?
1. Number
2. Temperature pH
3. Concentration
4. Mode of action
5. Resistance
6. Organic matter
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