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90 Cards in this Set
- Front
- Back
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are bacteria single or multiple celled organisms? |
single-celled prokaryotes |
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do bacteria have membrane bound organelles |
no |
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do bacteria have trancription and translation compartmentalised like in prokaryotes |
no |
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in what form is the DNA of bacteria contained |
long circular plasmids |
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what is the cell membrane of bacteria made |
protein and phospholipids |
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give the 3 main function of the cell wall |
1) rigidity- osmotic and mechanical structure 2) contains characteristic antigens for antibody formation 3) serves as a firm base for pili and flagella |
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describe the function of the glycocalyx in bacteria |
1) protection from attack of host immune system 2) adhesion 3) receptor functions |
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what are pili also known as? |
fimbriae |
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what are the 2 types of pili? |
sex pili and common pili |
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describe the functions of the 2 different types of pili |
-sex pili enable DNA transfer by conjugation -common pili are antiphagocytic and aid attachment to host cells
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describe the process which helps avoid antibody response in bacteria |
rapid changes in antigenic protein |
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are flagella larger or smaller than pili |
larger |
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what is the function of flagella |
to give the bacteria motility |
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do gram stain +ve bacteria have a high or low peptidoglycan concentration |
high |
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what happens to gram +ve bacteria upon staining |
retains purple colour |
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what happens to gram stain -ve bacteria upon staining |
loses colour with alcohol treatment and so need counterstaining with a pink dye |
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does gram stain -ve bacteria have a high or low peptioglycan concentration |
low |
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in general do the bacteria in gram stain positive treatment look like rods or cones? and what is the general species of gram stain positive bacteria? |
they look like circles the species is the coccus |
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In general do the bacteria in gram stain negative treatment look like rods or cones? what colour is gram stain negative bacteria normally? and what is the general species of gram stain negative bacteria? |
they look like rods they are normally red and they are often of the bascillus species |
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what are the 2 types of toxins released by bacteria, and what are their functions |
endotoxins- produced when bacteria alive exotoxins- produced when bacteria dead |
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when bacterial cells are in a hostile environment how do they react |
by producing spores which provides a stronger protein coat |
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are bacterial cells heterotrophic or autotrophic? |
heterotrophic (getting food from outside sources, rather than making it itself (autogenic) |
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do bacteria duplicate before or after replication ? |
before, they must duplicate prior to replication |
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what are the 2 factors which can make bacteria resistant to antibiotics |
natural mutation and selection pressure |
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where are the 2 areas where bacterial DNA can be found |
within the nucleic acid, they can also have independent nucleic acid molecules called plasmids§ |
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what is the name given to the transfer of DNA sequences from one DNA molecule to another within a cell |
transposition |
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give 3 benefits of bacteria to the human body |
1) competition - the natural by-products of bacteria inhibit the establishment of infection 2) vitamin K + B are produced in the gut as metabolic end products 3) immune stimulation by bacteria keeps it "well practiced" |
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what characteristic do bacteria exhibit to each other when in a species |
they are commensal organisms exhibiting MUTUALISM |
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what 2 components make up the cell wall of a bacterial cell |
the outer membrane and the inner peptidoglycan layer |
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what type of ribosomes are found in bacteria and what type are found in normal human beings |
70S - bacteria (prokaryotes) 80S - eukaryotes - made up of 40S and 20S parts |
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describe and explain the term obligate intracellular parasites in relation to viruses |
they need a host cell to: 1. survive 2. replicate 3. make copies of genetic material as well as the proteins and enzymes it needs to replicate |
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viruses exploit the host cells metabolic processes true or false? |
true bitches |
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is the nucleocapsid of a virus symmetrical or non-symmetrical |
symmetrical |
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what does the nucleocapsid sorround |
the DNA/RNA genome of the virus |
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what are the repeating units in a nucleocapsid known as |
capsomeres |
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what are the 2 types of capsomere (repeating nucleocapsid units) |
-helical symmetry (rod) -icosahedral symmetry (spherical) |
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what are the 2 layers of the viral envelope |
inner protein layer --> virus derived outer lipid layer --> host cell derived |
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which part of the virus attaches to host cells and what is it also known as? |
the glycoprotein also known as viral attachment protein
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what are the different areas of the body through which a virus can enter |
-skin (abrasion, inoculation, insect/animal bite) -respiratory tract -Gastrointestinal tract -conjunction -genital tract |
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what are the 2 types of viral nucleic acids called? |
SS and DS DNA/RNA |
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there are 2 types of RNA strand, positive and negative, what are the different functions of these strands |
+ve - mRNA -ve - RNA functioning as a template for mRNA |
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what is the enzyme used by RNA viruses |
replicase |
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what is the enzyme used by retroviruses |
reverse transcriptase |
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what is the enzyme which is used to integrate into the host |
integrase |
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in viral attachment, the first step taken by the virus is to bind to receptors on the host cell surface, after this it enters the cell, what are the 2 main ways in which the virus enters the cell |
1. endocytosis 2. membrane fusion (fuses with membrane then releases viral nucleic acid into cytoplasm of cell |
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explain viral release into the environment |
1. release only happens following cell death 2. into environment 3. when it buds through the cell membrane this is what causes it to acquire an envelope |
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explain the reasons viruses are hard to create vaccines for |
- 1 infection will produce 1000s of progeny - viruses will exchange genetic material with one another -viruses mutate rapidly |
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what is the function of replicase |
to copy RNA to RNA (but it makes many uncorrectable errors) |
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what is the term used to describe the uncorrectable mistakes made during the copying of RNA to RNA by the enzyme replicase |
virus divergence |
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what things happen as a result of virus divergence |
1) gives rise to epidemics and pandemics (e.g. influenza) where viruses can mutate to escape immune surveillance 2) allowed viruses to jump species (e.g. HIV) and can therefore attach to a new receptor 3) gives rise to resistant vaccines and therapies (e.g. HIV) |
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what is the 70S ribosome in a bacterial cell made of |
30S and 50S subunits |
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what is the smallest white blood cell? |
lymphocytes |
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what is the basic function of a B lymphocyte |
they produce antibodies that serve as receptors that recognise antigens and initiate a process of activation of the cells |
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what are the 2 different types of lymphocyte? (also give sub variants of any type of lymphocyte if relevant) |
B lymphocytes T lymphocytes --T helper (CD4+) and T killer/cytotoxic (CD8+) |
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describe the process by which T helper (CD4+) cells help recognise foreign antigens in the body |
T helper cells recognise peptide fragments of protein antigens that are bound to specialised peptide display molecules called Major Histocompatibility Complex (MHC) molecules on the surface of antigen-presenting cells (APCs) |
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describe the process by which T helper (CD4+) cells help activate other cells and promote activation of macrophages, inflammation and proliferation and differentiation of T and B Lymphocytes. |
the activation of T helper cells causes them to produce cytokines. the production of these cytokines causes activation of macrophages, inflammation and proliferation and differentiation of T and B Lymphocytes. |
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where are the antigen presenting cells that activate T helper cells? |
in the epithelium |
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when an antigen presenting cell captures an antigen where does it transport the cell to? |
the antigens are transported back to peripheral lymphoid tissue where they are presented to lymphocytes |
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how many lobes does the nucleus of a neutrophil typically have |
2-5 (nucleus contains granules btw) |
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what are the first cells to reach sites of inflammation |
neutrophils |
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what gives the puss its yellow/white colour |
dead neutrophils |
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what colour are neutrophils when stained |
neutral in colour |
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how do neutrophils destroy pathogens |
they phagocytose pathogens and the release of hydrolytic enzymes |
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of the following white blood cells which are part of the innate immune system and which are part of the adaptive: neutrophils lymphocytes monocytes basophils |
innate - neutrophils monocytes basophils adaptive - lymphocytes |
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what does the nucleus of a monocyte/macrophage look like |
a kidney shape |
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what is the largest circulating WBC? |
macrophage |
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how do macrophages work |
through phagocytosis, they also promote inflammation through the release of cytokines |
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monocyte and macrophage, which term is used for circulating differentiated version of the cell and which is used for the cell found in tissue |
monocyte- found in tissue macrophage- found in circulation |
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describe the nucleus shape of eosinophils |
"sausage shaped" bi-lobed nucleus |
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where are eosinophils primarily found |
they are found primarily in tissue |
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how long do eosinophils spend in blood |
less than an hour |
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what do eosinophils mainly target |
parasitic infections |
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would you find eosinophils in an allergic reaction |
yes...yes you would |
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what colour are eosinophils when stained |
red |
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do eosinophils phagocytose antigen/antibody complexes |
yes..yes they frickin do |
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what is the least common type of white blood cell |
basophils |
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what is the shape of a basophil nucleus |
s shaped bi-lobed nucleus |
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where do basophils mature |
in the bone marrow for 2-7 days |
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where in the blood are basophils usually found and how long do they spend there? |
peripheral parts of blood, spend up to 2 weeks there |
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through interactions with which substance do basophils cause local inflammatory responses |
Immunoglobulin E (IgE) |
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what cells are basophils quite similar to |
mast cells |
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what 2 areas is adaptive immunity split into |
cell-mediated and humoral |
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what is humoral immunity mediated by |
antibodies produced by B lymphocytes |
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what is humoral immunity |
the elimination/neutralisation of microbes/toxins outside of the host cell |
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what is cell-mediated immunity |
defence against intracellular microbes |
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what is cell mediated immunity mediated by |
T lymphocytes |
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describe how cell mediated immunity works |
T helper cells are activated when a microbial antigen is presented by the APC via the MHC. The T helper cells then release cytokines and other factors which promotes the activation of macrophages, inflammation, and the the proliferation of further T & B lymphocytes. There are also T killer cells which destroy infected cells expressing the microbial antigen. |
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when the innate immune system, one of the first white blood cells to be activated are neutrophils, but how are they activated |
they are recruited by activated endothelial cells which release E-selectin and P-selectin |
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list the different methods of achieving control against bacteria/viruses |
-aspetic techniques -hand docontamination -education -safe use and disposals and sharps -waste disposal |
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in which circumstances should hands immediately be washed |
-before and after direct patient contact, including aseptic techniques. -after any exposure to body fluids -after removal of gloves -any other situation that could potentially result in the hands being contaminated |
