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biology > Infection, Forensics Immune System > Flashcards

Infection, Forensics Immune System Flashcards

1
Q

explain how changes in the blood vessels results in reddening and swelling around the site of inflammation

A
  • histamine is released from mast cells as a result of damaged tissue
  • causes vasodilation
  • increases blood flow
  • vasodilation also causes permeability of capillaries to increase
  • allowing blood plasma to leave capillary/enter tissues causing swelling
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2
Q

Describe how HIV particles are able to enter T helper cells.

A
  • glyocproteins/GP 120 on the surface pf the virus
  • bind to CD4 receptors on the surface of T helper cells
  • viral envelope fuses with cell membrane of T helper cell
  • viral RNA enters cell
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3
Q

Explain why destruction of T helper cells causes symptoms of AIDS

A
  • reduces cytokine production
  • therefore reducing cloning/activation of B cells
  • reducing antibody production
  • there is an increased risk of opportunistic infections
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4
Q

bacteriostatic antibiotic

A

a substance which can prevent the multiplication of bacteria

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5
Q

Explain why the presence of microorganisms on the skin and in the gut helps to
prevent pathogenic organisms multiplying in the body.

A
  • flora in gut and skin are better adapted to the conditions
  • therefore they can outcompete pathogenic organisms
  • bacteria in the gut secrete chemicals/lactic acid that help destroy pathogens
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6
Q

why may stem cells from bone marrow prevent HIV causing AIDS

A
  • stem cells can differentiate into specialised cells
  • can differentiate into T helper cells that are resistant to HIV
  • T helper cells are destroyed by HIV so the patient cannot produce an immune response
  • mutated CD4 receptor prevents HIV entering the T helper cells
  • T helper cells are not destroyed therefore AIDS does not develop
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7
Q

A person who has been vaccinated becomes infected with HPV. Explain the role of the T
cells in the body of this person

A
  • vaccinated person has T memory cells
  • these recognise antigens specific to the virus
  • T helper cells activate T killer cells/B cells
  • T killer cells destroy cells infected with the virus
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8
Q

why is there few bacteria in the stomach

A
  • pH inside stomach is too low for enzymes of most bacteria to function
  • bacteria that live in stomach have adaptations that enable them to survive
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9
Q

HIV structure

A
  • protein capsid
  • two strands of RNA
  • spherical
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10
Q

interferon

A

produced by infected cells and inhibits viral replication

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11
Q

explain the role of T cells in the immunity to a virus after vaccination

A
  • T cells bind to antigen on APC
  • production of active T helper/memorycells
  • these activate B cells to divide/become cells capable of producing antibodies
  • memory cells remain in body so antibodies can be produced quickly on re-infection
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12
Q

vaccines type of immunity

A

artificial active

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13
Q

ribosomes of bacteria

A

smaller than ribosomes in eukaryotes

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14
Q

infection control practices hopsitals have introduced

A
  • doctors don’t wear long sleeves
  • disinfection of beds
  • hand wash
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15
Q

explain how skin flora protects body from infection

A
  • prevents growth of pathogens
  • competition for nutrients / space/ water
  • release of chemicals/toxins/antimicrobials
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16
Q

why is applying antihistamine cream better than taking antihistamine tablets

A
  • local reaction produced
  • cream applied to actual site of histamine production
  • more rapid treatment
  • higher concentration of antihistamine at site
  • antihistamines will not be digested by enzymes
17
Q

Suggest why common cold viruses cannot infect cells if they land on unbroken skin.

A

skin is a barrier
keratin
lack of receptors for virus

18
Q

Suggest why common cold viruses cannot infect cells if they enter the blood through a cut in the skin

A

virus only attaches to specific receptors
receptors not present on blood cells

19
Q

state two characteristic features of antibodies

A
  • produced by plasma cells
  • agglutination
  • glycoprotein
  • Y shape
  • antigen binding site
20
Q

differences between genetic material of viruses and bacteria

A
  • bacteria have dna and viruses have rna
  • bacteria have circular genetic material while viruses are linear
  • bacterial dna is double stranded while viral rna is single stranded
  • bacteria may have plasmids and viruses do not
21
Q

describe how macrophages ingest bacteria

A

phagocytosis
bacterium inside vacuole/phagosome
Lysosome fuses with the phagosome to form a phagolysosome
Lysozymes are released and destroy what was engulfed

22
Q

Suggest why treatment with antibiotics may not be effective against dormant bacteria in tubercles

A
  • bacteria need to be accessible to antibiotics
  • bacteria inside macrophages
  • waxy layer of bacteria
  • antibiotic resistancd
23
Q

How can a person develop artificial active immunity following vaccination

A
  • dead pathogen put into person
  • stimulated specific primary immune response
  • T helper cells activated
  • B h cell activated
  • T killer cells activated
  • memory cells produced
24
Q

Explain why activity of these bacteria and inhibition of T cells means a person may quickly develop severe symptoms leading to death

A

Further ling damage/ severe breathing problems
Bacteria can get into blood
Organ failure leads to death
Reduced immune response due to a loss of T helper cells
Opportunistic infections causing death

25
Q

role of DNA primers in amplification

A

primers have a specific base sequence
bind to complementary bases of the DNA to be amplified
provides a site for DNA polymease to bind to

26
Q

why are amplified fragments for alleles different

A

base sequence of alleles are different
restricvtion enzyme cuts a specific site
only present in this specific allele
therefore allele is shorter

27
Q

How to establish the time of death

A

record insects present
take into account stages of lifecycle are present
take environmental variable into account

28
Q

Describe how DNA profiling could be carried out to show that these snakes are different
species.

A

DNA obtaijed from two different types of snake
PCR/restriction enzymes used to produce fragments of dna
gel electropheresis to analyse dna samples
this separates dna fragments
more differences in patterns of bands indicate snakes are differetn species

29
Q

Describe the changes that occur inside a body in the first week after death

A

body temperature falls
rigor mortis
autolysis
putrefaction/bloating/discolouration

30
Q

Describe the role of decomposers, such as microorganisms, in the carbon cycle.

A

break down organic material
they respire
releasing co2 into the atmosphere

31
Q

explain electrophoresis

A

restriction enzymes cut dna into fragments
dna samples loaded onto agarose gel
electric crurent applied across the gel
use gene probe
markers used to visualise bandscompare bands

32
Q

Explain the effect of ambient temperature on the rate of decomposition.

A

increased rate of decompostion/decay
increased enzyme activity
increased growth rate of decomposers

33
Q

Explain how microorganisms in the soil break down the stems (made of polysaccharides)

A

enzymes secreted by the microorgansims
break down glycosidic bonds
releases glucose that is used by the microorganism in respiration

34
Q

Describe how one PCR cycle would increase the quantity of DNA present.

A

heat to 95 to break hydriogen bonds between dna
annealing/joingin primers at 55
elongating/addition of nucleotides
to double the quantity of dna

35
Q

Explain the advantages for this species of blowfly of increasing the temperature within
the dead rhinos

A

increased enzyme activity
high temp denatures enzymes of other species
increases food availbility due to reduced competition

biology (10 decks)

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