topic 2 cells/immunity Flashcards
Explain why its not possible to determine identity of structure
‘X’ using optical microscope {2}
. resolution too low
. wavelength of light too long;
Describe role of 1 named organelle digesting bacteria in cytoplasm {3}
. lysosomes
. fuse with vesicle/phagosome
. Releases hydrolytic enzymes
Give 2 structures in all prokaryotic and eukaryotic cells {2}
. cell membrane
. ribosomes
. Cytoplasm
. DNA
function of golgi apparatus
.makes lysosomes
.transporting lipids and protiens
function of RER
large SA for protien synthesis
function of SER
synthesise lipids and carbohydrates
Suggest 1 explanation for the faster rate of plasmid replication in cells growing in a culture with a high amino acid concentration. {2}
. Amino acid used for protien synthesis
.so more enzymes for plasmid replication
Describe how sample of chloroplasts could be isolated from leaves {4}
- Grind/blend leaves AND filter
- In cold, isotonic buffered solution
- Centrifuge low speed and remove nuclei/cell debris;
4.spin at higher speed, chloroplasts settle out;
Give 1 feature of chloroplast that allows protein to be synthesised
inside chloroplast and desc 1 diff between this feature in chloroplast and similar features in rest of the cell {2}
- DNA
- in chloroplast its circular but in nucleus its linear
contrast the structure of prokaryotic cell and animal {5}
. animal has dna in nucleus
prokaryote has free floating DNA
. animal has mitochondria
prokaryote doesn’t
. animal has no slime capsule
prokaryote does
. animal has no cell wall
prokaryote has murien cell wall
. animal DNA bound to histones
prokaryote not bound to histones
. animal has endoplasmic retic
prokaryote doesnt
Outline role of organelles in production, transport & release of
proteins from eukaryotic cells.
Dont include details of transcription/ translation in answer {4}
. mitochondria- produce ATP for protien synthesis
. ribosomes-produce proteins
.nucleus- contains DNA which codes for protien
. golgi apparatus- modifies proteins
. vesicle- transports protein by fusing with cell membrne
Suggest why nucleus is not visible in the plant cell image {1}
. nucleus isnt stained
. not in the section
The detail shown in diagram above wouldnt be seen using optical microscope. Explain why {2}
- Light has longer wavelength
- So lower resolution
Describe 3 properties of solution and explain how each property prevented damage to the organelles before centrifuge. {3}
. COLD- prevent enzyme activity;
. BUFFERED pH- prevent denaturing of enzyme
. SAME WATER POTENTIAL isotonic-to prevent bursting
what is cell membrane made out of [1]
. phospholipid
which microscope pruduces 3D images {1}
.SEM scanning electron microscope
Contrast how optical & transmission electron microscope work and contrast limitations of their use {6}
- TEM use electrons
optical use light; - TEM greater resolution;
- TEM smaller organelles observed
- TEM view only dead / dehydrated specimens
optical can view live specimens - TEM does not show colour
optical can - TEM requires thinner specimens;
- TEM requires a more complex/time consuming preparation;
- TEM focuses using magnets and optical uses glasses lenses
Suggest explanation for appearance of the cell-surface membraneas two dark lines {3}
1.Membrane has phospholipid bilayer
2. Stain binds to phosphate / glycerol
3. On inside and outside of membrane
Describe binary fission in bacteria{3}
. Replication of (circular) DNA
. Replication of plasmids
. Division of cytoplasm to produce daughter cells
Describe and explain two features you would expect to find in a cell
specialised for absorption. {2}
. Folded membrane/microvilli SO large sa for absorption
. Large number of cotransport/carrier proteins for active transport
.Large number of mitochondria so energy for active transport
define antigen
protien on surface of cell that trigger immune response
Describe how HIV is replicated {6}
. Attachment proteins attach to helper T cell receptor
. RNA enters cell
. Reverse transcriptase convert RNA to DNA
DNA/chromosome/genome/nucleus;
. DNA transcribed into mRNA;
. mRNA translated into (HIV/viral proteins.
. Viral protein/capsid produced;
. Virus particles assembled and released
Give two types of cells, other than pathogens, that can stimulate an immune response. {2}
. Cells from other organisms /transplants
. Abnormal/cancer/tumour (cells);
. Cells infected by virus;
Explain how HIV affects the production of antibodies when AIDS develops in a person. {3}
. Less antibody produced;
. cos destroys helper T cells;
. so less B cells stimulated to divide to plasma to antibody
Previously, the viruses infected only one species of frog.
Suggest and explain how the viruses started to infect other species of frog. {3}
. Mutation in the viral genetic material
. changes tertiary structure of attachment protein
. Allows virus to bind to receptors of other species
Determining genome of viruses could allow scientists develop a vaccine.
Explain how. {2}
. identify proteins that derive from the genetic code
. then identify potential antigens to use in the vaccine
What is a monoclonal antibody? {1}
.1 type of antibody with the same tertiary structure
Give 1 example of using monoclonal antibodies in a medical treatment. {1}
.carries drug to specific antigens/receptors
When a vaccine is given to a person, it leads to the production of
antibodies against a disease-causing organism.
Describe how. {5}
- Vaccine contains antigen from pathogen
- phagocyte presents antigen on its surface
- T cell with complementary receptor protein binds to antigen
- T cell stimulates B cell
- With complementary antibody on its surface
- B cell secretes large amounts of antibody
- B cell divides to form clone all secreting / producing same
antibody.
Describe the difference between active and passive immunity. {5}
. Active involves memory cells,
-passive does not;
. Active involves production of antibody by plasma cells /
memory cells;
. Passive involves antibody introduced into body from outside
. Active long term, cos antibody produced in response to antigen
. Passive short term, because antibody (given) is broken down;
. Active take time to work,
-passive fast acting
example of natural and artificial active immunity each
. natural - catching disease
. artificial - vaccination
example of natural and artificial passive immunity each
. natural - antibodies from breast milk
. artificial - injected antibodies e.g antivneom
