November mock prep- topic 2 Flashcards
what kind of image does a transmission EM produce?
photomicrograph
name the main difference between the samples needed when using electron microscopes
scanning electron microscopes do not need thin samples
what are viruses?
acellular(no cell structure)
akaryotes(non living)
describe the structure of viruses
capsid
attachment proteins
genetic material
what surrounds prokaryotic cells?
capsule
what are the functions of vacuoles?
acts as a food store
structural support for herbaceous plants
function of nucleolus
assembles ribosomes
function of rough endoplasmic reticulum
synthesis of proteins and glycoproteins
structure and function of mitochondria
matrix-contains proteins, lipids, ribosomes and DNA
cristae-attachment of enzymes and proteins
function of lysosomes
autolysis
release enzymes
digest worn out organelles
function of smooth endoplasmic reticulum
transportation and synthesis of lipids and carbohydrates
function of the golgi apparatus
modifies lipids and proteins
what happens during interphase?
DNA replicates
chromosomes visible
what happens during prophase?
nuclear envelope disintegrates
nucleolus disappears
what happens during metaphase?
spindle fibres form
chromosomes line up
what happens during anaphase?
chromosomes pulled to opposite poles
spindle fibres contract
what happens during telophase?
cytoplasm and cell membrane splits
spindles disintegrate
nucleolus and nuclear envelope reform
explain the process of virus replication
attaches to host cell via attachment proteins
nucleic acid injected which provides instructions to create viral components, nucleic acid etc.
new virus is assembled
what type of molecules can pass through the phospholipid bilayer?
lipid-soluble molecules
what are the functions of proteins in the phospholipid bilayer?
mechanical support
receptors
what type of molecules are involved in facilitated diffusion?
large, polar molecules
what factors affect facilitated diffusion?
concentration gradient
number of carrier or channel proteins
what is water potential?
pressure created by water molecules
how do plant cells appear in isotonic solutions?
flaccid
how do animal cells appear in hypotonic solutions?
lysed
how do plant cells appear in hypotonic solutions?
turgid
what happens to the vacuoles in plant cells in hypertonic solutions?
shrink
what type of proteins are used in active transport?
carrier proteins
how does co transport work?
ATP undergoes a condensation reaction which releases energy
binds to the carrier protein which changes shape releasing the molecule on the other side
phosphate is released meaning shape returns to normal
phosphate recombines with ADP
what are pathogens?
organisms that cause disease
what are antibodies?
proteins that detect antigens
what happens during inflammation?
histamine released from histamine granules
this leads to vasodilation which makes the area appear red
swelling caused by plasma leaks
describe the similarities and differences between the two types of phagocytes
both made in bone marrow
macrophages-
larger
specific defences
neutrophils-
short life span
apoptosis
lots made
what are antigens?
chemical markers on the outside of pathogens with a unique shape
what are APCs?
antigen presenting cells- antigens presented on outer membrane of a phagocyte after pathogen digested
describe the similarities and differences between the two types of lymphocytes
white blood cells found in the lymph nodes and blood
T lymphocytes-
made in bone marrow
produce antibodies
B lymphocytes-
made in thymus
directly affect cells
what type of immunity does a specific response lead to?
long term immunity
how does cell mediated immunity work?
antigens presented on outer surface (APC)
receptors on helper T cell fit onto antigens which activates the T cell to rapidly divide by mitosis
they either develop into memory T cells, activate cytotoxic T cells or simulate B cells to secrete antibodies
how does the humoral response work?
B cells receive antigens
B cells process it and present it
helper T cell binds and activates B cells which then divide by mitosis to clone plasma and memory cells
plasma cells secrete antibodies that attach and destroy pathogens
how do antibodies work?
agglutination- microbes dump together making it easier for the phagocyte
neutralising toxins- bind to toxins
present viruses entering entering host- binds and signals for macrophage
what are the 4 types of immunity?
active artificial- immune after vaccination
active natural- immune after initial exposure
passive artificial- infected by antibodies
passive natural- antibodies from mothers
why don’t vaccines eliminate all disease?
immunodeficiency
antigenic variability
objections
different strains
what does HIV do to helper T cells?
replicate inside them causing them to swell and burst
describe the structure of HIV
attachment protein
lipid envelope
RNA
capsid
matrix
reverse transcriptase
how does HIV replicate?
binds to CD4 protein on helper T cell
capsid fuses with membrane and RNA/enzymes enter
HIV reverse transcriptase coverts HIV RNA into DNA
moved into nucleus and inserted into cells DNA
creates mRNA which leaves through nuclear pore to be used in protein synthesis
what are monoclonal antibodies a clone of?
a single B cell
describe the hybridoma method of making monoclonal antibodies
mouse injected with antigen which simulates the production of plasma cells
bound with rapid dividing tumour cell to form a hybridoma which is assisted with an electrical current of polyethene glycol
grown in selective growth medium
cultured to produce large quantities of monoclonal antibodies
how does ELISA testing work?
apply to surface and wash to remove unattached antigens
add antibody and wash
add second antibody with an enzyme
add colourless substrate and look for a colour change
