ch11: not vaccinating your kids makes them gay Flashcards
explain the roles of named types of blood proteins in different defence mechanisms (8)
clotting factor is released by platelets of damaged tissues/cells
prothrombin is activated to thrombin
thrombin converts soluble fibrinogen to insoluble fibrin
mesh of fibres seals wound by trapping red blood cells
a clot is formed to prevent blood loss and entry of pathogens
enzymes in phagocytic white blood cells digest pathogens
phagocytes are attracted to pathogens
membrane engulfs pathogens by endocytosis with the formation of a vesicle
immunoglobulins are antibodies: specific to antigens on pathogens
variable regions for binding: constant region aids destruction of the pathogen
attracts phagocytes to engulf pathogen
burst pathogen cells
agglutination
neutralise toxins
memory cells retain the ability to produce antibodies
explain how antibodies are produced in response to infection in humans (8)
antibodies are necessary for immunity to disease
produced by beta lymphocytes
many types of lymphocytes in the body, each produce 1 specific antibody
each antibody corresponds to a specific antigen
macrophage recognises and engulfs pathogens by endocytosis
presentation of antigen by macrophage on membrane
helper T-cell are complementary to antigen: binds to macrophage
activated → binds to complementary inactive B-cell → activated → increases in size and clones by mitosis
plasma cells grow → ↑ no. of rough ER/Golgi apparatus
plasma cells begin to produce antibodies to the specific antigen
antibodies secreted through membrane by exocytosis
antibody binds to antigen & destroy them
after the infection clear → most lymphocytes disappear but some persist → memory cells
can quickly form clones of itself if the pathogen is re-encountered
allows long-term immunity
describe the production of hybridoma cells/monoclonal antibodies (2)
antigen injected into a laboratory animal
B lymphocytes are produced and extracted from the animal
fuse with tumour cells to form hybridomas → produce antibodies
e.g. HCG in pregnancy test
advantages
unregulated mitosis → large amount of antibody can be produced
all cells produce same type of antibody
outline the principle of immunity (6)
ability of an organism to resist infection due to presence of antibodies
can be active or passive
active: facing an infection (through vaccination)
passive: receiving antibodies from external sources
injection
breast milk
pathogen invades body
leads to formation of beta memory cells that produces specific antibodies
can form clones of itself by mitosis if the pathogen is re-encountered
antibodies produced faster + in greater amounts
outline the principles that form the basis of immunity (6)
1st line of defense: skin and mucous membranes form barriers
macrophage recognises and engulfs pathogens by endocytosis
presentation of antigen by macrophage on membrane
helper T-cell are complementary to antigen: binds to macrophage
activated → binds to complementary inactive B-cell → activated → increases in size and clones by mitosis
B-cells differentiate into plasma cells and memory cells
plasma cells begin to produce antibodies to the specific antigen
memory cells form basis of long-term immunity
polyclonal response: multiple B-cells activated by different molecules of antigen
explain the principles of vaccination (9)
vaccine = modified form of a pathogen
injected to patient
stimulates specific immune response called primary response
helper T-cell are complementary to antigen: binds to macrophage
activated → binds to complementary inactive B-cell → activated → increases in size and clones by mitosis
development of memory cells → can quickly form clones of itself if the pathogen is re-encountered
secondary response
person has immunity
may need booster shot to maintain immunity
an example of active and artificial immunity
discuss the benefits & risks associated with vaccination programmes (8)
pros: immunity can limit spread of infectious disease disease can be eradicated ↓ mortality can protect vulnerable groups ↓ health care costs
cons: produce symptoms of disease human error in administration allergic reaction not life-long immunity toxic effect of mercury-based preservatives
explain how skeletal muscles contract (8)
nerve impulse arrives at end of motor neurone → stimulate contraction
neurotransmitter released cause action potential in muscle fibre
sarcoplasmic reticulum releases Ca2+ → bind to troponin → cause tropomyosin to expose binding sites on actin
myosin heads bind to sites on actin → form cross-bridges
myosin head moves actin filament by ATP
actin moved towards M line → shorten sarcomere
ATP binding → break cross bridge
conversion of ATP to ADP & Pi → myosin heads change angle
cycle repeated during muscle contraction
google docs myofibrils: in muscle fibres sarcomeres: repeating units in myofibrils arranged end to end actin & myosin overlap actin: thin filament myosin: thicc filament light & dark bands light bands narrower when muscle contract
explain how the structure of the nephron and its associated blood vessels enable the kidney to carry out its functions/kidney helps to retain useful substances in the blood and eliminate substances which the body does not need (8)
function of the kidney: osmoregulation
most small soluble molecules, glucose and ions removed from blood in Bowman’s capsule through ultrafiltration in the glomerulus
high pressure in glomerulus due to larger afferent than efferent arteriole
basement membrane act as filter
proteins, blood cells and large molecules remain in blood
selective reabsorption of glucose by active transport in proximal convoluted tubule
all glucose and amino acid is reabsorbed, none should remain
most water reabsorbed through osmosis
urea remain in the filtrate → conc ↑
microvilli ↑ surface area
loop of Henle creates solute conc gradient in medulla → enhance water reabsorption
active transport of Na+ out of ascending limb
ascending limb is impermeable to water
reabsorbed in descending limb
distal convoluted tubule adjust conc of Na+/K+/H+
osmoregulation occurs in collecting duct
water is reabsorbed
permeability of membrane regulated by ADH depending on blood solute conc
water conc in urine is variable to maintain homeostasis in blood
water unabsorbed → urine
google docs
explain how the collecting ducts can alter the volume of urine produced by the kidney (9)
osmoregulation = control of water balance in blood
nephron is the functional unit of the kidney
water passes into the kidney tubules by ultrafiltration → glomerular filtrate collected by Bowman’s capsule
reabsorbed in proximal convoluted tubule, descending limb of loop of Henle and collecting duct by osmosis
transport of salts into kidney’s medulla → maintains hypertonic conditions in medulla so water is reabsorbed
ADH regulates water level & solute concentration
pituitary secretes ADH when water in blood too low
↑ aquaporins in collecting duct cell membranes → ↑ permeability of collecting ducts
collecting duct passes through medulla
medulla is hypertonic → ↑ water is reabsorbed from collecting duct
↓ urine is produced
no ADH secreted when solute concentration is too low
higher flow rates → less time for water reabsorption
dilute & large vol of urine produced
explain the presence of glucose in the urine of a diabetic person and its absence in the urine of a person with type I diabetes that is being successfully treated (8)
filtered out of blood in glomerulus
reabsorbed from filtrate in proximal convoluted tubule by active transport
there are specific pumps for glucose → limited capacity for glucose uptake
diabetic patients: glucose conc in plasma is high
capacity for reabsorption in proximal convoluted tubule exceeded capability → not all glucose can be reabsorbed
no glucose reabsorption after the proximal convoluted tubule
glucose still present at collecting duct
type I diabetes treated with insulin
reduce glucose conc of blood
all glucose reabsorbed from filtrate in type I if treated
explain how insects excrete nitrogenous wastes (8)
excreted as uric acid by Malpighian tubules
non-toxic
ammonia accumulates in hemolymph
absorbed by Malpighian tubules
converted to uric acid
requires ATP
high solute conc in Malpighian tubules
water absorbed by osmosis flushes uric acid to gut
water reabsorbed from the feces & returned to hemolymph
uric acid precipitates → pass out with little water
egested with the feces
explain the structure and role of the placenta (8)
disc-shaped structure embedded in uterus wall connected to fetus by umbilical cord contain fetal and maternal tissues placenta villi: large surface area for material exchange immune system of mother protects embryo
blood of fetus and mother flow close to each other
material exchange between mother and fetal blood
nutrients & oxygen diffuse thru membrane to fetus
CO2 & waste diffuse thru membranes to mother
alcohol/viruses/caffeine from mother may damage fetal development
barrier function: blood no mix
endocrine function: take over role of corpus luteum to produce estrogen, progesterone & HCG
HCG: prevents corpus luteum degeneration
estrogen: maintain endometrium + ↑ mammary gland growth
progesterone: maintains endometrium + prevents uterine contractions
outline the role of hormones in the process of birth in humans (4)
38 to 40 weeks pregnancy: level of progesterone ↓ b4 birth
removes inhibition of oxytocin secretion → oxytocin secreted from pituitary gland
stimulate contraction of uterus
cervix dilates
uterine contraction & stretching of cervix/vagina stimulates secretion of more oxytocin
positive feedback: ↑ intensity and rate of contractions
compare the processes of spermatogenesis and oogenesis (8)
produce haploid cells
involve mitosis & meiosis
have cell growth b4 meiosis
involve differentiation to produce a specialised gamete
