BIO FLASHCARDS

BACTERIA

prokaryotic

unicellular

peptidoglycan cell wall

no nucleus

no organelles

yes: plasma membrane, cytoplasm, ribosomes

BINARY FISSION

FUNGI

yeast uni, mould multi

have:

cell wall

plasma membrane

nucleus

cytoplasm

ribosomes

yeast ASEXUAL BUDDING

mould SPORE FORMATION

VIRUS

capsid protein coat

no:

nucleus

organells

cytoplasm

ribosome

REQUIRE HOST CELL PROTEINS N ENZYMES TO REPRODUCE

LIGHT DEPENDANT STAGE

light energy absorbed, converted to chemical (ATP)

split O2 and H+ (photolysis), to reduce NADP+ to NADPH

LIGHT INDEPENDANT STAGE

NADPH reduce CO2 to glucose (with ATP)

enzymes required

STOMATA OPEN N CLOSE

in light K+ ions are actively accumulated in guard cells

the WP is more negative in guard cells than surrounding cells

water eneters the cell by osmosis across SPCM and increase its turgor pressure

TRANSPIRATION

1) water on the surface of the intercellular air spaces evaporate into the air space
2) water vapour diffuses through the stomata

3) water potential on surface film is more negative
4) water moves from cells with less negative WP into the surface
5) these cells then draw water from cells deeper in the plant
6) suction force pulls water up xylem

TRANSPIRATION FACTORS

high humidity more water vapour, decrease conc gradient

high temp increase rate of evaporation

high winds sweep away water vapour, increase conc gradient

fibre

add bulk to contents of colon and retain water

soften faeces and reduce time needed for undigested residue to pass out of body

stimulate peristalsis

STARCH

salivary amylase > maltose

remaining starch: pancreatic amylase > maltose
maltase > glucose
enter epithilial cell from lumen via secondary AT and leave by FD

enter blood capilarries

FATS

emulsified by bile salts from liver thru gallbladder

pancreatic lipase > monoglyceride

some recombine to form fats in epithilial cells

mixed with cholestrol and coated w protein to form lipoprotein

passed into lacteal with lymph to form chyle

PROTEIN

pepsin (in stomach) > shorter polypeptides

trypsinogen > trypsin by enterokinase
trypsin CH of remaining proteins
short polypeptides > amino acids by peptidase

SMALL INTESTINE ADAPTATIONS

long for more time and total SA

transverse folds bearing thousands of finger like projections for total SA

one cell thick ephithilium to reduce diffusion distance

outer membrane has microvilli to increase SA to vol ratio and attatch more BB enzymes

blood clotting

when endothelium damaged, platelets aggregate at the site to form a plug for immediate blood loss

clotting factors secreted from liver n platelets (require vitamin K),

this result in enzymatic cascade that activates thrombokinase

thrombokinase convert prothrombin to thrombin
thrombin convert fribrinogen to meshwork of fibrin which form blood clot

phagocytis

phagocytes engulf and ingest foreign particles (innate) to stop them from entering the general circulation

squeeze through blood cap walls and attack bacteria

antibodies

B lymphocytes mature into plasma cells which produce antibodies

attatch to antigenic surface of bacteria causing it to agglutinate so phagocytes can easily ingest

SPECIFICITY - each antibody only attack 1 type

MEMORY - B lymphocyte remain in circulation and and divide rapidly to form more

HEART CYCLE

Atrial diastole - blood enter both atria at low pressure

pressure rise above ventricles, AV valves forced open (70% blood)

Atrial systole - both atria contract and push blood into ventricles (30% blood)

Ventricular systole - when ventricle muscles contract, pressure rises above atria and force both Av valves closed (prevent backflow)

higher pressure in ventricles than arteries force open semilunar valves

blood forced into aortic arch/ pulmonary arch

ventricular diastole - ventricles relax

higher pressure in aorta and pulmonary arch force some blood back into ventricles, force semilunar valves close

CORONARY HEART DISEASE

when arterioles blocked by buildup of cholestrol in arterioles, blood supply to heart is grearly reduced

rough surfaces increases the risk of blood platelet sticking to it

blood clot forms, blood and oxygen no longer supplied (heart attack)

AEROBIC RESPIRATION

complete breakdown of glucose in presence of oxygen to release ATP

passage epithelium have

1) gland cells - secrete mucus that trap dust and bacteria

2) ciliated cells - cilia sweep particles up bronchi and trachea into pharynx

ANAEROBIC RESPIRATION

glucose > pyruvic acid > CO2 + water (enzymes required)

when pyruvic acid exceeds oxidation to CO2 and water w oxygen, reduced to lactic acid by lactate dehydrogenase

lactic acid diffiuses from muscles to bloodstream and liver

some is oxidised back to pyruvic acid

some oxidised to form CO2 + water to release ATP, ATP used to convert remaining pyruvic acid to glucose

BREATHING MECHANICS

inhaling:

external intercostal contract

internal intercostal relax

diaphragm contract

ribcage pulled up and out

volume of air increases, pressure decreases below atm pressure, air enters

ALVEOLUS

large total SA

2 cell thick layer separating air in alveoli from blood in blood cells

rich supply of blood caps surrounding (steep conc gradient)

inner surface thin coat of moisture for O2 to dissolve

SMOKING

nicotine:

vasoconstriction of blood vessel

stimulate adrenaline release

stimulate blood clot formation

ALL INCREASE BLOOD PRESSURE

carbon monoxide:

damage endothelium lining > increase chance of cholestrol deposit > block coronary vessels

binds with high affinity to haemoglobin, higher than O2

tar:

stimulate excess mucus production + paralyse cilia of bronchi >

persistent coughing that damage epithelium > infection and inflammation > chronic bronchitis

THUS phagocytes release elastasee that breakdown elastin in walls on alveoli > emphysema

stimulate uncontrolled cell division >lung cancer

DECOMPOSITION

decomposers secrete extracellular enzymes that CH of complex organic matter into simple organic matter

simple organic matter absorbed into microorganisms by diffusion

when microorganisms respire simple sugarss broken down and CO2 is releases

EUTROPHIFICATION

excessive chemical fertilisers washed into lakes and rivers

excessive growth of algae

overgrowth of algae and surface plants prevent sunlight from reaching submerged plants

die due to lack of sunlight

decomposers decompose them using oxygen

reduce supply of oxygen to organisms

PESTICIDES

DDT non-biodegradable, persist for long time in soil and accumulate in the bodies of organisms

DDT much more soluble in fat than water, so they remain in fatty tissues and not excreted

insecticide passed along food chains increasing in concentration

higher trophic levels need to consume many organisms due to energy loss

BODY TEMP

when increase, temperature receptors in skin and deep body tissues send nerve impulse to the heat loss centre in the hypothalamus > sends impulse to relevant body parts

1) vasodilation of arterioles in skin blood capillaries, increases blood flow through skin blood capillaries instead of constricted shunt vessels, increasing heat loss by radiation

2) activity of sweat glands increases > greater production of sweat . faster rate of evaporation, higher rate of removal of latent heat of vaporisation

3) hair erector muscles relax and hair lies smoothly against skin, reducing amt of trapped air

BLOOD GLUCOSE

when BG increase

beta cells in islets of langerhans secrete insulin to:

1) increase permeability of cell membrane to glucose to increase rate of uptake of glucose via FD by cells

2) stimulate condensation of glucose to glycogen to be stored in the liver and muscles

3) promote conversion of carbs to fats

when BG decrease, alpha cells in the islets of langerhans secrete glucagon to stimulate breakdown of glycogen to glucose

DIABETES

type 1: inability of pancreas to produce sufficient insulin because immune system attacks the pancreas cells

type 2: target cells fail to respond to insulin

OSMOREGULATION

when WP is more negative,

osmoreceptors in the hypothalamus detect and stimulate the posterior pituary gland to secrete ADH

ADH increases permeability of cell membrane of epithilial cells of DCT and collecting duct to water (insert more aquaporin pores into cell membrane)

mopre water is reabsorbed into bloodstream by osmosis

ULTRAFILTRATION AND SELECTIVE REABSOROPTION

small molecules and ions filtered off from blood in glomerulus at high pressure (hydrostatic pressure) into bowmans capsule

blood cells platelets large molecules not filtered

50% of urea is reabsorbed by diffusion into blood capillaries

glucose and AAs transported against conc gradient into epithilial cells of PCT, move out of cells by FD using carrier proteins (to enter bloodstream)

DIALYSIS

haemodialysis (once every 2-3 week, need few hours every time)

-blood drawn from artery and flow through tubing in dialysis

small molecules diffuse through selectively permeable membrane

peritoneal dialysis (risk of infection)

-plastic tube inserted in abdominal cavity

peritoneum act as a SPCM

dialysis fluid added and left for hours

urea diffuse from tissue fluid to dialysis fluid

REFLEX ARC

stimulate the ____

nerve impulse generated and sent in sensory neurone to spinal cord

impulse reaches axon terminal branch of sensory neurone, cause release of neurotransmitter molecules across synapse, setting off impulse in motor neurone

rrelease of neurotransmitter molecule in motor neurone result in ____

ACCOMODATION

when near:

ciliary muscles contract

suspensory ligaments slacken

lens become thicker and more convex

when far: ciliary muscles relax

suspensory ligaments pulled taut

lens become thinner and less convex

PUPIL REFLEX

when bright

circular muscles contract, radial muscles relax

reduces size of the pupil to reduce amt of light

ADRENALINE

breakdown of glycogen to glucose

increased heart rate and force of contraction of heart muscles

general vasoconstriction

vasodilation of coronary blood vessels and blood vessels supplying brain and skeletal muscles

all so more blood containing oxygen and glucose supplied to skeletal muscles and brain

for higher rate of respiration and release of energy in the form of ATP for higher rate of skeletal muscle contraction and mental alertness

MENSTRUAL CYCLE

day 1-5:

endometrial lining of uterus break down

hypothalamus secrete GnRH that stimulate posterior pituarary gland to secrete FSH which travel to ovaries

FSH stimulastes dvlpment of follicles and 1 becomes Graafian follicle

stimulate cells to secret oestrogen

day 6-10: growth n repair of endometrium

oestrogen inhibits secretion of FSH

day 11-17: when oestrogen high, trigger secretion of LH from anterior pituarary gland

LH causes Graafian follicle to rupture which release secondary oocyte into the oviduct

LH casue formation of corpus luteum that secrete progesterone and oestrogen

day 18-28:progesterone keeps endometrium thick, vascular and stimulate formation of glands to prepare for implnatation

if fertilisation dont occur:

drop in LH cause corpus luteum to degenerate, progesterone production stop

uterine lining breaks down

if fertilisation occur: zygote develop into embryo, implanted into uterine lining

Human chorionic gonadotrophin prevent corpus luteum degenerate so it continue secrete progesterone and oestrogen before placenta

placenta adaptations

chorionic villus and blood capillaries increase SA for diffusion

maternal blood space low pressure so blood flow slowly for more time for diffusion

thin barrier to shorten diffusion distance