MOLECULAR BIO EXAM QUESTIONS Flashcards
DESCRIBE THE PROPERTIES OF WATER THAT MAKE IT A USEFUL COMPONENT OF BLOOD
water is a polar molecule/ hydrogen bonding
solvent
example of dissolved substances: salt
water is fluid/liquid at body temperature
high heat capacity/ specific heat capacity allows for water to carry heat w/o warming up
DISTINGUISH BETWEEN ANAEROBIC AND AEROBIC CELL RESPIRATION IN EUKARTOYES
aerobic: requires oxygen mitochondria krebs cycle large yield of ATP CO2 and water
anaerobic: no oxygen in cytoplasm no kreb cycle small yield of ATP lactate produced in animals ethanal + CO2 in yeast/ plants
EXPLAIN THE EFFECT OF CHANGES IN PH, SUBSTRATE CONCENTRATION AND TEMPERATURE ON ENZYME ACTIVITY
enzymes have optimal ph
activity increases as ph gets closer to optimal ph
extreme ph denatures enzymes
by breaking bonds/changing enzyme active site shape
EXPLAIN THE EFFECT OF CHANGES IN SUBSTRATE CONCENTRATION ON ENZYME ACTIVITY
as substrate increases activity increases
as substrate concentration increases the collisions
between substrate and enzyme increase
reaching a plateau
all active sites are saturated
EXPLAIN THE EFFECT OF CHANGES IN AND TEMPERATURE ON ENZYME ACTIVITY
enzymes have an optimal temperature
activity increases as it gets closer to optimal temperature
high temperatures stop enzyme activity due to irreversible change in structure: denaturation
by breaking bonds/ changing enzyme active site shape
EXPLAIN HOW AND WHERE ENERGY IS STORED IN PLANTS
energy is gained through photosynthesis
glucose from photo stored as starch
starch stored in chloroplast
starch stored as starch granules
in seeds
stored as lipids/oils
lipids store twice as much energy per gram as starch
OUTLINE THE DIFFERENCES IN ABSORPTION OF RED, BLUE AND GREEN LIGHT CHLOROPHYLL
blue and red light are absorbed the most
greatest absorption rate in blue light
red light absorbed in high amounts
leasts/ no absorption of green light: reflected
EXPLAIN HOW THE PROCESS OF PHOTOSYNTHESIS AFFECTS CARBON DIOXIDE CONCENTRATIONS IN THE ATMOSPHERE DURING A TYPICAL YEAR AND THE LIKELY CONSEQUENCES ON EARTH OF THE EARLY RISES IN CO2 CONCENTRATIONS
relationship between photosynthesis and CO2 conc:
photosynthesis uses CO2
CO2 fixed/ made into organic M
lower CO2 level in atmosphere
annual/seasonal flux of CO2 could be related to photo
caused by an increase in photo during spring/summer
consequences:
enhanced greenhouse effect caused by raised level of CO2
causing global warming
rising level of oceans
changes in weather patterns
ocean acidification
alter food webs
change/loss in habitats
may lead extinction
OUTLINE THE ROLE CONDENSATION REACTIONS INVOLVING CARBOHYDRATES
condensation is joining together of molecules with the release of water
two monosaccharides join to form a disacharride
e.g. 2 glucose= maltose
hydrolysis is the breaking down of molecules with the addition of water
disaccharides break into 2 mono saccharides
maltose–> 2 glucose
METABOLIC REACTIONS ARE CATALYSED BY ENZYMES. EXPLAIN HOW EMZYMES CATALYSE REACTIONS AND HOW A CHANGE IN PH COULD AFFECT THIS
enzymes speed up the rate of reaction
lock and key model
substrate fits into active site
enzyme substrate specificity
enzymes work best at optimal ph
increase/decrease from optimum ph decreases enzyme activity
change in ph changes structure of active site
not allowing substrate to fit in active site
enzymes can be denatured if change is extreme
denaturing is loss of its biological properties
DESCRIBE HOW THE RATE OF PHOTOSYNTHESIS CAN BE MEASURED
photosynthesis word equation:
carbon dioxide + water —> glucose + oxygen + water
measure production of O2
example of how: count bubbles from water
per unit of time using electronic equipment
measure CO2 uptake
measuring aquatic pH
shift per unit of time
measure increase in biomass
sample dry mass of crop before and after time period
not possible to measure water uptake since water is transpired and used in many chemical processes
EXPLAIN HOW CARBON DIOXIDE IS PRODUCED IN AEROBIC AND ANAEROBIC RESPIRATION
glycolysis is common to both
anaerobic: glycolysis occurs in cytoplasm pyruvate acid transformed into CO2 and ethanol in alcoholic fermentation lactic fermentation does not produce CO2
aerobic: glycolysis occurs in the mitochondria krebs cycle released CO2 pyruvate to acetyl CoA link reaction liberates CO2
EXPLAIN HOW VESICLES ARE USED TO TRANSPORT PROTEINS WITH A EUKARYOTIC CELL
protein syn by ribosomes/rER
proteins bound by vesicles
vesicles bud off rER
vesicles from rER transport proteins to Golgi apparatus
vesicle fuse with Golgi apparatus
Golgi modify proteins
secretory cells bud off
vesicle move across cytoplasm
vesicle fuse with plasma membrane
proteins may be secreted to exterior by exocytosis
ER, vesicle and plasma membrane have phospholipid bilayer structure
EXPLAIN HOW GLUCOSE IS USED IN BOTH ANAEROBIC AND AEROBIC RESPIRATION
glycolysis is the breakdown of glucose
glucose is broken down to pyruvate
pyruvate is converted into lactate in humans/animals
pyruvate converted into CO2 and ethanol in plants/yeast/ bacteria
pyruvate from glucose is broken down to CO2 and water
generic anaerobic and aerobic differences
CELL MEMBRANES SEPERATE AQUEOUS ENVIRONMENTS IN CELLS. EXPLAIN HOW THE PROPERTIES OF PHOSOPHOLIPIDS HELP MAINTAIN THE STRUCTURE OF THE CELL MEMBRANES
labelled phospholipid consisting of head and two tails
head is glycerol and phosphate
tails are fatty acid chains
head hydrophilic and tails hydrophobic
hydrophilic molecule/heads are attracted to/ soluble in water
hydrophobic molecules/tails are not attracted to water but are attracted to each other
formation of double layer in water
stability in double layer because heads on outer edge are attracted to water and tails are attracted to each other in the middle
phospholipid bilayer is fluid/flexible state because of attraction of non-polar tails to each other
fluidity allows membranes to change shape/ vesicle to form or fuse with membrane
non polar amino acid side chains are attracted to tails
