Bio Prac Theory Selective Flashcards
Uses of carbs 4
- provide energy
- form supporting structures
- conversion into other organic compounds
- form nucleic acid
Why starch is used as storage in plants
- large molecule, cannot pass thru ppm cell membrane -> retained in cell
- not soluble in water -> will not change water potential
- easily hydrolysed back to glucose
Lock and key hypothesis
Enzyme has specific 3D shape w active site. only the substrate has a complementary shape. An fit in the enzyme to form e-s complex, reaction occurs, products detach from AS
Incr temp with enzymes
Incr enzyme activity -> incr rate of collision -> incr rate of formation of e-s complex
Digestion of protein in small intestine
Protein -trypsin/pepsin-> polypeptide -peptidase-> amino acids
Adaptations of small intestine for incr SA:V ratio
Folds, villi, microvilli
- villi thin walls
- long length of SI
- dense network of blood caps ^conc gradients
Liver alcohol break down
Alcohol -alcohol dehydrogenase-> acetaldehyde
Guard cells in the sun
Psis-> Chem E-> pump K+ ions -> decr WP -> water molc move in -> turgid -> open stomata
Xylem vessel adaptations
- no cross walls or protoplasm -> continuous lumen -> reduces resistance to water flow
- strengthened w lignin
Phloem adaptations 3
- sieve tube cell -> decr resistance to flow of subs
- sieve plates -> pores (rapid flow)
- companion cells -> mitochondria (AT, loading of sugars into sieve tubes)
Stem arrangement
X&P in a ring around pith, between them cambium cells that differentiate
Translocation
Trans of sucrose/AA, bidirectional
Translocation study: aphid
Cut open long tubed mouth, sucrose + AA out
Translocation study: swelling
Accumulation of sucrose -> decr WP -> water molc move in -> swelling
Entry of water into plant
Root hairs have thin film of liquid, sap V WP -> osmosis until xylem
Entry of mineral salts into plant
Diffusion/ AT depending on conc of cell sap vs conc of soil
- cell mem -> prevents cell sap from leaking out, maintain V WP
Moving water against gravity
- root pressure
- capillary action (forces of attraction between h2o molc, between h2o and surface of tubes)
- transpirational pull
Importance of transpiration
- maintain turgidity (water lost replaced)
- loss of latent heat of vaporisation
Wilting
Occurs when rate of transpiration > rate of absorption of water
Cells lose turgor = flaccid
- vSA exposed to sunlight, v excessive loss of water
- closure of stomata = decr co2 = v psis
If the independent variable of a graph is time, the gradient is …
The rate.
Curve-> tangent shows rate
If graph is used to obtain reading …
Always draw dotted lines to show where it’s from
Minimum number of values / IVs for planning
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