paper threeeee Flashcards
how does water get out of the xylem?
water potential gradient due to evaporation
for translocation
ringing experiments respiratory poisons stops moving up at night sap companion sells have mitochondria
against translocation
solutes move at different speeds
movement at the same rate down the whole plant
sieve plates weird
what are sink cells
respiring cells
why does the bohr effect happen
lower ph changes the shape of haemoglobin
purpose of double circulatory system
allows pressure to be raised again after oxygenation so blood can get to organs
name of outside heart blood vessels
coronary artery, cardiac vein
diastole- valves
av open
sl closed
atrial systole- valves
av open
sl closed
ventricular systole- valves
av closed
sl open
what is tissue fluid made of
blood plasma
why do arterioles have thicker muscle layers
controls movement into capillaries
other way for tissue fluid to return to the blood
lymph fluid
what changing shape does to bonds of substrate
distorts
light-dependent reaction (5)
- chlorophyll absorbs light- it is photoionised
- some energy from photoionisation is conserved in the production of atp and nadph
- some atp is also produced from chemiosmosis, using energy from the electron transfer chain
- h+ are pumped into the thylakoid and catalyse atp synthase by moving out
- photolysis of water produces protons, electrons (which enter the etc) and oxygen
what are schwann cells?
myelin-containing cells that provide electrical insulation/general protection
where is myelin?
in the cell membranes of schwann cells
open at resting potential
k+ channels, net movement of na+ out of pump
overall negative inside positive outside (so it flips when action potentials arise)
when do na+ channels close?
when +40mv potential has been established
what causes hyper-polarisation?
outward transport of k+ through the channels that are able to close
repolarisation
voltage-gated k+ channels shut, resting potential restored
name for the node of ranvier thing
saltatory conduction
greater axon diameter
increases speed of conductance due to less ion leakage
types of summation
spatial- multiple neurones
temporal- high frequency of neurotransmitter release from one neurone
3 purposes of the refractory period
one direction only
discrete impulses
limits number of action potentials
action of an inhibitory synapse
- neurotransmitter causes chloride ion channels to open
- cl- move in, also triggers k+ channels to open, so they move out
- membrane potential drops
- this hyperpolarisation makes it less likely that an action potential will be triggered
structures in the mitotic spindle
centrioles at the poles, fibres attach to centromeres of chromosomes
when do spindle fibres develop?
prophase
at what point do the chromatids become known as chromosomes again?
anaphase
what happens during binary fission after dna replication?
cell wall splits
root tip cells
totipotent stem cells in meristem
what do you do to the root tips in rp2?
add to hot acid to denature the enzymes involved in mitosis so cells stop dividing
how to focus a microscope
coarse then fine knob
what is done to dna before it is fingerprinted?
cut into fragments using restriction endonucleases
how are fragments seen in elecrophoresis?
attached to dna probes
how are dna fragments produced from rna?
mrna from cells that produce a lot of the protein converted to cdna using reverse transcriptase
how gene machines make dna fragments
small, overlapping sequences of nucleotides assembled and replicated using pcr
pros of pcr
- fast
- doesn’t require living cell cultures
pros of vectors
- low risk of contamination due to the specific restriction endonucleases used
- less mistakes- mutations are rarer than mistakes with pcr
step in adding genes to a plasmid that allows it to be replicated
adding promoter and terminal regions to allow binding of rna polymerase
what is required by the ribosomes during translation?
enzyme to catalyse the formation of the peptide bond, atp
what are genome and proteome defined in terms of?
cells
where is iaa produced?
tips of the root/shoot
what does a kinesis change?
speed and direction of movement
pathway for control of heart rate
receptor > medulla > nervous system > san
word to describe heart muscle
myogenic
movement of electrical impulse from avn
bundle of his > av septum > purkyne tissue bundles > impulse released
benefits of reflexes
- free up the brain for more complex processes
- present from birth
- helps avoid harmful stimuli
