all7. Flashcards
Function of cholesterol
stabilise the membrane OR maintain / affect / control / AW,
fluidity OR reduces permeability to, polar / charged, particles
Function of protein / glycoprotein / intrinsic protein / protein channel /
protein pump / transport protein / carrier protein
allow communication across membrane OR allow, polar /
charged, particles to pass through membrane
Function of phospholipid (bilayer) / phospholipid head
to act as a barrier (to, polar / charged, particles) / select
what enters or leaves cell
Definition: cell signalling
communication between cells
cell, recognition / identification;
cells work together / coordination between action of different cells;
to trigger, response / reaction ( inside the cell
how a glycoprotein can act as a receptor
(receptor) specific shape / described;
complementary to (shape of), trigger / named trigger /
communicating;
molecule;
(trigger / AW) binds / attaches to receptor
why there was no transmission of light after the beetroot had been placed in water at 100 °C
cell surface / plasma, membrane damaged;
pigment, released / leaks out;
pigment, absorbs / takes up, the light;
The loss of water from the aerial parts of a plant is known as…
transpiration
Water is transported up the stem in
The…
xylem
From the air spaces in the leaf, the water vapour diffuses out of the leaf through
The….
stoma(ta) / stomatal pore
Explain why water loss from the leaves of a plant is unavoidable
stomata (open to) allow, gaseous exchange / carbon dioxide in /
oxygen out / AW;
(gaseous exchange) for photosynthesis;
(photosynthesis) essential for plant to, gain energy / make sugars;
some water lost through cuticle
the type of plant adapted to reduce water loss from its leaves
xerophyte
State and explain two adaptations of leaves that reduce evaporation
A 1] hairy leaves;
trap water vapour / moisture;
[A 2] stomata, in pits / sunken;
pits trap, water vapour / moisture;
[A 3] rolled leaves / presence of hinge cells;
reduce surface area OR (rolled leaves) trap water vapour /
moisture;
[A 4] high solute concentration in cells;
reduces water potential inside leaf cells;
[A 5] thick(er) cuticle;
(which is) waterproof / (relatively) impermeable;
[A 6] small leaves / needles; smaller surface area; [A 7] fewer stomata; reduces diffusion (of water vapour); [A 8] stomata close, during the day; reduces diffusion (of water vapour); [A 9] most stomata on lower surface; less exposure to sun OR cooler OR reduces diffusion (of water vapour); A 10] more densely packed spongy mesophyll; smaller surface area for evaporation (from mesophyll cell surface); key words: cuticle, impermeable, water vapour, potential gradient, diffuse / diffusion, stoma(ta), needles, surface area, hinge cells, saturated
Structure of prokaryotic cells
no true nucleus genetic material consists of ‘naked’ DNA average diameter of cell 0.5 – 5 µm (ribosomes) 18nm; cell wall (present);
Structure of eukaryotic cells
genetic material held in a nucleus as chromosomes / chromatin OR (genetic material) associated with, proteins / histones; (diameter of cell) 20 – 40 µm; ribosomes about 22 nm in diameter cell wall sometimes present
structure, associated with the cytoskeleton, which can bring about cell movement
flagellum / cilium / microtubule / microfilament / undulipodium
processes inside cells that rely on the cytoskeleton for movement
(movement inside cells of) chromosomes / chromatids (in cell division); (cytoplasm in) cytokinesis; organelles / named organelle; RNA (in protein synthesis); proteins;
During stage S, the genetic information is copied and checked.
Suggest what might happen if the genetic information is not checked
mutation / faulty DNA produced / error in copying;
daughter cells will not receive identical genetic information;
proteins / (daughter) cells, not made / do not function
During meiosis a cell undergoes two divisions.
Suggest how cells produced by meiosis may differ from those produced by mitosis
haploid / half genetic information / chromosome number is n;
genetic information not identical / produces genetically different
cells;
4 cells produced;
the type of muscle found in the walls of the heart chambers
cardiac
the process that creates pressure inside the heart chambers
muscle) contraction / systole