all8. Flashcards
Explain why organisms larger than organism C (single celled) need to have transport systems.
surface area relative to volume too small/AW;
diffusion too slow/AW; idea of speed needed
distance too great/some cells deep in body/not all cells in contact with
environment/AW; R large if unqualified
insufficient/AW, oxygen/(named) nutrient, supplied/(named) waste removed;
idea of linking (named) areas; look for ‘from…’ ‘to…’ with an
implication of organs, not just ‘all over body’
(may be,) more (metabolically) active/AW/, homoiothermic;
features of the alveolus/alveolar air, sac/space which make it suitable for gas exchange.
large surface area to volume (ratio)/AW; thin/one cell thick, wall/short diffusion distance/AW; A appropriate figures for width squamous epithelium; permeable; blood supply, qualified; elastic tissue/recoil (after expansion); surfactant;
a closed system
the blood flows in vessels
a double circulation
blood passes twice through the heart for one complete circuit of the body
Purkyne tissue
transmits waves of excitation to the base of the heart
conducts waves of excitation over the walls of the ventricles
fibrous tissue between the atria and the ventricles
is unable to conduct waves of excitation
atrioventricular node (AVN)
delays transmission of the waves of excitation by about 0.1 s
sinoatrial node (SAN)
initiates the cardiac cycle
coronary artery
carries oxygen to the heart muscle
neutrophil/phagocyte function
phagocytosis/engulfing
Describe how red blood cells are adapted for their function.
1 haemoglobin/haem, carries oxygen/AW;
2 detail of no. of oxygen molecules carried;
3 small size/large SA:V ratio, so haemoglobin never far from cell
surface/AW;
4 flexible/elastic/stretchy/changes shape/AW;
5 small size/‘stretchiness’/AW, allows red cells to, fit/squeeze, into
capillaries;
6 biconcave/AW [A ‘dimpled’], gives, increased/AW, surface area
relative to volume (for diffusion);
7 no nucleus to maximise room for, haemoglobin/oxygen/AW;
8 contain carbonic anhydrase;
9 describe, the reaction catalysed by carbonic anhydrase/role in
maintenance of diffusion gradient/AW;
10 transport of carbon dioxide as carbamino-haemoglobin/CO2
combines with Hb;
11 ref buffering effect;
12 AVP; e.g. further detail of oxygen carriage
variable oxidation state of Fe
idea that small size allows them to be close to tissue or cells
lack of, other/named, named organelles, also increases
room for Hb/O2
With reference to the definition of transpiration and the apparatus (photometer) in the diagram above, explain why the results gained by using the apparatus are not measures of the actual transpiration rate.
transpiration is the loss of water, vapour/by evaporation;
(apparatus) measures water uptake;
to replace loss;
assumes all uptake is lost/AW; ora some may be used
explanation of how some uptake may be used e.g. used to regain
turgor/used in photosynthesis;
uptake by detached shoot may not be same as whole plant
potometer set up- controls
cut shoot under water/insert into apparatus under water/AW;
cut shoot at a slant;
no, airlocks/bubbles/AW in, plant/apparatus, or airtight/watertight, joints;
dry off leaves/AW; use a healthy/undamaged/AW, shoot; A fresh
allow time to acclimatise/AW;
keep (named) condition(s) constant; R ‘control’ conditions if unqualified
measure per unit time;
Describe the precautions you would take when setting up and using a photometer in order to get valid readings from which the transpiration rate can be estimated.
cut shoot under water/insert into apparatus under water/AW;
cut shoot at a slant;
no, airlocks/bubbles/AW in, plant/apparatus, or airtight/watertight, joints;
dry off leaves/AW; use a healthy/undamaged/AW, shoot; A fresh
allow time to acclimatise/AW;
keep (named) condition(s) constant; R ‘control’ conditions if unqualified
measure per unit time;
why it is important that red blood cells are stored in a solution with a suitable water potential
prevents osmosis;
no net movement of water/AW;
prevents bursting/lysis/crenation/AW;
why xylem is described as a tissue
made up of, more than one / two / a few, types of cell
working together / AW;
with a, specific / particular / same, function / role / purpose / job;
Prokaryotic cell structure
no, nucleus / nucleolus / nuclear membrane / nuclear envelope A free DNA circular DNA A loop no, histones / (true) chromosome A naked DNA no membrane-bound organelles cell wall peptidoglycan / murein, cell wall ribosomes, 18 nm / 70S / smaller plasmids AVP e.g. no cytoskeleton flagellum not 9+2 pili fimbrae capsule mesosome
Eukaryotic cell structure
nucleus / nucleolus / nuclear membrane / nuclear envelope A DNA enclosed linear DNA histones / chromosome A DNA + protein membrane-bound organelles/ named e.g. (Allow up to 2 marks) may have cell wall cellulose cell wall (if present) ribosomes, 22 nm / 80S / larger no plasmids (except inside organelles) AVP e.g. cytoskeleton flagellum 9+2 no pili no fimbrae no capsule no mesosome
the stage of the mitotic cell cycle in which each of the following takes place
chromosomes become visible as two chromatids
prophase;
the stage of the mitotic cell cycle in which each of the following takes place
DNA replicates
interphase / S phase;