all6. Flashcards
Maximum magnification of a light microscope
1500;
Maximum magnification of a transmission electron microscope
500 000;
Definition: resolution
ability to see (two) objects (that are close together) as separate objects
see detail
one function of xylem tissue
transports water (up plant);
transports, minerals / ions, (up plant);
support (plant / stem / shoot);
the function of this spiral band of lignin and explain why it is important that the xylem vessel becomes lignified in this way.
Functions:
- (lignin), strengthens / thickens, the (xylem) wall;
- waterproofing (wall) / AW;
- (improving) adhesion of water (molecules);
- (spiral) pattern allows flexibility / stretching / movement;
Flexibility / stretching must ref, pattern of lignin laid down i.e. spirals
Explanation:
- prevents collapse of xylem;
- (water) under tension / at low pressure / negative pressure;
- reduces (lateral) loss of water, through wall;
- increases capillarity / AW;
- prevents stem breaking / AW;
the function of the pits in xylem tissue
(pits) allow water to move, in / out / between, vessel(s);
to bypass blockage;
supply water to other, tissues / (other types) cells / parts of plant;
Definition: tissue
collection / group, of cells (of one or more types);
(cells), working together OR with, common / same, function;
specialised (cells);
type of epithelial tissue found in the lungs
squamous / ciliated;
why the lungs can be considered to be an organ
(organ is) a collection of tissues / named tissues
(working together) to enable gas exchange
Cellular structure with the function: release of energy
mitochondria
Cellular structure with the function: movement of cilia
cytoskeleton
Cellular structure with the function: secrete mucus
Golgi (vesicle)
the functions of glycoproteins in the cell surface membrane
1 (acting as) antigens;
2identification / recognition, (of cells) as, self / non-self
3 cell signalling
ACCEPT description e.g. communication between cells / cell responds to, chemical / signal, from another cell
4 receptor / binding site, for, hormone / (chemical) signal / (medicinal /
named) drugs
5 ref. to receptor / binding site / trigger, on transport proteins /
6 cell adhesion / to hold cells together (in a tissue);
7 attach to water molecules (to stabilise membrane / cell)
8 three technical terms used and spelt correctly;
receptor, antigen, hormone, cell signal(ling), adhesion, recognition, facilitated diffusion, active transport
steps a student should take when setting up the potometer to ensure that the apparatus works correctly
shoot is healthy
assemble apparatus / cut shoot, under water
cut last 2-3 cm off cut end / cut at an angle
check there are no air bubbles in apparatus
apparatus, water tight / air tight / has no leaks
leaves dry
possible reasons, other than light and temperature, why the rate of transpiration was lower in the afternoon than in the morning
in afternoon: plant dying / less healthy / wilting ref to stomatal closure more humid / higher water (vapour) potential in air less air movement / wind / draughts
why the potometer only gives an estimate of the rate of transpiration
(potometer) measures (water) uptake
not all water (taken up) is lost
some water used (in photosynthesis / making cells turgid)
State two other ways in which the wall of an artery is different from the wall of a vein
Arteries have:
no valves
endothelium / tunica intima, folded
more / thicker, muscle / elastic tissue / tunica media
more / thicker, collagen / tunica externa
how this hydrostatic pressure is generated in the heart
contraction of ventricle, wall / muscle
why the hydrostatic pressure of the blood drops as blood moves away from the heart
more, (smaller) vessels / named vessels
(vessels) have larger, total lumen / cross sectional area
reduced resistance to blood flow
arteries, stretch / expand
loss of, fluid / plasma, from capillaries
plasma fluid
plasma / fluid, moves out of, capillary / blood
enters / forms, tissue fluid
(plasma) proteins, remain in capillary / too large to pass through
capillary wall
(fluid moves) down pressure gradient
hydrostatic pressure greater than, water potential / Ψ
Outline the mechanism of inspiration
diaphragm / intercostal muscles, contract:
diaphragm moves down / ribs move upwards and outwards;
volume of thorax increased;
pressure inside thorax falls;
to below atmospheric pressure (so air enters lungs);
accept any three from: diaphragm, intercostal, volume, pressure, thorax, thoracic cavity
A person breathes through the mouthpiece of a spirometer.
State what happens to the air chamber in the figure above during inspiration.
it falls / goes down
why a person using the spirometer to measure their vital capacity should wear a nose clip
to ensure all air breathed comes from chamber OR
to prevent, escape of air / entry of air, through nose
make results invalid
other precautions that should be taken when using a spirometer to measure vital capacity
use (medical grade) oxygen / fresh air; disinfect mouthpiece; ref. to health of subject; e.g. asthmatics ref to correct functioning of equipment;
Outline the sequence of events following the production of extracellular proteins that leads to their release from the cell.
proteins moved to Golgi (apparatus / body);
processed / modified ;
e.g. carbohydrate group added
into vesicles;
(vesicle) moved to, plasma / cell surface, membrane;
(vesicles) fuse with membrane;
exocytosis;
Explain, using the term water potential, what has happened to cell M
water moves out of cell;
by osmosis;
cell has, higher / greater / less negative, water potential (than surrounding solution) / ORA;
(water moves) down water potential gradient/from high to low water potential;
How they enter a cell through the plasma (cell surface) membrane
small, non-polar substances
diffuse (through membrane / phospholipid bilayer);
How they enter a cell through the plasma (cell surface) membrane
large substances
using), transport / carrier, proteins;
endocytosis / phagocytosis / described;
How they enter a cell through the plasma (cell surface) membrane
polar substances
through, pore / channel, proteins;
(using), transport / carrier, proteins
Definition: stem cell
a cell that is, unspecialised / not differentiated;
capable of, division / mitosis;
able to, differentiate / specialise / become other cell types
one tissue in plants that contains stem cells
cambium / meristem / early embryonic cells
reasons why mitosis is important to organisms
growth (of tissue / organism); replace (cells) / repair (tissues); asexual reproduction/cloning / producing genetically identical cells; maintain chromosome number in all cells;
Explain, using the term surface area to volume ratio, why large, active organisms need a specialised surface for gaseous exchange
large / active, organisms have high(er), demand for oxygen / need
to remove CO2;
small(er), surface area to volume ratio / SA:V / surface area:volume;
surface area too small / distance too large / diffusion takes too long
(to supply needs);
How the feature improves the efficiency of gaseous exchange
many alveoli
this increases the surface across which oxygen and carbon dioxide can diffuse
How the feature improves the efficiency of gaseous exchange
the epithelium of the alveoli is very thin
short (diffusion) distance;
How the feature improves the efficiency of gaseous exchange
there are capillaries running over the surface of the alveoli
delivers carbon dioxide (to be removed from
blood) / carries oxygen away (from alveoli);
short (diffusion) distance;
How the feature improves the efficiency of gaseous exchange
the lungs are surrounded by
the diaphragm and intercostal muscles
ventilation / supply of oxygen (to alveoli) /
removal of carbon dioxide (from alveoli);
Outline how the diaphragm and intercostal muscles cause inspiration
diaphragm (contracts / flattens and) moves downwards;
intercostal muscles contract to move ribs, up / out;
increase volume of thorax;
reduce pressure inside thorax;
to below atmospheric pressure/creates pressure gradient
Definition: single circulatory system
blood passes through the heart once for each, circulation / circuit / cycle, of the body;
Definition: closed circulatory system
the blood is maintained inside vessels
Fish circulatory system type
Single closed circulatory system
Describe how the action of the heart is initiated and coordinated
/ SAN, creates / initiates / starts / originates, excitation;
wave (of excitation) spreads over atrial, wall / muscle;
ref to, AVN / U;
atria contract / atrial systole;
contraction is synchronised / AW;
delay at AVN;
(excitation spreads) down septum;
ref to, bundle of His / Purkyne fibres;
ventricles contract / ventricular systole, from, apex / bottom;
any three from: pacemaker, sinoatrial node, atrioventricular node, excitation, atrial / atrium / atria, septum, Purkyne, bundle of His, ventricle(s) / ventricular, apex, systole.
Definition: source
site where, sucrose / sugars / assimilates, loaded (into phloem)
Definition: sink
site where, sucrose / sugars / assimilates, unloaded / removed
(from phloem)
When the bark is removed from a tree, the phloem is also removed. If a complete ring of bark is removed, the tree trunk can be seen to swell above the cut.
Suggest two reasons why the trunk swells above the cut.
(sugars) cannot pass the cut / AW; decrease water potential; water moves into cells; (damage triggers) increased cell division; to produce cells to store sugars; cut causes, gall / infection;
Types of cell that line the bronchus
goblet / mucus (secreting) cell;
ciliated (epithelium);
How goblet cells and ciliated epithelium cells work together to keep the lung surface clear of dust and other particles
(A / goblet cells) release mucus / AW;
(mucus) traps, dust / particles / named particle;
ciliated cell / B / cilia, wave / waft / move, mucus;
to, top of trachea / back of mouth / AW;
the function of the smooth muscle fibres in the bronchus wall
to constrict the bronchus
why blood capillaries and alveoli are very close together
short, distance / path
(so that) diffusion / concentration, gradient is, high / steep;
high rate of, (gas) exchange / diffusion
the function of these elastic fibres in the walls of the alveoli
recoil / expel air / prevent bursting
