all9. Flashcards
Why using a light microscope to produce an image to the magnification of x20,000 would be of little use
low resolution; ora
(close) points not easily distinguished;
wavelength (of visible light) is too long;
max resolution of light microscope =, 200 nm / 0.2 µm; A anything close
no more detail visible than seen at, ×1500 / ×1000;
Describe what happens within the vacuole after it fuses with the lysosome
enzymes / named enzymes / lysins; acid / low pH; digestion; A breaking down breaking, peptide / glycosidic / ester, bond; R if in wrong context hydrolysis; soluble / named, products;
Ovary cells contain large amounts of endoplasmic reticulum (ER).
Suggest the importance of this in using these cells for the production of Factor VIII.
(rough) ER has ribosomes; R produces for, protein synthesis / translation; ER transports protein through cell; forms vesicles; for transport to / forming, Golgi; (in Golgi) modification of protein / glycosylation;
the stage in mitosis that immediately follows prophase
metaphase
the behaviour of the chromosomes in metaphase
individual) chromosomes align at,
metaphase plate / equator / centre (of cell);
join to, spindle / microtubules;
by centromeres;
Features of the lung that permit efficient gas exchange
many, air spaces / alveoli;
large surface area; R ref to surface area to volume ratio
thin wall of, alveolus / capillary; A one cell thick R ‘thin wall’ on its own
good blood supply / large capillary network;
air passage / bronchiole;
capillary close proximity to alveolus;
At a certain point, the student was asked to breathe in as deeply as possible and then breathe out as much as possible. What is this measuring
vital capacity
Explain how differences in SA:V ratio have influenced the need for transport systems in mammals
diffusion not adequate / AW / ora;
as not enough area (relative to volume); ora
distance too great / cells deep in body / AW; ora, R large unqualified
mass flow system needed;
transport / blood (vascular), systems, link, the parts of the body /
named parts;
e.g. of substance needing to be transported; R ‘gases’ / ‘waste’ / ‘food’
ref to activity / high metabolic rate, of mammals;
parts of the mammalian body where the surface area is relatively large to allow effective functioning
alveoli lung villi gut small intestine A intestine capillary bed / capillaries / AW skin qualified e.g. elephant’s ears cerebral cortex / brain kidney (tubule) liver
Heart wall muscle is a special type of muscle called….
cardiac muscle
cardiac muscle can contract or relax without nervous stimulation and is thus described as….
myogenic
To ensure that the cardiac cycle stays in sequence
there is…
an in-built control mechanism
The wall of the right atrium contains a special
region of muscle called the…
sinoatrial node
The sinoatrial node sets up a wave of
electrical activity causing…
the atrial walls to contract almost simultaneously
There is a
band of fibres between the atria and ventricles which stop / prevent
the
wave of activity passing to the ventricle walls.
Transpiration definition
evaporation of water / water vapour lost (from plants);
diffusion,
into atmosphere / out of leaf / down a water potential gradient /
via stomata;
Explain why transpiration in plants cannot be avoided.
linked to gas exchange / AW; A refs to both oxygen and carbon
dioxide unqualified carbon dioxide for photosynthesis;
open stomata;
large area; can apply to leaf area or pore area
moist mesophyll to (relatively) dry air / water potential gradient / AW;
AVP; e.g. ref to some cuticular transpiration inevitable / AW
link open stomata to daytime when it is hottest / AW
Explain how a covering of leaf epidermal hairs helps xerophytes survive in their habitat.
hairs trap water vapour; R water unqualified / water particles A molecules
reduces water potential gradient / stops wind removing vapour /
more humid air around leaf; ecf for water
so less transpiration / AW;
AVP; e.g. ref reflective nature of hairs in context
ref to need of xerophytes to conserve water in dry habitat
Explain how water travels up the stem and into the leaf of a dicotyledonous plant.
1 in the xylem vessels; A tracheids
2 down a, water potential / Ψ, gradient;
R ‘along’ A refs to high to low water potential
3 most negative, at the leaf / in the atmosphere;
ora must refer to water potential
4 transpiration sets up a gradient / AW; any valid gradient
5 (places) water (in xylem) under, tension / suction / negative pressure /
pull / hydrostatic pressure gradient / AW;
6 cohesion; 7 description of cohesion; 8 ref to hydrogen bonding; 9 (continuous) water columns / AW; 10 mass flow; 11 root pressure, in context / described; 12 adhesion described / capillarity;
why squamous epithelium is described as a tissue
(made up of) one type of / (squamous) epithelium, cell(s);
A same R similar alone
(group of) cells performing the same function(s);
features of a gas exchange surface, such as the lining of the alveolus
large surface area; permeable; thin / short, diffusion path; moist; good blood supply / close to blood; well ventilated / in contact with respiratory medium;
Describe how other molecules or ions cross a plasma (cell surface) membrane by active transport and facilitated diffusion.
active transport
1 against concentration gradient / described; A up
2 uses, energy / ATP;
facilitated diffusion
3 down concentration gradient / described; A with R along / across
4 no, energy / ATP, required; A passive
protein carrier (in either or undefined)
5 attaches on one side of the membrane;
6 protein, moves / turns / changes shape;
7 releases on other side of the membrane;
channel protein (facilitated diffusion only) 8 forms, pore / passage, through centre of the protein; 9 hydrophilic conditions / water lined; 10 phospholipid (bilayer) prevents, diffusion / passage / entry, of (some), molecules / ions; R substances 11 polar / water soluble / not lipid soluble / too big / suitable named e.g.; 12 appropriate use of protein in both; 13 ref to specificity of protein to substance transported; 14 AVP; (for extra detail of transport mechanism)
The term which refers to any organism that causes infectious disease.
pathogen;
Diseases which cause a progressive deterioration of part of the body.
degenerative;
The type of exercise that uses the heart and lungs to provide oxygen for respiration in muscles.
aerobic;
The volume of air breathed in or out during a single breath.
tidal;
A term used to describe a disease that spreads across continents.
pandemic;
the carbohydrate that is transported in phloem
sucrose
Outline how = companion (cell) and sieve (tube) element / sieve tube cell; are involved in the transport of carbohydrate in phloem.
1 sieve elements / Q, end to end or sieve plates perforated /
sieve pores, for ease of flow / AW;
2 companion cells / P, metabolically active / have many mitochondria /
produce ATP / release energy / AW; R make energy
3 (active) loading into, companion cell / P; A into, sieve elements / Q
4 ref to proton pump;
5 ref to co-transporter;
6 role of plasmodesmata (between P and Q); R pores
7 sieve element / Q, has few organelles / AW, for, ease of flow /
more sucrose / AW;
8 ref to, unloading mechanism / (hydrostatic) pressure gradient;
9 ref to one role for sieve plate e.g. electro-osmosis or stops
‘bulging’;
Carbohydrate moves from regions of plants called sources to regions called sinks.
Explain how, at different times, the same plant root may be a source or a sink.
source when root converts, starch / insoluble carbohydrate, into sugars / AW;
sink when root either stores starch / (named) carbohydrate / assimilate
or uses carbohydrate for, respiration / growth / AW;
high hydrostatic pressure makes it a source and low hydrostatic pressure a sink;
when loading it is a source and when unloading a sink;
Describe how the structure of an artery is related to its function.
1 ref to tunica, intima / interna, tunica media and tunica,
externa / adventitia;
2 thick wall, stops bursting / withstands pressure idea;
3 (relatively) narrow lumen to maintain pressure;
4 elastic tissue / AW, allowing stretching / AW;
5 elastic arteries near heart;
6 elastic recoil;
7 to even out surges of pressure / to maintain flow / AW;
A push idea
8 collagen provides (main) strength / AW;
9 (smooth) endothelium (of tunica intima) to reduce friction / AW;
A epithelium or lumen lining / AW R epidermis
10 tunica media / AW, has (smooth) muscle and elastic tissue;
collagen is neutral
11 to prevent bursting / withstands pressure / AW;
look for link to tunica media
12 (smooth) muscle maintaining pressure;
A ref vasoconstriction / ‘blood shunts’
R pumping action
13 AVP; e.g. idea that circular cross section allows max blood
volume for minimum wall contact / AW
award QWC mark if three of the following are used
tunica (qualified once)
lumen
elastic / elastin
collagen
recoil
smooth muscle
endothelium
vasoconstriction
The blood also contains hydrogen carbonate ions (HCO3–). Describe how these ions are formed in the blood.
carbon dioxide (diffuses) into red blood cells; R blood only carbonic anhydrase; carbon dioxide reacts with water; to form, carbonic acid / H2CO3 / HCO3–; R if linked with incorrect reaction carbonic acid, dissociates / AW, to give HCO3–; accept from equations CO2 + H2O → H2CO3 H2CO3 → H+ + HCO3–
Suggest the consequences of a blockage at the coronary artery
oxygen / glucose, will not reach, (heart / cardiac) muscle; A less
reduced / no, respiration;
(possible) coronary / heart attack / myocardial infarction / (possible) death;
Definition: closed system
blood enclosed in vessels
why the mammalian system is called a complete double circulation whilst that of the frog is called a partial double circulation.
ventricles not separated / one ventricle / partial or no septum /
three chambers / left and right sides not separated; ora for mammal
single vessel from heart; ora for mammal A aorta
oxygenated and deoxygenated blood not (fully) separated;
ora for mammal
blood passes twice through heart for complete circulation /
systemic and pulmonary systems / to lungs and body;
why the system shown for the frog may be less effective at supplying the body tissues with oxygen
blood will not be fully oxygenated / Hb less fully saturated /
deoxygenated and oxygenated blood mixed / AW;
still carrying carbon dioxide;
lower pressure or less, force / push / AW;
one way in which the dissociation curve for lugworm haemoglobin differs from that for human haemoglobin
lugworm haemoglobin has a high affinity for oxygen ;
low oxygen in, lugworm habitat / water / ora ;
lugworm haemoglobin, stores oxygen / only releases oxygen when pp
O2 very low ;
two haemoglobins have different, structures / amino acid sequences ;
Describe the similarities and differences between the adaptations for gas exchange and transport of oxygen in mammals and lugworms.
D1 ref to lugworm gills and mammal, alveoli / lungs ;
D2 ref to internal and external, exchange surfaces ;
D3 less oxygen in, water / sand ; A ora
D4 lugworm haemoglobin adapted to, water / sand/ low O2
environment ; A ora
D5 lugworm has no red blood cells / ora ;
D6 detail of mammalian red blood cells ;
D7 lung ventilation tidal / lugworm, throughflow / unidirectional / AW ;
D8 AVP ; e.g. ref. water loss from lungs
similarities (max 5)
S1 both (gas exchange surfaces have) large surface area ;
S2 both, thin / have short diffusion distance ;
S3 both well-vascularised ;
S4 both moist ;
S5 ref to diffusion of, oxygen / carbon dioxide / gases ;
S6 (blood carries) oxygen to tissues ;
S7 haemoglobin transports oxygen ;
S8 both move medium over gas exchange surface ;
one way in which root hairs are adapted to increase uptake
long;
thin cell wall;
lack of, waterproof layer / cuticle;
large surface area; NOT if cilia / villi / microvilli / tails / etc
present in large numbers;
(membrane) proteins / carriers / channels / aquaporins;
many mitochondria;
method used by root hairs to take up nitrate ions
active transport / diffusion / facilitated diffusion / described;
A pinocytosis
Outline the process by which water enters the cells of the root from the soil
lower water potential inside / ora;
movement, down water potential gradient / from high Ψ to low Ψ;
through, channel proteins / partially permeable membrane /
aquaporins / AW;
walls freely permeable;
osmosis;
Outline what happens to chromosomes during the mitotic cell cycle.
prophase
1 C;
2 chromosomes / chromatids, condense / coil / shorten and thicken;
3 become visible;
4 consist of two chromatids;
5 joined by a centromere; A kinetochore NOT centrosome
metaphase 6 A; 7 chromosomes align at, equator / metaphase plate; 8 attached to spindle by centromeres;
anaphase 9 B; 10 centromere splits; 11 chromatids separate; 12 move to opposite poles; 13 by, contraction / shortening, of spindle; telophase 14 E; 15 chromosomes uncoil;
interphase 16 D; A for a description of early prophase 17 DNA replication; 18 transcription / formation of mRNA; 19 AVP; these must relate to behaviour of chromosomes 20 AVP; e.g. spindle made of microtubules chromatin becomes chromosomes (in prophase) ora in interphase centromere leads chromatid to pole gene switching during interphase 9 max QWC – clear well organised using specialist terms; 1 award the QWC mark if three of the following are used in correct context, but Q = 0 if names or names of stages of mitosis are used inappropriately chromatin equator / metaphase plate chromatid DNA replication centromere transcription spindle
Describe how the tissues in the gaseous exchange system contribute to the functioning of the lungs.
cartilage 1 in, trachea / bronchi; 2 holds airway open / prevents collapse; 3 prevents bursting (of trachea / bronchi as air pressure changes); 4 low resistance to air movement;
ciliated epithelium / cilia 5 move mucus; 6 ref to how movement brought about; e.g. metachronal rhythm / wave / sweep / waft goblet cells 7 secrete mucus; 8 trap, bacteria / dust / pollen / particles; 9 remove particles from lungs; blood vessels 10 supply, oxygen / nutrients (to tissues of lung); 11 surround alveoli / good blood supply to alveoli; 12 deliver carbon dioxide / pick up oxygen; 13 ref to wall of capillary being thin; 14 ease of / rapid, gaseous exchange or short diffusion pathway; smooth muscle 15 adjust size of airways (in, exercise / asthma); connective tissue / elastin / elastic tissue 16 stretch (inhalation); 17 prevents alveoli bursting; 18 recoil; R contract 19 helps exhalation / forces air out (of lungs); squamous epithelium / described 20 alveolus wall thin; 21 ease of / rapid, gaseous exchange or short diffusion pathway; 22 AVP; e.g. ref to large surface area of numerous alveoli 23 AVP; ref to macrophages removing pathogens
Features of xylem and how they help with function
lack of contents / no cytoplasm / hollow / lumen / continuous /
less resistance to flow / more space linked to idea of lack of contents
thickening / rings / spirals / lignin (in the wall); treat cellulose as neutral
prevents collapse / gives support / adhesion of water;
pits / AW; A pores / holes (in side walls)
allow lateral movement / AW;
Example in plants of a source
leaf / storage organ / named storage organ
Example in plants of a sink
root / tuber / storage organ / (young) growing region / leaf
qualified / flower / bud / fruit / seed;
explain how mass flow of materials between the source and the sink would be brought about
water will enter source; by osmosis; down / AW, a water potential gradient; increase in (hydrostatic) pressure; as source / sink cannot expand / AW; force / AW, solution along (tube to sink); AVP; e.g. explanation of mass flow
piece of evidence for the involvement of an active process in sugar transport from sources to sinks in plants
ATP involved / respiration involved / many mitochondria in companion
cells / reduced by metabolic inhibitors / oxygen dependent / temperature
dependent / loading against a concentration gradient
Describe an active mechanism which could possibly be involved in the transport of sugars from sources to sinks.
loading, into companion cell / from transfer cell / into sieve tube / into phloem – implied; H ions / protons, pumped out of, companion cell / sieve tube / phloem; diffuse back in with sucrose; protein carrier / co-transporter; possible active unloading by reverse mechanism; AVP to cover alternative mechanisms;;; e.g. electro-osmotic theory K+ pump via companion cell electrochemical gradient sieve pores provide a capillary bed
Definition: double circulatory system
(blood flows) twice through the heart / AW;
for one circuit / cycle (of the whole body) / AW; A for one heart beat
ref pulmonary and systemic systems / to lungs and to (rest of) body;
