Term
|
Definition
• Includes single-celled protozoans, such as Amoeba, and a broad range of algae, such as the seaweeds.
• The cells are eukaryotic, i.e. they have a nucleus and organelles with membranes.
• The basic body structure is relatively simple, being either uni cellular or unspecialized.
• This kingdom is not a very satisfactory taxon, since it contains many organisms that do not fit into any other kingdom. |
|
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Term
|
Definition
• Includes Bacteria and Blue-Green bacteria.
• Microscopic, typically less than 10 Micrometers across.
• No distinct nucleus. The nucleic acid is contained in a single chromosomes that has no protein.
• Cells do not have organelles such as mitochondria or chloroplasts that are surrounded by plasma membranes. |
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Term
|
Definition
• Includes mould, yeast and mushrooms.
• Eukaryotic, but most do not have separate cells.
• In most fungi, the main body consists of thread like hyphae, which contain many nuclei. The yeasts are unicellular.
• Hyphal walls do not contain cellulose; most are made from chitin.
• Fungi can not photosynthesise; most are saprophytic, absorbing nutrients from decaying matter after extra cellular digestion. Some are parasites. |
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Term
|
Definition
• Includes mosses, liverworts, ferns and conifers as well as flowering plants.
• Eukaryotic and multi cellular. Cell walls contain cellulose. In mature cells there is usually a large vacuole.
• The plant body consists of specialized organs, including roots, stems and leaves. Most have a branching structure and have only small groups of cells that grow. E.g. at the ends of the roots. |
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Term
|
Definition
• Includes all the invertebrated such as jellyfish, round worms, arthropods and mollusks, as well as vertebrates such as fish and mammals.
• Eukaryotic and multicellular. Cells do not have walls, and are specialized for a wide variety of functions.
• Animals cant photosynthises; they depend on other organisms for organic nutrients.
• Most can move from place to place and have a nervous system for co-ordination.
• Growth is not confined to a limited number of cells as in plants, so most have a compact body form. |
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Term
| Describe the function of centromere during the separation of chromosomes. |
|
Definition
Attaches (chromatids / chromosomes) to spindle (in
cell division) OR divides to separate chromatids; |
|
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Term
| Function of the Kidneys. What happens if the stop working? |
|
Definition
Removal of urea/waste products.
Levels of urea within the blood rise |
|
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Term
| Function of the Liver. What happens if the stop working as well as the Kidneys? |
|
Definition
*function: makes urea / adds urea to blood.
*no rise in urea (when liver not working) OR when working,
urea not removed, so level rises; |
|
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Term
| Suggest a reason for the use in an investigation of hot alcohol; |
|
Definition
Because stops reaction(s)/ process / pathway / enzyme action /
kills algal cells; |
|
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Term
| Suggest a reason for the use in an investigation of a rapid action tap. |
|
Definition
Because reactions occur quickly
OR need to remove samples after short / precise time; |
|
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Term
An investigation was carried out to find out the sequence of biochemical changes that occur
during photosynthesis. Radioactive carbon dioxide was added to a suspension of algal cells,
and they were allowed to photosynthesise. At intervals, samples of th |
|
Definition
(Radioactive) carbon dioxide is used / incorporated;
New compound(s) / intermediate(s) / names egs formed /
become labelled; |
|
|
Term
Organic Amount of radioactivity present / arbitrary units
compound 5 s 15 s 60 s 180 s 600 s
P 0.01 0.02 0.08 0.17 0.67
Q 1.00 2.00 3.10 3.15 3.15
R 0.10 1.50 2.20 2.30 2.40
S 0.05 0.11 0.16 1.00 1.00 |
|
Definition
Idea of cycle (or equivalent);
Compound Q is used / reformed; 2
If either above present allow identification of possible Q as: G3P /
PGA / triose phosphate / GALP / RuBP
Any two from three (noting special arrangement re. third point) |
|
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Term
| Explain how a change in light intensity results in an increase in pupil diameter. |
|
Definition
Reduced light intensity;
Receptors identified as in retina / rods / cones;
Nerve impulses to CNS / along sensory nerve;
Nerve impulses from CNS / motor;
Sympathetic action;
To radial muscles which contract; |
|
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Term
When ATP is added to a muscle, it causes the muscle to contract.
Describe and explain how this contraction is brought about. |
|
Definition
Structure of sarcomere explained re. chains of sarcomeres in fibres;
Actin – thin filaments, myosin – thick filaments;
Relating sarcomere structure to thin / thick filaments
OR acting / myosin;
Idea of sliding filament hypothesis;
Cross bridges formed between actin and myosin;
ATP to ADP releasing energy;
ATP / energy required for detachment / re-attachment;
Explanation of ratchet mechanism;
Need for Ca++ to move tropomyosin out of way / change its shape;
Movement of tropomyosin allows attachment;
Need for Ca++ in splitting of ATP; |
|
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Term
Light was shone on a suspension of these organelles while it was kept in an atmosphere of pure
nitrogen. During this time the organelles made large amounts of two different substances, and
gave off oxygen.
*Name the two substances that were made when t |
|
Definition
| NADPH2/ NADPH/ reduced NADP/reduced coenzyme;ATP; |
|
|
Term
Name the part of the organelle where the enzymes of the light-independent
reaction are located. |
|
Definition
|
|
Term
Name the part of the organelle where the enzymes of the light-dependent
reaction are located. |
|
Definition
|
|
Term
A garden snail was mated with a snail from a different continent. Offspring were
produced. What would you need to know about these offspring to be certain that both
parents belonged to the same species? |
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Definition
|
|
Term
Explain how these structures help to focus an image on the retina
when the object is a long distance away.
* Cornea
* Cillary body
* Lens
* Suspensory ligaments |
|
Definition
Cornea - converges light/refracts/ bends light;
suspensory ligament - in tension
Ciliary Body- relaxed;
Lens - the more convex/fatter the lens, the shorter focal length (or converse)
- pulled thin; |
|
|
Term
Explain how these structures help to focus an image on the retina
when the object is close to the eye.
* Cornea
* Cillary body
* Lens
* Suspensory ligaments |
|
Definition
Cornea - converges light/refracts/bends light;
suspensory ligament - tension relaxed;
Ciliary
Body - contracts;
Lens - allowed to become fatter/more spherical;
- the more convex/fatter the lens, the shorter focal length (or converse) |
|
|
Term
Explain the changes that would take place in rod cells to bring about an increase in
retinal sensitivity. |
|
Definition
rhodopsin was bleached/is resynthesised;
to/ from pigment/retinal;
and to/from protein/opsin; |
|
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Term
| Describe the part played by acetylcholine in synaptic transmission. |
|
Definition
(acetylcholine) made in/stored in synaptic vesicles;
released into (synaptic) cleft;
diffuses/moves across (cleft);
binds to protein/receptor molecules on (postsynaptic) membrane/neurone;
causes depolarisation/action potential/new impulse (in postsynaptic neurone); |
|
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Term
| Describe the function in synaptic transmission of the mitochondria. |
|
Definition
to provide energy for the (re)synthesis of Ach OR associated active
transport; |
|
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Term
Give the names of the stages in aerobic respiration in which energy is made available
from the respiration of lactate. |
|
Definition
Krebs cycle; electron transport/transfer chain/oxidative phosphorylation;
(glycolysis negates one point of credit)
(link reaction and glycogenesis etc. are ‘neutral’) |
|
|
Term
Pyruvic acid is an organic acid that can be used in respiration to release energy for the
cell.
* For this to happen, into which substances is pyruvic acid immediately converted? |
|
Definition
| acetate/acetyl coenzyme A (and carbon dioxide); |
|
|
Term
If a person becomes dehydrated e.g. after strenuous activity on a sunny day, the water
potential of the blood can fall. Blood water potential later rises as the result of a control
system in the body.
Describe the details of this control system. In you |
|
Definition
detection by osmoreceptors;
* in hypothalamus;
* impulses to pituitary;
* pituitary produces/stores ADH; (IGNORE issue of anterior or
posterior)
* ADH increases permeability of the collecting duct;
* of distal convoluted tubule;
* causes more water reabsorption;
* which raises blood WP;
* (negative feedback explained re.) explanation of norm level
(of blood water potential);
* departure from the norm brings about a corrective mechanism,
which restores the norm;
* ADH production inhibited/reduced if/as blood WP rises; |
|
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Term
| When observing dividing cells under a microscope, how would you recognise that crossing over had taken place? |
|
Definition
| presence of chiasma/chiasmata; or drawn |
|
|
Term
Give two factors, other than crossing over, which result in genetic variation in the
offspring produced by a sexually reproducing organism. In each case, explain how the
factor brings about genetic variation. |
|
Definition
(1) independent assortment/random alignment of chromosomes;
new arrangement of alleles;
(2) random fertilisation;
chance combinations of gametes;
(3) mutation (or suitable description of);
creates new alleles/allelic combinations (by changes in DNA); |
|
|
Term
| Describe how a resting potential is maintained in an axon. |
|
Definition
active transport/pumping of sodium (ions across
membrane);
out of neurone/higher concentration outside;
differential permeability to K+ and Na+; |
|
|
Term
Explain how movements of these ions (Na+ and K+) are involved in producing the action
potential. |
|
Definition
sodium ions diffuse in;
causing depolarisation/described;
potassium ions then diffuse out, to start recovery; |
|
|
Term
| What is meant by the refractory period? |
|
Definition
no (new) action potential/nerve impulse be produced
in this time; |
|
|
Term
Two of the products of the light-dependent reaction of photosynthesis are used in the
light-independent reaction.
* Name these products.
Product 1 ..........................................................................
Product 2 ................... |
|
Definition
1) reduced NADP/NADPH;
2) ATP; |
|
|
Term
| Describe how each product (reduced NADP/NADPH and ATP) is used in the light-independent reaction. |
|
Definition
reduced NADP reduces G3P (to sugar);
ATP supplies (extra) energy for reaction; |
|
|
Term
Describe two ways in which the structure of a chloroplast differs from the
structure of this bacterial cell. |
|
Definition
chloroplast has (and bacterium does not)/
no cell wall;
two membranes surrounding chloroplast;
grana/thylakoids;
starch granules; |
|
|
Term
| Describe how oxidation takes place in glycolysis and in the Krebs cycle. |
|
Definition
removal of hydrogen/dehydrogenation;
by enzymes/dehydrogenases;
H accepted by NAD/reduced NAD formed;
in Krebs cycle, FAD (used as well); |
|
|
Term
Water is a waste product of aerobic respiration. Describe how water is formed at the end
of aerobic respiration. |
|
Definition
oxygen is terminal/final electron acceptor;
combines with electron and hydrogen (to form water); |
|
|
Term
The changes in the neuromuscular junctions in myasthenia gravis result in fewer calcium
ions entering muscle fibres. Explain how this reduces interactions between actin and
myosin filaments and, thus, the strength of muscle contractions. |
|
Definition
tropomyosin on actin;
calcium ions needed to move it out of the way;
allows myosin to bind to actin/formation of cross bridges;
fewer calcium ions leads to fewer power strokes/
ratchet actions;
needed for activation of ATPase; |
|
|
Term
| Explain what is meant by a recessive allele |
|
Definition
| only expressed in phenotype if homozygous; |
|
|
Term
| Explain what is meant by a codominant alleles. |
|
Definition
| both expressed (in phenotype), if both present |
|
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Term
| Explain how natural selection produces changes within a species. |
|
Definition
variation between members of population/species;
predation/disease/competition results in differential survival;
some have adaptations that favour survival;
survive to reproduce/have more offspring/ pass on their alleles/genes;
produces changes in frequency of alleles/gene pool/
genotypes/phenotypes; |
|
|
Term
Fungi are eukaryotic organisms. Most consist of a mycelium made up of hyphae and
reproduce by spores. Give two other characteristics of fungi. |
|
Definition
heterotrophic/no photosynthesis;
saprotrophic/extracellular digestion/parasitic;
cell wall of chitin;
no motile cells/non-motile; |
|
|
Term
| Give two ways in which meiosis produces variation. |
|
Definition
independent assortment;
crossing over; |
|
|
Term
Suggest one advantage of sexual reproduction being stimulated by worsening
environmental conditions. |
|
Definition
some (new phenotypes) may survive adverse
conditions;
resistant offspring produced; |
|
|
Term
Describe and explain the differences between rod and cone cells in their sensitivity and
acuity. |
|
Definition
cones respond to colour, rods only light and absence/black and white;
cones require a higher light intensity to respond;
cones greater acuity/rods lower acuity;
cones connected singly to bipolar/ganglion cells;
so brain receives nerve impulses from small area (of retina/visual field);
rods (lower acuity because) connected in groups, to bipolar/ganglion cells;
rods higher sensitivity, because connected in groups/summation/convergence;
different pigment sensitivities; |
|
|
Term
explain how an image on the retina of the right eye results in
an object being identified and its name spoken. |
|
Definition
(image on the retina) detected by receptors;
nerve impulses along sensory neurones/optic nerve;
from right eye to left side of brain;
to visual sensory area, where nerve impulses/information/image is processed;
(nerve impulses) to visual association area, where image identified (from memory/experience);
nerve impulses to the speech association area;
where correct word selected/identified from memory to match information/nerve impulses;
nerve impulses to speech motor area;
where correct muscle movements selected to form word;
nerve impulses to motor area of face, which sends nerve impulses to
effectors/muscles in mouth and face; |
|
|
Term
A person received an injury to the head. When a doctor shone a bright light into each
eye, the person’s right pupil did not contract. Suggest an explanation for the failure of
the right pupil to contract. |
|
Definition
pupil constriction a reflex action;
circular muscles of iris contract;
under parasympathetic control;
failure indicates damage to brain/autonomic nervous system;
on left side of the brain; |
|
|
Term
| Describe the role of insulin in the control of blood glucose concentration. |
|
Definition
increase in blood sugar leads to lower blood sugar (homeostatic principle)/ (more) insulin secreted;
binds to (specific) receptors on (liver/muscle) cells;
leads to more glucose entering cells/carrier activity/increased permeability to glucose;
glucose leaves the blood;
glucose entering cell converted to glycogen; |
|
|
Term
Suggest why it is important that muscle cells do not convert glucose phosphate to
glucose. |
|
Definition
keeps glucose in muscle cells/glucose phosphate can not cross cell membranes;
muscle cells need glucose for respiration. |
|
|
Term
suggest how glycogen breakdown in liver and
muscle cells is increased when an animal runs away from a predator. |
|
Definition
sympathetic nervous system active, so adrenaline released;
adrenaline binds to receptors/acts on muscle cell;
causing increased glycogen phosphorylase activity;
more glucose (phosphate) for respiration;
calcium ions enter muscle cells and glycogen broken down/increase in phosphorylase activity;
lower blood sugar as glucose used by muscles;
glucagon released and binds to receptors/acts on liver cells;
causes glycogen to be broken down to glucose/glycogen breakdown increases; |
|
|
Term
| Explain how the reduced coenzyme produced in photosynthesis is used. |
|
Definition
used to reduce G3P;
to sugar/triose phosphate/fructose/glucose; |
|
|
Term
| Name the three-carbon end product of glycolysis. |
|
Definition
|
|
Term
Describe how pyruvate is converted into a substance that enters the Krebs
cycle. |
|
Definition
reacts (with coenzyme A) to give acetylcoenzyme A;
decarboxylation / CO2 given off;
NAD reduced / oxidation; |
|
|
Term
| Name molecule X and ion Y. |
|
Definition
X – ADP,
Y – phosphate/Pi/ P ; |
|
|
Term
After an animal dies, respiration stops and no more ATP is made. The muscles become
rigid and fixed in their length. Use the information in the diagram to suggest an
explanation for this. |
|
Definition
| without ATP, myosin heads remain bound (to actin); |
|
|
Term
| Describe the trichromatic theory of colour vision. |
|
Definition
cones sensitive to colour/different wavelengths of light;
three types of cones, red, green and blue absorbing;
colours due to combinations of cones stimulated; |
|
|
Term
| Explain what is meant by an allele; |
|
Definition
| one form of a (specific) gene; |
|
|
Term
| Explain what is meant a sex-linked gene. |
|
Definition
|
|
Term
Describe three features of all members of the animal kingdom which are absent from all
members of the plant kingdom. |
|
Definition
heterotrophic;
no cell walls;
blastula formation;
(chemical and) nervous control;
growth not confined to meristems;
starch in plants;
(accept have muscles) |
|
|
Term
Within each subspecies there is a range of phenotypes. Explain the factors that
give rise to this variation. |
|
Definition
phenotype depends on genotype and environment;
different local environments can produce variation;
different selection pressures;
mutations producing new alleles;
meiosis produces new combinations of
alleles/example;
random fusion of gametes / sexual reproduction |
|
|
Term
Explain how the loop of Henle maintains the gradient of ions which allows water to be
reabsorbed from filtrate in the collecting duct. |
|
Definition
(epithelial cell) of tubule cells carry out active transport;
transport chloride/sodium ions out (of filtrate);
against concentration gradient;
into surrounding tissue/tissue fluid;
creates/maintains water potential gradient for water reabsorption;
countercurrent multiplier; |
|
|
Term
| Explain how ADH is involved in the control of the volume of urine produced. |
|
Definition
if water potential of blood falls, detected by receptors in hypothalamus;
leads to ADH released from pituitary gland;
ADH makes cells of collecting duct/distal convoluted tubule permeable to water;
(accept DCT)
water leaves filtrate by osmosis;
smaller volume of urine produced;
(accept converse if water potential of blood rises) |
|
|
Term
explain how the autonomic reflex arc is different from a simple reflex arc involving
voluntary muscle; |
|
Definition
autonomic reflex),
autonomic ganglion involved;
extra synapse outside the spinal cord;
inhibitory rather than excitatory neurone;
more neurones involved; |
|
|
Term
| explain how emptying of the bladder is controlled consciously. |
|
Definition
full bladder) stimulation of stretch receptor;
sends nerve impulses to spinal cord;
synapse with neurone connecting to brain/nerve impulses go to brain;
impulses from brain to inhibitory motor neurone;
via synapse in spinal cord;
external sphincter relaxes;
internal sphincter already relaxed so bladder empties;
(1 mark for statement that both sphincters are relaxed for urination) |
|
|
Term
| Describe the role of calcium ions in the contraction of a sarcomere. |
|
Definition
interact with/move/touch tropomyosin; (allow troponin as alternative)
to reveal binding sites on actin; (not active sites)
allowing myosin (heads) to bind/touch actin / actinomyosin formed;
activate ATPase / energy released from ATP; |
|
|
Term
| A person looks at a familiar object. Explain how this object can be recognised. |
|
Definition
impulses along neurones/(optic) nerve; (not signal, message, image or
information)
to visual (sensory) area/cortex;
to (visual) association area;
linked with memory; (allow past experiences) |
|
|
Term
During a surgical operation the nerves connecting the two hemispheres were cut. As a
result, the two hemispheres were unable to communicate with each other. No other
nerve connections were affected.
After the operation the person was blindfolded and a |
|
Definition
(impulses) from (receptors in) hand to sensory area of brain;
(allow information – lose sensory area mark if eyes are involved)
to association area concerned with memory (to recognise the toothbrush’s
presence);
in right hemisphere/side of brain;
(do not credit references to association areas in the left hemisphere)
no communication with (left) hemisphere where speech centre is located;
(credit references to speech controlled on left side) |
|
|
Term
| Describe how insulin reduces the concentration of glucose in the blood. |
|
Definition
insulin binds to specific receptors (on membranes);
insulin activates carrier proteins / opens channels / causes more channels
to form;
insulin increases the permeability of liver/muscle cells/tissues to glucose;
insulin action results in glucose conversion to glycogen / glycogenesis; |
|
|
Term
| Give one dependent variable you could measure in order to determine the rate of photosynthesis in an aquatic plant. |
|
Definition
count the number of bubbles / measure the volume of gas / measure the
change in pH / carbon dioxide / hydrogen carbonate ions;
(credit oxygen produced) |
|
|
Term
A suspension of chloroplasts was isolated from an aquatic plant and a reagent was
added. The reagent is blue when oxidised and is colourless when reduced.
The suspension of chloroplasts in blue reagent was exposed to sunlight. The blue
colour disappea |
|
Definition
chlorophyll excited / reduced NADP formed;
electrons from chlorophyll / reduced NADP changes the dye
colour; |
|
|
Term
A suspension of chloroplasts was isolated from an aquatic plant and a reagent was
added. The reagent is blue when oxidised and is colourless when reduced.
A suspension of chloroplasts was set up as before. Small quantities of ADP
and phosphate ions w |
|
Definition
ADP and phosphate needed to produce ATP / ATP is a product of
the light dependent reactions;
ADP levels are a limiting factor;
(must explain the idea of limiting factors – do not credit answers
like more ADP causes more photosynthesis) |
|
|
Term
Describe how the release of acetylcholine into a neuromuscular junction causes the cell
membrane of a muscle fibre to depolarise. |
|
Definition
movement by diffusion;
binding to receptors on (post-synaptic) membrane;
causing sodium channels to open / sodium ions to move in to muscle
(cell); |
|
|
Term
| Amoeba is classified as a protoctist. explain why it is not a prokaryote; |
|
Definition
presence of a nucleus / membrane bound organelles /
named organelles only 80S ribosomes / lacks a cell wall; |
|
|
Term
| Amoeba is classified as a protoctist. explain why it is not a fungus. |
|
Definition
lacks a cell wall / no chitin / is motile / has one nucleus /
no hyphae;(do not credit it has a nucleus) |
|
|
Term
| Explain what is meant when two species are described as being closely related. |
|
Definition
| more recent common ancestor / DNA in common; |
|
|
Term
Explain how the amount of ATP is increased by reactions occurring inside a
mitochondrion. |
|
Definition
oxidation of/removal of electrons / removal of H+ from pyruvate/
acetyl CoA / 6 carbon compound; (credit oxidative decarboxylation)
substrate level production of ATP / ATP produced in Krebs cycle;
production of reduced NAD / FAD (allow they take up hydrogen);
in matrix of mitochondria;
electrons fed into electron transport chain / used in oxidative
phosphorylation / description of electron transfer;
on cristae / inner membrane;
linked to ATP production;
ATPase / stalked particles involved;
electrons lose energy as passed along chain / electron carriers
arranged in order of decreasing energy levels; |
|
|
Term
| In which part of a chloroplast does the light-independent reaction occur? |
|
Definition
|
|
Term
Which process is the source of the ATP used in the conversion of glycerate
3-phosphate (GP) to triose phosphate? |
|
Definition
light-dependent reaction / (photo)phosphorylation;
(accept photolysis) |
|
|
Term
What proportion of triose phosphate molecules is converted to ribulose
bisphosphate (RuBP)? |
|
Definition
| 5 out of 6 / 83% / equivalent; |
|
|
Term
Lowering the temperature has very little effect on the light-dependent reaction, but it
slows down the light-independent reaction. Explain why the light-independent reaction
slows down at low temperatures. |
|
Definition
enzymes involved / not a photochemical reaction;
slow rate of enzyme/chemical reaction at low temperature /
less kinetic energy / fewer collisions; |
|
|
Term
One effect of getting into a cold shower is a reduction in the amount of blood flowing
through the capillaries near the surface of the skin. Explain how the cold water causes
this response. |
|
Definition
(thermo)receptors in skin;
(accept receptors in hypothalamus if after reference to cooled blood)
impulses via nerves/neurones to or from; (once only)
hypothalamus;
heat gain/temperature centre (in hypothalamus);
contraction /constriction of arterioles; (not capillaries, or just
vasoconstriction)
diversion through shunt vessels; |
|
|
Term
When exercising at 30 °C, the body is more likely to overheat in humid conditions
than in dry conditions. Explain why. |
|
Definition
reduced/no evaporation of sweat;
due to reduced gradient / saturation/high water content of air;
less heat loss by (latent) heat of evaporation; |
|
|
Term
Strenuous exercise leads to exhaustion more quickly in hot conditions than in cool
conditions. One reason for this is a reduced blood supply to the muscles, which
means that they receive less oxygen.
Suggest an explanation for the reduced blood supply |
|
Definition
skin vessels open/vasodilatation; (movement dq)
blood diverted from muscles / limited total volume of blood; |
|
|
Term
| What is meant by a hierarchy? |
|
Definition
| large groups split into smaller groups (which do not overlap); |
|
|
Term
During meiosis, when the X and Y chromosomes pair up, they do not form a typical
bivalent as do other chromosomes. Explain why. |
|
Definition
X and Y chromosomes are different sizes / shapes;
chromatids unable to line up and form bivalent / only
short pairing region / most of length not homologous; |
|
|
Term
Which hormone causes the decrease in the water content in the distal convoluted
tubule? |
|
Definition
| ADH; (accept vasopressin) |
|
|
Term
Mitochondria in muscle cells have more cristae than mitochondria in skin cells. Explain
the advantage of mitochondria in muscle cells having more cristae. |
|
Definition
(more cristae / larger surface area) for electron transport chain /
more enzymes for ATP production/oxidative phosphorylation;
muscle cells use more ATP (than skin cells)(not just more respiration); |
|
|
Term
Substance X enters the mitochondrion from the cytoplasm. Each molecule of substance X has three carbon atoms.
Name substance X. |
|
Definition
|
|
Term
Substance X enters the mitochondrion from the cytoplasm. Each molecule of substance X has three carbon atoms.
In the link reaction substance X is converted to a substance with molecules
effectively containing only two carbon atoms. Describe what happe |
|
Definition
hydrogen released / reduced NAD formed;
acetyl coenzyme A produced; |
|
|
Term
The Krebs cycle, which takes place in the matrix, releases hydrogen ions. These
hydrogen ions provide a source of energy for the synthesis of ATP, using coenzymes and
carrier proteins in the inner membrane of the mitochondrion.
Describe the roles of th |
|
Definition
NAD/FAD reduced / hydrogen attached to NAD/FAD;
H+ ions/electrons transferred from coenzyme to coenzyme/carrier to carrier /
series of redox reactions;
energy made available as electrons passed on;
energy used to synthesise ATP from ADP and phosphate /
using ATPase;
H+ / protons passed into intermembrane space;
H+ / protons flow back through stalked particles/enzyme; |
|
|
Term
The iris of the eye contains antagonistic muscles which control the diameter of the pupil.
Use your knowledge of the iris muscles to explain what is meant by antagonistic
muscle action. |
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Definition
radial and circular muscles in iris;
opposing action = antagonistic;
radial contraction increases pupil diameter / circular contraction
reduces (or vice versa for iris). |
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Term
The diameter of the pupil is reduced in bright light. Describe the part played by
the autonomic nervous system in reducing the diameter. |
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Definition
(bright) light stimulates retinal cells / impulses from eye to brain;
parasympathetic system;
acetylcholine secreted;
stimulates contraction of circular muscles; |
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Term
Explain why it takes time for the rod cells to recover their sensitivity to light after
moving into darkness. |
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Definition
rhodopsin bleached/broken down by light;
time for resynthesis; |
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Term
| Explain how crossing over can contribute to genetic variation. |
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Definition
sections of chromatids exchanged;
sections have different alleles;
new combinations of (linked) alleles;
(allow 1 mark for idea that ‘genes’ are exchanged, if no other
marks gained) |
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Term
The Galapagos Islands are an isolated group about 900 km from South America.
Thirteen species of small birds called finches live on the islands. All species are thought
to have evolved from a single species which reached the islands from South America. |
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Definition
1. isolation of (ancestral) finches on (different) islands;
2. range of habitats/environmental conditions;
3. competition for seeds/food;
4. variation amongst finches;
5. some more suited to different food sources / differential survival;
6. alleles/genes for specific adaptations/features passed on;
7. different selection in separate populations, e.g. on different islands;
8. different populations unable to interbree |
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Term
Other substances are produced in the Krebs cycle in addition to the carbon compounds.
Name three of these other products. |
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Definition
reduced NAD/NADH/NADH2;
reduced FAD/FADH/FADH2;
ATP; |
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Term
| Give one characteristic feature of fungi which is not found in other kingdoms. |
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Definition
| cell walls with chitin / hyphae / mycelium; |
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Term
Explain what causes the conduction of impulses along a non-myelinated axon to be
slower than along a myelinated axon. |
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Definition
non-myelinated – next section of membrane depolarised / whole membrane;
myelinated – depolarisation / ion movement only at nodes;
impulse jumps from node to node /saltatory conduction; |
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Term
In an investigation, the tolerance to copper ions of the grass Agrostis tenuis was determined.
Samples were taken of plants growing in waste from a copper mine and from nearby areas just
outside the mine. The mean copper tolerance of plants from the min |
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Definition
variation present in (original population);
(copper) tolerant individuals more likely to survive;
(these reproduce and) pass on genes (to next generation/offspring);
more/increase (in frequency) of copper tolerance alleles/genes; |
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Term
Give two processes, other than crossing over, which result in genetic variation. Explain
how each process contributes to genetic variation. |
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Definition
mutation;
different/new allele formed / genes deleted or duplicated/ sequence of genes changed (reject genetic information);
random fusion of gametes / fertilisation;
new combination of alleles;
independent assortment (of chromosomes) (accept random);
shuffling of maternal and paternal chromosomes/new combination
of alleles; |
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Term
The amount of light entering the eye is controlled by a reflex involving the iris.
Where are the receptors for this reflex? |
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Definition
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Term
The human retina contains rods and cones. Describe the similarities and differences
between the pigments in the rods and cones and the ways in which these pigments
respond to light. |
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Definition
1. both pigments on lamellae;
2. both pigments break down/bleach in presence of light;
3. rods have rhodopsin;
4. cones have iodopsin;
5. rhodopsin/pigment/rods sensitive to white light/wide range of
wavelengths;
6. rhodopsin/pigment/rods sensitive to lower light intensities than
iodopsin/cones;
7. three types of pigment/iodopsin or three types of cone sensitive to
red, blue or green light (not red/green/blue cones without
further explanation); |
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Term
Like other mammals, seals produce urine which is more concentrated than their blood
plasma. Explain the role of the loop of Henle in producing concentrated urine. |
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Definition
1. salt/(sodium) ions diffuse into descending limb;
2. water moves out of descending limb;
3. salt/(sodium) ions actively removed from ascending limb;
4. ascending limb impermeable to water;
5. low water potential/ high concentration of ions in medulla/tissue fluid;
6. water leaves collecting duct / distal tubule;
7. due to difference in water potential / by osmosis; |
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