Shuffle Flashcards
Describe how R groups interact to determine the tertiary structure of a protein (4)
1 some R groups, attract / repel ;
2 disulfide, bridges / bond ;
3 between, cysteine / SH / S (atoms) ;
4 hydrogen / H, bonds ;
5 ionic bonds between, oppositely charged / + and -, R groups ;
6 hydrophilic R groups, on outside of molecule / in contact with
water (molecules) ;
7 hydrophobic R groups,
on inside of molecule / shielded from water (molecules) ;
What are 3 differences between the structure of glycogen and collagen? (3)
1 polysaccharide and protein / polypeptide ;
2 (alpha) glucose (units) amino acid (units) ;
3 identical units different amino acid units ;
4 glycosidic, bonds / links peptide, bonds / links ;
5 branched unb / linear ;
6 non-helical ;
7 one chain (per molecule) three chains (per molecule) ;
8 no cross links cross links (between
chains) ;
9 contains C H O contains C H O N ;
State 2 properties of collagen making it suitable for ligaments (2)
strong
insoluble
flexible
State two properties of cellulose making it suitable for cell membranes (2)
unreactive
insoluble
flexible
forms H bonds with neighbouring chains
Why may some cells not take up a stain? (1)
cells, dead / not respiring ;
no, (metabolic) energy /ATP, to take up stain
Describe the function of glycolipid in the cells surface membrance? (5)
1 (acting as) antigens ;
2 identification / recognition, (of cells) as, self / non-self / AW ;
3 cell signalling / described ;
4 receptor / binding site, for, hormone / (chemical) signal / (medicinal / named) drugs ;
5 ref. to receptor / binding site / trigger,on transport proteins / AW ;
6 cell adhesion / to hold cells together (in a tissue) ;
7 attach to water molecules (to stabilise membrane / cell) ;
What is the role of the phospholipid bilayer? (1)
to act as a barrier (to, polar / charged, particles) / select what enters or leaves cell ;
ACCEPT selectively permeable or partially permeable membrane
ACCEPT allows small / fat soluble molecules to pass through
Explain why new branches are seen growing just under the bark of the cut suface of the plant? (2)
This is where cambium / meristem / xylem / phloem / vascular bundle, is found ;
mitosis/cell division, occurs in cambium (to produce new cells for growth) ;
new cells, differentiate / specialise, (into xylem and phloem) ;
xylem supplies water for, (cell) elongation / (cell) growth ; phloem supplies, sugars / assimilates, for, energy / growth /respiration
Suggest why plants need lenticels (cells to allow gases to diffuse into living tissues of the trunk (2)
allow oxygen to reach, cells / tissues (under bark) ;
for (aerobic) respiration ;
animals transport oxygen in, blood / circulation / transport system ;
plants do not transport (much) oxygen in transport system ;
idea that (oxygen not supplied from leaves as) stomata only open in day / no leaves in winter ;
Complete this passage about the loop of Henle (6)
Electrolytes such as sodium —– are actively reabsorbed from the filtrate at the —– of the loop of Henle. This reduces the —– —– of the surrounging tissues in the —– of the kidney. The walls od the desending loop are —– to water. The result is that water is reabsorbed from the filtrate by the process of —–.
ions asending limb water potential medulla permeable osmosis
Predict the effect of a non functioning glucose transport protein on the volume of the filtrate (3)
- volume increase
- glucose lowers water potential graident
- reduction of water potential from the filtrate and cortex
- less water absorbed from desending limb
Where are podocytes located? (1)
Bowman’s capsule
How does ornithine and citrulline move into and out of the mitrochondria? (2)
- AT as need to be moved more quickly than would be met by diffusion
OR - Facilitated diffusion as conversion of ornithine to citrulline creates concentration graidents
Give one way in which a laser scanning confocal microscope differs from an electron microscope? (1)
LSCM has a …
- lower resolution
- can have a fluorescent tag
- can see movement
- can say different layers/depths
State two reasons why a cell may look in prophase? (2)
- chromosomes condensed
- chromosomes not organised
- nuclear envelope is present
- no nucleolus
Explain how the organisation of homologous chromosomes during Metaphase 1 increases genetic variation? (3)
- independent assortment
- (homologous chromosomes) line up along the centre of the cell/metaphase plate/equator
- either chromosome could end up in either cell
- each chromosome of the homologous pair is genetically different
Describe a procedure to observe the positions of xylem vessels in a leaf stalk of celery? (2)
- cut a cross-section
- add a stain and observe under a microscope
State 1 similarity and 2 differences between the structure of the xylem and the phloem (3)
Similarities: -both made up of cells joined end to end -both made up of more than one cell type -xylem vessels and sieve tube elements both lack nuclei Differences: X lignified P no lignin X no sieve plated P sieve plates X no companion cells P companion cells X pits P no pits X no cytoplasm/organelles P has cytoplasm and some organelles
Describe how you would do a dissection of a insect gaseous exchange system? (2)
- cup open exoskeleton
- observe tracheoles/ tracheae using saline solution
How is the trachea of a mammal different from that of an insect? (2)
- Mammals have 1 trachea and insects have multiple
- Mammals have a larger diameter
- Mammals have cartilage but insects have chitin
- Mammals have C - shaped cartilage and insects have spiral
- Mammals trachea branches into bronchi while plants into tracheoles
- Mammal trachea has smooth muscle/goblet cells and insect tracheae do not
Explain the differences in duration between primary and secondary infection? (2)
Primary is slower due to clonal selection/expansion/production of antibodies.
Secondary is quicker because of memory cells/more antibodies produced/immunological memory.
What do scientists need to control when doing biodiversity experiments? (1)
- same time of year/day
- same length/number of transects
- same counting/capture technique
- same place in habitat
State 3 adaptations to hydrophytes? (3)
- air spaces in leaves to allow leaves to float to receive light for photosynthesis
- stomata on upper side of leaf so they have access to C02
- roots reduced/absent as not required to obtain water/not wasting resources
- waxy cuticle so water does not block stomata
- reduced vascular tissues due to high water availability
Explain why an electrocardiogram may not be an accurate representation of a persons heart rate? (3)
- only 1 cardiac cycle shown
- could be anonymous/atypical
- mean of several cycles would be better
Explain how the structure of a phospholipid allows them to form the bilayer? (3)
- hydrophilic head and hydrophobic tail
- hydrophobic tail repelled by water
- hydrophilic head forms H bonds with water
- medium outside plasma membrane in aqueous
- hydrophobic nature of tail results in their facing towards each other
Suggest what roles these ions have in helping cut plants last longer? (2)
H+
Na+
H+ = maintain/regulate pH Na+ = regulate water potential
What causes the fluctuation of pressure in the aorta? (2)
- systole increases pressure
- diastole decreases pressure
- systole is ventricular
- left ventricle
Why does pressure have to decrease from the aorta to the capillaries? (2)
- capillary (wall) is, thin / only one cell thick ;
- (high pressure would) burst / damage, capillary (wall) ;
- reduce chance of, tissue fluid build up / oedema
Describe and explain how the wall of an artery is adapted both to withstand and maintain
high hydrostatic pressure (5)
To withstand pressure: wall is thick ; (thick layer of) collagen ; (wall / collagen) provides strength ; endothelium, corrugated / folded ; idea of: no damage to, endothelium / artery (wall) (as it stretches) ; max 3
To maintain pressure:
(thick layer of) elastic tissue / elastic fibres / elastin ;
to cause recoil / return to original size ;
(thick layer of) smooth muscle ;
narrows / constricts, lumen / artery ;
How can you tell the distance between the strands in DNA is not always the same? (1)
DNA creates a double helix shape which would not occur if the strands are the same length.
How does carrying out replicates improve an investigation? (2)
- calculate a mean
- anomalies can be identified
- improves repeatability
- allows statistical tests to be completed
Explain how paralysis of the diaphragm could lead to suffocation? (2)
- no/little increase in volume of thorax
- no/little decrease in pressure in the thorax
- less air drawn into lungs
What effect will reducing the speed of conduction of Purkyne fibres have on heart rate? (3)
- slows/decreases heart rate
- slows transmission of impulse from AVN to ventricles
- slows ventricular systole
- longer delay before ventricular systole begins
- increases time the heart is in diastole
Explain why the wall of the left ventricle is thicker than the wall of the left atrium? (3)
1 (more muscle to create) more force ; 2 (needs to create) higher pressure ; 3 push blood against greater , resistance / friction ; 4 (left ventricle) pumps blood further / pumps blood to all parts of body / supplies systemic circulation ;
Explain why the curve for fetal oxyhaemoglobin is to the left of the curve for adult oxyhaemoglobin? (4)
1 fetal haemoglobin has a higher affinity (for
oxygen) ( than adult haemoglobin) ;
2 (fetal Hb) takes up oxygen in low(er) partial
pressure of oxygen ;
3 placenta has low partial pressure of oxygen ;
4 at low partial pressure of oxygen / in placenta,
adult (oxy)haemoglobin will dissociate / AW ;
Suggest the effects of kidney failure on the composition of the blood (2)
- higher conc of urea
- higher conc of ions/salts
- increase in water
Explain the need for close matching of a donated kidney to a recipient (3)
Donated kidney will be recognised as foreign/non self
Antigens on donated kidney will be different
Causing rejection
By immune system
Explain the ways in which the Bowmans capsule and the Glomerulus are adapted (5)
Ultrafiltration
Afferent arteriole is wider than efferent arteriole
High hydrostatic pressure in glomerulus
Endothelium has gaps to allow passage of substances
Basement membrane stops removal of large molecules
Podocytes have projections
Projections ensure gaps to allow passage
ADH is a hormone which is produced by specialised nerve cells known as —- cells.
These cells detect changes in the water potential of the blood flowing through the —-. If the water potential of the blood is too low ADH is released. ADH s not secreted immediately into the blood but passes along the —- of the specialised nerve cells to the —- gland where it is released. ADH acts on the cells of the —-. The ADH molecule attaches to the —- of these cells. (6)
Osmoreceptor Hypothalamus Axon Posterior pituitary Collecting duct Cell membrane
ADH is a hormone. Suggest where it is removed in the blood describing what happens to the ADH molecule (3)
Liver cells Hydrolysis of protein Deamination occurs Ornithine cycle Amino acid used in metabolic pathway Ultrafiltration from blood Urea present in urine Excreted
State two processes which occur in a cell during interphase (2)
- ATP content of cell increased
- Cell growth
- Protein Synthesis
- Checking genetic material
- Increase in the number of organelles
Who is cell division in a plant different to that in an animal? (2)
Plant:
- plate/wall forms
- cytokinesis starts from middle of cell
- occurs in meristems
- no centrioles
What does meristematic tissue need to be stained for investigating the number of cells in each phase (2)
- to be able to see the individual chromosomes
- to provide a contrast between cell structures
- to determine the different stages of mitosis
Before division of the nucleus of the cell, the frantic material must replicate in mitosis. State why (2)
- both cells are genetically identical to mother
- both cells receive a diploid number of chromosomes
Describe how cells in a multicellular organisms are organised (5)
- cells are differentiated/specialised
- cells form tissue
- tissues form organs
- a group of organs form organ systems
- cells/tissues/organs/organ systems work together
- named example of tissue/organ/organ system
How might the peritoneum differ in its function from the artificial membrane in a dialysis
machine used in haemodialysis? (1)
it can perform , active transport / facilitated diffusion
Why does the dialysis fluid used in peritoneal dialysis contain dextrose solution rather
than water alone? (2)
1 idea that (dialysis is replicating function of kidney and)
part of kidney’s function is to remove
(excess) water from blood ;
2 (dextrose / sugar) reduces , water potential /
(of dialysis fluid)
or
(dextrose / sugar , solution)
has a lower , water potential / (than water) ;
3 water moves from blood (into dialysis fluid)
by osmosis
or
prevents water moving into the blood
(from dialysis fluid) by osmosis ;
4 (if it was water alone) cells would , swell / burst ;
Suggest why patients receiving peritoneal dialysis usually need to have the peritoneal
dialysis fluid replaced four times a day, but those receiving haemodialysis only need
treatment three times a week (2)
1 peritoneal dialysis can remove
less (named) waste
(than haemodialysis) ;
2 idea that
in haemodialysis dialysis fluid is constantly ,
refreshed / changed
(but not in peritoneal dialysis) ;
3
4
haemodialysis uses counter-current flow ;
idea that
haemodialysis maintains concentration gradient
or
in peritoneal dialysis the concentration gradient ,
reduces / is lower ;
5 (in peritoneal dialysis) the fluid reaches equilibrium
with the blood ;
The blood in the glomerulus has a high ………………………………………………. pressure,
which forces small molecules, such as glucose and …………………………………………….. ,
out of the glomerulus and into the lumen of the Bowman’s capsule. This process is
known as ……………………………………………… .
In the proximal convoluted tubule, the glucose, most of the ……………………………………….. and
some of the salts are reabsorbed into blood ………………………………………………. that surround
the nephron at this point.
hydrostatic ; water / urea / amino acids / vitamins / small proteins ; ultrafiltration ; water ; capillaries / vessels ;
Suggest and explain what effect the action of aldosterone will have on the secretion of
ADH (2)
-water potential of , plasma / blood , will ,
decrease / become more negative ;
-(ADH secretion) will increase ;
Which part(s) of the nephron corresponds to each of the statements in the table below?
walls are impermeable to water glucose is reabsorbed into the blood ADH acts on the walls contains podocytes most of the water is reabsorbed into the blood
ascending loop of Henle proximal convoluted tubule collecting duct Bowman's capsule Proximal convoluted tubule
State the effect that the environment has on discontinuous and continuous variation (2)
of
1 no / little , environmental effect for ,
(named example of) discontinuous variation /
example given for discontinuous variation in (i) as ecf ;
2 some / large , environmental effect for ,
(named example of) continuous variation /
example given for continuous variation in (i) as ecf ;
State one advantage and one disadvantage of using clones to test a treatment for a disease (2)
advantage (genetically identical so) all react the same or genetic variable controlled ; disadvantage expensive (to produce) or don’t see varied response to drug like in real populations (of mice) or idea that clones (of mice) may have unknown health issue (which would affect responses) ;
What is meant by homozygous and gene locus? (2)
(individual / cat / genotype with) 2 identical,
alleles / version of the gene / forms of the gene ;
gene locus
position / place / location, of, gene / allele, on chromosome
Suggest why physiological problems in pedigree animals are more common than wild animals (2)
1 inbreeding / small or decreasing, gene pool ;
2 homozygous recessive (genotypes) ;
3 gene / allele , for desired characteristic on same
chromosome as problem, gene / allele ;
4 selecting for one trait (unintentionally) selects for another ;
5 breeders select for looks not health ;
6 weaker selection against less healthy animals (than in wild) ;
Which ions along the axon are at higher concentrations in the extra cellular compared to the intracellular space? (1)
Na+ and Cl-
Which is the following brain regions is responsible for controlling balance? (1)
- hypothalamus
- medulla oblongata
- cerebellum
- temporal lobe
Cerebellum
Where precisely in the body is adrenaline produced? (1)
Adrenal Medulla
Are these insitu or exsitu forms of conservation? (1)
- seed bank
- botanic gardens
- SSSI forest
- marine reserve
Exsitu
Exsitu
Insitu
Insitu
Which of these is the specific location that light dependent reactions take place? (1)
1) chloroplast
2) thylakoid membrane
3) stroma
4) lumen of the grana
2
By what mechanism is a rare disease found at high frequencies?(1) A) genetic bottleneck B) mutation C) artificial selection D) founder effect
D
On a typical growth curve, what stage would penicillin be produced by the bacteria?(1) A) lag phase B) log phase C) stationary phase D) death phase
C
Which part of the lac operon codes for the transcription factor? (1)
The regulatory Gene
Why is it vital to give someone a booster dose of the same vaccine? (1)
The memory cells have undergone apoptosis
Outline the reasons why insects and other animals need well-developed transport systems (3)
high metabolic , demands / rate
need , large oxygen / rapid oxygen , supply
diffusion , not sufficient / too slow / distance too far
(to) maintain , steep / AW , concentration / diffusion , gradient(s)
surface area to volume ratio is (usually) low
(named) metabolite(s) needed by cells / (named) waste(s) removed from cells
How do you know a TEM microscope has been used? (2)
2D image internal details visible (named) organelles / ultrastructures , visible high magnification high resolution
Explain why a plant leaf is described as an organ (4)
organ is
collection / AW , of tissues
perform / carry out / adapted to , function / role
leaves have
two from: epidermis / spongy mesophyll / palisade mesophyll / vascular / phloem / xylem , (tissues)
(to carry out) photosynthesis / gaseous exchange
What can large standard deviations show on a graph? (1)
That a random error has occured
Explain why podocytes are usually unable to undergo mitosis (3)
have already / are , differentiated / specialised
(so cannot divide)
2 are in , G0 (phase of cell cycle) / resting phase
3 idea that shape is (too) , irregular / asymmetrical
(so cannot divide)
4 cytoskeleton cannot function / spindle (fibres)
cannot form
5 (if mitosis occurred) it would alter , number / size ,
of the , gaps / fenestrations
6 idea that it would alter an aspect of ultrafiltration
Explain why the toxins produced by the different strains are described as immunologically distinct and how they are dealt with by the immune system (6)`
1) toxins produced by each strain will be slightly different
2) each toxin with have a different 3D shape
3) toxin acts as an antigen
4) immune response determined by the shape of antigen
5) APC inject antigen and display antigens on surface
6) interaction causes production of interleukins
7) B cells activated by T-Helper cells
8) Clonal selection and clonal expansion
9) B cells differentiate into plasma cells
10) plasma cells produce antibodies
11) by protein synthesis antibodies bind to and neutralise toxins
What is meant by an autoimmune disease? (2)
An abnormal immune response
Against tissues normally in the body
Suggest why antibodies specific to nuclear proteins are not normally made (1)
They are usually hidden in the nucleus
Name two different types of T lymphocytes and describe their role in the immune system (2)
- Helper cells which produce interleukins
- Killer cells secrete perforin to kill cells
- Memory cells for a faster/secondary immune response
State two possible sources of natural medicines (2)
plants and microorganisms
Outline the processes that lead to the production of antibodies against an unfamiliar bacterium (3)
- B cells/lymphocytes carry an antibody on surface/complementary to one antigen
- Selected/activated B cell clones/divides by mitosis
- forms/differentiates into plasma/effector cells
- which secretes antibodies/complementary to antigen
Explain how helper T cells act to speed up B cell stimulation? (2)
T Helper cells are stimulated by antigen-presenting cells.
Release cytokines/interleukins.
Stimulate B cells/mitosis/clonal expansion
Explain why vaccinations are an example of active immunity (2)
Antibodies produced
Activation of lymphocytes of person being vaccinated
Memory cells remain
Explain why vaccinations are an example of active immunity (2)
- Different pathogens have different antigens
- Antigens have a specific shape
- Shape of antibody must be complementary to a specific antigen
- Different antibody needed for each pathogen
Describe the actions of the B lymphocytes in the immune response (8)
- Humoral response
- B cells have antigen receptor/carries antibody on its surface
- Matches to one antigen
- Clonal selection
- Selection of B lymphocyte
- by macrophages/ APC / T helper cells / interleukins
- Clonal expansion
- Cells divide by mitosis/clones
- Differentiate/specialise
- B cells form plasma/effector cells
- Secrete/produce antibodies
- Antibodies are specific/complementary to an antigen
- B cells form memory cells
- Secondary response
Explain why the response to the subsequent infection is much bigger than the response to vaccination? (3)
Clonal selection
Clonal Expansion
Differenciation
Describe two ways in which the structure of part C is adapted to its function (2)
1 contain , (named) pigment (molecules) /
photosystems ;
2 contain ,
(named) electron carriers / ETC / ATP synth(et)ase ;
3 idea that has a large surface area (in a small volume)
for , light absorption /
light dependent reaction(s) /
light dependent stage /
electron transport ;
With reference to the biochemistry of photosynthesis, explain why the theoretical rate of photosynthesis is not achieved at higher light intensities (2)
1 at high light intensity
other (named) factor becomes a limiting factor ;
2 idea that temperature becomes limiting as ,
Calvin cycle / light independent reaction ,
involves enzymes /
relies on kinetic energy of molecules ;
3 idea that CO2 (concentration) becomes limiting as it is
required for ,
Calvin cycle / light independent reaction /
formation of (named) Calvin cycle compound /
reaction with RuBP / fixation by Rubisco ;
Suggest one way in which the structure of a leaf in shaded area will differ (1)
shade leaf will have
1
2
3
large(r) / more , chloroplast(s) / (palisade) mesophyll ;
more , grana / thylakoids (in chloroplast) ;
large(r) surface area (of leaves) ;
State the advantage to the plant of having a range of accessory pigments in photosystems (1)
able to , absorb / use ,
a range of / different / more / other ,
(light) wavelengths / ;
Name the products of the light-dependent of photosynthesis (3)
reduced NADP / NADPH / NADPH2 / NADPH+ ;
ATP ;
oxygen ;
What stage of the DNA cycle does DNA Replication occur? (1)
The synthesis phase of interphase
What are the products of DNA replication compared to transcription? (1)
DNA replication produces two double stranded DNA molecules and transcription produces one mRNA molecule
What does a stop codon do to stop the formation of the polypeptide? (1)
A stop codon does not bring down any amino acids so the polypeptide chain stops
Choose three words which are wrong and replace them (3)
Replication takes place in the S-phase of mitosis.
The DNA molecules unwinds.
Free DNA nucleotides are activated.
Thymine pairs with adenosine.
The nucleotides are joined by DNA helicase.
Cytosine pairs with guanine.
Mitosis - Interphase
Adenosine - Adenine
DNA helicase - DNA polymerase
Outline the processes which occur in G1 and G2 (4)
G1 (2 marks maximum)(more) protein, synthesised / made;(more) cytoplasm volume increases;cell, grows / increases in size;(more) organelles, produced / grow anddivide / replicate;
G2(more) organelles, produced / grow anddivide / replicate;energy stores, increase / AW;idea of (DNA) proofreading / checkpoin
Outline the processes and organelles involved in the translation of these proteins from RNA (4)
(m)RNA transported out of nucleus (1)(m)RNA transported to / associates withribosome (1)translation / protein synthesis, occurs atribosome (1)(t)RNA brings specific amino acids or(t)RNA described (1)peptide bonds form between adjacentamino acids or peptide bonds described (1)polypeptide / protein processed through Golgi apparatus (1)
Describe how gene expression can be regulated after transcription (3)
primary mRNA is modified (1)removal of introns to produce maturemRNA (1)Alternative splicing can produce differentversions of mRNA (1)protein must be activated by cAMP /phosphorylation (1)binding (of cAMP) alters shape of protein
Explain why the rate of photosynthesis decreased at temperatures above 25 degrees (4)
1 denaturing of enzyme; 2 change in shape of active site; 3 named photosynthetic enzyme; 4 less photolysis; 5 less ATP produced; 6 named step in Calvin cycle which is affected; A step described
7 increase in rate of respiration; 8 respiration occurring at faster rate than photosynthesis; 9 temperature compensation point;
10 increased rate of transpiration; 11 stomatal closure; 12 less carbon dioxide uptake;
13 AVP; e.g. ref to photorespiration
Explain why CO2 was released when CO2 concentrations were low for the plant (2)
ref respiration;
production of carbon dioxide; R release
(at low concentrations, CO2 was) diffusing / moving down a concentration gradient;
respiration faster than photosynthesis / AW;
AVP; e.g. below compensation point
Suggest why it was important that the leaves remained attached to the plants while the measurement were made in photosynthesis? (2)
maintenance of water supply;
xylem / vascular bundles, intact;
water required for, photosynthesis / turgor; A water prevents wilting
stomata might close if the leaf detached;
leaves site of photosynthesis;
AVP; e.g. ABA, water stress, sugar transport
Outline the ways in which heterotrophic organisms are dependant on plants (3)
1 animals / heterotrophs (need to) , eat / obtain organic material from / AW , plants / autotrophs ; 2 (plants / autotrophs) produce (named) organic molecules during , photosynthesis / Calvin cycle / light independent stage ; 3 (plants / autotrophs) produce oxygen during , photosynthesis / photolysis / light dependent stage; 4 glucose / carbohydrate / oxygen , (produced in photosynthesis) are used in respiration by , animals / heterotrophs
Name two polysaccharides that can be synthesised from the end products of the light independent stage of photosynthesis (2)
starch / amylose / amylopectin
and
cellulose ;
Define what is meant by autotroph and heterotroph (2)
autotroph
can make ,
organic molecule(s) / named organic molecule(s) ,
from , inorganic molecule(s) / carbon dioxide ;
heterotroph
relies on / needs to use / has to obtain /
feeds on and digests ,
(named) organic molecules (that have been made
by another organism) ;
Explain what fat droplets in the chloroplast might be used for (1)
for membrane formation
or
phospholipid / cholesterol / glycolipid , for membrane ;
fatty acid / (named) pigment , synthesis
Suggest the effect of the herbicide binding to the electron carriers will have on photosynthesis (2)
1 prevents non-cyclic photophosphorylation ;
2 no electron(s) available to form reduced NADP ;
3 idea that ATP production by cyclic
photophosphorylation is not prevented ;
4 no / less , ATP and no reduced NADP available for ,
Calvin cycle / light independent reaction /
conversion of GP to TP ;
Describe why measuring carbon dioxide and oxygen production may both not be accurate (2)
1 2 3 4 5 oxygen oxygen only produced in one (named) stage of photosynthesis ; oxygen produced might be used for respiration ; carbon dioxide CO2 only used in one (named) stage of photosynthesis ; CO2 produced during respiration might be used for , photosynthesis / light independent reaction / Calvin cycle ; O2 / CO2 / both , could be an underestimate or represents net production (O2) or represents net use (CO2) ;
Paraquat binds to electrons in photosystem 1. Suggest how in results in death of the plant (2)
1 prevents photophosphorylation ; 2 cyclic and non-cyclic ; 3 no / less , ATP / reduced NADP , for , light-independent stage / Calvin cycle / GP to TP ; 4 no (named) substrate made for respiration ;
Suggest the role of DNA and ribosomes in the chloroplast(2)
1 (DNA) coding for , gene(s) / protein / enzyme
or
(ribosome) protein / enzyme , synthesis ;
2 (enzymes for production of / proteins for)
chlorophyll synthesis / pigment synthesis /
photosystem ;
3 (protein for) electron , acceptor(s) / carrier(s) ;
4 ATP synth(et)ase ;
5 (enzyme / PSII) for , photolysis / splitting of water ;
6 (enzymes for)
Calvin cycle / light independent reaction ;
Suggest why not all the oxygen produced by the plant in photosynthesis is collected (2)
1 would dissolve in the water ;
2 used in , respiration / oxidative phosphorylation ;
3 may escape the collection apparatus ;
4 trapped in , a bubble attached to / air spaces in ,
the leaf
Why might nitrogen be collected from a plant in a photosynthesis reaction? (1)
1 (nitrogen) was present in the air (spaces) in the ,
leaf / plant ;
2 (nitrogen) leaves the plant with the oxygen ;
3 idea that (nitrogen) comes out of solution /
‘undissolved’ (as less soluble in warm water) ;
Suggest the advantage of plants deep in water to having different accessory pigments (2)
intensity
1 in deeper water there is , less / lower , light intensity ;
2 (these pigments) can absorb what (little) light there is ;
wavelength
3 not all wavelengths of light can penetrate
or
mainly shorter wavelengths can penetrate
or
(mostly) blue light (450 – 520 nm) penetrates ;
4 (these pigments) can absorb
wavelengths of light that can penetrate
(deeper water) ;
Discuss the fate of TP in the Calvin Cycle (3)
1 regenerates / produces , ribulose bisphosphate / RuBP ;
2 so cycle can continue / for (further) CO2 fixation /
to combine with CO2 ;
3 formation of (named) , sugar / glucose / hexose / sucrose /
starch / cellulose ;
4 formation of (named) ,
fat / triglyceride / lipid / fatty acids / glycerol /
amino acids / protein /
nucleic acids / nucleotides ;
5 10x TP for RuBP and 2x TP for production
or
most TP used to produce RuBP and the rest for production
Explain why the Bohr effect occurs (2)
- reduces affinity for oxygen
- formation of haemoglobinic acid
- prevents a fall in pH
- alters shape of haemoglobin
- more 02 released where CO2 concentration is high
- Co2 binds to haemoglobin forming haemoglobinic acid
Describe the role of haemoglobin in transporting oxygen around the body (2)
1 haemoglobin has a high affinity for oxygen
2 oxygen binds to haemoglobin in high partial pressures
3 oxyhaemoglobin
4 oxygen released where oxygen partial pressure is low
Explain how selective breeding that led to this increased yield could have been done? (4)
- breed high yielding plants together
- access/test yield
- crossbreed best offspring
- over many generations
Define the term recombinant DNA (1)
DNA which has been combined from two sources
State what is meant by biotechnology using examples and suggest the advantages of using microorganisms for this (6)
- large-scale / industrial / commercial use (of living
organisms / enzymes) ; - to produce , food / named example ;
- detail of , microbe / enzyme , involved ;
- to produce , drugs / named example ;
- detail of , microbe / enzyme , involved ;
to make , (useful) enzymes / biogas / calcium citrate / - for bioremediation / for water treatment / for microbial
mining ;
Advantages of microorganisms - fast, growth / reproduction / products ;
- microbes can be genetically engineered ;
- processes occur at low , temperatures / pressures ;
- low , temp / pressure , cheaper / safer , to maintain ;
- products , pure / easy to separate ;
- grow on unwanted, food / nutrients ;
What is graphical evidence that a substance is a secondary metabolite? (2)
- it is produced after main growth cycle
- it is not needed for growth
What is the importance of maintaining aseptic technique in fermentation? (3)
to avoid unwanted microbe , entry / presence ;
so no competition for nutrients ;
so conditions remain unchanged ;
so no decrease in yield ;
so no contamination of , batch / product / penicillin
or
batch is unusable ;
to prevent escape of ,
microbes / fungus / Penicillium / spores ;
State 3 physical factors in a fermenter that need to be monitored and controlled and why (3)
pH - enzyme activity
temp - enzyme activity
oxygen concentration - respiration levels
Give 2 advantages of immobilised enzymes (2)
(enzyme can be removed to be) used again ;
(enzyme can) to leave pure(r) product ; ora
(enzyme) more stable / more efficient / works better ;
Outline the process by which bacteria can be genetically modified (6)
Section I - Obtaining the gene use restriction, enzyme / endonuclease ; to, cut out / get / isolate, (rennin) gene / DNA coding for rennin or to, fragment / digest, DNA ; gene probe ; OR obtain rennin mRNA ; (use) reverse transcriptase ; to make cDNA ; OR sequence, rennin (protein) ; work out base code ; make this DNA sequence ; sticky ends ; Section II - Vector cut (open), plasmid / phage ; using same restriction enzyme ; annealing / base pairing of sticky ends ; join sugar-phosphate backbones ; (using DNA) ligase ; recombinant, vector / plasmid / phage / DNA ; Section III - Introduction into host cell mix with bacteria ; detail of conditions ; transformation (plasmid) / transduction (phage) ;
Discuss the benefits of using immobilised enzymes for large scale production (4)
(enzyme) can be re-used so reduces cost ;
product, pure(r) / uncontaminated ;
reduced downstream processing costs ;
(immobilised enzyme) works at high(er) temperature ;
(immobilised enzyme) works in changed pH ;
reaction, can be faster / have higher yield ,
because can be done at higher temperature ;
Define the term recombinant DNA (1)
DNA (combined) from (two) , sources / organisms ;
Outline the process of somatic cell therapy (5)
somatic / adult, cell / nucleus ;
fused with / injected into ;
empty / enucleate , egg cell ;
from another goat ;
idea of electric shock / electrostimulation ;
this cell or embryo, grown on , in vitro / in tied oviduct ;
(early) embryo / blastocyst , split ;
idea that embryos replaced in , surrogate mothers
Outline the process of glycolysis (4)
1 phosphorylation of glucose ;
2 so forming hexose (1,6) bisphosphate ;
3 (then) splitting into / formation of ,
two / 2 , triose phosphate(s) / TP ;
4 (for formation of pyruvate) dehydrogenation /
oxidation / formation of reduced NAD ;
5 yruvate produced (from , TP / (3C) intermediate) ;
6 total production 4 ATP / net production of 2 ATP ;
Explain what might happen to a person if the liver did not break down insulin (2)
1 blood glucose (concentration) would fall ,
too low / below normal level ;
2 idea that
glucose would continue to be taken up by ,
cells / liver / muscle (results in low blood glucose)
or
idea that
glucose is continually converted into glycogen /
would store too much glucose as glycogen ;
3 (mitochondria eventually) cannot ,
release enough energy / generate enough ATP
(as less available glucose in blood) ;
4 coma / death ;
When mitochondria are extracted from cells, they are usually kept in a 0.25 mol dm-3 sucrose solution.
What is the purpose of the sucrose solution?
A it is used as a solvent
B it maintains a constant pH by acting as a buffer
C it acts as a source of food for respiration
D it prevents the mitochondria from changing structure
D
Which of the following is absent from prokaryotic cells?
A plasmids
B cell wall
C rough endoplasmic reticulum
D ribosomes
C
On complete hydrolysis, which of the following would produce the fewest molecules? A phospholipid B triglyceride C sucrose D polypeptide
C (only 2 molecules produced) - 1 fructose and 1 glucose
Which of the following molecules does not yield only α glucose molecules on complete hydrolysis? A amylose B glycogen C maltose D sucrose
D (produces fructose also)
Analysis of a sample of DNA found that 20% of the bases were adenine.
What percentage of the bases would be pyrimidines? A 20% B 30% C 60% D 50%
D
20% thymine
30% cytosine
What is the approximate temperature coefficient (Q10) of an enzyme-controlled reaction? A 50 B 10 C 2 D 1
C - the rate of the reaction doubles with temperature going up by ten degrees
When an enzyme is subjected to temperatures above the optimum, it denatures. Which of the following bonds are the first to be disrupted by high temperatures? A disulfide B hydrogen C ionic D peptide
B
Why do we store glycogen and not glucose? (3)
- insoluble so no affect on water potential
- metabolically inactive
- compact so lots can be stored in a small place
- able to store lots of energy
- has lots of ends to be broken down and release glucose quickly