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52 Cards in this Set

  • Front
  • Back
in eukaryotic cells, two organelles with a double membrane are?
a nucleus and a mitochondrion
white blood cells, plant cells and prokaryotic cells all contain?
ribosomoes
a structure present in prokaryotic cells but not present in a white blood cell is?
a cell wall
why there is a placebo effect?
The emotional state of the patient eg belief that they are receiving the drug and it will work have a placebo effect on their body.
two differences between genetic diversity and species richness
1, genetic diversity considers one species; species richness considers a number of species

2, genetic diversity considers alleles and genotypes; species richness is within an area
suggest reasons why it is better to store seeds rather than to store whole plants?
1, take less space
2, can have more individuals
3, greater genetic variety
4, less maintenance cost
5, survive longer
6, can freeze seeds
suggest why it is better to store seeds from several individual plants of one species rather than seeds from one individual plant?
1, greater genetic variety
2, less chance of inbreeding
3, reducing chance of storing seeds with disease
how seeds should be treated to ensure their long term survival in a seedbank?
1, drying, low humidity
2, sterilisation
3, low tempreture/freezing
4, low oxygen
5, absence of light
6, check viability
explain the importance of meiosis?
It is a form of cell division that:
1, halves the chromosome number
2, so that at fertilisation the full complement of chromosomes is restored
3, allows genetic variation in gametes
4, through independent assortment
5, through crossing over
describe how the acrosin is released from the acrosome
1, the sperm head touch zona pellucida. it is a stimulus.
2, acrosome swells
3, cell membrane fuses
4, exocytosis
using the data in the table, suggest why the student could NOT support all of his statement
No data on zero acrosin activity or zero percentage fertilisation cannot accurately extrapolate back from the data.
suggest why organs are considered more complex than tissues?
1, organs made up of tissues
2, organs made up of many different cell types (tissues made up of similar cell types)
3, organs can have more than one function
compare the structure of a cellulose molecule with the structure of starch
1, both made up of glucose
2, both have 1-4 glycosidic bonds
3, both made by condensation reactions
4, starch is a-glucose, cellulose is B-glucose
5, starch composed of more than one type of molecule, amylose and amylopectin
6, starch is branching, cellulose is straight chain
7,all monomers same orientation in starch
every other one inverted in cellulose
explain how the arrangement of cellulose microfibrils contributes to the physical properties of plant fibres
1, tensile strength
2, net like arrangement of microfibrils
two functions of xylem vessels?
1, transport water and minerals
2, support
roles of cell cycle?
1, growth
2, asexual reproduction
how to distinguish between metaphase and anaphase?
metaphase:
1, chromosomes at equator of cell
2, chromatids attached to each other
3, centromere complete
4, spindle complete

anaphase:
1, chromosomes pulled apart
2, chromatids seperated
3, centromere splits
4, fibres shortening and contracting
fibre strength.

suggest factors that would need to be kept constant in this investigation
1, length
2, diameter
3, temperature
4, fibre came from the same source
5, stored for the same length of time
6, same way of applying masses/knots
7, same humidity
8, water content of fibre/ levels of drying
suggest why increasing the mass by 50 grams each time rather than 100 grams could increase the accuracy
Break mass would be to the nearest 50 grams rather than 100 grams / smaller percentage error
safty role of container of soft fabric?
cannot land on foot and cause injury
explain why the mean for the plastic fibre was calculated using only these three results?
Sample 2 is outlier and does not fit the pattern.
suggest why the use of oil-based plastic fibres such as nylon, rather than plant fibres does not contribute to sustainbility
1, oil is a non-renewable resource
2, plant fibres can be regrown thus it is sustainable
3, time scale
explain phenotype?
1, appearance of a cell or organism
2, genotype contribution
3, environmental factors
why a control group is included?
it acts as a comparison shows the situation without ***
describe the effect of smoking on the increased risk of developing lung cancer, for the people who had close relatives who developed cancer?
1, the more smoked, the higher the chance of developing lung cancer / positive correlation
2, small increase in risk if smoke up to 20 packs per year
3, greater increase in risk if smoke 21 or more per year
4, linear increase for 21 or more
5, creadit correct manipulation of the data eg 35* greater
in polygenic inheritance, the phenotypes are affected by forms of genes called ? found at many ? on chromosomes.
alleles, loci/locations/positions
what the mode number?
the number that occurs most frequently
QWC stem cell
1. undifferentiated cell ;
2. that can give rise to other types of cell
3. idea that no limit to division ;
4. ttotipotent / pluripotent ;
potential sources of human stem cells
1. cord blood /umbilical cord / placenta ;
2. fertilised egg / zygote / blastocyst / (early)
embryo ;
3. detail of site within blastocyst
4. bone marrow;
5. brain / connective / skin / liver cells;
6. addition of adult nucleus to enucleated egg cell ;
reasons why there are regulating authorities for human embryo research
1. decide on max age of embryo allowed for research ;
2. setting or considering ethical / legal aspects / judging what is acceptable / follow a code of practice ;
3. idea on what is / is not acceptable ;
4. checking that source of stem cells is acceptable
5. stopping of cloning of humans ;
6. unnecessary repeating of research ;
suggest why these regulating authorities should include people involved in human embryo research and people not involved in embryo research
people involved in embryo research:
1. idea of being able to fully understand the science / recognise what is possible benefits or risks judge in an informed manner ;

people not involved in embryo research:
2. idea of giving a balanced view;
which two domains are most DISTANTLY RELATED?
eukaryote and archaea
describe the structure of a plant cell wall
1. cellulose as microfibrils held together by hydrogen bonds
2. detail of microfibril (e.g. bundle cellulose molecules ;;
3. arrangement of microfibrils in primary cell wall ;
4. matrix / hemicelluloses / pectins;
5. primary and secondary cell walls;
6. detail of different laying down arrangement in secondary cell wall / lignin
site where there was no cell wall and the cytoplasm linked the two adjacent cells
plasmodesmata /
plasmodesma
dark line that is the
boundary between one cell
and the next cell
middle lamella
look at the photo of mitochondrion and study the structure
P = crista ;
Q = matrix ;
R = outer (mitochondrial) membrane / envelope /
double membrane ;
explain the function of mitochondria in sperm cells
1. they carry out aerobic respiration ;
2. provide ATP / energy ;
3. to move tail ;
4. allows sperm to swim ;
5. towards the egg ;
how the structure of starch is related to its function?
1. Starch is made up of many glucose monomers, thus it acts as an energy storage / glucose is the respiratory substrate
2. Starch molecule is large, so it is un-reactive / insoluble /no osmotic effect ;
3. molecule coiling / compact / amylose more can be stored in available space;
4. branches / glycosidic 1-6 bonds / amylopectin; rapid / increased mobilisation of glucose units ;
describe the effect of temperature on the mean percentage of amylose in the rice grains of all three varieties of rice plant
1. increase in temperature {decreases / eq }
(the mean percentage of amylose present)/
negative correlation ;
2. but by differing percentages in all 3 varieties
/ C, then A & then B ;
3. credit correct manipulation of the data for 1
variety (e.g. by 4.0 % in variety A / 1.5% in
variety B / 5% in variety C) eq ;
using the information in the graph, suggest which set of data is least supportive of the statement that temperature has an effect on the percentage of amylose present in rice grains. explain.
1. (variety) B ;
2. idea of smallest difference between (means /
amylose content) in B for the two different temp regimes ;
3. biggest error bars ;
4. error bars for the 2 different temp regimes overlap ;
5. explanation of overlap e.g. some of the data
for the lower temp falls within that of the higher temp ;
niche?
the role of a species within the community
species richness
number of different species in a habitat at any one time
suggest why the cheetah is the cat at most risk if the environment changes(cheetah with the lowest percentage of genes with different alleles)
1. cheetah has lowest genetic variation of the listed cats ;
2. lack of adaptation / no selective advantage when
environment changes;
3. therefore less likely to survive ;
4. therefore more at risk of extinction ;
a female cheetah often mates with several different males and gives birth to two or three cubs at a time, each having a different father. suggest why this may be advantageous to cheetahs.
1. greater genetic diversity ;
2. greater chance that will survive ;
3. increased chance of fertilisation ;
4. increase in population size
suggest what effect transferring Rafa from one zoo to another had on genetic diversity in this species
1. increases genetic diversity ;
2. because it allows outbreeding / mating with genetically different individuals
3. reduces inbreeding which reduces genetic diversity ;
look at the picture in "fertilisation in plants"
where and how is the pollen tube
which the chromosome number increases at fertilisation?
female gamete nucleus, polar nuclei
using the information in the graph, compare the mean pollen tube length in these two sugar solutions, over this 30-hour period
1. positive correlation;
2. pollen tube length always greater when boron present
3. rate of growth greater with boron ;
4. linear without boron (for 25 / 30 hours) and not linear with boron ;
5. correct comparative manipulation of the data
using the result of this investigation, a student concluded that boron was necessary for pollen tube growth. suggest why another student disagreed with this conclusion
idea that pollen tube does grow even in the absence
of boron ;
suggest the advantages to flowering plants of increased pollen tube growth
1. more likely to reach the ovule ;
2. fertilisation more likely to occur ;
3. idea of fertilisation in shorter time period ;
suggest why a prediction of the number of cells undergoing mitosis, if the nitrate ion concentration used were 9.9 mmol dm-3, would be unreliable
1. only two concentrations were used /
additional nitrate ion concentrations should
be used ;
2. no trend as only 2 data sets ;
3. If one of the two sets of data was anomalous ;
4. reference to one with no nitrate ions present
;
describe an experiment to find the optimum nitrate ion concentration for the growth of wheat seedling roots
1. 3 + / sensible range of nitrate ion concentrations ;
2. repeats at each concentration
3. uniformity of seedlings (e.g. all from same parent plant, same age, same
original root length) ;
4. solution used should contain other mineral ions / named mineral ions ;
5. mention one other variable maintained / kept
constant (e.g. temp, all run for same length of time, light intensity, volume of mineral
solution) ;
6. reference to mechanism of judging root growth to measure optimum nitrate
concentration ;