OCR Biology F215 Control, Genomes and Environment Fri 15 June 2012
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Meiosis produces cells that are genetically different; genetic variation is the differences that exist between individual's genetic material. The reason meiosis is important is that it creates variation - it makes gametes that are all genetically different. This is done in three ways;
1) Crossing-over of chromatids;
- During prophase 1, homologous chromosomes come together and pair up
- In each pair, one chroomosome is maternal (From your mum) and one is paternal (from your dad). They have the same genes but different versions of the genes, called alleles (e.g genes for hair colour)
- The non-sister chromatids twist around each other and bits of the chromatid swap over (they break off their chromatid and join onto the other chromatid)
- The chromatids still contain the same genes but now have a different combination of alleles
- The crossing-over of chromatids during prophase 1 means that each of the four daughter cells formed from meiosis contains chromatids with a different combination of alleles.
2) Independent assortment of chromosome (in metaphase 1)
- During meiosis 1, different combinations of maternal and paternal chromosomes go intoeach cell (e.g. one cell gets maternal chromosomes 1 and 2 and paternal 3, the other cell gets paternal 1 and 2 and maternal 3). so each cell ends up with a different combination of alleles.
- Indepdentent assortment of chromatids (in metaphase II)
During meiosis II, different combinations of chromatids go into each daughter cell. So each cell ends up with a different combination of alleles.
1) Crossing-over of chromatids;
- During prophase 1, homologous chromosomes come together and pair up
- In each pair, one chroomosome is maternal (From your mum) and one is paternal (from your dad). They have the same genes but different versions of the genes, called alleles (e.g genes for hair colour)
- The non-sister chromatids twist around each other and bits of the chromatid swap over (they break off their chromatid and join onto the other chromatid)
- The chromatids still contain the same genes but now have a different combination of alleles
- The crossing-over of chromatids during prophase 1 means that each of the four daughter cells formed from meiosis contains chromatids with a different combination of alleles.
2) Independent assortment of chromosome (in metaphase 1)
- During meiosis 1, different combinations of maternal and paternal chromosomes go intoeach cell (e.g. one cell gets maternal chromosomes 1 and 2 and paternal 3, the other cell gets paternal 1 and 2 and maternal 3). so each cell ends up with a different combination of alleles.
- Indepdentent assortment of chromatids (in metaphase II)
During meiosis II, different combinations of chromatids go into each daughter cell. So each cell ends up with a different combination of alleles.
Original post by darkxangel
What's the difference between somatic and autonomic?
Explain how the parasymphatetic and symphatetic systems work.
Explain/describe how energy is transferred at each trophic level.
Explain how the parasymphatetic and symphatetic systems work.
Explain/describe how energy is transferred at each trophic level.
Somatic nervous system is controlled voluntarily/consciously whereas autonomic is not (self-governing). The majority of autonomic responses are homestatic mechanisms whereas the majority of somatic is skeletal muscle movement - autonomic is also further subdivided into parasympathetic and sympathetic nervous systems. Neurones of the autonomic nervous system are usually non-myelinated whereas somatic neurones tend to be myelinated. Autonomic connections (to effectors) tend to consist of 2 or more neurones whereas somatic are generally only a single neurone. The 2 neurones of the autonomic nervous sytem connect at a ganglion.
Parasympathetic nervous system is primarily active during relaxation - the neurotransmitter at synapses is acetylcholine and the ganglion occurs within the target tissue. Conversly the sympathetic nervous system is most active in times of stress. The neurotransmitter at these synapses is noradrenaline and the neurones are linked at a ganglion just outside the spinal cord therefore neurones tend to be very short (allows for fastest possible action.) The two are described as antagonistic to one another.
Energy from one trophic level is transferred to the next via consumption and digestion (via enzymne) of an organism from the previous trophic level. This process generally hydrolyses the complex organic molecules to monomer subunits such as monosacharides and amino acids which can then be used as resiratory substrates for the production of ATP or used as monomers for protein or other complex molecule production.
(edited 11 years ago)
Original post by darkxangel
What's the difference between somatic and autonomic?
Explain how the parasymphatetic and symphatetic systems work.
Explain/describe how energy is transferred at each trophic level.
Explain how the parasymphatetic and symphatetic systems work.
Explain/describe how energy is transferred at each trophic level.
1. Somatic nervous system controls conscious activities, e.g. thinking/running.
Autonomic nervous sytem controls the unconscious activities e.g. digestion. It has two divisions which have opposite effects on the body (sympathetic and parasymphathetic)
2. The sympathetic nerovus system gets the body ready for action by the "flight or flight" system, Sympathetic neurones release the neurotransmitter noradrenaline.
On the other hand, the parasympathetic nervous sytem calms the body down, this releases acetylcholine neurotransmitter.
3.Not all energy is passed through to the next tropic level. 90% of it i lost.
60% is not used in the first place, e.g. plants cant use all wavelengths of sunlight, sunlight may not hit the plant, etc.
That leaves 40%;
30% is lost when organisms use energy produced from respiration for movement/body heat. This is respiratory loss.
10% is the net productivity and available to the next trophic level.
Original post by walkbesideme
Somatic nervous system is controlled voluntarily/consciously whereas autonomic is not (self-governing). The majority of autonomic responses are homestatic mechanisms whereas the majority of somatic is skeletal muscle movement - autonomic is also further subdivided into parasympathetic and sympathetic nervous systems. Neurones of the autonomic nervous system are usually non-myelinated whereas somatic neurones tend to be myelinated. Autonomic connections (to effectors) tend to consist of 2 or more neurones whereas somatic are generally only a single neurone. The 2 neurones of the autonomic nervous sytem connect at a ganglion.
correct-could have added-motor neurones in autonomic carry impulses from cns to glands, cardiac muscle and smooth muscle in gut
Parasympathetic nervous system is primarily active during relaxation - the neurotransmitter at synapses is acetylcholine and the ganglion occurs within the target tissue. pre-ganglionic neurones vary considerably in length- Conversly the sympathetic nervous system is most active in times of stress. The neurotransmitter at these synapses is noradrenaline and the neurones are linked at a ganglion just outside the spinal cord therefore neurones tend to be very short (allows for fastest possible action.) The two are described as antagonistic to one another. s=orgasm, increased heart rate, ventilation, pupil dilation, para=sexual arousal, pupil constriction, decreased heart rate,
Energy from one trophic level is transferred to the next via consumption and digestion (via enzymne) of an organism from the previous trophic level. This process generally hydrolyses the complex organic molecules to monomer subunits such as monosacharides and amino acids which can then be used as resiratory substrates for the production of ATP or used as monomers for protein or other complex molecule production.
correct-could have added-motor neurones in autonomic carry impulses from cns to glands, cardiac muscle and smooth muscle in gut
Parasympathetic nervous system is primarily active during relaxation - the neurotransmitter at synapses is acetylcholine and the ganglion occurs within the target tissue. pre-ganglionic neurones vary considerably in length- Conversly the sympathetic nervous system is most active in times of stress. The neurotransmitter at these synapses is noradrenaline and the neurones are linked at a ganglion just outside the spinal cord therefore neurones tend to be very short (allows for fastest possible action.) The two are described as antagonistic to one another. s=orgasm, increased heart rate, ventilation, pupil dilation, para=sexual arousal, pupil constriction, decreased heart rate,
Energy from one trophic level is transferred to the next via consumption and digestion (via enzymne) of an organism from the previous trophic level. This process generally hydrolyses the complex organic molecules to monomer subunits such as monosacharides and amino acids which can then be used as resiratory substrates for the production of ATP or used as monomers for protein or other complex molecule production.
correct, sometimes energy is wasted because of death (hwver available to decomposers,) heat energy, excretion, also some used for living processes, so the next trophic level can keep fewer living tissue alive, therefore less organisms are alive in the next level if all organisms are same size,
Describe how pyramids of biomass and number can be used.
also what are the limts of the pyramids?
-describe how yield can be reduced in crop and how we can prevent it and how humans maximise energy efficiency
describe and explain apoptosis
Original post by Bi0logical
1. Somatic nervous system controls conscious activities, e.g. thinking/running.skeletal, myelinated nerones,
Autonomic nervous sytem controls the unconscious activities e.g. digestion. It has two divisions which have opposite effects on the body (sympathetic and parasymphathetic)two neurones that connect at ganglion, glands, cardiac muscle, smooth muscle in gut, non-myelinated, self-governing,
2. The sympathetic nerovus system gets the body ready for action by the "flight or flight" system, Sympathetic neurones release the neurotransmitter noradrenaline.
On the other hand, the parasympathetic nervous sytem calms the body down, this releases acetylcholine neurotransmitter.correct,
3.Not all energy is passed through to the next tropic level. 90% of it i lost.
60% is not used in the first place, e.g. plants cant use all wavelengths of sunlight, sunlight may not hit the plant, etc.
That leaves 40%;
30% is lost when organisms use energy produced from respiration for movement/body heat. This is respiratory loss.
10% is the net productivity and available to the next trophic level.correct how do you know so much detail
Autonomic nervous sytem controls the unconscious activities e.g. digestion. It has two divisions which have opposite effects on the body (sympathetic and parasymphathetic)two neurones that connect at ganglion, glands, cardiac muscle, smooth muscle in gut, non-myelinated, self-governing,
2. The sympathetic nerovus system gets the body ready for action by the "flight or flight" system, Sympathetic neurones release the neurotransmitter noradrenaline.
On the other hand, the parasympathetic nervous sytem calms the body down, this releases acetylcholine neurotransmitter.correct,
3.Not all energy is passed through to the next tropic level. 90% of it i lost.
60% is not used in the first place, e.g. plants cant use all wavelengths of sunlight, sunlight may not hit the plant, etc.
That leaves 40%;
30% is lost when organisms use energy produced from respiration for movement/body heat. This is respiratory loss.
10% is the net productivity and available to the next trophic level.correct how do you know so much detail
describe how energy transfer can be manipulated
Describe PCR and DNA probes
Can someone explain what pg 167 is on about in the textbook? What's the point in cutting the genome up then putting it back together again, and what's the actual process?
Thank you to anyone that helps!
Thank you to anyone that helps!
Original post by Salmaa!
Can someone explain what pg 167 is on about in the textbook? What's the point in cutting the genome up then putting it back together again, and what's the actual process?
Thank you to anyone that helps!
Thank you to anyone that helps!
The BACs are cloned so producing many copies of gene fragment. And then they are cut and are automated processed
Original post by darkxangel
correct, sometimes energy is wasted because of death (hwver available to decomposers,) heat energy, excretion, also some used for living processes, so the next trophic level can keep fewer living tissue alive, therefore less organisms are alive in the next level if all organisms are same size,
Describe how pyramids of biomass and number can be used.
also what are the limts of the pyramids?
-describe how yield can be reduced in crop and how we can prevent it and how humans maximise energy efficiency
describe and explain apoptosis
Describe how pyramids of biomass and number can be used.
also what are the limts of the pyramids?
-describe how yield can be reduced in crop and how we can prevent it and how humans maximise energy efficiency
describe and explain apoptosis
Pyramids of biomass (constructed using the dry mass of organisms), these ppyramids show the exact changes in the amount of living matter at each trophic level. Pyramids of number simply show the number of organisms present at each trophic level. The drawback of these pyramids are that the pyramid of numbers does not always show an accurate representation of how much living tissue is present at each trophic level and the pyramid of biomass can be very destructive to an ecosystem- for this reason if a pyramid of biomass is taken it is usually carried out via wet mass and converting this wet mass to dry mass using data tables.
Yield of crops can be reduced via a number of different factors:
A insufficient light source can lead to a low rate of the light-dependant stages of photosynthesis, as such the rate of the light-independant stages will drop meaning less growth can occur due to a lower conc of complex organic molecules. This can be reduced by ensuring optimum light conditions at all times for the plant via planting crops earlier to provide a longer growing season or growing under light banks.
A lack of water can reduce the rate of growth significantly - this can be reduced by the use of irrigation and selectivly breeding (or genetically modifying) to produce drought resistant crops.
A low temperature will reduce enzyme activity with the plant 9as well as reducing the kinetic energy of particles) therefore limiting the speed at which metabollic reactions can occur. This can be stopped by growing plants with a greenhouse where temperature conditions can be more carefully controlled or again planting earlier.
lack of nutrients can also limit growth by limiting the rate of photosynthesis and proteinsynthesis. This can be combated by crop rotation every few years and the occasional growth of legumes in the field to promote the nitrogen fixation process by the rhizobium present in their root nodules (which can in turn be 'ploughed in') to increase the soil nitrate conc.
Pests (eg insects), or pathogens (eg fungi) can removes biomass from the plants by consuming or destroing roots via rot. These can be avoided by the use of artificial pesticides or the genetic modification to introduce resistance to fungal infections or possible introduction of genes to produce natural pesticides (as with the current wheat trials and the introduction of natural 'mint' genes)
Interspecific Competition from weeds may reduce the rate of growth - this can easily be combated bythe use of selective herbicides to reduce the numbers of weeds.
Apoptosis: This is the natural mechanism for controlled cell death. It's purpose is to cleanly dispose of and recycle cells which have reached their hayflick limit. It is also useful for preventing the devopment of tumours and to ensure that during development, a feutus has it's fingers develop as seperate entities as oppossed to a solid mass.
The process is as follows:
1) The chromatin condenses and enzymes begin to hydrolyse the cytoskeleton of the cell
2) The cytoplasm also begins to condense as the organelles tightly pack together
3) changes occur in the cell surface membrane and 'blebs' form.
4) DNA breaks into fragments as the neclear envelope breaks down.
5) The cell seperates into several seperate vesicles which are in turn taken up by Macrophages (phagocytosis occurs).
Can someone please explain fixed action patterns? I know that releaser mechanisms are released in the brain in response to a stimulus, which produce this response...however applying this would be difficult.
This was posted from The Student Room's iPhone/iPad Ap
This was posted from The Student Room's iPhone/iPad Ap
Original post by walkbesideme
Pyramids of biomass (constructed using the dry mass of organisms), these ppyramids show the exact changes in the amount of living matter at each trophic level.show drymass of all oransisms at each trophic level Pyramids of number simply show the number of organisms present at each trophic level.i think this is calclating by burning organisms in calorimeter, temp change water shows how much energy per joule is released-very destructive The drawback of these pyramids are that the pyramid of numbers does not always show an accurate representation of how much living tissue is present at each trophic level and the pyramid of biomass can be very destructive to an ecosystem- for this reason if a pyramid of biomass is taken it is usually carried out via wet mass and converting this wet mass to dry mass using data tables.
only a snapshot of the ecosystem at that moment-ecosystem is dynamic/fluctuates so can be misleading,
Yield of crops can be reduced via a number of different factors:
A insufficient light source can lead to a low rate of the light-dependant stages of photosynthesis, as such the rate of the light-independant stages will drop meaning less growth can occur due to a lower conc of complex organic molecules. This can be reduced by ensuring optimum light conditions at all times for the plant via planting crops earlier to provide a longer growing season or growing under light banks.
A lack of water can reduce the rate of growth significantly - this can be reduced by the use of irrigation and selectivly breeding (or genetically modifying) to produce drought resistant crops.
A low temperature will reduce enzyme activity with the plant 9as well as reducing the kinetic energy of particles) therefore limiting the speed at which metabollic reactions can occur. This can be stopped by growing plants with a greenhouse where temperature conditions can be more carefully controlled or again planting earlier.
lack of nutrients can also limit growth by limiting the rate of photosynthesis and proteinsynthesis. This can be combated by crop rotation every few years and the occasional growth of legumes in the field to promote the nitrogen fixation process by the rhizobium present in their root nodules (which can in turn be 'ploughed in') to increase the soil nitrate conc.
Pests (eg insects), or pathogens (eg fungi) can removes biomass from the plants by consuming or destroing roots via rot.so reduce yield These can be avoided by the use of artificial pesticides or the genetic modification to introduce resistance to fungal infections or possible introduction of genes to produce natural pesticides (as with the current wheat trials and the introduction of natural 'mint' genes) herbicied/fungicied/
Interspecific Competition from weeds may reduce the rate of growth - this can easily be combated bythe use of selective herbicides to reduce the numbers of weeds.
Apoptosis: This is the natural mechanism for controlled cell death. It's purpose is to cleanly dispose of and recycle cells which have reached their hayflick limit. It is also useful for preventing the devopment of tumours and to ensure that during development, a feutus has it's fingers develop as seperate entities as oppossed to a solid mass.no hydrolytic enzymes released compared to necrosis, cytokinins control it, nitric oxidase makes inner mitochondrial walls more permeable to proton ions dissipating proton gradient and protons bind to apopstosis inhibiotr enzymes so apoptosis can happen
The process is as follows:
enzymes break down the cytoskeleton
-cytoplasm becomes dense with tightly packed organelles
chromatin condenses, nuclear envelope disintergrated, dna splits into fragments
1) The chromatin condenses and enzymes begin to hydrolyse the cytoskeleton of the cell
2) The cytoplasm also begins to condense as the organelles tightly pack together
3) changes occur in the cell surface membrane and 'blebs' form.
4) DNA breaks into fragments as the neclear envelope breaks down.
5) The cell seperates into several seperate vesicles which are in turn taken up by Macrophages (phagocytosis occurs).
only a snapshot of the ecosystem at that moment-ecosystem is dynamic/fluctuates so can be misleading,
Yield of crops can be reduced via a number of different factors:
A insufficient light source can lead to a low rate of the light-dependant stages of photosynthesis, as such the rate of the light-independant stages will drop meaning less growth can occur due to a lower conc of complex organic molecules. This can be reduced by ensuring optimum light conditions at all times for the plant via planting crops earlier to provide a longer growing season or growing under light banks.
A lack of water can reduce the rate of growth significantly - this can be reduced by the use of irrigation and selectivly breeding (or genetically modifying) to produce drought resistant crops.
A low temperature will reduce enzyme activity with the plant 9as well as reducing the kinetic energy of particles) therefore limiting the speed at which metabollic reactions can occur. This can be stopped by growing plants with a greenhouse where temperature conditions can be more carefully controlled or again planting earlier.
lack of nutrients can also limit growth by limiting the rate of photosynthesis and proteinsynthesis. This can be combated by crop rotation every few years and the occasional growth of legumes in the field to promote the nitrogen fixation process by the rhizobium present in their root nodules (which can in turn be 'ploughed in') to increase the soil nitrate conc.
Pests (eg insects), or pathogens (eg fungi) can removes biomass from the plants by consuming or destroing roots via rot.so reduce yield These can be avoided by the use of artificial pesticides or the genetic modification to introduce resistance to fungal infections or possible introduction of genes to produce natural pesticides (as with the current wheat trials and the introduction of natural 'mint' genes) herbicied/fungicied/
Interspecific Competition from weeds may reduce the rate of growth - this can easily be combated bythe use of selective herbicides to reduce the numbers of weeds.
Apoptosis: This is the natural mechanism for controlled cell death. It's purpose is to cleanly dispose of and recycle cells which have reached their hayflick limit. It is also useful for preventing the devopment of tumours and to ensure that during development, a feutus has it's fingers develop as seperate entities as oppossed to a solid mass.no hydrolytic enzymes released compared to necrosis, cytokinins control it, nitric oxidase makes inner mitochondrial walls more permeable to proton ions dissipating proton gradient and protons bind to apopstosis inhibiotr enzymes so apoptosis can happen
The process is as follows:
enzymes break down the cytoskeleton
-cytoplasm becomes dense with tightly packed organelles
chromatin condenses, nuclear envelope disintergrated, dna splits into fragments
1) The chromatin condenses and enzymes begin to hydrolyse the cytoskeleton of the cell
2) The cytoplasm also begins to condense as the organelles tightly pack together
3) changes occur in the cell surface membrane and 'blebs' form.
4) DNA breaks into fragments as the neclear envelope breaks down.
5) The cell seperates into several seperate vesicles which are in turn taken up by Macrophages (phagocytosis occurs).
correct
shall we continue tomorrow at 8?
Original post by Sparkzz
Can someone please explain fixed action patterns? I know that releaser mechanisms are released in the brain in response to a stimulus, which produce this response...however applying this would be difficult.
This was posted from The Student Room's iPhone/iPad Ap
This was posted from The Student Room's iPhone/iPad Ap
is that in the ocr specification?
Original post by darkxangel
is that in the ocr specification?
Its an aspect of innate behaviour so i assume they expect we know it!
This was posted from The Student Room's iPhone/iPad Ap
Original post by darkxangel
is that in the ocr specification?
nope, I just checked
Don't even think it's in my textbook so I'm hoping we don't need to know about it! haha
Original post by chemicalX
is it because they are produced as 'waste products' from the micro-organisms which we harvest and use to our advantage?
Produced in stationary phase to prevent competition from other organisms, would be a waste of energy producing them in the lag/log phase as all there are no limiting conditions e.g. plenty of space, nutrients, water.
Describe how the nervous and endocrine system work together to bring about a 'fight or flight' response.
Original post by hash007
Describe how the nervous and endocrine system work together to bring about a 'fight or flight' response.
autonomic system-symphatetic->hypothalamus/pituirtary gland releases noradrenaline, blood carries noradrenaline and adrenaline released by adrenal gland (endocrine), which causes response heart beat increases, ventilation increases, pupils dilate, more alert,
-ganglionic neurones carry impulses to target cells, like cardiac cells, glands, smooth muscle in the gut,
Original post by darkxangel
octrivine, still here?
hi how are you
im backOriginal post by otrivine
hi how are you im back
im backdescribe PCR and DNA Probes. (12)
can we contineu tomorrow at 8?
Original post by hash007
Why are secondary metabolites produced after the main growth period in a micro-organism?
because it is slower as less nutrient is provided ? and chemcials are not released by part of an organims ?
Original post by darkxangel
describe PCR and DNA Probes. (12)
can we contineu tomorrow at 8?
can we contineu tomorrow at 8?
yes sure
sorry for being late i went to the cinema and watch a movie sorryyPcr the procedure is DNA double stranded so raise temperature to 95 so that fragements can break and separate (strands) and then temperature is lowered to 55 to allow primers annealing to occur(complementary base pairing and hydrogen bonds forming) and then temperature is at 72 and what happens is that DNA polymerase extends the chain by adding free nucleotides. DNA probes are where free nucleotides are added and annealing occurs due to complementary base paring and forms hydrogen bond and dna probes are used to help identigy any missing genes which caused the disease and helps to search for that particular allele(gene) and can use radioactive marker which gives colour to be able to identify the sequence
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