Looking at the excretion of Urea (nitrogen – toxic to the body and cannot be stored) the original form is amino acids. This is the role of the liver and kidneys
Liver – amino acids are broken down and turned into urea. Released into the blood stream where it circulates to the kidneys
Kidneys – will filter urea from blood, it is added to water to form urine, where it collects in the bladder to be excreted (peeing) the filtered blood returns to circulation.
Unborn child is in amniotic fluids within the uterus. It cannot digest, breathe or excrete.
So growing out of the embryo there is a placenta attached to the child by the umbilical cord.
The placenta grows out of the embryo not the mothers. The blood vessels are the child’s not the mothers.
The placenta grows into the wall of the uterus
When the woman eats through pregnancy (glucose, amino acids and fats) these vital nutrients will pass through the woman’s blood to the child’s blood through the placenta
The placenta has a large surface area and is very thin.
The child also produces carbon dioxide and urea which will pass onto the mother to excrete.
Recap: nucleus contains chromosomes, during interphase cells are involved in DNA replication.
Signs:
1.Break down of nuclear membrane (nucleus breaks down) known as PROPHASE, chromosomes become visible as a pair of chromatids.
2.With the nucleus gone, a network of protein molecules “spindle/fibres” extended from one side of the cell to the other. What occurs in late prophase the chromatids will move towards the spindle.
3.METAPHASE: chromatids are attached to the spindle fibre in the “middle”
4.ANAPHASE: the spindle fibre shortens pulling one chromatid one way and the other chromatid another way, they are moving apart, they move to the poles of the cell, separate pair of chromatids.
5.TELOPHASE: the nucleus begins to reform around the chromosomes at both ends of the cell, so we see the formation of 2 nuclei at opposite sides of the cell
6.CYTOKINESIS: the cell splits into 2 NOT PART OF MITOSIS, the cell moves inwards dividing the cytoplasm in half, resulting in 2 halfs, NB: the each have 1 chromosome (same as parental cell)
7.In humans we don’t see 1 cell dividing but 23 pairs separating at 1 time.
In this process it forms and identical copy of its cell, held together by the centrolmere“pair of chromatids” this takes place in the nucleus whilst it is still intact, it is called the “interphase” of the cell cycle
+ A chromosome contains thousands of genes
+ Looking at 1 gene loci you can magnify it to see a double helix - they apear parallel
+ Expanding more you can see the 2 sugar phosphate back bone sides and in between holding them together are the bases.
+ There are 4 types of bases: Adenine (A) Thymine (T) Cytosine (C) Guanine (G)
+ They are always found in DNA in pairs T-A G-C
+ On one side the order of them is ACTGAACCAG "order of bases" this is the order we call a gene
+ The gene is found in the nucleus of a cell: order of the bases and number of the bases = protein in cytoplasm -> characteristic.
+ A gene is a section of a molecule of DNA
+ Gene carries the information which forms the characteristic of the organism eg: petal colour, blood group
+ Located in the Nucleus the information is then passed onto the cytoplasm, transformed to protein - which controls characteristic.
+ Chromosomes are the genetic information within a cell.
+ Chromosomes have DNA which forms a shape called a "Double Helix"
+ Genes controls the production of protein which controls a characteristic eg: Blood type.
+ Each species has a different amount of chromosomes per cell: eg: Cat= 38 Chicken= 78 Chimp= 42 Human = 46
+ They operate in pairs "Homologous" -> based on the length
+ Looking at the same length place on each chromosome there will be the same gene loci -> same gene -> same place
+ Therefore there are two versions of each gene with 1 characteristic = Alleles
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+ Sexual reproduction: Show sex (genders – male/female)
Produce cells called gametes (male=sperm female=egg)
Meiosis- the type of cell division that produces gametes –effect: half the total number of chromosomes in the gamete cell (e.g. chromosomes. Humans: 46 per cell Gametes: 23 per cell, the process from going from 46 to 23 is called Meiosis.
Fertilisation (gametes cells from a male (sperm) fuse together with the gamete cell from a female (egg))
Broad variation (many differences in individuals of population)
+ Asexual reproduction:
DO NOT show sex (genders – male/female)
No gametes
Mitosis (in eukaryotic cells) /binary fission (in prokaryotic bacterial cells) cell with 20 chromosomes 2 cells (each with 20 chromosomes -identical)
No fertilisation (because no gametes)
Small variation – due to mutation (they are identical ‘clone’)
Quetion: What are eukaryotic cells and prokaryotic bacterial cells?
2.Feeding producer -> primary consumer takes in carbon from producer and uses it for growth -> secondary consumer (carbon passes down food chain) all levels send out co2 into the atmosphere through respiration
3.RespirationC6H12O6+02 -> break down enzymes in the cell releasing enegy+co2 +h20
Respiration adds co2 to the atmosphere
4.Decomposition.Death and the organic molecules that remain are broken down by decomposition organisms i.e.: bacteria, fungi
5.Combustionfossil fuels -> oils and coals after loads of years -> they are combusted to release c02
Industrial applications and motor vehicles are good examples of using combust fuel
It can also occur in the environment naturally: lightening striking vegetation resulting in land fires
a) UV light from the sun, has short wave length/high energy
b) 50% of this light is reflected back out to space causes= clouds
c) Absorption on earth surface- where UV is converted as infra-red
d) Infrared is shows longer wave
e) Lost to space as heat
F) Represents some of the green house gases such as water vapour co2 and methans ch4
g) The infrared light will hit green house gas will absorb this energy and then re emit it in all directions raising surface temp. Higher = green house effect
Enhanced green house effect – co2 and ch4 will absorb more escaping infrared and put it back to earth raising temps. Higher leading to climate change
CFC’s – well known for their effect in ozone layer
Carbon fluorine
Ccl3F ->sunlight – ccl3f +cl this breaks down o3 to o2, o3 is better at absorbing sunlight so we are taking that effect away.
+ Sulphur dioxide – SO^2 gas, Is added to the atmosphere when we have the combustion of fossil fuels in factories or vehicles, in atmosphere it combines with water vapour and forms sulphuric acid can be foundin clouds and when it rains it is called “acid rain” -> affects plants and animals
+Trees and plants are often burned by the direct sulphuric acid also sulphuric acid could be soaked up by the roots. Ca2+ and mg2+ then cannot be obtained by the root
+Acid rain in lakes and streams harms fish gills by thickening mucus from AL3+ O2 from H2O is reduced
+ Carbon Monoxide – produced when fossil fuels such as coal and gas are burned with insufficient oxygen.
+CO-> combines with haemoglobin in RBC forms carbamino haemoglobin the problem is that it blocks haemoglobin from carrying oxygen so therefore reducing oxygen circulation = toxic and too much can cause death
Bush Grass -> Impala -> Leopard -> Lion
Producer = light energy - > chemical energy - organic molecules = Carbohydrates, Proteins, Lipids
Which make bonds such as : C-H, C-O, C-C, O-H, C-N = energy
CHON= substances/matter contain energy
As each level of trophic gets eaten by the next level the energy is passed on - substances/ matter
+ Pyramid of Energy Producer = 100% -> primary consumer = 10% -> secondary consumer= 1%
eg: Grass -> Rat -> Owl 100kg -> rat only gets 10% of the energy because: Respiration, rat can't digest celulose, so it is lost in faeces.
+ Owl only gets 1% of energy because: respiration, and energy used in flight etc.
+ Eventually all levels die and are broken up by decomposers.
+ Producer -> 1 -> 2 -> 3 consumer = Basic/simple description on feeding in community.
+ Quantify Trophic Levels:
1. Pyramid of Number (count organisms at each level)
eg: 1000 leaves of carrot plant -> 100 carrot fly -> 10 fly catcher -> 1 sparrow hawk = *Pyramid* each level 1/10th of the size of the level before.
Problems: eg: 1 tree -> 100,000 Aphids -> 1000 Lady Birds -> 10 birds = In energy terms this is wrong, the size of tree to Aphids is wrong scientifically.
2. Pyramid of Bio Mass "living material mass"
Problems: Water level mass. Because this pyramid is based on "Dry Mass" = better understanding of mass of matter
Disadvantages: need to work out dry mass of each level which is very difficult.
Pyramid should be shown in units of mass kg/g or unit of area m2/km2
3. Pyramid of Energy (ideal)(transfer of energy from 1 level to the next)
+ cannot be inverted (put upside down)
+ This type of pyramid measures efficiency too. eg: Sun Light 100% = 10% producer = 10% efficiency
+ Requires unit of energy (J/ kJ)
+ unit of area (m2)
+ unit of time (secs/mins/years)
+ however it is complex and time consuming.
++ Pyramid of number = popular
inbetween- Biomass = hard
Pyramid of energy = hard and complex Progressing downwards in production of Pyramids.
+ Food webs allow us to provide a good description of the ecosystems -> composed of community of organisms which are communicating.
+ In this case feeding.
+ Advantages: shows feeding at different trophic levels:
+ 1. Oraganisms have multiple predictors
2. feeding on multiple prey
3. results in linked food chains
+ In this case the Hawk acts as both a secondary consumer and a tertiary consumer.
+ Food Chains = producer -> primary consumer -> secondary consumer -> tertiary consumer
+ Only 1 organism per trophic level
+ You cannot show organism as a omnivore, more than 2 trophic levels.
+ Food chains show the flow of matter and energy.
+ Sand dune: using the quadrate technique to sample the population of daisies
+ Sample must be random (not biased) and representative (large enough for estimate to be closer to the truth)
+ Draw simple grid -> take random numbers Eg: 3, 3 and draw your quadrate in that square. Then count the amount of daisies in THAT quadrate.
+ For the representative the bigger the better. Eg: ten quadrates would be sufficient = 10% of actual area would be better.
+ Make table of two columns 1. The quadrate number Eg: 1,2,3,4 then the second column for the number of daisies in that quadrate. -> Add up the number of daisies and divide by the no. Of quadrates = the value= No. of daisies per m2.
+ using this we can estimate the population in area. Or we could compare the no. of daisies in two different areas.
+ Looking at a Sand Dune Ecosystem- it is made up of a number of populations with format the community and the habitat
+ The Fence splits the sand dune into 2 regions, 1 side is grazed from cattle and the other side is not grazed.
+ Counting population has a technique called Quadrating.
+ Quadrates contain of squares 1m by 1m to take samples and we would count individuals inside 1 grid – repeat this a number of times to get an estimation of the population size
+ Quadrates are a method of sampling different locations so populations can be compared.
+ Ecosystem: Community of Organisms and Habitiat + Community of Organisms: -> Populations of different species -> number of individuals of a particular species -> oraganisms that reproduce to give fertile offsprin/ interacting -> feeding
+Habitat -> Abiotic 1. Daylight/dark 2.temperature 3. Rainfall4. Humidity 5. Slope of land 5. Geology = NON BIOLOGICAL
+ Anther -> Stigma using air, wind
+ Adaptations: 1. Light Pollen Grain (maybe wing feature?) 2. Anther will hang clearly sticking out on plant structure = exposed to the wind. 3. The Stigma will have a large surface area to catch the pollen as it travels in the wind.
+ Grass has no: colour, scent, nectaries, because it doesnt need to attract an insect - this would be a waste of energy.
+ The porcess of pollinating is where pollen from an Anther is transfered to another plants Stigma, this is done by insects.
+ Pollen contains male nuclei.
+ Plant -> Plant = cross polination.
+ For this process to happen the insect needs to be attracted : -Signals - coloured petals
-Scents
-Value for Insect = food, Necaries produce Fructose -> Pollen protein.
+ Parts of a plant: Male = Stamen : Anther, Filaments
Female= Carpel: Style (which connects) stigma, ovary - ovules
+ Pollen grain on the Stigma begins to germinate, a tube begins to grow joining the grain and the ovule, the nucleus travels down this tube.
+ Pollen nucleus fertilises ovule -> Zygote/ embryotic plant
+ The outside of the ovule forms Seed coat : Testa
+ Also, inside the Ovule there are food stores inside seed called : Cotyledons
+ There is also thickening of walls of Ovary, includes sugars, proteing. forms fruit by wall of ovary/carpel.
+ Geotropic the word split up means:Geo =Gravity Tropic = Growth Response
+ Positive Geotropism = Embryotic root growing towards the stimuli (source)
+ Negative Geotropism = Embryotic root growing away from the stimuli (source)
+ When rotated it will cange direction, growing either upwards or downwards
+ Stimuli are changed in the environment by for example: Gravity, Light Chances or Temperature
+The plant has Receptors which can detect the stimuli
+ This is then turned it into a Response,
+ Which is taken the form of Growth (Tropism)
+Tropism (light) called Phototropism.
+Tropism (gravity) is called Geotropism
+ Tropisms might include mitosis and cell elongation.
+ Evaporation of water (liquid -> gas) needs heat. This heat is produced by sunlight as absorbed by leaf structure through the stomatle pores. + water goes up the the roots, up the plant structure to the leaf, this is where eveaporation happens. + Looking at a cross section of the leaf: not all light is absorbed by the chloroplasts some generates heat. + Just above the stomatle pores, phase change occurs (liquid -> gas) = evaporation + water vapor gas diffuses down through pore, which has a steep diffusion gradient.
Thursday, March 10, 2011
A potometer is used to measure the rate of water uptake up a leafy shoot.
+ Root Structure has a branching pattern, this increases SURFACE AREA and the ABSORBTION OF WATER.
+ the Root has ROOT HAIR, contains of epidermal cells (surface)
+ the ROOT HAIR activly concentrates minerals, inside the root. This encourages the take of water by OSMOSIS.
+ OSMOSIS = dilute region -> concentrated region
+ water then travels from the ROOT to the XYLEM also using OSMOSIS.
