2.75 Urine

• urine conatins: salts, water, urea
• salt and water affects the composition of tissue fluid called osmoregulation
• the removal of urea is part of the process of the excretion of metabolic waste.
• the composition of urine varies on the conditions in which a person is operating

2.74 ADH

• ADH - Anti-dirretic hormone
• it is produced in the hypothalamus region of the brain
• it flows through the blood as the kidney as it's target
• ADH has the ability to make the blood more or less concentrated
• ADH targets the collecting duct, and makes it possible for more water to be absorbed through the collecting duct (2.72)
• it makes the walls more pours, allowing more water to pass
• the consequence of this would be that the urine would have a smaller volume and a higher concentration

How does ADH react with:
a hot day -


a cold day -



dehydration -

2.73 glucose reabsorbtion

• selective reabsorbtion - the molecule is selected (glucose) and put back into the blood
• filtration occurs in bowman's capsule
• Gluscose was one of the filtrates taken out of the blood.
• Urine does not usually contain glucose (urine containing glucose is usually diagnosed as diabetes)
• But the reason why glucose is present in the urine after being filtrated out of the blood is because in the proximal convoluted tubule section glucose is removed and taken back into blood
• so glucose is reabsorbed into the blood in the PCT

2.71 Ultrafiltration

• The nephron carries of the filtration of blood which results in filtered blood (clean) as well as waste represented by urine.
•The urine will emerge from the end of the Medulla and carry on into the pelvic region.
• urine contains water, salts and (urea)
• The filtration begins in the bowman's capsule.
• First the blood arrives in the kidneys through the afferent arteriole with HIGH pressure.
• It continues into a twisted part in the arteriole called the glomerulus (inside the capsule)
• Then the blood exits the capsule out of a smaller arteriole than the Afferent called the Efferent
• The blood pressure increases in the glomerulus
• The high pressure forces plasma (water, salts, amino acids, glucose and urea) out inside the blood.
• These are forced into the inside of the bowman's capsule
• When the plasma is forced into the capsule we change the name of it to glomerula filtrate
• so the blood has been filtered by pressure due to the smaller blood vessel generating a high pressure forcing the liquid into the tube

2.70 nephron structure

• The Aorta has blood taken into the kidney through the the renal artery
• the kidney filters the blood and the urine (as waste) goes down the ureter to the bladder for storage
• The filtered blood exits through the Renal vein to the Vena Cava

structure of kidney:
- cortex is the outer region (light brown)
- Medulla is the inner region (dark brown)
- pelvic region is the space, from where the urine moves into the ureter

the reason behind the different colours is because the kidney is made up of millions of tubes (Nephrons)
• the tube starts on the edge of the medulla and moves out into the cortex, where it has a little twisting section (convoluted tubules), then dipping back down into the medulla (the dip is known as a loop of Henle)and repeating until coming to a dead end.
• the dead end is known as a bowman's capsule
• The tight knot of blood vessels inside the capsule is known as a glomerubus
• The first convoluted tubule after the capsule is known as the proximal.
• the second is known as a distal (dct)
• The nephron structure gives the different colours to the kidney

2.69 urinary system

• in the urinary system we have a left and right kidnney
• there is a tube for each kidney that leads to the bladder, called the ureter
• then the urine travels out through the urethra

2.68b Osmoregulation

• the water coming into and out of the cells (which is isotonic) remains the same so the cells stay the same size
• the blood circulating into the tissue would be concentrated causing a hypertonic or hypotonic (dilute)  which are both undesirable as hypertonic would remove too much water and hypotonic would add too much water
• this is achieved by controlling the composition of the blood the kidney controls the composition of blood
• the excess salts and water can be excrted through the urintary
• by controlling the salts and water the kidney can keep the blood and therefore the water stays isotonic

2.68a excretion

• urea contains nitrogen which is toxic
• amino acids (that are used for growth) contain nitrogen but excess AA have to be excreted
• the amino acids circulates to the the liver and urea comes out which re-enters into the bloodstream which circulates to both kidneys so that the kidneys can filter the urea from the blood which is added to the water to create urine which circulates to the bladder.

this is an example of excretion.

2.67b human organs of excretion

1. Lungs
• carbon dioxide is the waste of respiration (excretion)

2. Kidneys
• responsible for excretion of excess water, urea (amino acids) and salts

3. skin
• excretes water, salts (in sweat) and a little bit of urea

2.67a excretion in plants

 1.
• photosynthesis - light being absorbed into the leaf = CO2 + H20 -> C6H12O2 + O2
the O2 is the excretion here
2.
•respiration - C6H12O2 + O2 ->(enzyme) A.T.P + CO2 + H20
the CO2 is the excretion here

3.34 causes of mutation

• radiation can cause changes in genes such as x-rays, sunshine (ultraviolet). sunshine can for example cause skin cancer
• second way it can be mutated is by chemicals like tar that can cause cancer. These chemicals that cause mutation are called mutagens and ones that inflict cancer as well are called carcinogens

3.33 antibiotic resistance

3.32 types of mutation

• gene --->(mutation) new allelels, which can beneficial or harmful, or have no affect (neutral)
• a beneficial enzyme might be the efficiency of an enzyme
• a harmful enzyme might be a non functional enzyme
• a neutral enzyme would have no particular effect, but in time (depending on the environment) it would become a beneficial or a harmful enzyme

3.31

• evolution: is the change in the new forms of organisisms
  as well as: change in the frequency of alleles
• natural selection: the mechanism of evolution

staphlococcus aureus: causes skin infections and lung infections, associated with infected wounds, in particular wounds in operations

the original form of staphlococcus aureus is susceptible to methecilline (antibiotic)
MSSA (methecilline susceptible to staphlococcus aureus): 100% in the original form

a random mutation was able to break down methecilline, making it resistant towards the antibiotic, which keeps on increasing (the allele that can resist the antibiotic is increasing and becoming more common).

• Random muation (the MRSA form)
• non-random selection (antibiotic)

these 2 components are features of natural selection
natural selection is a process, not a thing

3.30

• Form of the gene is called the allele
• the base sequence changes so a new allele is created which might mean the production of a completely new protein, having a different effect on the phenotype
• Different alleles exist because of mutation which changes the base sequence of a gene

3.29

(differences in species' appearances)
• The phenotype of an individual is different because of their genotype which varies as a result of the varying environment
• 1 variation: In the first graph everyone falls into classes as a result of the variation of the genotype (nothing to do with the environment) e.g. blood groups. this is called discontinuous variation
• 2 variation: The variation in graph to is caused by the genotype AS WELL as the environment e.g. height. someone might inherit tall genes from their parents but the environment would always play a role in their height as well as their diet. this is called continuous variation
• 3 variation: the variation in a population is completely caused by the environment (no genotypes involved) e.g. the language spoken. this cannot be inherited

3.21b

3.21a

3.20b

3.20a

3.18c

3.19b

3.19a

3.18b

3.18a

2.4

Animal cell uncludes:
• Nucleus
• cytoplasm
• cell membrane

- stores CH as glycogen

Plant cell include:
• nucleus
• cytoplasm
• cell membrane
• central vacuole
• chloroplast
• cell wall

- more regularly shaped
- stores CH as starch

3.12

• During pregnancy the uterus is filled with a fluid called the amniotic fluid, which is mostly made out of water
• It protects the developing embryo
• The fluid prevents damage to the unborn child by absorbing forced pressure

3.11

• The uterus and the placenta come together for the exchanging of nutrients that the baby needs to develop
• The uterus is filled with amniotic fluid when the baby is inside the uterus
• the child cannot digest food and cannot breath, as well as not being able to excrete.
• The placenta does not grow out of the mother but from the embryo.
• The blood vessels inside the placenta belong to the baby.
• The placenta grows into the wall of the uterus.
• At the placenta all the nutrients cross over into the babies blood stream
• to make this effective the placenta has a large SA
• There is a very thin barrier between the babies and the mothers blood

3.9 b

Female reproductive system
• before pregnancy the uterus is quite small, no bigger than an orange

3.9 a

male reproductive system

3.24c

• the first sign of the chromosomes splitting is when we see the nuclear membrane start to break down' and the chromosomes become visible as a pair of chromotids
•this is known as 'prophase'
• with the nucleus gone a network of protein molecules called 'spindle' which extend from one pole of the cell to the other
• what happens is the chromotids connect to one of the spindles called 'metaphase'
• the chromosomes are in the middle of the cell (at the equator)
• anaphase - the fibre shortens pulling one chromotip in one direction and the other one in the opposite direction and the pair separates and move towards the poles of the cell
• telophase - the nucleus begins to reform at either end, creating two new cells
• cytokinesis - the cell finally splits into two (NOT REGARDED AS PART OF MITOSIS) now both cells include one chromosome.
• in human cells we see 23 cells cells seperating instead of two

3.24b

details of mitosis
• copying chromosomes is called TNA replication.
• here each chromosome undergoes a copying process to produce an identical copy of itself
• these two copies are held together by the centromere.
• we refer to the the pair as a 'pair of chromatids'
• there is also a process called interphase (that we cannot see) that separates the pair

3.24a

outline of the process of mitosis:
- the number of chromosomes in the cells nucleus is known as the 'diploid' number (abbreviated 2n)
for humans 2n = 46
for cats 2n = 38

• mitosis will make the cell divide in two, each with it's own nucleus. these cells are described as identical, daughter cells
• each of these cells has a diploid nucleus
• the cells have the same number of chromosomes as well as the same set of chromosomes
• this means that if we take a chromosome from either cell and you will find an identical chromosome

how are the copies of chromosomes made? and how to they separate?

3.16

• 1 chromosome = 1000 genes
• if you magnify 1 gene loci you find a double helix (genes are parallel)

• when magnifying it even more you can see that there is what we call a base holding them together
• four different base types: Adenine (A) Thymine (T) Cytosine (C) Guanine (G)
• base types are always found in pairs T-A G-C T-G
• one side of the chromosomes has a ACTGAACCAG order to the bases which we call a gene

3.15

3.14

• chromosome - the genetic data inside a cell which is in the nucleus (brain) of the cell
• chromosomes are made up of DNA molecules which come in a helix shape
• a section of DNA is called genes
• depending on what kind of organism you are, the chromosome count in your body will be different
• chromosomes function in (homologous) pairs, which means that if you took a gene on one chromosome (called gene loci), and when you would go to the corresponding gene on the opposite chromosome, it would be the same gene
• therefore we have 2 versions of each gene, called alleles

3.1 sexual and asexual reproduction

• Organisms that show sexual reproduction show sexes (male/female). No sexes exist in Asexual reproduction.
• Sexual reproduction has Gameke cells in the sperm and egg cells. Asexual does not have Gameke cells.
• Meiosis is a cell division that produces Gamekes. One of Meiosis' effects is to half the number of chromosomes in the Gameke cell. 
•  Total number of chromosomes in a human is 46 per cell. In Gamekes the total number is 23 per Gameke cell. From 46 to 23 is the process of Meiosis.
• In Asexual reproduction there is Mitosis and Binary fission bacterial cells. Number of chromosomes is maintained constantly.
• In Sexual reproduction there is the process of fertilisation, where the sperm cell and egg cell fuse together. In Asexual reproduction there is no fertilisation and no fusion of cells.
• Many differences in the individuals of a sexual reproducing population. Where as Asexual show a small amount of variation, mainly identical (clone).  

credit to samir

4.14

• the uv light passes through the atmosphere, reflects of the surface of the earth
• greenhouse gases reflect light back down, results in increased temperature, and climate change consequently

consequences:
- ice caps melting
- rise in sea level
- change in ocean currents
- change in the way winds are generated
- distribution of the worlds biomes changes (major vegetational ecosystem)
- rise in temp

4.13

how human activity adds to the greenhouse effect:

• burning fossil fuels (as well as cars, factories) leads to more CO2,NO2,SO2
• farming (cows) cause methane (CH4)
• evaporation of water -> water vapour (clouds)
• refrigeration/ solvents/ propellants
--> CFC chlorine, fluorine, carbon C(CL3)F

4.12 - green house effect

4.11

• combustion of fossil fuels (as well as vehicle combustion) gives off sulphur dioxide (SO2)
• When the SO2 combines with H2O in the atmosphere, sulphuric acid is made which leads to acid rain.
• Trees and plants are affected by the acid rain by getting burned
• Ca2+ and mag 2+ are leached from the soil, meaning plants cannot obtain calcium or magnesium that they need to grow
• the ph of lakes is reduced which releases Al3+ ions, which means more fish die. The aluminum forms as a mucus to the fishes gills which decreases the ability for oxygen to get in


• Fossil fuels are burned with an insufficient amount of oxygen resulting in carbon monoxide
• Carbon monoxide is toxic as it attaches to your haemoglobin cells inside your red blood cells which blocks oxygen getting around your body
• does not smell, cannot be seen, can lead to death

4.7

• A pyramid of energy is used
• Reasons for loss of energy:
- respiration
- excretion (energy which has not been able to be digested)
- heat loss
• Since the mouse can only use 10% of the energy from the producer, this would suggest that the owl can only use 1% of the energy it gets from eating the mouse
• When the organisms eventually die, when they will be broken down by micro organisms, which are called decomposers

4.6 : Energy and substances in food chains

producer = Bush grass
primary consumer = Impala
secondary consumer = Leopard
tertiary consumer = Lion

• producer converts light energy into chemical energy
• CE takes the form of different organic molecules such as:
- carbohydrates
- proteins
- lipids

These molecules (called food) consist of
C-H
C-O
C-C
O-H
C-N
bonds
• These bonds represent energy and carbon, hydrogen, oxygen and nitrogen are the matter(substances)

• The substance (the energy in the bonds) is passed down at each stage in the food chain

4.5a: Food chain & 4.5b: Food webs

• Producer -> Primary Consumer -> Secondary Consumer -> Tertiary Consumer

• Only one organism per trophic level
• In a food chain you cannot show an animal as an omnivore (eating at more than one level)
• food chains show the flow of matter and energy

• provides us with a better description of the ecosystem (in this case, feeding)
• Can show feeding at different trophic levels. This can have consequences:
- multiple predators
- feeding on multiple prey
-results in food chains being linked

4.4 Trophic levels

• Trophic = feed


For example: 
A carrot plant (producer) is doing photosynthesis, turning light energy into chemical energy


The carrot fly (a herbivore) is eating the carrot plant, which is called a primary consumer. It takes in the CE of the plant and turn it into CE of the fly


The fly catcher eats the carrot fly (a carnivore), a secondary consumer. It changes the CE once again from one form to another


The sparrow-hawk (top carnivore) eats the fly catcher, a tertiary consumer. It changes the CE again to suit itself


• All these die at some point, where decomposers break the molecules into nitrates and phosphates
• examples of decomposers: fungi, bacteria

4.3: Quadrates samples

Describe the use of quadrats as a technique for sampling the distribution of organisms in their habitat



• The quadrat sample that you take has to be random so there is no bias, and has to be representative (large enough) so that the estimate is as close to the true population as possible
• A grid system would be set up across the field. There would be an x and y axis, as well as numbers running across the sides of the graph
• Then random numbers would be generated for the x and y coordinate so we know where we want to place our quadrat
• Then we would count the number of whatever species we are counting.
• Your representative sample would be ideally around 10 quadrats or 10% of the whole area.
• The number of that species would be recorded into a table, then


   total of species        = number of species/m²
number of quadrats 

4.2: quadrates

recall the use of quadrats to estimate the population size of an organism in two different areas



• The sand dune ecosystem: it is made up of a number of different species of population which form the community of the ecosystem (and the habitat).
• There is a fence that splits the area in two: an ungrazed area and a grazed area (grazed by cattle and agriculture).
• quadrating: counting the size of a population.
• The quadrat is a square (0.5mx0.5m) and used to sample different areas of the land, and gain an estimate of the populations size.
• This way populations between two different areas can be compared.

4.1: Ecosystems

Understand the terms: population, community and ecosystem.




Ecosystem
An ecosystem is a community of organisms in a certain habitat

Habitat
(abiotic factors)
eg sunlight, temperature, rainfall, humidity, slope of the land, geology
note they are all non-biological

Community of organisms
made up of a population of varying species which interact with each other

Population
Number of individuals of a specific species

Species
Organisms that reproduce and make offspring

plant fertilisation - continued

in the picture below, on the very left after all the ovarys have fertilised, the stigma and the style degenerate since they are not needed any more.

after this picture, the fruit gets eaten by an animal, which excretes out the seeds with its feces, which means the seed gets the necessary nutrients to grow.

in these two pictures you see that the seeds are in the middle and the fruit outside is due to the plant sending sugars around the seeds. Note where the style and stigma have degenerated (bottom part on the red apple)

credits to savannah and harriet for the two last pictures

3.4 PLant fertlisation

• pollen grains grow all the way down the stigma, making a pollen tube
• the nucleus travels down the tube and into the ovule

A number of things will occur:
1. Ovule will fertilise that leads to formation of zygote that grows into a embrionic plant
2. Oustide of the ovule: seed coat (TESTA)
3. Formation of cotyletons (food stores for seedling)
4. Thickning of the walls of the ovary, putting things like sugar, protein that will create fruit

3.3a insect pollination & 3.3b wind pollination

• PLant sex = pollen grain (contains male nuclei) transfers from the anther of a plant to the stigma of another plant
• Insect gets attracted to a plant because of its nectar and colourful petals. Then some pollen grains get stuck on it, and as the insect goes to another plant the pollen grains transfer into that plants stigma
•There are 2 reasons why insects are attracted to plants
- Signals: SCENTS AND COLOUR PETALS
- Value: POLLEN (source of protein for insects) AND FOOD (nectaries produce fructose)



• The pollen is transfered by wind into the air from the anther to the stigma
• features of wind pollination:
- light pollen grain (wing features, which allow to move through the air efficiently)
- tall anthers so they are exposed to wind
- stigmas have large SA, and feather like surface so it can catch pollen easily
• The plant has no colours or scent to attract insects as it uses wind as its only transport for the pollen
• It would be a waste of nectar, since all the pollen is wind pollinated, so it it focuses all its energy on making pollen.

Flowers

2.81 Phototropism

• phototropism = growth responses towards light
• If light is coming from all directions, the stem will grow upwards
• If the light is coming from one side (lateral light source), the stem bends towards the light
• The light on one side causes the movement of auxim (plant hormone), which causes the bending of the stem

2.80 geotropism

• geotropism = growth responses to gravity
• positive geotropism = when the stem of a seed grows downwards
• negative geotropism = when the stem of a seed grows upwards
• If you were to rotate the seed, the negative geotropism grows upwards, and the embryonic root will grow downwards showing positive geotropism.

2.79

• stimuli - changes in the environment, temeperature changes, light changes
• Receptors detect these stimuli, which makes it respond
• Responses are usually growth (tropism) e.g. the response to light being stimulated would be called phototropism
• A response to gravity is called a geotropism
• Connection between receptor and response is usually plant hormones (plant growth regulators) e.g. auxin

2.54 Transpiration

2.54 Transpiration
• Where water turns from a liquid into a gas, which requires heat
• Heat is supplied by sunlight
• Evaporation (liquid to gas) happens through the stomatal pores in the leaves
• Water vapor gas diffuses through the stomatal pore into the atmosphere

potometer

A potometer is used to measure the rate of water uptake of a plant

2.53 Root Structure

• The root structure has a branching pattern which increases the amount of water absorbed and the surface area of the root.
• There is a root hair in the root that contains of epidermal cells (surface) 
• the root hair concentrates minerals inside the root, which encourages the take of water by osmosis
• osmosis = water enters dilute region and goes to the epidermal cell, concentrated region
• Water travels from the root to the xylem using osmosis