2.75 Urine

Urine contains:
-Salts (Affects the composition of the tissue fluids = osmoregulation)
-Water (same as salts)
-Urea (Part of excretion of metabolic waste)

2.74 ADH - Anti Diuretic Hormne

-This hormone is produced in a region of the brain called the Hypothalamus
-Like all hormones it flows through the blood streams and its target is the kidney
-The effect of ADH is to control and alter the quantity of water in blood
-The tissue fluid is isotonic with the cytoplasm of the cell (role of ADH)
- ADH actually targets collecting ducts
-ADH allows more water to go out of the collecting duct
-ADH makes the collecting duct walls more porous (more water can escape)
-The water goes back into the blood
-The consequence is that the urine is more concentrated and it has a lower volume.

Extension:
Hot day = more ADH (sweat)
Cold day = less ADH (not as much sweat)
Dehydrated= more ADH (body needs more water for it to work)

2.73 Glucose re-absorbtion

-Glucose is selected to be put back into the blood
-Filtration happens in the bowman's capsule
-Urine does not contain glucose
-If there is glucose in the urine, the person might be suffering from diabetes
-In the first tubule (PCT) glucose is removed and put back into the blood

2.72 Water re-absorbtion

-When ultrafiltration happens there is too much water is filtered
-Water is removed from the filrate when it passes through the collecting duct
-Then it is returned back to blood vessels
-it goes back into the blood stream.
-The water has been selected and has been reabsorbed into the blood
-This is called "selective re-absorption" (of water)

2.71 Ultrafiltration

The filtration of the blood happens in the nephron
The filtration makes 2 products:
-Clean blood
-Waste/Urine
urine= water&salts&urea

-The filtration process begins in the Bowman's Capsule
-The filtration of blood begins when the blood comes in (high pressure) from the afferent arteriole into the kidney
-The blood vessel starts too branch off in a twisted and coil structure know as the glomerulus.
-The diameter of the Efferent arteriole is a lot smaller than the Afferent arteriole.
-This leads to high preassure
-The plasma (Water, salts, amino acids, glucose & urea) is forced out of the blood vessel and into Bowman's Capsule
-This is called glomerular filtrate

2.70 Nephron Structure

2.69 - Urinary system

Urinary system has:
-2 Kidneys (Each with its separate blood supply. Conducts excretion, filtration and osmoregulation)
-2 Ureters (Carries urine from the kidney to the bladder)
-1 Bladder
-Urine is carried down the urethra to the outside of the body

2.68 - Excretion & Osmoregulation

EXCRETION


Kidneys excrete urea
-Urea contain nitrogen
-Nitrogen is toxic to the body and cannot be stored
-Amino acids contain nitrogen
-Amino acids are used for growth but excess amino acids must be removed because they are toxic.
-Removing the excess amino acids is the job of the liver and the kidneys


1) Blood circulates to the liver and the amino acids are broken down and are converted to urea
2) This reenters the blood stream and to be removed from the body it circulates to the kidneys
3) The kidneys filter the urea from the blood and water will be added to the urea and forms urine.
4) Urine drains down the uriters to collect in the bladder.
Urea is now in the bladder in the form of urine. (Removed from the body)

OSMOREGULATION

Osmo = Osmosis
Regulation = Control


-The tissue fluid which surround the cells must be isotonic with the cytoplasm of these cells (Amount of water in&out is =. The cells will remain the same size/shape and maintain their function)
-The danger to the tissue is that blood circulating into the tissue would be concentrated causing a hypertonic tissue fluid or it may be very dilute causing a hypotonic tissue fluid (Both of these are undesirable) 


We want to keep the tissue fluid isotonic to the cell cytoplasm.
This is achieved by controlling the composition of blood. blood forms the tissue fluid.
It is the role of the kidney to control the composition of our blood.
Blood which circulates through our kidney
Excess water and salts can be removed and excreted through the ureter to control the composition of the blood and this means that the tissue fluid could be kept isotonic with the cells cytoplasm.

2.67 - Excretion

a) In plants:

1) Photosynthesis =absorbing light energy
CO2 + H2O --------> C6H12O6 + O2
O2 is the waste molecule, the release of metabolic waste is an example of excretion

2) Respiration
C6H12O6 + O2 ---------> ATP + CO2 +H2O
The CO2 is also metabolic waste so plants excrete:
-Oxygen
-Carbon Dioxide

b) In Humans (Human organs of Excretion)

1) Lungs - excretion of metabolic waste = Carbon dioxide
2) 2 kidneys - excretion of excess water, urea(nitrogen wastes from amino acids) and salt
3) Skin - mostly water and salts and a bit of urea

3.34 - Causes of mutation

Mutation is a change in base sequence and is caused by two things:

1) Radiation
           -Ionising radiation (gamma/X-rays)
           -Sunshine (UV-B), which causes skin cancer
2)Chemicals - Mutagens
chemicals which cause mutation are called Mutagens
chemicals which cause mutation and cancer are called Carcinogens
eg: Tar in tobacco (also causes cancer)

3.33 - Antibiotic resistance

Staphylococcus Aureus can be treated with an anti-biotic called methacilline, this cures SA in its susceptible form (MSSA)
However, through random mutation there is a type of SA that doesnt die when given methecilline, this type of mutation is the resistant form of SA (MRSA)

3.32 - Types of mutation

There can be 3 types of mutation:
-Harmful (Creates and enzyme that doesnt work - non-functional enzyme)
-Neutral (no apparent effect)
-Beneficial

Over time the neutrality can become either beneficial or harmful depending on the enviromental change

3.31 - Evolution

Evolution:
-Change in the form of organisms
-Change in the frequency of alleles
Natural selection is a mechanism of evolution and was first proposed by Charles Darwin

3.30 - Mutation

-Certain processes/events result a change it the base sequance (ACT --> AAT)
-this change creates a new version of the allele
-This allele can produce an entirely different protein and a different effect on the phenotype (Big A, Little a)
-The reasons why different alleles exist is because of the process known as mutation
-Mutation changes the base sequence

3.29 - Species Variation

Variation = Differences in phenotypes (how things appear)
possible to count/measure these differences in graphic form

These variation of species depend on the species genotype and  environment

3.21a/b Genetic Probability

3.21a - RR x rr

3.21 b - Rr x Rr

3.20a/b - Pedigree Diagrams

3.18c - Co-dominance

3.19a/b Crosses

3.19a P1 x P1

3.19b F1 x F1

3.18a/b - Phenotypes/Genotypes

3.18a - Phenotypes:

3.18b - Genotypes

Genetics

3.9 b - Female reproductive system

3.9 a - Male reproductive system

3.12 - Amniotic Fluid

Between the uterus and the embryo there is amniotic fluid to protect the embryo
-this is because it cant be compressed and any blows/force to the uterus wall will be absorbed by the amniotic fluid and therefore protect the embryo

3.11 - Placenta

-An unborn child is in the uterus and he/she is surrounded by amniotic fluid
-at this time the child can not digest/breathe or excrete.
-So to obtain nutrients from the placenta (from the mother)
-The placenta grows from the embryo and the arteries/veins are the ones from the baby
-The placenta grows into the wall of the uterus
-In the bloodstream of the mother there is glucose amino acids and fats, this will flow into the wall of the uterus and cross into the childs blood(at the placenta)
-The placenta has a large surface area and the walls are thin to facilitate the statement above
-Carbon dioxide and urea is exchanged back into the blood of the mother

Animations for mitosis

Examples of mitosis:
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__mitosis_and_cytokinesis.html

http://cellsalive.com/mitosis.htm
Video of mitosis


Another mitosis video in 3D

3.24 - Mitosis

a) Outline/summary
number or chromosomes in neucleus = diploid number (2n)
in humans 2n=46
in cats 2n=38
In the process of mitosis a cell divides into 2 identical cells:
                        -they have the same number of chromosomes
                        -same set of chromosomes
Each new cell has a diploid nucleus


b) Details
Copying the chromosomes is a process called DNA replication
-Each chromosome undergoes a copying process to form an identical copy of itself (same genes)
-These 2 copies are held together by the structure around the centre region, know as the centromere
-These are known as a pair of chromatids
-The process (DNA replication) takes place in the nucleus (the process cant be seen because the nucleus stays intact). this is know as the interphase


c) Stages of mitosis
We would normally see that the nucleus has a spherical structure if we looked at it down a microscope and we would be unable to see the chromosomes.
It is during that interface that DNA replication occurs
Prophase- The membrane breaks down and the chromosomes (pair of chromatids) can be seen. each chromosome got copied

The nucleus is gone and there is a network of protein molecules inside the cell called a spindle
-These go from one pole of a cell to the other
-The pair of chromatids will join on one of the spindles fibres at the centromere

Metaphase: When the pair of chromatids are attached to a spindle fibre by the centrometer
-The chromatid is in the middle across the equator of the cell

Anaphase: the spindle fibre shortens pulling one chromatid in one direction and the other chromatid in the other direction. This pulls the chromatides to the poles of the cell.
-This seperated the chromatids

Telophase: Nucleus begins to reform around the chromosomes at either end of the cells (new nucleus of the new cell)
We see the formation of 2 nuclei at opposite ends of the cell

Cytokinesis: The cell splits into 2 (not a part of mitosis)

3.16 - DNA, nature of genetic code

DNA is shaped as a double helix, they appear to be parrallel
In the center there are bases:
-Adenine (A)
-Thymine (T)
-Cytosine (C)
-Guanine (G)
These molecules hold the two helices together, they are held together by bonding:
A - T
C - G
The base pairs hold one side of the helix to the other

the order of the bases (the gene): ACTGAACCAG

3.15 - Genes

Genes: A section of a molecule of DNA
The gene is the characteristic of an organism
Genes are located in the nucleus
The information is then passed to the cytoplasm, the genetic information is transformed into a protein.

3.14 - Chromosomes

Chromosomes: genetic information within a cell
Chromosmes is composed of a molecule called DNA
DNA has a shape known as the double helix
section's of DNA are called genes, a chromosome is composed of 1000's of genes (DNA = 3.15)
each gene has the information for the construction of the protein (see 3.16)
The protein gives the characteristics associated with the gene (eg. Blood group)

Different organisms have different numbers of chromosomes (eg cat = 38, chicken = 78, chimp = 42, humans=46 chromosomes per cell)
Chromosomes are known to work in pairs (homologous pairs)

(3.17)

3.1 - sexual and asexual reproduction

4.9 -carbon cycle

1) Photosynthesis (CO2 + H2O -----> C6H12O6 + O2)
CO2 comes from the atmosphere (0.03%)                        This reduces the atmospheric CO2

2)Feeding 

• Produce ------> Primary consumers (Takes carbon from the producer for growth) -------> Secondary consumer (Same thing happens)
• The Consumers and producers respire, which sends CO2 into the atmosphere

                                                  Enzyme
3) Respiration (C6H12O6 + O2 ------->Energy + CO2 +H2O
                                                     Adds CO2 in the atmosphere

4) Decompostion:

• Eventually the producers & Consumers will die and will be decomposed (broken down) by bacteria and fungi (Decomposer Organisms)
• Releases CO2 back into the atmosphere

5) Combustion:

• Fossil fuels formed over millions of years (animals and plant materials) = oil/coal
• These are combusted to form CO2
• Best examples = Industrial applications and motor vehicles (cars, trucks, airplanes)
• But it can also be combusted naturally = lightning striking vegetation (forest/grassland fires)

4.14 - Enhanced Greenhouse Effect

Infrared light is re-emitted backwards to the surface
-the consequence is the increase of the average global temperature (Global warming)

Global Warming:
Consequences:
-Melting ice caps
-Rising sea levels
-Ocean currents change (Also effects how wind is generated)
-Climate change
-Changes in the distribution of the worlds Biomes
-Deserts would expand

4.13 - Greenhouse Gases

The burning of fossil fuels result in formation of:
CO2
NO2     these are the greenhouse gases
SO2

The things that produce those gases are:
-Industries
-Cars
-Domestic coal burning
-Farming,
Cows emit methane gas to the atmosphere (9% of total gases)

Clouds also contribute to the greenhouse effect (see 4.12)

CFC catalyses the brake down of the ozone layer

4.12 - Greenhouse Effect

CFC are the main gases that effect the ozone layer

4.11 - Gas pollution

Sulphur dioxide (SO2) is a gas that is added to the atmosphere when there is the combustion of fossil fuels:
-In factories (fossil fuels being burnt)
- From cars (let out SO2)

SO2 + H2O ----> Sulphuric acid
this combines to make clouds and creates acid rain.

Acid rain affects plants and animals:
-Trees are burnt by the direct effect of the acid
-Plants don't absorb Mg or Ca so the plants suffer of chlorosis
-The precipitation will produce streams and then go into lakes which makes the lakes more acidic and it makes aluminium
-The Al causes a thickening of the mucus on the gills. this reduces the fishs ability to take in oxygen from the water (kills the fish through suffocation)

Carbon Monoxide
This combines with the haemoglobin inside red cells and forms carbaminohaemoglobin. This blocks the hemoglobin from carrying oxygen.
This reduces the oxygen circulation. Too much Carbon monoxide can be fatal.

4.7 - Energy efficiency

Out of 100% of energy only 10% makes it to the next trophic level (primary consumer)
And only 1% of that makes it to the secondary consumer

The loss of energy is because the organism needs to:
-Respire
-Grow
-Move
Another reason for the lost of energy is that, for example:cellulose, cannot be digested so the energy is lost through faeces.

4.6 - Transfer of substances and energy along the food chain

-Producer (grass) - Transfers light energy (from the sun) to chemical enegry
-Chemical energy = organic molecules
                             - This includes carbohydrates, protein and lipids (food)
-These molecules and up being food for the primary, secondary and tertiary consumers
-The energy consumed is used for:
                                                   -Growth
                                                   -Respiration
                                                   -Life processes

Bonds:

4.5b - Food Webs

1) The food web provides a better description of the ecosystem.
2) The food webs shows organisms feeding at different trophic levels

Consequences of (2):
1.Organisms can have multiple predators
2.It could be feeding on multiple pray.
3.This results in the food chain being linked

4.5a - Food Chain

This links together {{ Producer ----> Primary consumer ----> Secondary consumer ----> Tertiary consumer}}

-You cant show an organism being an omnivore
-You cant show organism feeding at more than 2 trophic levels

Food chains shows the flow of matter and energy

4.4- Trophic Levels

Trophic = feed
trophic levels = feeding levels

Primary consumer: Eats the producer (producer = changes light energy to chemical energy)
Secondary consumer: Eats the primary consumer (turns the energy to its own)
Tertiary consumer: Eats the secondary consumer (turns the energy to its own)

4.3 Quadrates samples

-Use quadrates to sample the population
The samples have to be:   -Random
                                       -Large
                                       -Random number (for the grid, x & y coordinates)
                                       -Count the number of daisies (species) in one of the squares
                                       -That ='s 10% of the original area.

4.2 Quadrates

Quatrating:
1. Count the number of individuals in the population
2. Quadraring is used to sample an area and count the number of individuals in that area
3.This is repeated a number of times to gain an estimate of the population size

(quadrating is a method of sampling different locations to compare them)

4.1 Ecosystems

-An ecosystem is a community of organisms in a particular habitat

-The community is made up of different population of different species interacting within that habitat.

Species = A group of organisms reproducing to give fertile offspring

Habitat (abiotic factors):

-Cycle of daylight

-Temperature

-Rainfall

-Humidity

-slope

(All are non-biological)

Different types of seeds

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