2.75

recall that urine contains water urea and salts
two kidneys filter.
urine collects in bladder
urine contains salts and water and urea
osmoregulation
removal of urea is excretion of metabolic waste.
variable

2.74

describe the role of ADH in regulating the water content of the blood



ADH - Anti - Diruetic - Hormone
flows through bloodstream, aimed at the kidney, specifically the collecting duct
ADH has ability to make blood more/less concentrated.

2.73

understand that selective reabsorption of glucose occurs at the proximal convelated tubule








reabsorption goes from glomerial filtrate to blood
*at end of nephron urine exits*
urine does not contain glucose.
if urine contains glucose, you have DIABETES.

2.72

understand that water is reabsorbed into the blood from the collecting duct








bowmans capsule - location of ultrafiltration
glomerula filtrate contains- glucose, water, salts, and urea
flitration filters too much water.
when filtrate reaches the 'collecting duct' the water is removed from the filtrate.
water is returned back to blood vessels
called 'sclected rehabsorptoin of water' - occurs in collecting duct.

2.71

describe ultrafiltration in the Bowmans capsule and the composition of the glomerular flitrate.

2.70

videos for 2.67-2.69

2.67 a -


2.67 b -


2.68 a -


2.68 b -


2.69 -

2.69

describe the structure of the urinary system including the kidneys, uteres, bladder and urethra
each kidney has a separate blood supply
uterer is the tube from the kidney to the bladder
there is only 1 bladder, (common bladder)
urine--travelles through urethra- and out.

2.68 b

understand how the kidney carries out its roles of excretion and of osmoregulation
the tissue fluid must be isotonic with the cells cytoplasm. so the compostion of blood here must be controlled (the kidney does this)
if it was hypotonic there would be too much water, if it was hypertonic, there would be too little water
excess H(2)O + salts --> excreted down

2.68 a

understand how the kidneys carries out its role of excretion and of osmoregulation
(nitrogen --- urea)
amino acids in excess have to be removed as they are toxic
the liver converts the excess amino acids into urea which re-enters bloodstream
the urea enters both kidneys, which filter it and add it so it is urea+water (urine( and then go down a common pipe to collect in the bladder.

2.67 b

recall that the lungs, kidneys and skin are organs of excretion
1. lungs (first organ of excretion) excretes CO(2)
2. kidneys (second organ of excretion) excretes excess water, urea and salts,
-urea is nitrogen waste from excess amino acids-
3. skin. excretes water, salts (in sweating) and a tiny bit of urea

2.67 a

recall the origin of carbon dioxide and oxygen as waste products of metabolism and their loss from the stomata of  a leaf

considering the process of photosynthesis -combining carbon dioxide and water to create C(6) H (12) O(6) and O(2) <-- waste product.
1. excretion = release of metabolic waste
2. respiration = (C(6) H(12) O(6)) aerobic respiration O(2) + C(6) H(12) O(6) --> ATP (the product\0 --> waste--> CO(2) + O(2). <-- excretion.
plants excrete-- oxygen and carbon dioxide. 

3.34

objective 3.34: understand that the incidence of mutation can be increased by exposure to ionizing radiation (for example gamma rays, x rays and ultraviolet rays) and some chemical mutagens (for example chemicals in tobacco)
 mutation can be triggered by
*radiation (x-rays, uv light which causes cancers)
*chemicals (found in tobacco often)
chemicals which cause mutation are called mutagens
chemicals that cause mutation and cancer are called carcinogens.

3.33

objective 3.33 ; understand how resistance to antibiotics can increase bacterial populations

Bacteria Staphylococcus aureus: causes skin or lung infection.
an antibiotic can kill the Staphylococcus aureus.
The bacteria killed are susceptible, MSSA.
random mutation occurred to the genome of the bacteria.
When antibiotic is applied, the bacteria is not killed
This is resistant, creating a new type of bacteria, MRSA.
mutation has created genes to allow bacteria to break down the antibiotic, allowing it to be able to resist it and survive
This new bacteria increasingly survives and becomes more common.
this resistant bacteria is a problem for hospitals to treat

3.32

Objective 3.32:understand that many mutations are harmful but some are neutral and a few are beneficial

mutation creates new alleles
alleles are responisble for phenotypes.
the mutations can be harmful beneficial or neutral
e.g.
harmful - nonfunctional enzymes
beneficial - improved efficiency of enzyme
neutral - a new allele that has no effect at the present time but in the future environment changes may make this harmful or useful

3.31

Objective 3.31: describe the process of evolution by the means of natural selection
evolution
is the change in the form of organisms and the frequency of alleles
natural selection is the mechanism of evolution (charles darwins theory)
an example of evolution- staphylococcus aureus- leads to skin and lung infection
the original form of this could be killed by methecilline. (MSSA)
there was a mutation and now it cannot be killed. the immune version is MRSA

as MRSA is immune, it is becoming more common.

3.30

Objective 3.30: recall that mutation is a rare, random change in genetic material that can be inherited.

Mutation:
rare.
is a random change in the base sequence of a gene.
it can be inherited
changes base sequences in genes to form new alleles.
we have allele variation because of mutation

3.29

Objective 3.29: understand that variation within a species can be genetic, environmental or a combination of both

Variation: differences in phenotypes. measured in graphs

population’s phenotypes controlled by their Genotype and/or Environment

Genotype: Some phenotypes are controlled just by a variation in the organism’s genotype, the environment has no control in the phenotype
e.g. blood group. discontinuous variation

Genotype + Environment: Sometimes variation of a population’s phenotype is controlled by their genotype and environment.
e.g. Height. If parents are tall, your genotype might make you tall and changes in environment can also make you tall. continuous variation

Environment: variations in a population can be controlled by just environment. e.g. home language. cannot be inherited.

3.20 b

3.20 a

3.21 b

3.21 a

3.18 c

recall the meaning of the terms; dominant, recessive, homozygous, heterozygous, phenotype, genotype, codominance

3.19 a+b

3.18 a+b

Website for genetics questions

http://click4biology.info/c4b/4/gene4.3.htm#eleven

3.2

understand that fertilisation involoves the fusion of a male and female gamete to produce a zygote that undergoes cell division and develops into an embryo

fertilisation
adult male + female. cells have complete number of chromosomes (diploid. 2n)
in human male they divide in testis in human female in ovary to produce gametes which are haploid (n) only have 23 chromosomes instead of usual 46.
in sexual reproduction the egg and sperm (haploid gametes) join/fuse to form 1 cell called the zygote. this process is called fertilisation. (n+n=2n>>hapliod+haploid=diploid) 23+23=46
then zygote undergoes mitosis (cell division). all contain all 46 chromosomes. 2n. diploid. once many have formed the mass of celles is known as an embryo.

3.9b

recall structure and function of female reproductive system.
before pregnancy uterus is small, no larger than an orange.

ovary - meiosis occurs, production of female gamete (egg)
oviducts - carry eggs to uterus, also location of fertilisation
uterus -
wall made of muscle which expands and contracts during pregnancy and just after to accomodate unborn child.
lining accepts and develops the fertilised egg
space allows the egg to turninto a embryo and then an unborn child.
development of placenta in uterus too.
cervix - enterance to uterus (where the sperm cells enter)
vagina - collects sperm cells, allows them to pass.

3.9a

recall structure and function of male reproductive system



bladder - stores urine
testes - carry out proces of miosis, producing male gametes (sperm cells)
epydidymus - stores sperm cells
vas deferens - carry sperm cells to penis during sexual stimulation
prostate - 20-30 percent of semen (alkali mix containing sugars)
seminal vesicles - produce sugar based alkali 70 percent of semen
urethra - common tube connects L+R testes and vas deferens. takes semen down penis and also takes urine.
penis - carries sperm cells into vagina during sexual intercourse.

3.24 b

3.24 b understand that division of a diploid cell by mitosis produces 2 cells which contain identical sets of chromosomes.

copying chromosomes is called DNA replication.
in this process each chromosome undergoes a copying process to form an identical copy of itself with the same genes and alleoles. these 2 copies are held together by a 'centomere'
while the chromosomes are in a copied pair held together by a centomere we refer to them as a 'pair of chromatids'
process of DNA replication takes place inside the nucleus while the nucleus is stil intact. this is the 'interphase' of the cell cycle.

3.24 a mitosis 1

3.24 a
understand that the division of a diploid cell by mitosis produces two cells which contain identical sets of chromosomes

mitosis-form of cell division which results in growth and the growth occurs by an increase in the number of cells#
begin with a cell with nucleus. no. of chromosomes in a nucleus is the diploid (2n)
for humans= 2n= 46
in mitosis the cell divides into 2 identical cells. each with a nucleus. in the nucleus cells are identical 'daughter cells'
1. same number of chromosomes
2. same set of chromosomes

3.16

objective 3.16. describe a DNA molecule as 2 strands coiled to form a double helix. the strands being linked by a series of paired bases adenine (a) with thymine (t) and cytosine (c) with guanine (g)

one chromosome is likely to contain thousands of genes
on the gene loci expand it and you will find a double helix. the helix appear to be parallel
zoom in and the 2 helix are known as the 'sugar phosphate backbone'
inbetween/centered between these you will find a group of molecules called bases
there are 4 different bases known. adenine, thymine, cytosine and guanine.
in a molecule the bases are holding together th 3 helixes. they are held together by pairing between a+t and c+g. these are known as base pairs.
they are always found in dna holding each sides together.
an example on oneside of a double helix an order could be a,c,t,g,a,a,c,c,a,g. this is 'order of the bases.
this order is called the gene. the gene is inside the nucleus.

gene- order of the bases (a,t,c,g) on one side of double helix and number of base.

this is the code for construction of protein in cytoplasm. this gives a characteristic

3.15

objective 3.15. understand that a gene is a section of a molecule of D.N.A.

*D.N.A. is in a double helix shape. a section of the molecule is called a gene

*genes have information which has a characteristic of an organism e.g. blood group or petal colour -in a flower-

genes are located in the nucleus. this information passed to cytoplasm

in cytoplasm genetic information is transformed into a protein which controls the production of the characteristic,

the information flows to the gene (in nucleus) to protein (in cytoplasm)

3.14

objective 3.14. recall that the nucleus of a cell contains chromosomes on which genes are located.

chromosomes= genetic information in a cell

typical cell has a nucleus, within the nucleus there are a number of chromosomes depending on the species.

a chromosome is composed of d.n.a.

which forms a shape known as a double helix.

sections of this molecule are called genes. one chromosome may have up to 1000 genes.

each gene carries the information for the construction of a protein. the protein gives the characteristic associated with the gene for instance blood group.

so a gene controls the production of a protien, which controls the production of the characteristic of the cell.

different organisms have different numbers of chromosomes here are some examples:

cat=38. chicken=78. chimpanzee=42. human=46. chromosomes per cell.

chromosomes operate in pairs called homologous pairs.

homologous nature based on length of chromosome

on any homologous pair they have same gene but different variation in same area. (2 versions of each gene for one characteristic) a characteristic is an 'alleles'

Objective 3.1

objective 3.1: describe the differences between sexual and asexual reproduction

sexual reproduction:

1. sexually reproducing organisms have 'sexes' and you can determine between male and female.

2. they produce celles called gametes. the male gamete is known as sperm and female gamete as the egg. in plants the male is the pollen grain and the female is the ovule.

3. meiosis produces gametes by cell division halving the chromosome in an adult cell.

4. total number of chromosomes per ordinary cell:46. per gamete (m+f) is 23.

5. . fertilisation is when the egg and sperm fuse.

6. there are broad variations in organism with sexual reprooduction.

asexual reproduction

1.no sexes exist

2. no gametes exist either

3. no miosis, just mitosis and binary fission which cause duplication in the cell not dividing chromosomes.

4. no cell fusion so no fertilisation,

5. there are small variations between organisms due to mutation, otherwise they are identical or clone.

question: why are there 46 chromosomes per ordinary cell? why not any other number?

photos in class 14/06/11

2.14

understand how an increase in greenhouse gases results in an enhanced greenhouse effect that may lead to global warming and it's consequences

pollution molecules are; carbon dioxide, methane, suplhur dioxide, nitrous dioxide, water vapour

these gases increase in concentration in the upper atmosphere, which raises the average global temperature (global warming)
simple ideas of the consequences are
*melting ice caps
*raised sea levels
*ocean currents changing
*winds generated elsewhere
this contributes to CLIMATE CHANGE
which changes the distribution of the worlds biomas. ecosystems
polar ice cap melt, forest distribution changes, deserts expand.

4.13

understand how human activities contributre to greenhouse gases

1. the burning of fossil fuels results in the formation of carbon dioxide nitrous dioxide and sulphur dioxode
carbon dioxide and nitrous dioxide are greenhouse gases (absorb infra red light and distribute it back in all directions, but crucially towards the earths surface
these are released from factories and vehicles-exhaust emissions. burning of coals in domestic facilities, although that is less prominent now

2. farming
animals in their digestion of crops emit methane gas into the atmosphere. cows are mainly the blame. 9 percent of methane blamed on farm animals

3. evaporation of water to form water vapour, clouds are a significant contributer to the greenhouse effect

4. refrigiration, solvents anmd propellents contain CFC's
CFC's--> chlorofluorocarbons
C, Cl (small 3) F
well associated with UV LIGHT and CATALYSING THE BREAKDOWN OF THE OZONE LAYER

4.12

objective 4.12 - recall that water vapour, carbon dioxide, nitrous oxide, methane and CFC's are greenhouse gasses

4.11

objective 4.11 understand the biological consequences of pollution of air by sulphur dioxide and carbon monoxide

1. sulphur dioxide

*sulphur dioxide as a gas is released into the atmosphere when there is combustion of fossil fuels. this often occurs in factories and vehicles (oil and petrol)

*suplhur dioxide = SO2
*sulphur dioxide and water vapour (in the clouds) --> sulphuric acid
*sulphuric acid falls as acid rain
*acid rain affects plants and animals.

*trees are burned by the acid, so they die, the acid gets into the soil and this causes magnesium ions and calcium ions to be leached out of the soil so the trees cannot reach them, the trees leaves yellow and the tree dies.
*the precipitation of acid rain, it gets into streams and rivers and lowers the pH, to acid levels. this increases aluminium ions, which cause the thickening of the mucus which lines the fish gills, which reduces the fishes ability to take oxygen so in the end the fish suffocates and dies.

2 carbon monoxide
caused when fossil fuels (coal and GAS)  are burned with insufficient levels of oxygen.
fossil fuels -->(insufficient oxygen)--> CO
CO  combines with haemoglobin in red blood cells to make carbino haemoglobin, which blocks haemoglobin from carrying oxygen which reduces the circulation of oxygen arounf the body
CO is TOXIC, and is often FATAL. it causes the body to suffocate.

4.3

objective 4.3- descibe the use of quadrats as a technique for sampling the
distribution of organisms in their habitats.



sample has to be random
so it is not bias.
a sample also needs to be representative
so the samples need to cover a wide area

number the strings in a quadrat 1-10 (if ten strings)

select 2 random numbers.

then use these to selsct a square to count the organisms.

repeat this 10 times and divide the number of all the organisms together by 10 if repeating this 10 times. preferably cover 10% of the area you are surveying

4.2

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

a quadrat- method of sampling
quadrat size range between 0.25x0.25m to 1x1m
quadrat is a square grid
quadrats can be made of wood, metal, string or plastic
it helps compare the population in two different places.
you place the quadrat down and count the number of organisms within the grid and you do this sevral times and average it in each area

4.1

objective 4.1- understand the terms population, community, habitat and ecosystem.



*an ecosystem is a community of organisms
*abiotic means non-living, for example daylight, temperature, rainfall humidity, and slope of area.
*a community is a population of different species interacting with eachother.
*a habitat is a community including all the abiotic factors
*a species is an organism that reproduce to give fertile offspring
*a population is the number of individuals of a particular species.

3.4

objective 3.4: understand that the growth of the pollen tube followed by fertilisation leads to seed and fruit formation



1. the male nucleus travels down the pollen tube to the ovulw
2. the male nucleus will fertilise the ovule
3. this leads to the formation of the zygote which in turn leads to the growth of the embrionic plant
4. outside of the ovule the seed coat forms
5. another name for seed coat is testa
6.inside, in addition to the zygote, the cotyledon forms
7. the cotyledon is a food store used for the plant before the leaves can provide energy
8. the walls of the ovary thicken by adding sugar and protein.
9. fruit is the wall of ovary/carpel 

3.3b

objective 3.3b: describe the structures of an insect pollinated and a wind pollinated flower and explain how each is adapted for pollination.



wind pollination= transfer of pollen grain from anther of one plant to stigma of the other through the air carried by the wind

the adaptations a wind pollinated plant would have would be:
lightweight pollen grain, maybe with wings so to catch the wind better.

the anther will hang well clear of the main flower structure so they are exposed to the wind.

the stigma will have a large surface area maybe in a feather-like structure to catch the pollen grains as they pass through the air. the stigma will also be well clear of the main flower structure and be exposted.

grass is an example of a wind pollinated plant

grass has no colour, scent, or nectaries as there is no need to attract insects as it is wind pollinated. the features if an insect pollinated plant would be a waste of energy.

3.3a

3.3a: describe the structures of an insect pollinated and a wind pollinated flower and explain how each is adapted for pollination.



in pollination there must be a transfer of pollen from the anther of one plant to the stigma of another.
when pollination occurs between 2 separate plants it is called cross pollination.

pollen is a small structure which contains the male nuclei

the transfer of pollen in an insect pollinated plant is by insects. the flowers must attract insects.
adaptions of plant to attract insects include;
signals. - the colourful petals, scents
value/reward- food (from nectaries produce fructose), pollen as protein

the male part of the flower= stamen composed of anther and filament
the female part of flower= carpel composed of stigma, style, ovary (which contains eggs called ovules)

2.81

objective 2.81 : describe posotive phototropism of stems




phototropism= growth in responce to light

posotive phototropism= growth towards light

if a stem's tip is exposed to uniform light (light from all directions) the stem will grow upwards

if the light source is from the side the tip will grow towards the light
this is an exaple of posotive phototropism of the stem

light on one side causes the hormone AUXIN on the other side to grow sideways towards the light. this is how the stem grows sideways.

2.80

objective 2.80 : describe the geotropic responses of roots and stems.





Geotropic=growth in response to gravity

growth downwards= posotive geotropism
growth upwards= negative geotropism

stems/shoots grow up, therefore they have negative geotropism
roots grow down, therefore they have posotive geotropism

2.79

Objective 2.79: understand that plants respond to stimuli

Stimuli is changes in the environment, examples are temperature and light changes.
Plants have receptors to detect stimuli and respond
the  responce is growth.
growth in responce to stimuli is called TROPISM
trpism in responce to:
gravity; geotropism
light; phototropism

the connection between the receptor and the responce usually takes the form of plant hormones, often known as plant growth regulators
an example of this would be AUXIN

Biology

For evaporation to occur there must be heat
the heat is from sunlight (light energy to heat energy)
tthe leaf is warmed by sunlight
evaporation occurs (where the water changes from liquid to gas state) in the spongey mesophile.
diffusion of water vapour through the stomatal pore to the outside atmosphere through a steep diffusion gradient.

Biology 2.53

Roots increase surface area by having a branching pattern. This is on a tissue level.
Roots increase surface area also by having root hairs.
Root hairs are extensions of the cell wall. They increase surface area on a molecular level.
Osmosis is the movement of water from a higher water concentration to a lower water concentration through a concentration gradient.
Water moves across the cortex of the root to the xylem by osmosis.