Monday, October 31, 2011

2.69 Urinary system



describe the structure of the urinary system, including the kidneys, ureters, bladder and the urethra.
-2 kidneys- right and left kidney- each with its own blood supply carry out the process of excretion and filtration and osmoregulation.
-from each kidney there is a tube that leads to the bladder- called the ureter- carries the urine from the kidney to the bladder.
-there is a common bladder for both ureters- urine is conducted from the outside of the body through the urethra down through the vagina or through the penis.


2.68b Osmoregulation



understand how the kidney carries out its role of excretion and of osmoregulation.
-osmo: osmosis
-regulation: control

-the fluid which surrounds the cell- must be isotonic with the cytoplasm of the cells- the water going in and out of is equal and the cells will remain the same size and the same 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 (remove to much water) or it may be very dilute causing a hypotonic tissue fluid (add too much water).

-so we want to keep the tissue fluid isotonic to the cells cytoplasm- achieved by controlling the composition of blood.

-blood forms the tissue fluid- role of kidney to control the composition of blood.

-blood with circulates through our kidney excess water, salts can be removed and excreted down the ureter.

-by controlling the content of water and salts in the blood the kidney can keep the blood and therefore the tissue fluid isotonic with the cells cytoplasm maintaining the function of the cell.

2.68a Excretion



understand how the kidney carries out its role of excretion and of osmoregulation
-excretion of the molecule urea (carries nitrogen and it is toxic to the body and cannot be stored)
-the original form of nitrogen circulating in our blood stream and is potential toxic are the amino acids.
-amino acids are normally used for growth but extra amino acids must be removed- they are toxic, rule of both liver and kidney.
-first stage- blood circulates to the liver and the amino acids are broken down and converted into the molecule urea.
-the urea re-enters the bloodstream and circulates to both kidneys.
-the kidneys will filter the urea from the blood and the urea will be added to the water to form urine.
-urine drains down the ureter to collect in the bladder.
-the urea is now in the bladder in the form of urine- been removed from the body.
-the filtered blood returns to the circulation in the veins with the toxic amino acids and urea removed- example of excretion.

Sunday, October 30, 2011

2.67b Human organs of Excretion



recall that the lungs, kidneys and skin are the organs of excretion.
-1) lungs- lungs excrete carbon dioxide- waste from respiration that need to be eliminated from the body.
-2) kidney- kidneys excrete excess water, the molecule urea (the nitrogen waste from amino acids- we cannot store them so we excrete them) and salts.
-3) skin- known to excrete water (sweat), salts (sweat), and a little bit of urea. (mainly water and salt)

2.67a Excretion in plants



recall the origin of carbon dioxide and oxygen as waste products of metabolism and their loss from the stomata of a leaf
-photosynthesis: absorbing light energy and in the process of doing so it combines (CO2) carbon dioxide and water (H2O) to form glucose (C6H12O6) and gives of the gas (O2) oxygen- waste molecule example of excretion which is the release of metabolic waste.
-process of respiration: glucose (C6H12O6) + O2 (oxygen) --enzyme reaction-----> ATP (produced in the process) + CO2 (waste molecules also excretion) + H2O.

-plants excrete O2 (oxygen) or CO2 (carbon dioxide) depending on whether they are doing photosynthesis or respiration.

Wednesday, October 12, 2011

3.31 Evolution



describe the process of evolution by means of natural selection.
-evolution: change in the form of organisms. (new form of organisms arising)
                : change in frequency (how many) of alleles.
-natural selection: the mechanism of evolution (first proposed by Charles Darwin)
-SA (Staphlococcus aureus) causes skin infection and also lung infection


evolving SA

first graph
-normal form is susceptible to methicillin (antibiotic) (antibiotic can kill SA)
-MSSA (methicillin susceptible SA)

second graph
-random mutation in SA allow breaking down of methicillin. 
-because it can break down it can no longer killed by the antibiotic (resistant form)
-MSRA (red on graph)

-2 forms of bacteria (called evolution) [MSSA, MSRA]
-when antibiotic are applied to the population MSSA is decreased and MRSA is becoming increasing common
-evolution: increase in frequency of allele (or resistance) 


2 features
-random mutation produces MRSA form
-the non random selection (due to antibiotics) selects MRSA to survive and MSSA to be selected and killed.
-natural selection is a process not a list.


Tuesday, October 11, 2011

3.34 Causes of mutation




understand that the incidence of mutations can be increased by exposure to ionizing radiation (for example gamma rays, X-rays and ultraviolet rays) and some chemical mutagents (for example tobacco)
-radiation (ionizing radiation) eg. x-rays and UVB (ultraviolet) rays (sunshine) can cause skin cancer.
-due to chemicals (tars in tobacco) cause mutation to base sequence producing new alleles and causes cancer.
-chemicals that cause mutations are called mutagens.
-mutagens which also causes cancer are called carcinogens.

3.33 Antibiotic resistance



understand how resistance to antibiotics can increase in bacterial populations.
-bacterial population is Staphlococcus aureus- known to cause skin infection and lung infection.
-if infected can be treated with drug called methicillin (type of antibiotic)
-type of chemical will kill the SA (Staphlococcus aureus)
-the type of SA which is killed by the methicillin is called the susceptible form (can be abbreviated to MSSA) (MSSA- methicillin susceptible Staphlococcus aureus)

-there was a random mutation to SA. when the methicillin (antibiotic) was applied the bacteria did not die (resistant form)
-the type of SA which is resistant to the methicillin is abbrivated to MRSA (MRSA- methicillin resistant Staphlococcus aureus)
-the mutation has create genes in SA, when expressed, allows it to break down the antibiotic and resists which causes bacteria to not die.
-if antibiotic is used across time the form of bacteria increasing survives, becomes more common and this becomes a serious problem in hospitals because antibiotic no longer work.

3.32 Types of mutation



understand that many mutations are harmful but some a neutral and a few are beneficial.


- gene ---mutation---> new alleles (responsible for phenotypes)
-new alleles can be beneficial (eg. improve efficiency of enzyme), harmful (eg. non functional enzyme), or no effect (neutral effect)- may not last forever and with the environmental change the mutation can become harmful or beneficial.

3.30 Mutation



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


-form of gene is called the allele.
-certain processes can cause a change in the base sequence which creates a new version of the allele. (possible that the allele will result in the production of an entirely different protein and have an entirely different effect on the phenotype)
-different alleles exist because of mutation. (Allele A and Allele a)
-mutation changes base sequence of the gene.

3.29 Species Variation



understand that variation within in a species can be genetic, environmental or a combination of both.

-variation- difference in phenotype of individuals. it is possible to count or measure and shown in graphic form.
-individual has a phenotype, appearance of an individual is because of their genotype, modified by the environment.
-variation in population is the variation of the individuals.
- Vpopulation= Vgenotype + Venvironment    (V- variation)

1. -different classes or group, this suggests variation in the population (which is variation in the spices) is entirely due to the variation in the genotype. environment is playing no role.
-eg. blood groups (A, AB, B, O)


2.
- variation in population, variation in the spices- causes by genetic variation (variation in genotype) but the different group is modified to form the smooth curve (distribution curve) caused by the environment.
-eg. height (quality of your diet [environment])
-continuous variation



3. 
-variation in population or species (phenotypic variation) entirely due to environmental variation. genes have no role.
-eg. home language
-cannot be inherited.