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