2.69 Urinary System - Describing the Structure

Notes


Urinary system
1. Kidneys (x2) (each with own blood supply / carries out excretion, osmoregulation
2. Ureter (x2) = tube from each kidney = carries urine from kidney to bladder
3. Bladder (x1) = stores urine
4. Urethra (x1) = urine to outside the body by tube through the (penis / vagina)

2.68b Osmoregulation

Notes


"Role of kidney in process of excretion an osmoregulation"

Osmo = 'osmosis'
Regulation = 'to control'

Cells in body
-> Tissue fluid (surrounding cells) = MUST be ISOTONIC with cytoplasm of cells
------> Water (In to cells) = Water (Out of cells) ---> Cells same size/shape, functions properly

**Danger to tissue (cells) by circulated blood**
-> Hypertonic = concentrated blood --> Remove too much water
-> Hypotonic = dilute blood --> Add too much water

ISOTONIC = Achieved by controlling composition of blood (forms tissue fluid) -> Role of kidneys

Blood circulates through kidney (in excess) are removed & excreted:
-> Salts = hypertonic
-> H2O = hypotonic


Excreted to control blood to be isotonic with cells cytoplasm -> maintains functions of cell & tissue

2.68a Excretion (Roles of the kidney & liver in excretion)

Notes


"Role of kidney in process of excretion and osmoregulation"

Excretion of Urea (contains nitrogen - toxic to body and cannot be stored)
-> Original form of nitrogen (circulatory system) = amino acids
-> EXCESS amino acids MUST be removed as TOXIC
-> Removal = role of liver & kidneys


PROCESS OF EXCRETION (of Urea)
1. Blood circulates to liver ---> amino acids broken down and converted --> Urea molecule
2. Urea circulates in blood stream -> Kidneys (both) --> Kidneys filter urea from blood
3. Urea + Water = Urine ----> Bladder (therefore removed from blood circulatory system
4. Filtered blood (from kidneys) returns to circulatory system

2.67b Human Organs of Excretion

Notes


1. Lungs 
-> CO2

2. Kidneys 
-> Salts
-> Urea (Nitrogen waste from amino acids -> amino acids not stored -> amino acids excreted)
-> Excess water

3. Skin
-> Salts (Sweat)
-> Urea (very small amounts)
-> Water (Sweat)

2.67a Excretion in Plants

Notes


1. DAY Leaf absorbs Light energy by Photosynthesis (metabolic reaction):
-> CO2 + H2O ------> C6H12O6 (glucose) + O2 (gas = waste molecule = excretion)
-> O2 metabolic waste = excreted

2. NIGHT Aerobic Respiration
-> C6H12O6 (glucose) + O2 ---Enzyme reactions (glucose broken down) ---> ATP + CO2 + H20
-> CO2 = metabolic waste = excreted

Excretion = Through stomatal pores

3.34 Causes of Mutation

Notes


Mutation
Gene (ACT) ---- mutation changes base sequence ----> New allele (AAT)

Causes


1. Ionising Radiation 
   -> X-rays / gamma rays
   -> Ultraviolet: UV-B rays (sunshine) -> mutations such as skin cancer

2. Chemicals (mutagens = chemicals which cause mutations)
  -> Tars (tobacco) -> cancerous conditions

* mutagens which also cause cancer = carcinogens

3.33 Antibiotic resistance

Notes


Antibiotic resistance = increase in population of new allele

*see 3.31 evolution for details on MSSA/MRSA

MSSA --- random mutation (evolution) = MRSA---- process of natural selection ---> MRSA

As antibiotics used over time 
-> MSSA: less common

-> MRSA: more common (resists antibiotic = population expands as normal) / antibiotic no longer 'works'

3.32 Types of Mutation

Notes


Gene --- mutation ----> New Alleles

Alleles (responsible for phenotype) = harmful/beneficial/neutral

-> Beneficial = improve efficiency of enzyme

-> Harmful = production of non-functional enzyme

-> Neutral = second new allele / no effect AT PRESENT -> environmental change might render it beneficial or harmful

3.31 Evolution

Notes


"Evolution by means of natural selection."

Evolution
- change in the form of organisms (new forms of organisms)
- change in frequency of alleles

Natural selection = mechanism of evolution (Charles Darwin)

Example:

Stapholococcus aureus = infection of skin, lungs (due to wounds e.g. operations)
-> Susceptible to being killed by Methecillin (Antibiotic)

S.A. which can be killed are known as the susceptible forms of the population

-> SUSCEPTIBLE: MSSA (methecillin susceptible s.a)
-> RESISTANT: Random Mutation to S.A. allows it to break down methecillin = no longer susceptible

When both forms are treated by methecillin (MSSA, MRSA)

-> SUSCEPTIBLE: less common, decrease in population
-> RESISTANT: more common, increase in population = increase in FREQUENCY of allele for resistance

*different forms = definition of evolution -> MRSA = evolved form of MSSA due to alterations in genome

PROCESS of NATURAL SELECTION
-> Random mutation = produces MRSA form
-> Non-random selection = applying antibiotics, MRSA selected for survival/MSSA

3.30 Mutation

Notes


Mutation = Rare, random change in genetic material that can be inherited

DNA -> Base sequence (gene) -> Form of gene = Allele

1. Changes in base sequence due to certain events
2. New version might result in production of NEW PROTEIN
3. Change in Phenotype

Dominant vs. Recessive = due to mutation, which changes base sequence of gene

3.29 Species Variation

Notes


Variation = differences in phenotype of individual (possible to measure and show in graphic form)

Individual phenotype = Genotype + Modified by environment

Variation in Population = V P.genotype + V P.environment

-> Differences in Phenotypes of Species (appearance) = different genotypes + different habitats

Situations

1) Discontinuous Variation in Population/Species (GENOTYPE)

Variation in Genotype ONLY
-> Blood groups (O, A, A/B)

2) Continuous Variation in Population/Species (GENOTYPE + ENVIRONMENT)

Variation in Genotype + Environment
-> Height in humans = genes for height + diet

3) Variation in Population/Species (ENVIRONMENT)

Variation in Environment ONLY
-> Language spoken (not defined by genes at all) -> NOT INHERITABLE

3.18, 3.20, 3.21 Screen Capture

3.18c Co-dominance

3.21a Genetic Probabilities

3.21b Genetic Probabilities

3.20a Pedigree Diagrams

3.20b Pedigree Diagrams