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

3.19 (a) and (b) Screen Capture

3.19a

3.19b

3.18 (a) and (b) Screen Capture

3.18a

3.18b

3.2 Fertilisation

Notes


Fertilisation = "fusion of male and female gamete to produce a zygote that undergoes cell division and develops into an embryo"

1. In both Adult male & Adult female:
-> Each is in terms of a Diploid (2n) (diploid = complete set of chromosomes, 46)
-> Diploids divide in testis to produce gametes (meiosis = sperm and egg)
    -> Diploid (2n) / 2 = Haploid (n)
    -> 23 per sperm/egg

2. Fertilisation = two cells are fused together (Sperm gamete & egg gamete) to form ONE CELL

In human:
-> Haploid (n = 23) + Haploid (n = 23) => Diploid (2n = 46) =  new cell known as ZYGOTE
-> Zygote combination of male and female cells but same no. of cells as adult human

3. Mitosis = cell divides (1-2-4-8-16, etc.), 2n -- mitosis --> 2n ALL CELLS CONTAIN DIPLOID (2n = 46) NUMBER OF CHROMOSOMES
-> Embryo = large collection of diploid cells

*Note: process is true for all sexually reproducing animals, variance in no. of chromosomes

3.9b Female Reproductive System

Notes

*before pregnancy, size of uterus = approx. orange

Ovary = meiosis (production of female gametes = eggs)

Oviducts (fallopian tube) = carries eggs to uterus BUT also location of where feritlisation may occur

*Fertilisation = occurs in oviducts NOT in uterus

Uterus = centre structure, wall of uterus which is a muscle stretches during pregnancy, contracts during birth

Lining of Uterus = develops fertilised eggs --> embryo --> child, placenta implants on wall of uterus

Uterus space = where embryo develops into unborn child, stretches to accommodate growing child

Cervix = where sperm cells from the penis enter, entrance to uterus, where sperm cells make way up to oviducts AND where eggs descend down towards

Vagina = collects sperm cells at top of vagina & allows sperm to enter through the cervix

3.9a Male Reproductive System

Notes


Bladder = stores urine

Testis = carry out meiosis produces gametes (sperm cells)

Epididymus = ('coil tube' system), stores sperm cells

Vas deferens = carry sperm cells to penis during sexual stimulation (during sex tube contracts and pushes sperm to penis)

Prostate = Adds 20% - 30% of volume of semen, contains sugars, alkali (alkali nature may neutralise acidic secretions vagina)

Seminal Vesicles = Adds remaining 70% of volume of semen so sperm can travel, produces sugar based secretion, alkali

*SEMEN = sperm cells + (seminal vesicle & prostate secretions)

Urethra = Runs length of penis, common tube joining R + L testis & vas deferens, exit for urine stored in bladder

Penis = Carry sperm cells into vagina during sexual intercourse

3.12 Amniotic Fluid

Notes


Amniotic fluid: Protects developing embryo, surrounds embryo in uterus space

-> Fluid (protection of developing embryo)
     -> Cannot be compressed, 
     -> Absorbs pressure when squeezed
= Prevents damage to embryo by absorbing forces on uterus wall
= Supports foetus as it cannot support own weight during development (bones = not calcified)

e.g. Trying to kick swiftly in water, but pressure (force) of kick is absorbed, slowing leg down

3.11 Placenta

Notes


Embryo: Unborn child, encompassed by uterus (amniotic fluid filled environment), with placenta on spinal side.

Placenta (provides nutrition to embryo)


-> Grows out of embryo in form of umbilical cord

-> Cord spreads out to form placental structure

-> Placenta grows into wall of uterus (past wall lining)

-> Glucose, amino acids & fats (maternal blood stream) --- crossing at (placenta) ---> embryo's blood stream

-> Efficiency/speed of blood/nutrition transfer:
   -> Large S.A. of placenta
   -> Very thin barrier (distance between) mother and embryo

-> Urea, carbon dioxide (embryo) --- crossing at (placenta) ---> maternal blood stream

** Placenta and placental blood vessels(including p. arteries & p. veins) belong biologically to embryo NOT mother

Mitosis Animations

Mitotic Cell Division

(http://www.youtube.com/watch?v=NR0mdDJMHIQ&feature=related)

The Stages of Mitosis

 (http://www.youtube.com/watch?v=VGV3fv-uZYI)

Mitosis

(http://www.youtube.com/watch?v=ATlUv-AGhEU&feature=related)

3.24c Mitosis (3)

Notes


Process of Mitosis


-------------- START OF MITOSIS ---------------

1. Interphase (resting state) = nucleus visible, but chromosomes are not

2. Prophase = Break down of nuclear membrane (nucleus breaks down)-> chromosome visible as a 'pair of chromatids'

3. Pro-metaphase = Inside cell (no nucleus remains), network of protein molecules (spindle/fibres) extends from one pole of the cell to the other:
-> Pair of chromatids join onto protein fibre in centre (via centromere)

4. Metaphase = Pair of chromatids joined onto protein fibre in 'spindle' via centromere.
-> Chromosomes are arranged in the 'equator' of cell

5. Anaphase = 'spindle' fibre shortens -> splits pair of chromatids in opposite directions

6. Telophase = Two nuclei form at opposite ends of the cell, around the seperated chromatids.

--------------------- END OF MITOSIS -----------------------

(7.) Cyto-Kinesis (not regarded as part of mitosis) = Cell begins to move inward dividing cytoplasm in half -> Membrane fuses across equator = Two cells each containing a chromosome (same as parental cell)

-> Human: 23 pairs undergo mitosis at the same time

(http://www.ba-education.com/dna/mitosis.jpg)

3.24b Mitosis (2)

Notes


Mitosis - creating identical 'daughter' cells requires 'DNA replication'

-> Process: Each chromosome undergoes copying process -> Identical copy with identical genes & alleles
---> Takes place inside nucleus (unobservable) = Interphase of cell cycle

-> Two copies held together by centromere (structure around central region) = referred to as 'pair of chromatids'

3.24a Mitosis (1)

Notes


Mitosis = form of cell division -> growth, by increase in number of cells

Outline
Cell, with nucleus -> Diploid number (2N) number of chromosomes (human 2N = 46 chromosomes/cell)

-> Mitosis = cell divides into two, each with 1 diploid nucleus (identical/'daughter' cells):
  --> same number of chromosomes
  --> same set of chromosomes = same chromosome found in copy nucleus

3.16 DNA and Genetic Information

Notes


Chromosomes -> Gene loci

---> Double helix structure (DNA), interwoven parallel helixes

------> Outside sections = 'sugar phosphate backbone'
------> Inside contains 'base pairs' = Adenine (A) <--> Thymine (T), Cytosine (C) <--> Guanine (G) which hold two sides of the 'backbone' together
------------> Base pairs order (right side of helix structure): GENE
(R) (L)

A  T
C  G
T  A
G  C
A  T
A  T
C  G
C  G
A  T
G  C
C  G

Gene inside nucleus = order of bases & number of bases -> codes for construction of protein in cytoplasm -> organism characteristics

3.14 Recall that a nucleus of a cell contains chromosomes on which genes are located

Notes

Chromosome = genetic information within a cell

Typical cell -> Nucleus -> Chromosomes -> DNA (double helix structure) -> Repeating structure known as 'Gene'

Gene = instructions for construction of a protein which define organism characteristics
-> Different organisms contains different number of chromosomes, humans = 46 per cell.

Chromosomes operate in homologous pairs (X,Y), based upon LENGTH of chromosomes (similar lengths will operate together)
-> Identical genes located at identical postion on the chromosomes - known as the gene loci
   -> 2 versions of each gene for 1 characteristic, known as alleles

3.15 Understand that a gene is a section of a molecule of DNA

Notes


DNA - Deoxyribonucleic acid = Double-helix structure
 ->Nucleus
   --> Gene - carries information (characteristics) of organism, individual genes for:
      ---> Blood group (animal)
      ---> Petal colour (plant)
      ---> Etc.

Nucleus, Gene (genetic information) -- passed to Cytoplasm --> Cytoplasm, Protein
 - Protein controls production of characteristic 


Below (http://publications.nigms.nih.gov/thenewgenetics/images/ch1_dnagenes.jpg)
 -> Diagram of DNA relative to cell structure

3.1 Differences in Sexual and Asexual Reproduction

Notes


Sexual

-> Identifiable: Distinguish between male/female
-> Meiosis (gamete cell division): 1/2 total number of adult chromosomes in gamete cells
-> Produce 'gamete' cells (male - sperm / female - egg)
-> Fertilisation: gamete cells fuse together (male / female cells fuse together - 23 x 2 = 46)
-> Variation: Populations of individual sexually reproducing species show broad amount of variations

Asexual

-> NOT Identifiable
-> Mitosis / binary fission: 20 chromosome cell -- divides --> 20 x 2 chromosome cells
-> NO Gamete cells produced
-> NO Fertilisation: no gamete cells = no cell fusion = no fertilisation
-> Small variations: identical population (clones)


*Question: What factors affect whether a species will be a sexually or asexually reproducing animal? What are the advantages/disadvantages of each method, that lends itself to particular circumstances (e.g. Scarce populations of species in an area, therefore asexual would be more advantageous)?

Process of Dry/Wet Deposition and Locations

Notes


Dry Deposition: Sulphur dioxide bonds with transpired water molecules on SA of leaf, causing the leaves to 'burn'

Wet Deposition: Conventional Acid Rain cycle

In Europe (prevailing wind travels NE)

- Dry deposition, where the sulphur dioxide is carried on wind currents, and is deposited on the top parts of trees in that region.

- Wet deposition, AFTER mountainous regions, where wind currents carrying sulphur dioxide condense, and bond with water molecules and acid rain occurs.

4.14 Enhanced Greenhouse Gases

Notes


GHE brought about by GHG (water vapour, carbon dioxide, methane)
  - Increased gases = increased amount of IR light re-emitted back to Earth, RAISE AVERAGE GLOBAL TEMPERATURE (Global Warming)

Consequences


-> Melting of ice caps in polar region = CLIMATE CHANGE
   - raised sea levels,
   - changing ocean currents
   - changing wind currents

-> Raising ave. global temperature = changes in distribution of biomes (major vegetation ecosytems)
  - polar ice-caps melts
  - Deserts expand
  - Deciduous, coniferous forests would change

4.13 Greenhouse gases

Notes


Human activity (fossil fuels) ---> Increased (CO2, NO2) <-- GHG & SO2


  - Industrial
  - Vehicles
  - Domestic (homes)
  - Farming = cows digest crops, emit methane gas to GHE (9% of gases)
  -Water vapour = clouds are main contributors
  - Refrigeration (CFCs) = absorption of UV light, catalysing breakdown of Ozone layer

4.12 Greenhouse Effect

Notes


a) UV light (sun) - Short wavelength, high energy

b) 50% reflected back out to space (before atmosphere penetration) = due to clouds

c) Absorption on Earth SA = UV light converted and emitted as infrared

d) Infrared light = emitted back towards outer space (Space - as heat)

Greenhouse effect


f) Greenhouse gases - Water vapour, CO4 , CH4


    - d) -- IR hits GHG --> f) =  g) absorbs energy BUT re-emitts in ALL DIRECTIONS (backdown, raising SA temp.).

4.11 Gas Pollution Consequences

Notes


Sulphur dioxide (SO2)


 - Combustion of fossil fuels, coals, oils
      - Factories
      - Vehicles

--> Sulphuric acid (SO2 + H2O) = Acid Rain
     - Vegetation: Leaves 'Burned' , Root system leached of magnesium and calcium = no growth
     - Lakes: Reduces Ph (acidic), brings aluminium ions = Al causes mucus thickening in fish,
fish not able to take in enough oxygen (suffocates)

Carbon monoxide


- Combustion of fossil fuels, coals, oils, with INSUFFICIENT OXYGEN

--> Bonds with Hb in RBC = Carbaminohaemoglobin, blocks Hb from carrying oxygen
   - Reduces oxygen circulation, toxic.

4.7 Energy efficiency

Why is only 10% of energy passed from one trophic level to the next?


- Not all energy available to next consumer...lost in:

   - Consumer's life processes (Respiration)
   - Undigested food (faeces)

e.g. 90kJ of plant's energy used by aphid for above, 10kJ left for next consumer

...Because the 90% is used by the consumer (not producer, e.g. grass) for life processes, and in undigested food.

4.6 Energy & Substances in food chains

Producer


Light E -- Photosynthesis --> Chemical E 

= Organic molecules (Carbohydrates, Proteins, Lipids) - Food to next in-line food chain

---> Substances / matter =  (C, H, O, N) contain ENERGY in bonds are passed through food chain