3.15

3.14

• chromosome - the genetic data inside a cell which is in the nucleus (brain) of the cell
• chromosomes are made up of DNA molecules which come in a helix shape
• a section of DNA is called genes
• depending on what kind of organism you are, the chromosome count in your body will be different
• chromosomes function in (homologous) pairs, which means that if you took a gene on one chromosome (called gene loci), and when you would go to the corresponding gene on the opposite chromosome, it would be the same gene
• therefore we have 2 versions of each gene, called alleles

3.1 sexual and asexual reproduction

• Organisms that show sexual reproduction show sexes (male/female). No sexes exist in Asexual reproduction.
• Sexual reproduction has Gameke cells in the sperm and egg cells. Asexual does not have Gameke cells.
• Meiosis is a cell division that produces Gamekes. One of Meiosis' effects is to half the number of chromosomes in the Gameke cell. 
•  Total number of chromosomes in a human is 46 per cell. In Gamekes the total number is 23 per Gameke cell. From 46 to 23 is the process of Meiosis.
• In Asexual reproduction there is Mitosis and Binary fission bacterial cells. Number of chromosomes is maintained constantly.
• In Sexual reproduction there is the process of fertilisation, where the sperm cell and egg cell fuse together. In Asexual reproduction there is no fertilisation and no fusion of cells.
• Many differences in the individuals of a sexual reproducing population. Where as Asexual show a small amount of variation, mainly identical (clone).  

credit to samir

4.14

• the uv light passes through the atmosphere, reflects of the surface of the earth
• greenhouse gases reflect light back down, results in increased temperature, and climate change consequently

consequences:
- ice caps melting
- rise in sea level
- change in ocean currents
- change in the way winds are generated
- distribution of the worlds biomes changes (major vegetational ecosystem)
- rise in temp

4.13

how human activity adds to the greenhouse effect:

• burning fossil fuels (as well as cars, factories) leads to more CO2,NO2,SO2
• farming (cows) cause methane (CH4)
• evaporation of water -> water vapour (clouds)
• refrigeration/ solvents/ propellants
--> CFC chlorine, fluorine, carbon C(CL3)F

4.12 - green house effect

4.11

• combustion of fossil fuels (as well as vehicle combustion) gives off sulphur dioxide (SO2)
• When the SO2 combines with H2O in the atmosphere, sulphuric acid is made which leads to acid rain.
• Trees and plants are affected by the acid rain by getting burned
• Ca2+ and mag 2+ are leached from the soil, meaning plants cannot obtain calcium or magnesium that they need to grow
• the ph of lakes is reduced which releases Al3+ ions, which means more fish die. The aluminum forms as a mucus to the fishes gills which decreases the ability for oxygen to get in


• Fossil fuels are burned with an insufficient amount of oxygen resulting in carbon monoxide
• Carbon monoxide is toxic as it attaches to your haemoglobin cells inside your red blood cells which blocks oxygen getting around your body
• does not smell, cannot be seen, can lead to death