Biology unit 1 (AQA GCSE)
- Created by: liv
- Created on: 02-11-15 21:12
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- Biology (AQA)
- DNA
- They consist of long strands of DNA
- The gene is the unit of inheritance and each chromosone has thousands of genes in it.
- http://www.bbc.co.uk/staticarchive/678f62dce35d0fc7ef2333d6d3bfbf53744374ff.jpg
- The genes on those chromosomes carry the code that determines our physical characteristics, which are a combination of those of our two parents.
- Decay
- The main groups of decomposer organisms are bacteria and fungi
- They both cause decay by releasing enzymes which break down compounds in their food so it can be absorbed by their cells.
- The factors that affect decay rate are moisture, temperature and amount of available oxygen
- http://www.bbc.co.uk/schools/gcsebitesize/science/aqa/energy_biomass/thecarboncyclerev1.shtml
- Reproduction
- Sexual
- Sex cells are called gametes
- Male sex cells: sperm
- Female sex cells: eggs or ova
- Sex cells are called gametes
- Asexual
- Asexual reproduction is a type of reproduction where offspring arise from a single organism, and inherit the genes of that parent only; it does not involve the fusion of gametes
- Plants
- http://www.bbc.co.uk/staticarchive/5aaa8b345a205395c996e69fa812f8f92949ceb5.gif
- --------> Example of Asexual reproduction in plants.
- http://www.bbc.co.uk/staticarchive/5aaa8b345a205395c996e69fa812f8f92949ceb5.gif
- Animals
- http://www.bbc.co.uk/staticarchive/9c7cc8f9772c8e1087f3da7b1affa4c00bb5109c.gif
- --------> Example of fusion cell cloning
- http://www.bbc.co.uk/staticarchive/9c7cc8f9772c8e1087f3da7b1affa4c00bb5109c.gif
- Plants
- Asexual reproduction is a type of reproduction where offspring arise from a single organism, and inherit the genes of that parent only; it does not involve the fusion of gametes
- Sexual
- Evolution
- Charles Darwin
- Darwin believed that we evolved from apes
- He got this idea from when he saw the same species of bird with different types of beak.
- Scientists ridiculed him because :
- Darwin's theory conflicted with religious beliefs that God put all animals and plants on Earth.
- Darwin did not have enough evidence at the time to convince many scientists
- t took 50 years after Darwin’s theory was published to discover how inheritance and variation worked.
- Darwin believed that we evolved from apes
- Jean-Baptiste Lamarck
- A characteristic which is used more and more by an organism become bigger and stronger and one that is not used eventually disappears.
- Any feature of an organism that is improved through use ispassed on to its offspring.
- An example would be that Lamark thought that giraffes had long necks due to them trying to reach up to get it, which stretched their neck and the gene of a longer neck was passed on to the offspring.
- A characteristic which is used more and more by an organism become bigger and stronger and one that is not used eventually disappears.
- An example would be that Lamark thought that giraffes had long necks due to them trying to reach up to get it, which stretched their neck and the gene of a longer neck was passed on to the offspring.
- Natural Selection
- individuals in a species show a wide range of variation
- this variation is because of differences in their genes
- individuals with characteristics most suited to the environment are more likely to survive and reproduce
- the genes that allow these individuals to be successful are passed to their offspring.
- Charles Darwin
- The Carbon Cycle
- Visit these links to understand
- http://www.bbc.co.uk/schools/gcsebitesize/science/aqa/energy_biomass/thecarboncyclerev2.shtml
- GCSE Bitesize
- Slideshow:
- http://www.slideshare.net/kumartekchandani/carbon-cycle-14155695
- http://www.bbc.co.uk/schools/gcsebitesize/science/aqa/energy_biomass/thecarboncyclerev2.shtml
- Visit these links to understand
- Cells
- Animal
- Nucleus: controls activities of the cell.
- Cytoplasm: where chemical reactions take place.
- Cell membrane: controls passage of substances in and out of the cell.
- Mitachondria: aerobic respiration
- ribosomes: protein synthesis
- Plant
- The same as the animal cells with added features
- Cell wall: strengthens cell.
- Chloroplasts: used for photosynthesis.
- Vacuole: filled with liquid sap
- Bacterial
- Same as animal cells.
- cytoplasm, membrane surrounded by cell wall.
- DNA isn't stored in nucleus.
- Yest
- Nucleus, cytoplasm, membrane surrounded by cell wall.
- Special cells
- Sperm cell
- To fertilise the egg. carries half the genetic information
- Tail to swim to egg. Pointed head to burrow into the egg. mitochondria to provide energy.
- To fertilise the egg. carries half the genetic information
- Muscle cell
- Used for movement
- Special proteins which contract and relax
- Used for movement
- Nerve cell
- To carry nerve impulses about stimuli around the body & impulses that muscles contact.
- Long axon to reduce number of nerve cells. Long axon to cover with fatty tissue to speed up nerve impulses.
- To carry nerve impulses about stimuli around the body & impulses that muscles contact.
- Root hair cell
- Absorb water water into plant roots
- Large surface area to long tube shaped membrane to take in more water
- Absorb water water into plant roots
- Xylem cell
- Carries water through plant stems&leaves
- Long hollow tube, lingin makes strong.
- Carries water through plant stems&leaves
- Ploem cell
- Carries sugar through plant stems.
- Long hollow cells, end wall (sieve plates) holes for sugar to pass through.
- Carries sugar through plant stems.
- Sperm cell
- Animal
- DNA
- Fertilisation begins when these two meet
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