Biology Chloe Price

Anmerkungen:

• Biology

1. Cell Biology
   1. Cell Structure
      1. Eukaryotes & Prokaryotes

         Anmerkungen:

         • All living things are made of cells. Cells can be either prokaryotic or eukaryotic. Eukaryotic cells are complex and include all animal and plant cells. Prokaryotic cells are smaller and simpler (bacteria). Eukaryotes are organisms that are made up of eukaryotic cells. A prokaryote is a prokaryotic cell (it's a single called organism).
      2. Animal Cells

         Anmerkungen:

         • 1. Nucleus - contains genetic material that controls the cells activity. 2. Cytoplasm - gel-like substance where most of the chemicals reactions happen. It contains enzymes that control these chemical reactions. 3. Cell membrane - hold the cell together and keeps everything inside. 4. Mitochondria - these are where most of the aerobic respiration reactions take place. Respiration transfers energy that the cell needs to work. 5. Ribosomes - these are where proteins are made in the cell.
      3. Cell Differentiation

         Anmerkungen:

         • Bacteria don't have chloroplasts or mitochondria. They don't have a true nucleus - instead they have a single circular strand of DNA that floats freely in the cytoplasm. They do have cytoplasm, cell membranes, cell walls and they may also contain one or more small rings of DNA called plasmids. Differentiation is the process by which a cell changes to become specialised for its job. As Cells change, they develop different sub cellular structures and turn into different types of cells. This allows them to carry out specific functions. Most differentiation occurs as an organism develops. In most animal cells, the ability to differentiate is then lost at an early stage, after they become specialised. However, lots of plant cells don't ever lose this ability. The Cells that differentiate in mature animals are mainly used for repairing and replacing cells, such as skin or blood cells. Some cells are undifferentiated cells - they're called stem cells.
      4. Plant Cells

         Anmerkungen:

         • 1. Nucleus - contains genetic material that controls the cells activity. 2. Cytoplasm - gel-like substance where most of the chemicals reactions happen. It contains enzymes that control these chemical reactions. 3. Cell membrane - hold the cell together and keeps everything inside. 4. Mitochondria - these are where most of the aerobic respiration reactions take place. Respiration transfers energy that the cell needs to work. 5. Ribosomes - these are where proteins are made in the cell. Plus 6. Rigid cell wall - made of cellulose. It supports the cell and strengthens it. 7. Permanent vacuole - contains cell sap, a weak solution of sugar and salts. 8. Chloroplasts - these are where photosynthesis occurs, which makes food for the plant. They contain a green substance called chlorophyll, which absorbs the light needed for photosynthesis.
   2. Cell Division
      1. Chromosomes

         Anmerkungen:

         • Most cells in your body have a nucleus. The nucleus contains your genetic material in the form of chromosomes. Chromosomes are coiled up lengths of DNA molecules. Each chromosome carries a large number of genes. Different genes control the development of different characteristics (hair colour). Body cells normally have two copies of each chromosome - one from the organism's 'mother' and one from its 'father'. So, humans have two copies of chromosome 1, two copies of chromosome 2, etc.
      2. Mitosis and the Cell Cycle

         Anmerkungen:

         • Body cells in multicellular organisms divide to produce new cells as part of a series of stages called the cell cycle. The stage of the cell cycle when the cell divides is called mitosis. Multicellular organisms use mitosis to grow or replace cells that have been damaged. The end of the cell cycle results in two new cells identical to the original cell, with the same number of chromosomes. The first stage of the cell cycle: Growth & DNA Replication 1. In a cell that's not dividing, the DNA is all spread out in long strings. 2. Before it divides, the cell has to grow and increase the amount of sub cellular structured such as mitochondria and ribosomes. 3. It then duplicates its DNA - so there's one copy for each new cell. The DNA is copied and forms X-shaped chromosomes. Each 'arm' of the chromosome is an exact duplicate of the other. The second stage of the cell cycle: Mitosis Once it's contents and DNA have been copied, the cell is ready for mitosis... 4. The chromosomes line up at the centre of the cell and cell fibres pull them apart. The two arms of each chromosome go to opposite ends of the cell. 5. Membranes form around each of the sets of chromosomes. These become the nuclei of the two new cells - the nucleus has divided. 6. Lastly, the cytoplasm and cell membrane divide. The cell has now produced two new daughter cells. The daughter cells contain exactly the same DNA - they're identical. Their DNA is also identical to the parent cell.
   3. Transportation in Cells
      1. Diffusion
      2. Osmosis
      3. Active Transport
   4. Specialised Cells
      1. Sperm Cells

         Anmerkungen:

         • The function of a sperm is basically to get the male DNA to the female DNA. It has a long tail and a streamlined head to help it swim to the egg. There are a lot of mitochondria in the cell to provide the energy needed. It also carries enzymes in its head to digest through the egg cell membrane.
      2. Nerve Cells

         Anmerkungen:

         • The function of nerve cell is to carry electrical signals from one part of the body to another. These cells are long (to cover more distance) and have branched connections at their ends to connect to other nerve cells and form a network throughout the body.
      3. Muscle Cells

         Anmerkungen:

         • The function of muscle cells is to contract quickly. These cells are long ( so that they have space to contract ) and contain lots of mitochondria to generate the energy needed for concentration.
      4. Root Hair Cells

         Anmerkungen:

         • Root hair cells are cells on the surface of plant roots, which grow into long 'hairs' that stick out into the soil. This gives the plant a big surface area for absorbing water and mineral ions from the soil.
      5. Phloem & Xylem Cells

         Anmerkungen:

         • Phloem and xylem Cells form phloem and xylem tubes, which transport substances such as food and water around plants. To form the tubes, the cells are long and joined end to end. Xylem Cells are hollow in the centre and phloem cells have very few sub cellular structures, so that stuff can flow through them.
2. Organisation
   1. Digestive System
   2. The Heart and Blood Vessels
   3. Blood
   4. Coronary Heart Disease
   5. Health Issues
   6. Cancer
   7. Plant and Tissue
3. Infection & respomsd
4. Bioenegetics
5. Homeostasis & response
   1. Human nervous system
   2. Hormonal coordination in humans
      1. Human Endocrine System
      2. Control of blood glucose
6. Ecology
7. Inheritance, variation & evolution
   1. Reproduction