Biology

• Palisade cells contain lots of chloroplasts so they can carry out maximum photosynthesis
• Plants and algae produce their own biomass through photosynthesis, and so are the producers in food chains
• Eukaryotic cells are complex
• Animal and plant cells are eukaryotic
• Prokaryotic cells are simple and smaller
• Bacteria is a prokaryotic cell
• Nucleus contains genetic material that controls the activities of the cell
• Mitochondria is where most of the reactions for a aerobic respiration take place
• Respiration transfers energy that the cell needs to work
• cytoplasm is a gel like substance, where most chemical reactions happen, it contains enzymes that control these chemical reactions
• The cell membrane holds the cell together and controls what goes in and out
• Ribosomes are where proteins are made in the cell
• rigid cell walls are made of cellulose and supports the cell and strengthens it
• chloroplasts is where photosynthesis occurs, which makes food for the plant. They contain a green substance, called chlorophyll, which absorbs the light needed for photosynthesis
• A permanent vacuole contains cell sap, which is a weak solution of sugar and salts
• Bacterial cells don’t have a true Nucleus. Instead, they have a single circular strand of DNA that flows freely in the cytoplasm.
• Electron microscopes let is see much smaller things in more detail
• Light microscopes use light on lenses to form an image of a specimen and magnify it.
• Differentiation is the process by which a cell changes to become specialised for its job
• As cells change They develop different subcellular structures and turn into different types of cells. This allows them to carry out specific functions.
• Stem cells are undifferentiated
• Sperm cells are differentiated and the function of it is to get the male DNA to a female DNA
• Sperm is differentiated as it has a long tail to help it swim and a lot of mitochondria in the cell to provide the energy needed
• Nerve cells are specialised, and the function is to carry electrical signals from one part of the body to another. Nerve cells are long to cover more distance and have branched connections at their ends to connect to other nerve cells and form network
• The function of a muscle cell is to contract quickly, they are long so they have space to contract and contain lots of mitochondria to generate energy needed for contraction. This is specialisation
• Root hair cells are specialised for absorbing water and minerals. They 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.
• Phloem and xylem cells are specialised for transporting substances
• Phloem and xylem cells from phloem and xylem tubes which transports substances such as food and water around the plants
• Stem cells divide to produce lots more undifferentiated cells
• Stem cells are found in early human embryos. They have the potential to turn into any kind of cell. adults have stem cells, but theyre only found in places like the bone Marrow.
• Stem cells from embryos and bone marrows can be from in a lab to produce a clone which is a genetically identical cell and made to differentiate into specialised cells to use in medicine or research
• Medicine already uses adult stem cells to cure disease. For example, stem cells transferred from the bone marrow of a healthy person can replace a faulty blood cell.
• Embryonic stem cells can be used to replace faulty cells in sick people, you can also make insulin producing cells for people with diabetes or nerve cells for people paralysed by spinal injuries
• In therapeutic cloning, an embryo could be made to have the same genetic information as a patient. This means that stem cells produce from it will also have the same genes, and so wouldnt be rejected by the patient’s body if used to replace faulty cells.
• The risk of using stem cells in medicine is that some stem cells grown in the lab may be contaminated with a virus which could be passed on to the patient and make them sicker
• Some people are against stem cell research because they feel that human embryos shouldn’t be used for experiments since each one is potential human life however, some believe that curing patients who already exist and are already suffering is more important than the rights of embryos
• Stem cells used in research are usually unwanted from fertility clinics, whoever didn’t go to research, they would most likely be destroyed
• In some countries stem cell research is banned but is allowed in the UK as long as it follow strict guidelines
• in plant stem cells are found in the meristem
• Throughout life of a plant, stem cells in the meristem tissue can differentiate into any type of plant cell. The stem cells can be used to produce clones of whole plants quickly and cheaply.