Biology

• Units

  identify

  units

  substitute

  solve

  present
• Eukaryotic include animal and plant cells. They contain nucleus
• Prokaryotic are bacteria, they do not have a nucleus
• Cell membrane is the outer layer that controls what goes into and out of cell.
• Prokaryotic are smaller and simpler. They don’t have a nucleus
• mitochondria is where most of the reactions for aerobic respiration take place. required energy that respiration transfers
• chloroplasts are found in plants and algae. it contains chlorophyll which absorbs light energy from sunlight to make glucose through photosynthesis
• Ribosomes are where proteins are made in the cell
• Plant cells have a rigid cell wall, made of cellulose. Supports the cell and strengthens it.
• vacuole contains cell sap - a weak solution of sugar and salts
• Bacteria are prokaryotes. Don’t have a true nucleus. Instead have a singilar strand of DNA called plasmids. Don’t have a true cytoplasm.
• Light microscopes use light and lenses that form an image of a specimen and magnify it. Lets us see individual cells and large subcellular structures, like nuclei
• Electron microscope uses electrons instead of light. It can be used to view very small objects such as viruses or bacteria. The electron beam is focused onto a screen by magnetic fields. This produces an image on the screen.
• Differentiation is where the process of by which a cell changes to become specialised for its job
• As cells change, they develop subcellular structures and turn into different types of cells
• Most differentiation occurs as an organism develops. In most animal cells, the ability to differentiate is then lost early stage, after they become specialised. Mainly used for repairing and replacing cells e.g skin or blood cells.
• Undifferentiated cells are stem cells
• Sperm cells are used for reproduction
• Sperm cells carries enzymes in its head to provide the energy needed.
• Nerve cells are specialised for rapid signalling, From one part of the body to another
• Nerve cells are long (to cover more istance) and have branched connections at their ends to connect to other nerve cells from a network throughout the body
• Muscle cells are specialised for contraction.
• The function of a muscle is to contract quickly
• Cells are long so that they have space to contract and contain lots of mitochondria to generate the energy needed for contraction
• Root hair cells are specialised for absorbing water and minerals
• Root hair cells are on the surface of plant roots, which grow into long hairs that stick out in the soil
• the long hairs that stick out in the soil gives the plant a big surface area for absorbing water and mineral ions from the soil
• Stem cells are found in early human embryos
• Stem calls have the potential to turn into any kind of cell at all
• Stem cells from embryos and bone marrow can be grown in a lab to produce clones (genetically identical cells) and made to differentiate into specialised cells to use in medicine or research.
• Stem cells may be able to cure many diseases by replacing faulty cells with healthy ones
• Embryonic stem cells could also be used to replace faulty cells in sick people.
• Therapeutic cloning- an embryo could be made to have the same genetic information as the patient, which means the stem cells produced from it would also contain the same genes and so wouldn’t be rejected by the patients body if used to replace faulty cells
• There are risks involved in using stem cells for medicine e.g stem cells grown in a lab may become contaminated with a virus that can be passed on to the patient, making them sicker
• Some people are against stem cell research as they feel that human embryos shouldn’t be used to experiment since each one is a potential human life
• Coronary Heart Disease.

  when the coronary arteries that supply blood to the muscle of the heart get blocked by the layers of fatty deposits building up. Causes the arteries to become narrow-> blood flow is restricted.
• Coronary Heart disease 


  Can be fatal as blood flow is restricted to the layers of fatty build up in arterie, leading to lack of oxygen to the heart muscle, which can result in a heart attack.
• Stents


  Tubes that are inserted in arteries to keep them open, making sure blood passes through to the heart muscles, which keeps the heart beating.
• Strokes can cause damage to parts of the brain responsible for movement, speech and memory. This can lead to paralysis, loss of speech and difficulty remembering things.
• Stroke - when the blood supply to part of the brain is cut off or reduced due to blockage or bursting of a blood vessel.