B1-Cell Biology

• all living things are made of cells
• eukaryotic cells are all complex cells like plant and animal cells
• prokaryotic are smaller and simpler like bateria cells
• nucleus contains genetic material that controls the activities of the cell
• cytoplasm is a gel - like substance where most of the chemical reactions happen
• cell membrane holds the cell together and controls what goes in and out
• mitochondria is where most of the reactions for aerobic respiration take place. respiration transfers energy that the cell need in order to work
• ribosomes this is where proteins are made in the cell
• animal cells have a nucleus, cytoplasm, cell membrane, mitochondria and ribosomes
• cell wall is made of cellulose and strengthens and supports the cell
• permanent vacuole contains cell sap a weak solution of salt and sugarr
• chloroplast is where photosynthesis occurs which makes food for the plant
• green substance is called chlorophyll which absorbs light
• plant cells have a cell wall, permanent vacuole, chloroplast, nuclease, cytoplasm, cell membrane, mitochondria and ribosomes
• bacteria cells are prokaryotic
• bacteria cells have cytoplasm, cell membrane, cell wall, singular strand of DNA and plasmids
• light microscopes use light and lenses to form an image of a specimen and MAGNIFY it
• electron microscopes use electrons instead of light to form an image. they have a higher magnification than light microscopes
• magnification = image size / real size
• to convert um to mm you need to divide by 1000
• add a drop of water to middle of a clean slide, cut an onion into layers and peel of some EPIDERMAL TISSUE, using tweezers place the layer on the slide, add a drop of iodine solution, place a cover slip on top then carefully tilt and lower it to cover the specimen
• clip the slide onto the stage, select the lowest objective lens, use the coarse knob to move the stag up , look down the eye piece and use the coarse knob to gain focus, adjust focus with the fine knob
• differentiation is the process by which a cell changes to become specialised for its job
• a cell changes its subcellular structure to turn into a different type of cell
• sperm cells are specialised for reproduction and have a long tail and a streamlined head to swim faster
• nerve cells are specialised for rapid signalling and they are long and thin to travel long distance
• muscle cells are specialised for contractions and they are long and contain lots of mitochondria to generate the energy needed for contraction
• root hair cells are specialised for absorbing water and minerals they have long hairs to give the plant a big surface area for absorbing water and mineral ions from the soil
• phloem and xylem are transporting substances and they transport food
• xylem cells are hollow in the centre
• phloem cells have very few subcellular structures so that stuff can flow through them
• chromosomes contain genetic information
• humans have 23 pairs of chromosomes
• mitosis before it divides it must grow and increase the subcellular structure such as mitochondria and ribosomes, then duplicate its DNA until the DNA copies and forms a x-shaped chromosome, the chromosome line up and the cell fibres pull apart to form two identical daughter cells
• stem cells can cure many dieses such as paralysed by spinal injuries, diabetes and heart disease
• people are against stem cell research because they harvest embryos which are seen killing life
• diffusion is the spreading out of particles from an area of a high concentration to an area of lower concertation
• diffusion happens in solutions and gases
• cell membranes are semi permeable letting oxygen and water through but not starch and protiens
• osmosis is the movement of water molecules across a partial permeable membrane from a region of high water concentration to a region of lower water concentration