Biology Past Paper PDF

mos the cell) - Growth - DNA Replication + Mitosis Stage will have full set of NA Increases the number Mitochondrin...

mos the cell) - Growth - DNA Replication + Mitosis Stage will have full set of NA Increases the number Mitochondrin eg and ribosomes of A Sub-Cellular Structures ② Duplication Forms X-Shaped chromosomes. Each arm of the Chromosome is an exact duplication of the other ③ Division DNA (Cytokinesis) - Jame 'identical 2 daughter cells  Stem Cells Embryonic Stem Cells /can turn into any cell -found in bone marrow lab to Clones can be in produce - grown a Igenetically differentiate identical cells and made to into specialized cells to use in medicine or research Can be used to cure many diseases replace insulin faulty cells cells in sick for people diabetes producing people with In Cloning called a type of therapeutic clonning could made to have the same an embryo be genetic information as a patient therefore will have same genes Stem cells Can produce identical Plants found in meristems in plants Throughout the plants life the cell can differentiate into any type of plant cell  Usmosis : · Osmosis is the movement of water molecules across a partially permeable membrane from a region of higher water concentration to region a of Lower water concentration. · 1. Partially permeable membrane is just one with So small very small holes in it. , in fact only tiny molecules (water) can pass through them , and bigger molecules (e. g sucrose) can't. The water ↑. 2 molecules actuall pass through both ways the membrane during. osmosis his - happens because water molecules more about randomly all the time. J 3. But because there are more water molecules on or side than the other , there's a steady net flor of water into the region with fewer molecules into the sugar solution. stronger sugar 4. This means the dilute stronger solution gets more. / The water acts like it it's trying to "even up the concentration either side of the membrane. 5 Osmosis of diffusion passive is a type -. movement of water particles from an to area of higher water concentration an area of lower concentration. water Sucrose Solution Experiment potato concentration - > absorption Pure water Cas Sugar -Potatde > - Solution  Diffusion is the spread out of particles from an area love of higher carc to on , concentration. area of The bigger the conc. gradient the faster diffusion will take place. Active Transport Sometimes substances needs to be absorbed against a Lac. gradient 29 from. lower to highe concentration This is Active transport process  ExchangingSubstances Gas exchange happens in the lings. The 1 Job of the lungs is to transfer to the oscygen blood and to remove waste carbon dioxida from it.. 2 To do this the lungs curtain millions of little air says called alvedi where gas exchange takes place. &  Circulatory System 7 Heart. 1. Blood flaws into two atria from the rena Cava and the pulmonary veir.. 2 The atria contract. blood pushing the into the ventricles 3 The blood into. ventricles contract , forcing the the pulmonary artery and the aorta and out of S the heart 4. Blood flaws to the organs through arteries , and return through veins.. The fills 5 arteria again and the whole cycle starts over. The heart also needs its own Supply of oxygenated blood. Arteries called coronary arteries branch off the curta and surround the heart, that all the oxygenated blood, making sure it gets  Blood Vessels 1) Auction - These carry the blood away from the heart -. 2 Capillaries - exchange of materials at the fissues 3. Veins-these carry blood to the heart Capillaries are Really Small 1 Arteries Branch. into capillaries. 7 Capillaries are really tiny. TheyCarry 3 blood close to every in the really cell the body to exchange substances with them, 4. permeable walls , so substances can diffuse in and. out 5 , Walls only one cell thick. This increases the rate of diffusion by deceasing the distance over which it occurs,  Blood Adaptations Red blood cells carry Oxygen 1 carry oxygen from lungs body. the to all the cells in 2 - Shape is biconcave dis this gives a. 3 large dar surface / area for absorbing oxygen. They have a nucleus - allows more room to carry osgen 4 contain red called haemoglobin. a pigment 5 In the. lungs , haemoglobin binds to agen In to become ayhaemoglobin. body tissues S the reverse happens any haemoglobin and oxygen to release pitsupintohaemogla