Biology
- Created by: RobbieMoore
- Created on: 03-03-19 00:44
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- Cell biology
- Cells
- Prokaryotic cells are smaller and simpler e.g. bacteria
- Chromosomes and mitosis
- Chromosomes are coiled up lengths of DNA molecules
- Each chromosome carries a large number of genes
- A human cell has 23 pairs of chromosome,46 chromosomes
- Each chromosome carries a large number of genes
- Body cells have 2 copies of each chromosomes, one from the organisms 'mother' and one from its 'father'
- A human cell has 23 pairs of chromosome,46 chromosomes
- The DNA is spread out in long springs
- Before it divides it has to grow the amount of subcellular structures
- It then duplicates its DNA
- The chromosomes line up at the center of the cell and cell fibres pull them apart
- Membranes form around each set of chromosome and become the nuclei of the two new cells
- Lastly the cytoplasm and cell membrane divide
- Membranes form around each set of chromosome and become the nuclei of the two new cells
- The chromosomes line up at the center of the cell and cell fibres pull them apart
- It then duplicates its DNA
- Before it divides it has to grow the amount of subcellular structures
- Chromosomes are coiled up lengths of DNA molecules
- Diffusion
- The spreading out of particles from an area of HIGHER concentration to an area of LOWER concentration
- Happens in both solutions and gases because the particles are free to move about randomly
- The bigger the concentration gradient, the faster the diffusion rate
- Happens in both solutions and gases because the particles are free to move about randomly
- Cell membranes hold the cell together but they let stuff in and out as well
- dissolved substances can move in and out of cells by diffusion
- Only small molecules can diffuse through cell membranes like oxygen, glucose, amino acids and water
- The larger the surface area of the membrane, the faster the diffusion rate because more particles can pass through at once
- Only small molecules can diffuse through cell membranes like oxygen, glucose, amino acids and water
- dissolved substances can move in and out of cells by diffusion
- The spreading out of particles from an area of HIGHER concentration to an area of LOWER concentration
- Osmosis
- Osmosis is the movement of water molecules across a partially permeable membrane from a region of higher water concentration to a lower water concentration
- Osmosis is a type of diffusion
- A partially permeable membrane is a membrane with small holes in it
- Water molecules pass both ways through the membrane during osmosis
- The water acts like its trying to even up the concentration either side of the membrane
- Water molecules pass both ways through the membrane during osmosis
- Osmosis is the movement of water molecules across a partially permeable membrane from a region of higher water concentration to a lower water concentration
- Active Transport
- Active transport allows the plant to absorb minerals from a very dilute solution, against a concentration gradient
- Active transport needs energy from respiration to make it work
- Active transport is used in the gut when there is a lower concentration of nutrients in the gut, but a higher concentration of nutrients in the blood
- Active transport allows the plant to absorb minerals from a very dilute solution, against a concentration gradient
- Cells
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