cell biology b1
- Created by: user101123
- Created on: 26-03-20 01:10
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- Cell biology
- Cells
- Eukaryotes are complex organisms which include all animal and plant cells.
- Eukayotes made out of eukaryotic cells
- Prokaryotes - are small, simple cells, like bacteria. They are single-celled
- Prokaryotes made of prokaryotic cells.
- Bacteria dont have a 'true' nucleus, chloroplasts or mitochondria.
- They have plasmids.
- Animal and plant cell structures
- Nucleus - contains genetic material that controls cell activity.
- Cytoplasm - gel like substance where most chemical reactions happen.
- Cell membrane - holds cell together and controls what goes in and out.
- Mitochondria - site of aerobic respiration, this transfers energy needed for cell to work.
- Ribosomes - where proteins are made in cell.
- Plant only structures
- Rigid cell wall - supports and strengthens cell. It is made of cellulose.
- Vacuole - contains cell sap, sugars and salts.
- Chloroplasts - where photosynthesis occurs which makes food for plant. Contains chloroplasts.
- Eukaryotes are complex organisms which include all animal and plant cells.
- Microscopy
- Light microscopes
- Use light and lenses to form image of specimen and magnify it.
- They let us see individual cells and large subcellular structures like nuclei.
- Use light and lenses to form image of specimen and magnify it.
- Electron microscopes
- Use electrons to form an image. They have a higher magnification and resolution than light microscopes.
- Let us see small things like internal structures.
- Use electrons to form an image. They have a higher magnification and resolution than light microscopes.
- Magnification== image size / real size
- Light microscopes
- Differentiation
- When a cell changes to become specialised for it function
- develop different subcellular structures
- Sperm speciallised for reprod, nerve cells....
- Most animal cells only can differentiate as embryos wheres plants can differentiate throughout whole life
- undifferentiated cells = stem cells
- When a cell changes to become specialised for it function
- chromosomes and mitosis
- Chromosomes contain genetic info. Nucleus contains genetic material in form of chromosomes.
- 23 pairs of chromosomes in a human cell.
- mitosis
- dividing of cells. Multicellular organisms use mitosis to grow or replace damaged cells
- producees 2 genttically identical daughter cells. clones of parent
- dividing of cells. Multicellular organisms use mitosis to grow or replace damaged cells
- Chromosomes contain genetic info. Nucleus contains genetic material in form of chromosomes.
- stemcells
- can turn into any type of cell
- stem cells are found in 2 places: human embryos or bone marrow
- May be able to cure many dieassse, e.g. diabetes and parralysis
- stem cell use controversial as each embryo a potential human life
- stem cells used in plants. found in meristems
- stem calls can produce plants quickyl and cheaply, prevent extinction of rare plant species and grow disease resistant crops
- can turn into any type of cell
- diffusion
- the movement of particles from an area of high conc. to an area of lower conc.
- the bigger the conc gradient, the faster the diffuion rate
- higher temp = faster diffusion rate as particles have more enrgy so move mroe.
- osmosis
- movement of water molecules from an area of high water conc to low water conc through a partiallt permeable membrane
- water molecules can ppass both ways through membrane during osmosis
- movement of water molecules from an area of high water conc to low water conc through a partiallt permeable membrane
- active transport
- when substances move agianst a conc gradient, from a lower ocnc to a higher con
- root hairs take in minerals and water by using active transport
- essential for plant growth
- active transport is used in the gut when there is a higher of nutrients in the gut but a lower of nutrients in the blood
- exchange surfaces
- Cells can use diffusion to take in substances they need and to get rid of waste products
- How easy it is for the organism to exchange surface with its environment depends on the organisms surface area to volume ratio.
- Multi cellular organisms have a small surface area to volume ratio
- How easy it is for the organism to exchange surface with its environment depends on the organisms surface area to volume ratio.
- Cells can use diffusion to take in substances they need and to get rid of waste products
- Cells
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