IB standard biology: cells (cell theory to stem cells)
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- Created by: ameliahilton
- Created on: 10-12-16 14:56
What are the statements of the cell theory?
1) All living things are made of cells 2) New cells come from old cells 3) Cells contain genetically inherited information
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Give 2 examples of multi-nucleated cells (exception to cell theory)
Spirited muscle cells (cells fuse, so there are multiple nuclei in one membrane), Aseptate fungal hyphae (have continuous cytoplasm)
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Give an example of a large single-celled organism (exception to cell theory)
Giant algae (up to 7 cm in size)
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Why are viruses considered 'non-living'
They don't contain their own DNA replicating machinery, they only reproduce by infecting host cells)
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What is the anagram for the functions of life?
MRHGREN
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What is the M?
Metabolism - living things perform essential chemical reactions
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What is the R?
Response - living things react to internal or external stimuli
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What is the H?
Homeostasis - living things maintain a stable internal environment
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What is the G?
Growth - living things increase in size or cell number
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What is the R?
Reproduction - living things produce offspring, asexually or sexually
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What is the E?
Excretion - living things remove potentially harmful waste products
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What is the N?
Nutrition - Living things ingest vital substances that are broken down to produce energy
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What is the Magnification equation
Magnification = size of image/ actual size
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How do bacteria reproduce?
Binary fission
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What is the size of a molecule?
1 nm
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What is the size (thickness) of a cell membrane?
10 nm
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What is the size of a virus?
100 nm
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What is the size of a Prokaryote?
1 um
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What is the size of a Eukaryote?
10 um
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What is the size of a cell?
100 um
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As the volume of a cell increases....
waste production increases, use of nutrients and O2 increases, SA:vol decreases
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What are the advantages of a large SA:vol ratio?
More effective exchange and reactions, larger area for actions to occur on
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How can a large cell increase its SA:vol ratio?
splitting into 2 cells, developing villi
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Name 2 unicellular organisms which carry out all the functions of life?
Paramecium, Scenedesmus
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What are emergent properties?
the interaction of separate cellular components to allow the production of new functions
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Define differentiation
the expression of some genes but not others in a cells genome (specialise for a specific function in early development)
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How does differentiation occur?
Chemical signals activate certain genes in the genome (identical in call cells) which are expressed.
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What are 'activated' genes?
They are genes (from the genome) that are expressed, and are packing in euchromatin (which can be accessed by transcriptional machinery)
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What are 'inactive' genes?
unexpressed genes , packaged in heterochromatin (which isn't transcribed)
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What are the properties of a stem cell?
Self-renewal = can continuously divide and replicate, Potency - can differentiate into specialised cells
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What are the 3 different sources of stem cells?
embryos, placenta/umbilical cords, adult bone marrow
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Name 2 + and 2 - stem cells from embryos?
+ unlimited differentiation and growth potential + less chance of genetic damage - more risk of tumors - embryo dies if more than 1/2 cells taken
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Name 2 + and 2 - stem cells from placenta/umbilical cords?
+ recognised as 'self' by immune system + commercial collection already available - limited quantity - limited differentiation capacity
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Name 2 + and 2 - stem cells from adult bone marrow?
+ fully compatible with adult tissues + les chance of malignant tumors - painful and difficult to extract - limited growth and differentiation potential
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What are artificial stem cell production methods?
Somatic cell nuclear transfer, Nuclear reprogramming
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How can stem cells treat Stardgart's disease (genetic disease which can cause blindness)?
Retina cells (from embryonic stem cells) are implanted into eye to replace damaged cells
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How can stem cells treat Leukaemia (abnormal no. of white blood cells produced due to genetic mutation)?
Stem cells removed from bone marrow of donor, and implanted into patient (using catheter) where they travel to bone marrow in blood stream and make healthy bone marrow cells
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Other cards in this set
Card 2
Front
Give 2 examples of multi-nucleated cells (exception to cell theory)
Back
Spirited muscle cells (cells fuse, so there are multiple nuclei in one membrane), Aseptate fungal hyphae (have continuous cytoplasm)
Card 3
Front
Give an example of a large single-celled organism (exception to cell theory)
Back
Card 4
Front
Why are viruses considered 'non-living'
Back
Card 5
Front
What is the anagram for the functions of life?
Back
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