Biology Revision Key Concepts

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What is Eukaryotic Cell and what is a Prokaryotic Cell?
A cell with a nucleus is Eukaryotic and a cell with no nucleus is Prokaryotic
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1)Describe sub-cellular structures of a Eukaryotic Cell(animal cell)
Cytoplasm-watery jelly-cells activities occur here Mitochondria-jelly bean structure-aerobic respiration Ribosomes-tiny round structures-make new proteins Cell membrane-controls what enters and leaves the cell-seperates one cell from another
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2)Describe sub-cellular structures of a Eukaryotic Cell(animal cell)
Nucleus-controls cell and its activities Small Vacuole-stores nutrients
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Describe sub-cellular structures of a Prokaryotic Cell(bacteria cell)
Flagellum-tail like structure- uni-cellular organism to move Cell membrane-controls what goes in and out Chromosomal DNA-main DNA-large loop of DNA found in bacteria Ribosomes-sphere shape-protein synthesis Plasmid DNA-DNA found in plasmids
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1)Plant Cell
Nucleus-inside the cell Cell wall-made of cellulose-supports cell Chloroplasts-contains chlorophyll-traps suns energy-photosynhesis Cytoplasm-cells activities occur Large Vacuole-stores cell sap-keep cell firm rigid
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2)Plant Cell
Mitochondria-Aerobic Respiration occurs Cell membrane-controls what enters and leaves the cell-separates on cell from another
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What are specialised cells
Has a specific function or job inside the cell
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Specialised cells in egg cell
Cytoplasm-packed with nutrients-supplies fertilised egg with energy-raw materials-growth development-embryo Haploid cell-23 chromosomes fuses with sperm
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Specialised cells in sperm cell
Stream lined shape-help sperm to move to meet egg Haploid cell-23 chromosomes-fuses with egg cell Acrosomes-tip of head-contains enzymes break down substances-egg cell jelly coat-allows sperm inside Mitochondria-spiral-top of tail-energy for tail
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Ciliated Epithelial Cells
Cells-line structure in body-epithelial cells epithelial cells with cilia-ciliated epithelial cells. Fertilisation occurs-oviduct-female reproductive system. Oviduct adapted-like short sperm cell tails-wave side to side-sweep substances along
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Ciliated Epithelial Cells
Cilia(like sperm tails) are covered in cell membrane-contain strands of substance-cause wavy movement
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Advantages of electron microscopy and what it is
Use electrons energy to show image of cell. 1)Higher Magnification 2)Resolution is better 3)Electron microscopes enbale us to see cell strcuturs with miore clarity and detail. Increased understanding of the role of sub-cellular structures.
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Disadvantages of electron microscopy
1)Only use dead organisms 2)Really Expensive 3)Preparation and equipment is very expensive
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Advanatges of light microscopy and what it is
Use light energy to show image. 1)Orgamisms can be alive 2)Reasonably Cheap 3)Large field view
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Disadvantages of light microscopy
1)Low magnification 3)Low resolution
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How do you work out magnification?
multiply magnification of both lenses (eyepiece lend and objective lens)
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Practical Microscopes
Wear eye protection. 1) Decide which cells to observe and how you will collect them. Consider using your own cheek cells or pieces of tissue from onion bulbs. 2) Collect a small specimen of the cells.
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Practical Microscopes
3)Add a drop of water or stain to the centre of a microscope slide. Record the name of any stain that you use. 4) Place your specimen on the drop of water or stain.Use a tweezer to slowly lower a coverslip onto the specimen.
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Practical Microscopes
5) The cover slip keeps the specimen flat, holds it in place and stops it drying out.6) Examine your specimen under a microscope. Start with the lowest magnification and work up to higher magnifications.
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What are enzymes?
Biological catalyst-increase the rate of chemical reactions without being used up. Enzymes-proteins folded-complex shapes-allow molecules to fit into them. The place where the molecules fit is called the active site.
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what is Enzyme Specificity?
The enzyme will catalyse only one reaction. every enzyme can only work with specific substrates that fit the active site
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Denatured enzymes
Changing the shape of the active site of an enzyme will cause its reaction to slow down until the shape no longer fits.When this happens the reaction stops. This is when enzymes become denatured.
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Reasons to be denatured
High temperature and extreme pH.Both high temp and extreme pH change the bonds between the amino acids.This will change its shape-substrate will no longer fit.
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What is optimum temperature?
The temperature at which an enzyme works fastest.
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What is substrate concentration?
The substrate concentration is the concentration of the molecules an enzyme works on.If you raise the substrate concentration, then more enzymes will be catalyzing the chemical reaction and the overall rate of reaction will increase.
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What are three ways in which substances can be transported out of cells?
1)Diffusion 2)Osmosis 3)Active Transport
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What is Diffusion?
Smells spread by diffusion.Particles-consistently moving past eachother-all directions.Overall movement of particles-from high concentration to low concentration.
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What is a concentration gradient?
Difference between 2 concentration. Particles diffuse down a concentration gradient. Bigger difference=steeper concentration=diffusion occurs faster
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What is Osmosis?
A membrane that allows some molecules in and not others is partially permeabale. Osmosis is the diffusion of small molecules of a solvent-water-through a semipermeable membrane . overall movemnt stops when conc. of solutes is same on both sides.
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How to calculate Osmosis?
(final mass-initial mass)/initaial mass x100% negative answer will be a loss in mass
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What is Active Transport?
When cells need to transport molecules against a concentration gradient or transport molecules that re too big to diffuse through cell membrane.Low conc.-High conc.
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Other cards in this set

Card 2

Front

1)Describe sub-cellular structures of a Eukaryotic Cell(animal cell)

Back

Cytoplasm-watery jelly-cells activities occur here Mitochondria-jelly bean structure-aerobic respiration Ribosomes-tiny round structures-make new proteins Cell membrane-controls what enters and leaves the cell-seperates one cell from another

Card 3

Front

2)Describe sub-cellular structures of a Eukaryotic Cell(animal cell)

Back

Preview of the front of card 3

Card 4

Front

Describe sub-cellular structures of a Prokaryotic Cell(bacteria cell)

Back

Preview of the front of card 4

Card 5

Front

1)Plant Cell

Back

Preview of the front of card 5
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