Year 10 Chapters 1-3 Flashcards
What is diffusion?
The net random movement of particles from an area of high concentration to low concentration. No energy is required to move
What effects the rate of diffusion?
- Concentration gradient: the higher the concentration on one side compared to the other the faster the rate of reaction.
- Temperature: the molecules gain kinetic energy therefore the net random movement increases increasing the rate of reaction.
What is osmosis?
It is the movement of water molecules from an area of high water potential to an area of low water potential, it must be across a partial permeable membrane, e.g. a cell membrane.
What is a hypertonic solution?
If the solution outside the cell has a higher concentration than inside the cell.
What is a hypotonic solution?
If the solution outside the cell has a lower concentration than inside
What is an isotonic solution?
If the solution outside the cell has the same concentration as inside
What is a eukaryotic cell?
A multicellular organism which contains a cell membrane, cytoplasm and genetic material in strings of chromosomes which is enclosed in the nucleus. Animal and plant cells are examples of eukaryotic cells.
What is a prokaryotic cell?
A single cellular organism, they have cytoplasm and a cell membrane surrounded by a cell wall (which doesn’t contain cellulose) and a plasmid (which is freely moving inside the cytoplasm)
What is active transport?
The movement of substances from an area of low concentration to an area of high concentration against the concentration gradient.
What are xylem cells?
- Transpiration
- Moves water and minerals from the roots to the shoots to the leaves
- The structure has a strong cellulose cell wall and continuous columns of dead hollow cells.
What are phloem cells?
- Translocation
- Moves glucose created by photosynthesis in the leaves to the rest of the plant for food
- The structure is a series of columns of living cells
What is in interphase? The first stage
G1, S and G2 phases
What is in the mitosis phase? The second stage
Mitosis and cytokinesis
What happens during interphase?
- The cell prepares to divide
- G1: the cell grows and new organelles and proteins are made
- S: DNA synthesis, this is when the cells DNA is copied e.g. 46 chromosomes are doubled to 96
- G2: the cell keeps growing
What happens during mitosis?
- The chromosomes become shorter and thicker to fit into the smaller dividing cells.
- The chromosomes line up along the centre of the cell
- They get pulled to opposite ends (poles) of the cell
- Cytokinesis: the cytoplasm divides to produce twin genetically identical cells.
What is the purpose of mitosis?
- To replace worn or damaged cells
- To repair damaged tissue (e.g. Bone/muscle)
- To grow
Wha is differentiation?
When cells in their early stage become specialised for particular functions, they cannot change into a different type of cell.
What is cell division used for in animals?
It is restricted to replacement and repair, but in plants they keep the ability to differentiate.
Sources of stem cells?
- Embryos (embryonic stem cells)
- Bone marrow (adult stem cells)
Examples of treatments stem cells could provide?
- Spinal cord injuries
- Diabetes
- Could restore eyesight in the blind
- Skin grafting
What is a tissue?
A group of cells with similar structure and function working together
What is an organ?
Organs are collections of tissues, each organ contains several tissues working together to perform a specific function.
What is a catalyst?
It speeds up the chemical reaction but is not used up in the reaction itself. It can be used over and over again.
What are enzymes?
They are biological catalysts which catalyse specific reactions in living organisms.
What is the shape and molecular structure of an enzyme?
Enzymes are large protein molecules, it has long chains of amino acids which are folded to produce a molecule with an activation site. This site has a unique shape so that it can bind to a specific substrate molecule.
How does the lock and key theory work?
- The enzyme first combines with the substrate at the activation site
- The substrate fits into the activation site
- The substrate splints into its products and leaves the activation site
- The enzyme is ready to use again with no change to it
What is metabolism?
The sum of all the reactions in a cell or the body
What are the key factors that effect enzyme reaction rate?
Temperature and PH, the optimum temperature for enzymes in the bod is 37 degrees (body temperature).
What does denatured mean?
When an enzyme has had too high of a temperature and the long amino acid chains have begun to unravel. When an enzyme is denatured it can no longer act as a catalyst, so the rate of reaction drops drastically.
How does PH effect enzymes?
The shape of the activation site comes from the forces between the different parts of the protein molecule. These forces hold the folded chains in place. A change in PHeffects these forces and so a drastic change in PH may prevent an enzyme from working completely.
Why does the digestive system break down food?
It breaks down food so it is small enough to fit into the bloodstream so that glucose can travel to the cells and organs to create energy.
Which enzyme focuses carbohydrates?
Amylase catalysts the break down of carbohydrates into sugars in your mouth and small intestine.
Which enzyme focuses proteins?
Protease catalyses the break down of proteins into amino acids in your stomach pancreas and small intestine.
Which enzyme focuses fats?
Lipase catalyses the break down of fats into fatty acids and glycerol in the small intestine and pancreas.
Why does the stomach include hydrochloric acid?
Because it provides a suitable PH for the protease working there to work efficiently.
What is alkaline bile used for?
Alkaline bile is used to neutralise the acid coming from the stomach and gives a high PH for the enzymes of the pancreas and small intestine to work well.
What is bile?
It is not an enzyme as it does not break down fat molecules. Instead it emulsifies the fat into tiny droplets to increase the rate of reaction.
What is an advantage and disadvantage of a light microscope?
- They are cheaper and easier to use
- They have poor axial resolution, ie they cannot measure depth nearly as well as other microscopes
What is an advantage and disadvantage of an electron microscope?
- It has extremely high magnification
- It is very expensive, large and requires lots of maintenance
What is the formula for magnification?
IAM
Image size = actual size x magnification
