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.