1 - Cell Biology

• Active transport: The movement of substances from a more dilute solution to a more concentrated solution (against a concentration gradient) with the use of energy from respiration
• Embryonic stem cell: A type of stem cell that can form many types of cells
• Agar jelly: A substance placed in petri dishes which is used to culture microorganisms on
• Cell differentiation: The process where a cell becomes specialised to its function
• Cell membrane: A partially permeable barrier that surrounds the cell
• Cell wall: An outer layer made of cellulose that strengthens plant cells
• Chloroplast: An organelle which is the site of photosynthesis
• Chromosomes: DNA structures that are found in the nucleus which are made up of genes
• Concentration gradient: The difference in concentration between two areas
• Diffusion: A net movement of particles (in a solution or gas) from an area of higher concentration to an area of lower concentration
• Embryonic stem cell: A type of stem cell that can differentiate into most types of human cells
• Eukaryotic cell: A type of cell found in plants and animals that contains a nucleus
• Magnification: How much bigger an image appears compared to the object
• Meristematic cells: A type of stem cell that can differentiate into any type of plant cell
• Mitochondria: An organelle which is the site of respiration
• Mitosis: A type of cell division which produces two genetically identical daughter cells from one parent cell
• Nucleus: An organelle found in most eukaryotic cells that contains the genetic material of the cell and controls the activities of the cell
• All living things are made of cells, which can either be prokaryotic or eukaryotic.
• Organelle: A specialised structure found inside a cell
• Animal and plant cells are eukaryotic and have a cell membrane, cytoplasm, nucleus containing DNA, and a permanent vacuole.
• Osmosis: The diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane
• Plasmid: Loops of DNA found in the cytoplasm of prokaryotic cells
• Bacterial cells are prokaryotic and have a cell wall, cell membrane, cytoplasm, single circular strand of DNA and plasmids.
• Organelles are structures in a cell that have different functions.
• Prokaryotic cell: A type of cell found in bacteria that does not contain a nucleus
• Resolution: The ability to distinguish two different points in a specimen
• Specialised cells: Cells that are adapted to perform a specific function
• In the gut, substances such as glucose and amino acids from food have to move from the gut into the bloodstream.
• Sometimes there can be a lower concentration of sugar molecules in the gut than the blood, meaning diffusion cannot take place.
• Active transport is required to move the sugar to the blood against its concentration gradient.
• Mineral ions are usually in higher concentrations in the cells, meaning diffusion cannot take place.
• This requires energy from respiration to work.
• Root hairs take up water and mineral ions for healthy growth from the soil.
• Stem cell: An undifferentiated cell that can divide to produce many specialised cells of the same type
• In animal and plant cells, the nucleus contains DNA coding for a particular protein needed to build new cells, is enclosed in a nuclear membrane, and controls what enters and leaves the cell.
• Surface area: The amount of contact an object has with its environment
• In animal and plant cells, the cytoplasm is a liquid substance in which chemical reactions occur, contains enzymes, and organelles are found in it.
• Surface area to volume ratio (SA:V): The size of the object compared with the amount of area where it contacts its environment
• In animal and plant cells, the cell membrane controls what enters and leaves the cell, and organelles are found in it.
• The cell cycle: A series of stages preparing the cell for division