Cellular Biology (all subunits)

Question	Answer
Cell theory	All living things are made of cells. Cells are the smallest unit of life. Organelles are unable to survive on their own.
Functions of life	Metabolism. Response. Homeostasis. Growth. Reproduction. Excretion. Nutrition.
Emergant properties	When cells start working together in multicellular organisms in tissues, organs, and organ systems, they start displaying properties that individual cells do not have.
Differentiation	A process through which cells become specialised, where genes are "turned on and off" as required (called gene expression).
Prokaryotes	Bacteria. Simple structure, no compartments.
Eukaryotes	Plants, animals, fungi, protoza. Complex and compartmentalised.
Plasma membrane	A semi-permeable membrane which controls what enters/leaves the cells.
Ribosomes	Site of protein synthesis. Can be associated with endoplasmic reticulum, secreted proteins. Can be free in cytoplasm, internal proteins.
Mitochondria	Site of cellular respiration. The number in a cell is related to energy requirements of the cell. Contain their own DNA.
Endoplasmic reticulum	Series of interconnected spaces (cisternae) which are connected to nuclear envelope. When surrounded by ribosomes it is called rough ER, makes and transports proteins. With no ribosomes it is called smooth ER, lipid production.
Golgi apparatus	Made up of stacks of flattened cisternae. Vesicles bud off the end of one layer and pass to the next layer. Proteins produced by rough ER are sorted and modified in the golgi. Found in high numbers in secretory cells.
Nucleus	Surrounded by double nuclear envelopes which contain pores. Contains chromosomes. Nucleolus, make rRNA (ribosomes).
Liposomes	Vesicles containing digestive enzymes, break down worn out organelles, digest bacterial cells.
Cilia	Some cells have hair-like structure called cilia which are used for movement along or creating a current near to the surface.
Animal cell	No cell wall. No chloroplasts. Contains small vacuoles.
Plant cell	Has a cell wall surrounding the plasma membrane. Contains chloroplasts, site of photosynthesis. Contains a large vacuole for storage of material.
Cell wall	Maintains the plant cell shape. Provides strength, rigidity, and support to plants. Made mainly of cellulose fibres.
Chloroplasts	Contains a series of interconnected discs which contain chlorophyll. Site of photosynthesis. Contains own DNA.
Centrioles	Produces spindle fibres which are important in cell division.
Cell membranes	All cells have a plasma membrane. Control of entry/exit to the cell. Keeps different parts separate. Recognition and communication.
Amphipathic	A hydrophilic head and a hydrophobic tail.
Diffusion	high concentration -> low concentration. Rate increases with short distance.Large surface area has higher diffusion rate. Rate is higher when the difference in concentration between two areas in greater. Molecules move quicker when temperature is increased.
Facilitated diffusion	Some molecules are not able to pass through but are "helped" by protein channels through the membrane. The protein channels are specific to molecules they transport.
Osmosis	The movement of water from an area of high concentration to low concentration across a semi-permeable membrane. Adding solutes to water will change the tonicity (osmotic pressure) of the solution. Osmosis will continue until both sides are the same tonicity = isotonic.
Active transport	Requires energy in the form of ATP. Substances move against the concentration gradient (low concentration -> high concentration).
Ion/Protein pumps	Larger molecules or ions are able to pass through the membrane using special proteins. These proteins are specific for the molecule. They require ATP to work, the ATP binds with the protein to change its shape which moves the molecules through the protein.
Endocytosis	The cell membrane folds around the material, engulfing it, which forms a vesicle inside the cell. The vesicle may then be digested by enzymes. Has 2 forms: phagocytosis = solid material, pinocytosis = liquid material
Exocytosis	The reverse process of endocytosis is used to transport material out of the cell and between cell organelles.
Endosymbiotic theory	The eukaryotes evolved through a process whereby different types of free-living prokaryotes became incorporated inside larger prokaryotic cells and eventually developed into mitochondria, chloroplasts, and possibly other organelles.
Mitosis: Interphase	G1: cell contents are duplicated. S: DNA replication and chromosome duplication. G2: Metabolic changes assemble material ready for mitosis.
Mitosis: Prophase	The nuclear membrane breaks down. DNA condenses by supercoiling which makes the chromosomes shorter and wider. The centrosomes/MTOC produce microtubules that form the spindle fibres.
Mitosis: Metaphase	The chromosomes migrate to the midline of cell. The spindle fibres bind to a structure associated with the centromere of each chromosome called a kinetochore.
Mitosis: Anaphase	The sister chromatids of each chromosome are pulled apart to the opposite ends of the cell by the spindle fibres.
Mitosis: Telophase	The final stage of mitosis, and a reversal of many of the processes observed during prophase. The nuclear membrane reforms around the chromosomes which uncoil and become diffuse, and the spindle fibres disappear.
Cytokinesis	The final cellular division to form two new cells. In plants a cell plate forms along the line of the metaphase plate. In animals there is a constriction of the cytoplasm. The cell then enters interphase: the interval between mitotic divisions.

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	Created by Chloe Schuster over 7 years ago