biology

• nucleus

  a double membrane bound organelle that contains genetic material (DNA, RNA)
• smooth endoplasmic reticulum


  the smooth ER [does not have ribosomes attached], synthesises and transports lipids
• rough endoplasmic reticulum

  the rough ER [has ribosomes attached ~ which make proteins], job is to make proteins and then transport them in vesicles to the golgi apparatus
• ribosomes


  since they are super tiny, it isn’t technically classified as an organelle. at the ribosomes, the proteins are formed/synthesised (the process is called translation), located in the cytosol and on the rough ER
• golgi apparatus


  to identify it in a cell, think of it as a splat, and vesicles around it. it’s job is to modify and package proteins into secretory vesicles for exporting from the cell by exocytosis
• vesicles


  a general term for a membrane-bound SAC. it moves toward the plasma membrane, and those proteins can get released outside of the cell. it’s primary job is to transport material between organelles and within the cell - exocytosis: exporting of molecules from the cell - endocytosis: bringing in molecules into the cell
• lysosomes (ONLY ANIMAL CELLS)

  breaks down material no longer required, or foreign matter, using enzymes. lysosomes contain enzymes to break substances down, vesicles transport substances. a cell can force a lysosome to break open, releasing all the enzymes, and the cell will start to break down, and hence it will die
• vacuoles


  vacuoles store substances such as water and ions, and in plants, it helps to maintain the structure. found mainly in the large central vacuole are only in plant cells, not animals.
• mitochondria

  site of aerobic cellular respiration, which releases usable energy (ATP production)
• chloroplasts

  site of photosynthesis, which converts carbon dioxide and water, with the assistance of light, to glucose and oxygen. chlorophyll captures the energy in sunlight to use in photosynthesis ~ it allows them to make their own proteins. these organelles are specialised to capture sunlight ~ not in animal cells
• cell wall (ONLY IN PLANTS)


  provides cellular structure and protection. it is next to the cell membrane and outside of it. it consists of cellulose
• cilia/flagella [ONLY ANIMAL CELLS]


  provides motility (ability to move), or movement of fluid - cilia are generally shorter, and flagella are longer - plants and fungi generally do not have cilia/flagella
• cytosol


  the liquid inside a cell, between the organelles (doesn’t include the organelles)
• cell membrane


  a membrane made up of two layers (known as a bilayer) of phospholipids that encloses the contents of a cell
• organism


  something that is living
• The cell theory states that cells are the basic unit of life. All living things are made up of at least one cell. Cells come from pre-existing cells.
• The cells of plants, animals, bacteria and protists all have four common factors including genetic material, cytosol, cell membrane, ribosomes
• The smaller the volume, the surface area to volume ratio gets larger. The easier it is to move substances into and out of it via diffusion. If you are a cell, and you need materials quickly for reactions to occur, then it is an advantage to have a small volume in comparison to the surface area. This would allow important substances to come in quicker, and get waste products out quicker.
• Volume is the total content of an object expressed as a cubic measurement
• Surface area is the total amount of surface area covering an object. Surface area determines how much material can be exchanged with the surrounding environment.
• In the example of a mouse and an elephant, the mouse has a greater surface area to volume ratio, even though the elephant has a larger volume. Having a larger surface area to volume ratio, means the mouse would be able to lose the heat quickly, whereas the elephant might not be able to lose heat as quickly.
• Heat energy is lose from every body surface. Penguins huddle together, to keep themselves warmer. By huddling they reduce the amount of surface area being exposed to the cold. Acting as a large huddle is like being one large animal with a smaller SA:V ratio.
• Insects are small, and so have a large SA:V. Heat energy is lose from every surface of their body, and would freeze in the Arctic. The arctic bumblebee has adaptations that would help them stay warm, such as rapid muscle movements, and thick fur to stay warm in the cold environment
• Cells are small so that they can exchange materials with their surroundings. If the cell’s volume gets too large it cannot transport enough nutrients in or waste out.
• endosymbiosis


  symbiosis where one organism lives inside another
• eukaryote

  a single-celled or multicellular organism whose cells include membrane-bound organelles; includes protists, fungi, plants and animals
• hydrophillic

  dissolves easily in water; also called lipophobic
• hydrophobic

  does not dissolve readily in water; also called lipophilic
• nucleoid


  an irregularly shaped area in a prokaryote where the genetic material is located
• organelle

  a compartment within a cell that performs specific functions
• plasma membrane

  a membrane made up of two layers (known as a bilayer) of phospholipids that encloses the contents of a cell
• prokaryote


  a single-celled organism that does not have membrane- bound organelles; includes bacteria and archaea
• semi-permeable membrane


  a membrane that only lets certain substances cross it; also called partially permeable, differentially permeable or selectively permeable
• symbiosis

  a beneficial relationship between two organisms
• unicellular


  made up of only one cell
• multicellular


  made up of more than one cell
• fluid mosaic model

  a model that represents the plasma membrane as a combination (mosaic) of phospholipids, proteins, cholesterol and carbohydrates that gives the membrane its fluid nature
• energy transformations

  light energy -> chemical energy -> kinetic energy -> heat energy
• light energy is converted into chemical energy by photosynthesis
• chemical energy is released by breaking down organic molecules into smaller subunits by cellular respiration (process in mitochondria)