Organelles Flashcards
Mitochondria
Produces energy for the cell to use for metabolic reaction / regulation and other such function, releases energy via aerobic respiration in the presence of oxygen or anaerobic respiration if there is an insufficient supply of oxygen. The mitochondria will use nutrients from digested food-stuffs as a fuel for their cellular respiration
The mitochondria is also responsible for the synthesis of ATP which is used in muscle contraction and nerve impulses
Has folded inner membranes called cristae, this increases the organelles’ surface area and thus aids the mitochondria in its production of ATP.
Plasma membrane
Prevents pathogenic access into the cell by acting as a barrier. The membrane helps the cell to retain its shape as well as providing structural support to the cellular body. The membrane is comprised of a phospholipid bilayer with embedded proteins as well as being partially permeable to ions and molecules, allowing for the cell to regulate what enters and exits the cell. Another function of the plasma membrane is to act to help in cell adhesion, ion conductivity and cell signalling. The outside of the membrane acts as an attachment surface, allowing for extracellular bodies to bind to the membrane.
Rough Endoplasmic Reticulum
The Rough ER is a system of flattened air sacs.
Ribosomes are attached to the edge of the Rough ER.
The ribosomes synthesise proteins and these ribosomes are attached to the rough ER.
The proteins that have been synthesised by the ribosomes usually are transported through the rough ER into the rest of the cell’s parts so that they can be used
Smooth Endoplasmic Reticulum
Main function is to make cellular structures such as hormones and lipids
Also helps to regulate and release calcium ions and process toxins
What the Smooth ER produces varies depending on the location of the cell
For example, in muscle cells, calcium ions will be produced as they are required for muscle contraction
However, in cells of the endocrine system, which is responsible for regulating hormones, it produces steroid hormones
Long, tube-like structure with an interior lumen enclosed by a phospholipid membrane
Cytoplasm
Fills the cell and gives the cell its shape
Holds the cells organelles together
Holds the cells water, salts, sugars, amino acids and proteins
The site of most of the reactions that happen in the cell
Holds the reactants of these reactions
The site of anaerobic respiration
Cell wall
The function of the cell wall is to keep the cell rigid and to provide the cell with protection. In-plant cells the cell wall protects the cell when bursting when it is in a hypotonic solution. In plants, it is made of chains of cellulose which have hydrogen bonds cross-links between the -OH groups of neighbouring chains called Microfibrils. The large amount of these microfibrils give the cell wall high tensile strength.
Ribosome
Ribosomes assemble amino acids to form specific proteins in protein synthesis. They do this by translating the mRNA into a chain of proteins that is specifically coded and synthesized to make a protein. Ribosomes are made of two subunits known as the large and small subunits. When joined to the ER they make up the rough endoplasmic reticulum
Centrioles
Every animal cell has 1 pair of centrioles
The structure of these are cylinders that contain a ring of 9 microtubules
These microtubules are arranged in a helix shape that help form a hollow tube structure
They are involved in the formation of the spindle in nuclear division and they are involved in the transport of molecules in the cell cytoplasm
Microtubules are released to help split the cell apart during a cell division
Microtubules are long, stiff fibres that help make up the centrioles
Lysosome
A lysosome is a membrane-bound spherical sac that contains digestive enzymes. These digestive enzymes will aid the cell in the removal of unwanted structures in the cell, these could be pathogens, food particles, waste or excess organelles. Reminiscent of the stomach. Additionally, these enzymes can be used to fully or partially destroy a cell in the case that a specific cell needs replacing in the event that a cell has grown too old or if a cell’s plasma membrane becomes damaged.
There is a specialised form of the lysosome; the acrosome.
Parts of Nucleus
Chromatin - Allows the cell to store two copies of the genetic information, ready for cell division. This makes sure both sister cells get the same genetic material.
Nuclear envelope - Protects the genetic material from chemical reactions. It also keeps the cytoplasm separate from the contents of the nucleus.
Nuclear pore - Control the passage of proteins and RNA but lets ATP other small molecules through
Nucleolus - Makes ribosomes and takes up 25% of the nucleus
Golgi Apparatus
Found in eukaryotic cells
Stacks of flattened membrane-bound sacs formed by fusion of vesicle from the endoplasmic reticulum
They modify proteins and packages them in vesicles for transport
Part of the endomembrane system in the cytoplasm
A major function is the modifying, sorting and packaging of proteins for secretion
Involved in the transport of lipids around the cell, and the creation of lysosomes.
Tonoplast
Structure found in plant cells that surrounds the vacuole
Helps provide vacuole with structure
Also helps to regulate nutrients and ions inside and out of the vacuole, keeping turgor pressure in the plant cell
Tonoplast is a lipid bilayer and is semi-permeable, meaning a correct balance of ions can be maintained inside and out of the vacuole, further maintaining turgor pressure
Plasmodesmata
Narrow fluid channels
Cross the cell walls making the cytoplasm of one cell continuous with the cytoplasm of the next
Located in the pits- some places the cell wall is thin because only the first layer of cellulose is deposited
A narrow thread of cytoplasm that passes through the cell walls of adjacent plant cells and allows communication between them.
Grana envelope
Made of a thylakoid which are little disks of membrane on which the light-dependent reactions of photosynthesis take place.
Stacked into grana, the shape of the thylakoids allow for optimum surface area, maximizing the amount of photosynthesis that can happen.
Thylakoids that make up grana contain important light-absorbing pigments, such as chlorophyll. When light strikes these pigments, they split water, releasing oxygen as a byproduct in the process of photolysis.
Chlorophyll
Makes plants green. The chlorophyll is vital to the process of photosynthesis as the chlorophyll can absorb the ref and blue sections of the electromagnetic spectrum (giving plants a green colour). The primary function of the chlorophyll is to absorb light energy and to transfer the energy to other parts of the photosystem to complete photosynthesis. Plants generally have many chlorophyll in order to maximize the amount of sunlight that can be absorbed during the limited period of sunlight.
