functions of structures Flashcards
Cell membrane
A flexible phospholipid bilayer that controls the entry and exit of substances and encloses the cell; also known as the plasma membrane
Cytoplasm and cytosol
The cytoplasm is all of the cell contents (including organelles) between the nuclear membrane and the cell membrane. The cytosol is the semi-liquid (jelly-like) part of the cytoplasm and does not include the organelles. Metabolic activity occurs both in the organelles (in the cytoplasm) and in the cytosol.
Endoplasmic reticulum (ER) (rough and smooth)
A network of channels and flattened sacs that extends almost everywhere in the cytoplasm. It transports materials such as proteins throughout this region. It is continuous from the nuclear envelope. There are two types: * smooth ER, which does not have ribosomes attached; it has a unique set of enzymes and carries out many functions, such as the production of membrane phospholipids* rough ER, which does have ribosomes attached and therefore is a site for protein synthesis
Lysosomes
A sac of enzymes that can digest (break down) foreign substances, including bacteria, and macromolecules, including lipids, carbohydrates, nucleic acids and proteins
Golgi apparatus
A structure of flattened sacs which collect, package, modify and distribute materials such as proteins synthesised in the cell. It:* modifies products of the ER such as proteins* manufactures certain macromolecules* sorts and packages materials into transport vesicle
Mitochondria
The site of aerobic cellular respiration, a metabolic process that generates large quantities of a usable form of energy known as ATP (adenosine triphosphate)
Nucleus
The structure that contains most of the cell’s DNA. It includes: * a nuclear membrane (envelope), which has pores to allow communication between the nucleus and the rest of the cell* a nucleolus, which is involved in the production of ribosomes* chromatin, which is the loose form of DNA and its proteins, and which only becomes visible as chromosomes during cell division
Ribosome
A non-membranous structure that carries out protein synthesis in two locations:* in the cytosol* on the outside of the rough ER
Centrosomes and centrioles
Two structures that play a major role in cell division (which is discussed in more detail in Units 3 and 4). The centrosome is located at one end of the cell, close to the nucleus. In many cells microtubules (spindle fibres) grow out from a centrosome. In animal cells, the centrosome has a pair of centrioles
Chloroplast
plant strcuture onky bitch
The site of photosynthesis in plant (and algae) cells. Inside these, the light energy from the Sun is converted into chemical energy and stored in carbohydrates
Cell wall
A structure made of tough cellulose fibres which protects the plant cell, maintains its shape and prevents excessive uptake of water.Prokaryotes, fungi, and some protists also have cell walls; however, their cell walls are made of different substances from plants
Large vacuole
A plant cell (or fungal cell) may have one or several large vacuoles which can store water, nutrients, metabolic wastes and toxins (ready for their removal and also to protect the rest of the cell). In plants, full vacuoles can provide rigidity for the whole organism
membrane function
recognition of other cells, the transportation of materials into and out of the cell, the provision of attachment sites for enzymes and hormones, and in nerve cells, the transmission of neural impulses. Both the physical and chemical properties of the cell membrane enable it to control the exchange of materials and messages. Organelle membranes have the same general structure as cell membranes
-selectively permeable>maintaining concentration difference
the communication between the cells in tissues and different types of cells through it cell membrane can lead to…
the cell growing, becoming a specialized type of cell, or dying.
what do cell have to do in order to create something else sometimes
Depending on its activities, a cell will need to take in certain useful molecules and ions from the external environment and excrete others. For example, a cell that is producing protein needs to take in a variety of amino acids.
cholesterol doooooppp in plant and bacteria cells
phytosterol
During cell division and vesicle formation, membranes can..
break and reassemble themselves. Additionally, if the cell membrane is punctured, some of the cytoplasm will leak out but the hole will quickly seal
cell walls in plant cells prevent..
osmosis
cell to burst when fresh water enters the cell by osmosis
vacuole in plant cells
osmosis
large, fluid-filled vacuoles and firm but permeable cell walls that surround the cell membrane. Like the cell membrane, the vacuole membrane is selectively permeable. Plant cell vacuoles contain cell sap that is rich in solutes: it is a solution of high concentration. When a hypotonic solution surrounds a plant cell, water molecules diffuse by osmosis, first into cytosol and then into the vacuole. The vacuole swells, pushing the cytoplasm and cell membrane against the cell wall.
function of cyptoplasm
Housing and maintaining an optimal environment for cellular organelles.
Supporting and suspending organelles and cellular molecules.
Serving as the site for many enzymatic reactions and metabolic activities.
Initiating cellular respiration and protein synthesis.
Storing molecules required for cellular processes.
function of cytosol
Serving as the medium for intracellular processes.
Being involved in signal transduction between the cell membrane and the nucleus and organelles.
Transporting metabolites from their production site to other parts of the cell.
Playing a role in cytokinesis during cell division.
Supporting other organelles and allowing transport of molecules across the cell.
function of nucleus
Control and regulation of cell activities, such as growth and metabolism.
Storage of genetic material (genes) necessary for heredity.
Initiation of cellular reproduction.
Regulation of gene expression.
Protein synthesis with the help of ribosomes.
function of mitichondria
Generate energy in the form of adenosine triphosphate (ATP)12345.
Store calcium for cell signaling activities.
Generate heat.
Mediate cell growth and death.
function of cell membrane
Acts as a barrier, keeping cell constituents in and unwanted substances out.
Regulates the materials that enter and leave the cell.
Separates and protects the interior of a cell from the outside environment.
Allows certain substances into the cell while keeping others out.
Supports the cell and helps maintain its shape.
cell wall
Structural support: The cell wall surrounds the plasma membrane and provides tensile strength.
Protection: It protects against mechanical and osmotic stress.
Turgor pressure: The cell wall allows cells to develop turgor pressure.
Intercellular communication: Small pores called plasmodesmata in the cell wall allow the exchange of nutrients and hormones between cells.
vacoules/ vessicles function
Vesicles and vacuoles are membrane-bound sacs that function in storage and transport. Other than the fact that vacuoles are somewhat larger than vesicles, there is a very subtle distinction between them: the membranes of vesicles can fuse with either the plasma membrane or other membrane systems within the cell.
Vacuoles are somewhat larger than vesicles, and the membrane of a vacuole does not fuse with the membranes of other cellular components. Vesicles can fuse with other membranes within the cell system
lysosome
Digesting used materials in the cytoplasm, both inside and outside the cell.
Breaking down excess or worn-out cell parts.
Destroying invading viruses and bacteria.
Recycling the cell’s organic material.
function of smooth er
Synthesizing and storing lipids, including cholesterol and phospholipids.
Assisting in the production of new cellular membranes.
Playing a role in the synthesis of steroid hormones from cholesterol.
Being involved in lipid metabolism and steroid production.
Functioning in drug detoxification and calcium concentration.
function of rough er
Synthesis, folding, and modification of proteins.
Transport of proteins to their targeted destinations.
Quality control of proteins, including identifying misfolded or aberrant proteins.
Rapid signaling to the nucleus when problems in protein synthesis and folding occur.
ribosomes
Convert genetic code into protein molecules by reading messenger RNA (mRNA) sequences and determining the order of transfer RNA (tRNA) molecules1.
Produce proteins by linking amino acids together based on the mRNA template
golgi apparatus function
Transporting, modifying, and packaging proteins and lipids into vesicles for delivery to targeted destinations.
Delivering vesicles to different locations throughout the cell.
Tagging vesicles with proteins and sugar molecules for proper targeting.
Serving as the site for the synthesis of complex polysaccharides in plant cells.
Packaging and secreting proteins.
glycolipids
Glycolipids are components of cellular membranes comprised of a hydrophobic lipid tail and one or more hydrophilic sugar groups linked by a glycosidic bond.
Maintaining the stability of the cell membrane
Facilitating cellular recognition, which is crucial to the immune response and in the connections that allow cells to connect to one another to form tissues
Providing energy to the cells
Being an essential part of cell membranes
Helping in determining the blood group of an individual
high SA: vol ratio
gives faster diffusion rate as the greater surface area is available for particles to transfer
the higher the concentration gradient
the higher rate of diffusion
need for homeostasis
cell composition needs to remain within narrow limits when faced with changing external conditions. therefore needs to alter inputs and outputs
enzyme substrate complex
temporary molecule formed when an enzyme comes into perfect contact with its substrate. Without its substrate an enzyme is a slightly different shape. The substrate causes a conformational change, or shape change, when the substrate enters the active site.
substrate
molecule acted upon by an enzyme. A substrate is loaded into the active site of the enzyme, or the place that allows weak bonds to be formed between the two molecules. An enzyme substrate complex is formed, and the forces exerted on the substrate by the enzyme cause it to react, and become the product of the intended reaction.
role of inhibitor
prevent building of substaret to enzyme either bi binding preferentially or changing shape of active site so no longer fits reactants. this slows or prevents reactions
